iverilog/vpi/fstapi.c

/*
 * Copyright (c) 2009-2010 Tony Bybell.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#include "fstapi.h"
#include "fastlz.h"

#undef  FST_DEBUG

#define FST_BREAK_SIZE 			(32 * 1024 * 1024)
#define FST_WRITER_STR 			"fstWriter"
#define FST_ID_NAM_SIZ 			(512)
#define FST_DOUBLE_ENDTEST 		(2.7182818284590452354)
#define FST_HDR_SIM_VERSION_SIZE 	(128)
#define FST_HDR_DATE_SIZE 		(128)
#define FST_GZIO_LEN			(32768)


#if defined(__i386__) || defined(__x86_64__) || defined(_AIX)
#define FST_DO_MISALIGNED_OPS
#endif

#if defined(__APPLE__) && defined(__MACH__)
#define FST_MACOSX 
#endif

#if defined(__CYGWIN__) && defined(__GNUC__)
#define FST_USE_FWRITE_COMBINING
#endif


/***********************/
/***                 ***/
/*** common function ***/
/***                 ***/
/***********************/

#ifdef __MINGW32__
#include <io.h>
#define ftello ftell
#define fseeko fseek
#endif


/* the recoded "extra" values... */ 
#define FST_RCV_X (1 | (0<<1))
#define FST_RCV_Z (1 | (1<<1))
#define FST_RCV_H (1 | (2<<1))
#define FST_RCV_U (1 | (3<<1))
#define FST_RCV_W (1 | (4<<1))
#define FST_RCV_L (1 | (5<<1))
#define FST_RCV_D (1 | (6<<1))

#define FST_RCV_STR "xzhuwl-?"
/*                   01234567 */


/* 
 * to remove warn_unused_result compile time messages
 * (in the future there needs to be results checking)
 */
static size_t fstFread(void *buf, size_t siz, size_t cnt, FILE *fp)
{
return(fread(buf, siz, cnt, fp));
}

static size_t fstFwrite(const void *buf, size_t siz, size_t cnt, FILE *fp)
{
return(fwrite(buf, siz, cnt, fp));
}

static int fstFtruncate(int fd, off_t length)
{
return(ftruncate(fd, length));
}


/*
 * mmap compatibility
 */
#if defined __CYGWIN__ || defined __MINGW32__
#include <limits.h>
#define fstMmap(__addr,__len,__prot,__flags,__fd,__off) fstMmap2((__len), (__fd), (__off))
#define fstMunmap(__addr,__len)				free(__addr)

static void *fstMmap2(size_t __len, int __fd, off_t __off)
{
unsigned char *pnt = malloc(__len);
off_t cur_offs = lseek(__fd, 0, SEEK_CUR);
size_t i;

lseek(__fd, 0, SEEK_SET);
for(i=0;i<__len;i+=SSIZE_MAX)
	{
	read(__fd, pnt + i, ((__len - i) >= SSIZE_MAX) ? SSIZE_MAX : (__len - i));
	}
lseek(__fd, cur_offs, SEEK_SET);
return(pnt);
}
#else
#include <sys/mman.h>
#if defined(__SUNPRO_C)
#define FST_CADDR_T_CAST (caddr_t)
#else
#define FST_CADDR_T_CAST
#endif
#define fstMmap(__addr,__len,__prot,__flags,__fd,__off) (void*)mmap(FST_CADDR_T_CAST (__addr),(__len),(__prot),(__flags),(__fd),(__off))
#define fstMunmap(__addr,__len) 			{ if(__addr) munmap(FST_CADDR_T_CAST (__addr),(__len)); }
#endif


/*
 * regular and variable-length integer access functions
 */
#ifdef FST_DO_MISALIGNED_OPS
#define fstGetUint32(x) (*(uint32_t *)(x))
#define fstWriterSetUint32(x,y) (*(uint32_t *)(x)) = (y)
#else
static uint32_t fstGetUint32(unsigned char *mem)
{
uint32_t u32;
unsigned char *buf = (unsigned char *)(&u32);

buf[0] = mem[0];
buf[1] = mem[1];
buf[2] = mem[2];
buf[3] = mem[3];

return(*(uint32_t *)buf);
}


static void fstWriterSetUint32(unsigned char *mem, uint32_t u32)
{
unsigned char *buf = (unsigned char *)(&u32);

mem[0] = buf[0];
mem[1] = buf[1];
mem[2] = buf[2];
mem[3] = buf[3];
}
#endif


static int fstWriterUint64(FILE *handle, uint64_t v)
{
unsigned char buf[8];
int i;

for(i=7;i>=0;i--)
	{
	buf[i] = v & 0xff;
	v >>= 8;
	}

fstFwrite(buf, 8, 1, handle);
return(8);
}


static uint64_t fstReaderUint64(FILE *f)
{
uint64_t val = 0;
unsigned char buf[sizeof(uint64_t)];
int i;

fstFread(buf, sizeof(uint64_t), 1, f);
for(i=0;i<sizeof(uint64_t);i++)
	{
	val <<= 8;
	val |= buf[i];
	}

return(val);
}


static uint32_t fstGetVarint32(unsigned char *mem, int *skiplen)
{
unsigned char *mem_orig = mem;
uint32_t rc = 0;
while(*mem & 0x80)
	{
	mem++;
	}

*skiplen = mem - mem_orig + 1;
for(;;)
	{
	rc <<= 7;
	rc |= (uint32_t)(*mem & 0x7f);
	if(mem == mem_orig) 
		{
		break;
		}
	mem--;
	} 

return(rc);
}


static uint32_t fstGetVarint32NoSkip(unsigned char *mem)
{
unsigned char *mem_orig = mem;
uint32_t rc = 0;
while(*mem & 0x80)
        {
        mem++;
        }

for(;;)
        {
        rc <<= 7;
        rc |= (uint32_t)(*mem & 0x7f);
        if(mem == mem_orig)
                {
                break;
                }
        mem--;
        }
 
return(rc);       
}


static unsigned char *fstCopyVarint32ToLeft(unsigned char *pnt, uint32_t v)
{
unsigned char buf[5];
unsigned char *spnt = buf;  
uint32_t nxt;

while((nxt = v>>7))
        {
        *(spnt++) = (v&0x7f) | 0x80;
        v = nxt;
        }
*(spnt++) = (v&0x7f);

do      {
        *(--pnt) = *(--spnt);
        } while(spnt != buf);

return(pnt);
}
 

static uint64_t fstGetVarint64(unsigned char *mem, int *skiplen)
{
unsigned char *mem_orig = mem;
uint64_t rc = 0;
while(*mem & 0x80)
        {
        mem++;
        }

*skiplen = mem - mem_orig + 1;
for(;;)
        {
        rc <<= 7;
        rc |= (uint64_t)(*mem & 0x7f);
        if(mem == mem_orig)
                {
                break;
                }
        mem--;
        }
 
return(rc);       
}


static uint32_t fstReaderVarint32(FILE *f)
{
unsigned char buf[5];
unsigned char *mem = buf;
uint32_t rc = 0;
int ch;

do
	{
	ch = fgetc(f);
	*(mem++) = ch;
	} while(ch & 0x80);
mem--;

for(;;)
        {
        rc <<= 7;
        rc |= (uint32_t)(*mem & 0x7f);
        if(mem == buf)
                {
                break;
                }
        mem--;
        }
 
return(rc);       
}


static uint32_t fstReaderVarint32WithSkip(FILE *f, uint32_t *skiplen)
{
unsigned char buf[5];
unsigned char *mem = buf;
uint32_t rc = 0;
int ch;

do
	{
	ch = fgetc(f);
	*(mem++) = ch;
	} while(ch & 0x80);
*skiplen = mem - buf;
mem--;

for(;;)
        {
        rc <<= 7;
        rc |= (uint32_t)(*mem & 0x7f);
        if(mem == buf)
                {
                break;
                }
        mem--;
        }
 
return(rc);       
}


static uint64_t fstReaderVarint64(FILE *f)
{
unsigned char buf[16];
unsigned char *mem = buf;
uint64_t rc = 0;
int ch;

do
	{
	ch = fgetc(f);
	*(mem++) = ch;
	} while(ch & 0x80);
mem--;

for(;;)
        {
        rc <<= 7;
        rc |= (uint64_t)(*mem & 0x7f);
        if(mem == buf)
                {
                break;
                }
        mem--;
        }
 
return(rc);       
}


static int fstWriterVarint(FILE *handle, uint64_t v)
{
uint64_t nxt;
unsigned char buf[10]; /* ceil(64/7) = 10 */
unsigned char *pnt = buf;
int len;

while((nxt = v>>7))
        {
        *(pnt++) = (v&0x7f) | 0x80;
        v = nxt;
        }
*(pnt++) = (v&0x7f);

len = pnt-buf;
fstFwrite(buf, len, 1, handle);
return(len);
}

#ifndef FST_USE_FWRITE_COMBINING
static int fstWriterUint32WithVarint(FILE *handle, uint32_t *u, uint64_t v)
{
uint64_t nxt;
unsigned char buf[10 + sizeof(uint32_t)];
unsigned char *pnt = buf + sizeof(uint32_t);
int len;

memcpy(buf, u, sizeof(uint32_t));

while((nxt = v>>7))
        {
        *(pnt++) = (v&0x7f) | 0x80;
        v = nxt;
        }
*(pnt++) = (v&0x7f);

len = pnt-buf;
fstFwrite(buf, len, 1, handle);
return(len);
}
#else
static int fstWriterUint32WithVarint(FILE *handle, uint32_t *u, uint64_t v, const void *dbuf, size_t siz)
{
uint64_t nxt;
unsigned char buf[10 + sizeof(uint32_t) + siz]; /* gcc extension ok for cygwin */
unsigned char *pnt = buf + sizeof(uint32_t);
int len;

memcpy(buf, u, sizeof(uint32_t));

while((nxt = v>>7))
        {
        *(pnt++) = (v&0x7f) | 0x80;
        v = nxt;
        }
*(pnt++) = (v&0x7f);
memcpy(pnt, dbuf, siz);

len = pnt-buf + siz;
fstFwrite(buf, len, 1, handle);
return(len);
}
#endif

/***********************/
/***                 ***/
/*** writer function ***/
/***                 ***/
/***********************/

/*
 * private structs
 */
struct fstBlackoutChain
{
struct fstBlackoutChain *next;
uint64_t tim;
unsigned active : 1;
};


struct fstWriterContext
{
FILE *handle;
FILE *hier_handle;
FILE *geom_handle;
FILE *valpos_handle;
FILE *curval_handle;
FILE *vchn_handle;
FILE *tchn_handle;

off_t hier_file_len;

uint32_t *valpos_mem;
unsigned char *curval_mem;

char *filename;

fstHandle maxhandle;
fstHandle numsigs;
uint32_t maxvalpos;

unsigned vc_emitted : 1;
unsigned is_initial_time : 1;
unsigned fastpack : 1;

off_t section_header_truncpos;
uint32_t tchn_cnt, tchn_idx;
uint64_t curtime;
uint64_t firsttime;
off_t vchn_siz;

uint32_t secnum;
off_t section_start;

uint32_t numscopes;
double nan; /* nan value for uninitialized doubles */

struct fstBlackoutChain *blackout_head;
struct fstBlackoutChain *blackout_curr;
uint32_t num_blackouts;

uint64_t dump_size_limit;

unsigned compress_hier : 1;
unsigned repack_on_close : 1;
unsigned skip_writing_section_hdr : 1;
unsigned size_limit_locked : 1;
unsigned section_header_only : 1;

/* should really be semaphores, but are bytes to cut down on read-modify-write window size */
unsigned char already_in_flush; /* in case control-c handlers interrupt */
unsigned char already_in_close; /* in case control-c handlers interrupt */
};


/*
 * header bytes, write here so defines are set up before anything else
 * that needs to use them
 */
static void fstWriterEmitHdrBytes(struct fstWriterContext *xc)
{
char vbuf[FST_HDR_SIM_VERSION_SIZE];
char dbuf[FST_HDR_DATE_SIZE];
double endtest = FST_DOUBLE_ENDTEST;
time_t walltime;

#define FST_HDR_OFFS_TAG 			(0)
fputc(FST_BL_HDR, xc->handle);			/* +0 tag */

#define FST_HDR_OFFS_SECLEN 			(FST_HDR_OFFS_TAG + 1)
fstWriterUint64(xc->handle, 329);		/* +1 section length */

#define FST_HDR_OFFS_START_TIME			(FST_HDR_OFFS_SECLEN + 8)
fstWriterUint64(xc->handle, 0);			/* +9 start time */

#define FST_HDR_OFFS_END_TIME			(FST_HDR_OFFS_START_TIME + 8)
fstWriterUint64(xc->handle, 0);  		/* +17 end time */

#define FST_HDR_OFFS_ENDIAN_TEST		(FST_HDR_OFFS_END_TIME + 8)
fstFwrite(&endtest, 8, 1, xc->handle); 		/* +25 endian test for reals */

#define FST_HDR_OFFS_MEM_USED			(FST_HDR_OFFS_ENDIAN_TEST + 8)
fstWriterUint64(xc->handle, FST_BREAK_SIZE); 	/* +33 memory used by writer */

#define FST_HDR_OFFS_NUM_SCOPES			(FST_HDR_OFFS_MEM_USED + 8)
fstWriterUint64(xc->handle, 0);			/* +41 scope creation count */

#define FST_HDR_OFFS_NUM_VARS			(FST_HDR_OFFS_NUM_SCOPES + 8)
fstWriterUint64(xc->handle, 0);			/* +49 var creation count */

#define FST_HDR_OFFS_MAXHANDLE			(FST_HDR_OFFS_NUM_VARS + 8)
fstWriterUint64(xc->handle, 0);			/* +57 max var idcode */

#define FST_HDR_OFFS_SECTION_CNT		(FST_HDR_OFFS_MAXHANDLE + 8)
fstWriterUint64(xc->handle, 0);			/* +65 vc section count */

#define FST_HDR_OFFS_TIMESCALE			(FST_HDR_OFFS_SECTION_CNT + 8)
fputc((-9)&255, xc->handle);			/* +73 timescale 1ns */

#define FST_HDR_OFFS_SIM_VERSION		(FST_HDR_OFFS_TIMESCALE + 1)
memset(vbuf, 0, FST_HDR_SIM_VERSION_SIZE);
strcpy(vbuf, FST_WRITER_STR);
fstFwrite(vbuf, FST_HDR_SIM_VERSION_SIZE, 1, xc->handle); /* +74 version */

#define FST_HDR_OFFS_DATE			(FST_HDR_OFFS_SIM_VERSION + FST_HDR_SIM_VERSION_SIZE)
memset(dbuf, 0, FST_HDR_DATE_SIZE);
time(&walltime);
strcpy(dbuf, asctime(localtime(&walltime)));
fstFwrite(dbuf, FST_HDR_DATE_SIZE, 1, xc->handle);	/* +202 date */

#define FST_HDR_LENGTH				(FST_HDR_OFFS_DATE + FST_HDR_DATE_SIZE)
						/* +330 next section starts here */
fflush(xc->handle);
}


/*
 * mmap functions
 */
static void fstWriterCreateMmaps(struct fstWriterContext *xc)
{
off_t curpos = ftello(xc->handle);

fflush(xc->hier_handle);

/* write out intermediate header */
fseeko(xc->handle, FST_HDR_OFFS_START_TIME, SEEK_SET);
fstWriterUint64(xc->handle, xc->firsttime);
fstWriterUint64(xc->handle, xc->curtime);
fseeko(xc->handle, FST_HDR_OFFS_NUM_SCOPES, SEEK_SET);
fstWriterUint64(xc->handle, xc->numscopes);
fstWriterUint64(xc->handle, xc->numsigs);
fstWriterUint64(xc->handle, xc->maxhandle);
fstWriterUint64(xc->handle, xc->secnum);
fseeko(xc->handle, curpos, SEEK_SET);
fflush(xc->handle);

/* do mappings */
if(!xc->valpos_mem)
	{
	fflush(xc->valpos_handle);
	xc->valpos_mem = fstMmap(NULL, xc->maxhandle * 4 * sizeof(uint32_t), PROT_READ|PROT_WRITE, MAP_SHARED, fileno(xc->valpos_handle), 0);
	}
if(!xc->curval_mem)
	{
	fflush(xc->curval_handle);
	xc->curval_mem = fstMmap(NULL, xc->maxvalpos, PROT_READ|PROT_WRITE, MAP_SHARED, fileno(xc->curval_handle), 0);
	}
}


static void fstDestroyMmaps(struct fstWriterContext *xc, int is_closing)
{
fstMunmap(xc->valpos_mem, xc->maxhandle * 4 * sizeof(uint32_t));
xc->valpos_mem = NULL;

#if defined __CYGWIN__ || defined __MINGW32__
if(xc->curval_mem)
	{
	if(!is_closing) /* need to flush out for next emulated mmap() read */
		{
		unsigned char *pnt = xc->curval_mem;
		int __fd = fileno(xc->curval_handle);
		off_t cur_offs = lseek(__fd, 0, SEEK_CUR);
		size_t i;
		size_t __len = xc->maxvalpos;

		lseek(__fd, 0, SEEK_SET);
		for(i=0;i<__len;i+=SSIZE_MAX)
		        {
		        write(__fd, pnt + i, ((__len - i) >= SSIZE_MAX) ? SSIZE_MAX : (__len - i));
		        }
		lseek(__fd, cur_offs, SEEK_SET);
		}
	}
#endif

fstMunmap(xc->curval_mem, xc->maxvalpos);
xc->curval_mem = NULL;
}


/*
 * file creation and close
 */
void *fstWriterCreate(const char *nam, int use_compressed_hier)
{
struct fstWriterContext *xc = calloc(1, sizeof(struct fstWriterContext));

xc->compress_hier = use_compressed_hier;

if((!nam)||(!(xc->handle=fopen(nam, "w+b"))))
        {
        free(xc);
        xc=NULL;
        }
        else
        {
	int flen = strlen(nam);
	char *hf = calloc(1, flen + 6);

	memcpy(hf, nam, flen);
	strcpy(hf + flen, ".hier");
	xc->hier_handle = fopen(hf, "w+b");

	xc->geom_handle = tmpfile();	/* .geom */
	xc->valpos_handle = tmpfile();	/* .offs */
	xc->curval_handle = tmpfile();	/* .bits */
	xc->vchn_handle = tmpfile();	/* .vchn */
	xc->tchn_handle = tmpfile();	/* .tchn */

	free(hf);
	if(xc->hier_handle && xc->geom_handle && xc->valpos_handle && xc->curval_handle && xc->vchn_handle && xc->tchn_handle)
		{
	        xc->filename = strdup(nam);
		xc->is_initial_time = 1;

		fstWriterEmitHdrBytes(xc);
		xc->nan = strtod("NaN", NULL);
		}
		else
		{
		if(xc->hier_handle) fclose(xc->hier_handle);
		if(xc->geom_handle) fclose(xc->geom_handle);
		if(xc->valpos_handle) fclose(xc->valpos_handle);
		if(xc->curval_handle) fclose(xc->curval_handle);
		if(xc->vchn_handle) fclose(xc->vchn_handle);
		if(xc->tchn_handle) fclose(xc->tchn_handle);
	        free(xc);
	        xc=NULL;
		}
	}

return(xc);
}


void fstWriterClose(void *ctx)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;
if(xc && !xc->already_in_close && !xc->already_in_flush)
	{
	unsigned char *tmem;
	off_t fixup_offs, tlen, hlen;

	xc->already_in_close = 1; /* never need to zero this out as it is freed at bottom */

	if(xc->section_header_only && xc->section_header_truncpos)
		{
		fstFtruncate(fileno(xc->handle), xc->section_header_truncpos);
		fseeko(xc->handle, xc->section_header_truncpos, SEEK_SET);
		xc->section_header_only = 0;
		}

	xc->skip_writing_section_hdr = 1;
	if(!xc->size_limit_locked)
		{
		if(xc->is_initial_time) /* simulation time never advanced so mock up the changes as time zero ones */
			{
			fstHandle dupe_idx;

			fstWriterEmitTimeChange(xc, 0); /* emit some time change just to have one */
			for(dupe_idx = 0; dupe_idx < xc->maxhandle; dupe_idx++) /* now clone the values */
				{
				fstWriterEmitValueChange(xc, dupe_idx+1, xc->curval_mem + xc->valpos_mem[4*dupe_idx]);
				}
			}
		fstWriterFlushContext(xc);
		}
	fstDestroyMmaps(xc, 1);

	/* write out geom section */
	fflush(xc->geom_handle);
	tlen = ftello(xc->geom_handle);
	tmem = fstMmap(NULL, tlen, PROT_READ|PROT_WRITE, MAP_SHARED, fileno(xc->geom_handle), 0);
	if(tmem)
		{
		unsigned long destlen = tlen;
		unsigned char *dmem = malloc(destlen);
	        int rc = compress2(dmem, &destlen, tmem, tlen, 9);

		if((rc != Z_OK) || (destlen > tlen))
			{
			destlen = tlen;
			}

		fixup_offs = ftello(xc->handle);
		fputc(FST_BL_SKIP, xc->handle);			/* temporary tag */
		fstWriterUint64(xc->handle, destlen + 24);	/* section length */
		fstWriterUint64(xc->handle, tlen);		/* uncompressed */
								/* compressed len is section length - 24 */
		fstWriterUint64(xc->handle, xc->maxhandle);	/* maxhandle */
		fstFwrite((destlen != tlen) ? dmem : tmem, destlen, 1, xc->handle);
		fflush(xc->handle);

		fseeko(xc->handle, fixup_offs, SEEK_SET);
		fputc(FST_BL_GEOM, xc->handle);			/* actual tag */

		fseeko(xc->handle, 0, SEEK_END);		/* move file pointer to end for any section adds */
		fflush(xc->handle);

		free(dmem);
		fstMunmap(tmem, tlen);
		}

	if(xc->num_blackouts)
		{
		uint64_t cur_bl = 0;
		off_t bpos, eos;
		uint32_t i;

		fixup_offs = ftello(xc->handle);
		fputc(FST_BL_SKIP, xc->handle);			/* temporary tag */
		bpos = fixup_offs + 1;
		fstWriterUint64(xc->handle, 0);			/* section length */
		fstWriterVarint(xc->handle, xc->num_blackouts);

		for(i=0;i<xc->num_blackouts;i++)
			{
			fputc(xc->blackout_head->active, xc->handle);
			fstWriterVarint(xc->handle, xc->blackout_head->tim - cur_bl);
			cur_bl = xc->blackout_head->tim;
			xc->blackout_curr = xc->blackout_head->next;
			free(xc->blackout_head);
			xc->blackout_head = xc->blackout_curr;	
			}

		eos = ftello(xc->handle);
		fseeko(xc->handle, bpos, SEEK_SET);
		fstWriterUint64(xc->handle, eos - bpos);		
		fflush(xc->handle);

		fseeko(xc->handle, fixup_offs, SEEK_SET);
		fputc(FST_BL_BLACKOUT, xc->handle);	/* actual tag */

		fseeko(xc->handle, 0, SEEK_END);	/* move file pointer to end for any section adds */
		fflush(xc->handle);
		}

	if(xc->compress_hier)
		{
		unsigned char *mem = malloc(FST_GZIO_LEN);
		off_t hl, eos;
		gzFile zhandle;
		int zfd;
#ifndef __MINGW32__
		char *fnam = malloc(strlen(xc->filename) + 5 + 1);
#endif

		fixup_offs = ftello(xc->handle);
		fputc(FST_BL_SKIP, xc->handle);			/* temporary tag */
		hlen = ftello(xc->handle);
		fstWriterUint64(xc->handle, 0);			/* section length */
		fstWriterUint64(xc->handle, xc->hier_file_len);	/* uncompressed length */
		
		fflush(xc->handle);
		zfd = dup(fileno(xc->handle));
		zhandle = gzdopen(zfd, "wb4");
		if(zhandle)
			{
			fseeko(xc->hier_handle, 0, SEEK_SET);
			for(hl = 0; hl < xc->hier_file_len; hl += FST_GZIO_LEN)
				{
				unsigned len = ((xc->hier_file_len - hl) > FST_GZIO_LEN) ? FST_GZIO_LEN : (xc->hier_file_len - hl);
				fstFread(mem, len, 1, xc->hier_handle);
				gzwrite(zhandle, mem, len);
				}
			gzclose(zhandle);
			}
			else
			{
			close(zfd);
			}
		free(mem);

		fseeko(xc->handle, 0, SEEK_END);
		eos = ftello(xc->handle);
		fseeko(xc->handle, hlen, SEEK_SET);
		fstWriterUint64(xc->handle, eos - hlen);
		fflush(xc->handle);

		fseeko(xc->handle, fixup_offs, SEEK_SET);
		fputc(FST_BL_HIER, xc->handle);		/* actual tag */

		fseeko(xc->handle, 0, SEEK_END);	/* move file pointer to end for any section adds */
		fflush(xc->handle);

#ifndef __MINGW32__
		sprintf(fnam, "%s.hier", xc->filename);
		unlink(fnam);
		free(fnam);
#endif
		}

	/* finalize out header */
	fseeko(xc->handle, FST_HDR_OFFS_START_TIME, SEEK_SET);
	fstWriterUint64(xc->handle, xc->firsttime);
	fstWriterUint64(xc->handle, xc->curtime);
	fseeko(xc->handle, FST_HDR_OFFS_NUM_SCOPES, SEEK_SET);
	fstWriterUint64(xc->handle, xc->numscopes);
	fstWriterUint64(xc->handle, xc->numsigs);
	fstWriterUint64(xc->handle, xc->maxhandle);
	fstWriterUint64(xc->handle, xc->secnum);
	fflush(xc->handle);
	
	if(xc->tchn_handle) { fclose(xc->tchn_handle); xc->tchn_handle = NULL; }
	if(xc->vchn_handle) { fclose(xc->vchn_handle); xc->vchn_handle = NULL; }
	if(xc->curval_handle) { fclose(xc->curval_handle); xc->curval_handle = NULL; }
	if(xc->valpos_handle) { fclose(xc->valpos_handle); xc->valpos_handle = NULL; }
	if(xc->geom_handle) { fclose(xc->geom_handle); xc->geom_handle = NULL; }
	if(xc->hier_handle) { fclose(xc->hier_handle); xc->hier_handle = NULL; }
	if(xc->handle) 
		{ 
		if(xc->repack_on_close)
			{
			FILE *fp;
			off_t offpnt, uclen;
			int flen = strlen(xc->filename);
			char *hf = calloc(1, flen + 5);

			strcpy(hf, xc->filename);
			strcpy(hf+flen, ".pak");
			fp = fopen(hf, "wb");

			if(fp)
				{
				void *dsth;
				int zfd;
				char gz_membuf[FST_GZIO_LEN];

				fseeko(xc->handle, 0, SEEK_END);
				uclen = ftello(xc->handle);

				fputc(FST_BL_ZWRAPPER, fp);
				fstWriterUint64(fp, 0);
				fstWriterUint64(fp, uclen);
				fflush(fp);

				fseeko(xc->handle, 0, SEEK_SET);
				zfd = dup(fileno(fp));
				dsth = gzdopen(zfd, "wb4");
				if(dsth)
					{
					for(offpnt = 0; offpnt < uclen; offpnt += FST_GZIO_LEN)
						{
						size_t this_len = ((uclen - offpnt) > FST_GZIO_LEN) ? FST_GZIO_LEN : (uclen - offpnt);
						fstFread(gz_membuf, this_len, 1, xc->handle);
						gzwrite(dsth, gz_membuf, this_len);
						}
					gzclose(dsth);
					}
					else
					{
					close(zfd);
					}
				fseeko(fp, 0, SEEK_END);
				offpnt = ftello(fp);
				fseeko(fp, 1, SEEK_SET);
				fstWriterUint64(fp, offpnt - 1);
				fclose(fp);
				fclose(xc->handle); xc->handle = NULL; 

				unlink(xc->filename);
				rename(hf, xc->filename);
				}
				else
				{
				xc->repack_on_close = 0;
				fclose(xc->handle); xc->handle = NULL; 
				}

			free(hf);
			}
			else
			{
			fclose(xc->handle); xc->handle = NULL; 
			}
		}

#ifdef __MINGW32__ 
	{
	int flen = strlen(xc->filename);
	char *hf = calloc(1, flen + 6);
	strcpy(hf, xc->filename);

	if(xc->compress_hier)
		{
		strcpy(hf + flen, ".hier");
		unlink(hf); /* no longer needed as a section now exists for this */
		}

	free(hf);
	}
#endif

	free(xc->filename); xc->filename = NULL;
	free(xc);
	}
}


/*
 * generation and writing out of value change data sections
 */
static void fstWriterEmitSectionHeader(void *ctx)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;

if(xc)
	{
	unsigned long destlen;
	unsigned char *dmem;
        int rc;

	destlen = xc->maxvalpos;
	dmem = malloc(destlen);
        rc = compress2(dmem, &destlen, xc->curval_mem, xc->maxvalpos, 9);

	fputc(FST_BL_SKIP, xc->handle);			/* temporarily tag the section, use FST_BL_VCDATA on finalize */
	xc->section_start = ftello(xc->handle);
	xc->section_header_only = 1;			/* indicates truncate might be needed */
	fstWriterUint64(xc->handle, 0); 		/* placeholder = section length */
	fstWriterUint64(xc->handle, xc->is_initial_time ? xc->firsttime : xc->curtime); 	/* begin time of section */
	fstWriterUint64(xc->handle, xc->curtime); 	/* end time of section (placeholder) */
	fstWriterUint64(xc->handle, 0);			/* placeholder = amount of buffer memory required in reader for full vc traversal */
	fstWriterVarint(xc->handle, xc->maxvalpos);	/* maxvalpos = length of uncompressed data */

	if((rc == Z_OK) && (destlen < xc->maxvalpos))
		{
		fstWriterVarint(xc->handle, destlen);	/* length of compressed data */
		}
		else
		{
		fstWriterVarint(xc->handle, xc->maxvalpos); /* length of (unable to be) compressed data */
		}
	fstWriterVarint(xc->handle, xc->maxhandle);	/* max handle associated with this data (in case of dynamic facility adds) */

	if((rc == Z_OK) && (destlen < xc->maxvalpos))
		{
		fstFwrite(dmem, destlen, 1, xc->handle);
		}
		else /* comparison between compressed / decompressed len tells if compressed */
		{
		fstFwrite(xc->curval_mem, xc->maxvalpos, 1, xc->handle);
		}

	free(dmem);
	}
}


void fstWriterFlushContext(void *ctx)
{
#ifdef FST_DEBUG
int cnt = 0;
#endif
int i;
unsigned char *vchg_mem;
FILE *f;
off_t fpos, indxpos, endpos;
uint32_t prevpos;
int zerocnt;
unsigned char *scratchpad;
unsigned char *scratchpnt;
unsigned char *tmem;
off_t tlen;
off_t unc_memreq = 0; /* for reader */
unsigned char *packmem;
unsigned int packmemlen;
uint32_t *vm4ip;

struct fstWriterContext *xc = (struct fstWriterContext *)ctx;

if((!xc)||(xc->vchn_siz <= 1)||(xc->already_in_flush)) return;
xc->already_in_flush = 1; /* should really do this with a semaphore */

xc->section_header_only = 0;
scratchpad = malloc(xc->vchn_siz);

fflush(xc->vchn_handle);
vchg_mem = fstMmap(NULL, xc->vchn_siz, PROT_READ|PROT_WRITE, MAP_SHARED, fileno(xc->vchn_handle), 0);

f = xc->handle;
fstWriterVarint(f, xc->maxhandle);	/* emit current number of handles */
fputc(xc->fastpack ? 'F' : 'Z', f);
fpos = 1;

packmemlen = 1024;			/* maintain a running "longest" allocation to */
packmem = malloc(packmemlen);		/* prevent continual malloc...free every loop iter */

for(i=0;i<xc->maxhandle;i++)
	{
	vm4ip = &(xc->valpos_mem[4*i]);

	if(vm4ip[2]) 
		{
		uint32_t offs = vm4ip[2];
		uint32_t next_offs;
		int wrlen;

		vm4ip[2] = fpos;

		scratchpnt = scratchpad + xc->vchn_siz;		/* build this buffer backwards */
		if(vm4ip[1] == 1)
			{
                        while(offs)
                                {
                                unsigned char val;
                                uint32_t time_delta, rcv;
                                next_offs = fstGetUint32(vchg_mem + offs);
                                offs += 4;   
                        
                                time_delta = fstGetVarint32(vchg_mem + offs, &wrlen);
                                val = vchg_mem[offs+wrlen];
				offs = next_offs;

                                switch(val)
                                        {
                                        case '0':
                                        case '1':               rcv = ((val&1)<<1) | (time_delta<<2);
                                                                break; /* pack more delta bits in for 0/1 vchs */
        
                                        case 'x': case 'X':     rcv = FST_RCV_X | (time_delta<<4); break;
                                        case 'z': case 'Z':     rcv = FST_RCV_Z | (time_delta<<4); break;
                                        case 'h': case 'H':     rcv = FST_RCV_H | (time_delta<<4); break;
                                        case 'u': case 'U':     rcv = FST_RCV_U | (time_delta<<4); break;
                                        case 'w': case 'W':     rcv = FST_RCV_W | (time_delta<<4); break;
                                        case 'l': case 'L':     rcv = FST_RCV_L | (time_delta<<4); break;
                                        default:                rcv = FST_RCV_D | (time_delta<<4); break;
                                        }
                
                                scratchpnt = fstCopyVarint32ToLeft(scratchpnt, rcv);
				}
			}
			else
			{
			while(offs)
				{
				int idx;
				char is_binary = 1;
				unsigned char *pnt;
				uint32_t time_delta;

				next_offs = fstGetUint32(vchg_mem + offs);
				offs += 4;

				time_delta = fstGetVarint32(vchg_mem + offs, &wrlen);

				pnt = vchg_mem+offs+wrlen;
				offs = next_offs;

				for(idx=0;idx<vm4ip[1];idx++)
					{
					if((pnt[idx] == '0') || (pnt[idx] == '1'))
						{
						continue;
						}
						else
						{
						is_binary = 0;
						break;
						}
					}

				if(is_binary)
					{
					unsigned char acc = 0;
					int shift = 7 - ((vm4ip[1]-1) & 7);
					for(idx=vm4ip[1]-1;idx>=0;idx--)
						{
						acc |= (pnt[idx] & 1) << shift;
						shift++;
						if(shift == 8)
							{
							*(--scratchpnt) = acc;
							shift = 0;
							acc = 0;
							}						
						}					

	                                scratchpnt = fstCopyVarint32ToLeft(scratchpnt, (time_delta << 1));
					}
					else
					{
					scratchpnt -= vm4ip[1];
					memcpy(scratchpnt, pnt, vm4ip[1]);

	                                scratchpnt = fstCopyVarint32ToLeft(scratchpnt, (time_delta << 1) | 1);
					}
				}
			}

		wrlen = scratchpad + xc->vchn_siz - scratchpnt;
		unc_memreq += wrlen;
		if(wrlen > 32)
			{
			unsigned long destlen = wrlen;
			unsigned char *dmem;
		        int rc;

			if(!xc->fastpack)
				{
				if(wrlen <= packmemlen)
					{
					dmem = packmem;
					}
					else
					{
					free(packmem);
					dmem = packmem = malloc(packmemlen = wrlen);
					}

		        	rc = compress2(dmem, &destlen, scratchpnt, wrlen, 4);
				if(rc == Z_OK)
					{
					fpos += fstWriterVarint(f, wrlen);
					fpos += destlen;
					fstFwrite(dmem, destlen, 1, f);
					}
					else
					{
					fpos += fstWriterVarint(f, 0);
					fpos += wrlen;
					fstFwrite(scratchpnt, wrlen, 1, f);
					}
				}
				else
				{
				if(((wrlen * 2) + 2) <= packmemlen)
					{
					dmem = packmem;
					}
					else
					{
					free(packmem);
					dmem = packmem = malloc(packmemlen = (wrlen * 2) + 2);
					}

				rc = fastlz_compress(scratchpnt, wrlen, dmem);
				if(rc < destlen)
        				{
					fpos += fstWriterVarint(f, wrlen);
					fpos += rc;
					fstFwrite(dmem, rc, 1, f);
        				}
        				else
        				{
					fpos += fstWriterVarint(f, 0);
					fpos += wrlen;
					fstFwrite(scratchpnt, wrlen, 1, f);
        				}
				}
			}
			else
			{
			fpos += fstWriterVarint(f, 0);
			fpos += wrlen;
			fstFwrite(scratchpnt, wrlen, 1, f);
			}

		vm4ip[3] = 0;
#ifdef FST_DEBUG
		cnt++;
#endif
		}
	}

free(packmem); packmem = NULL; packmemlen = 0;

prevpos = 0; zerocnt = 0;
free(scratchpad); scratchpad = NULL;

indxpos = ftello(f);
xc->secnum++;

for(i=0;i<xc->maxhandle;i++)
	{
	vm4ip = &(xc->valpos_mem[4*i]);

	if(vm4ip[2])
		{
		if(zerocnt)
			{
			fpos += fstWriterVarint(f, (zerocnt << 1));
			zerocnt = 0;
			}

		fpos += fstWriterVarint(f, ((vm4ip[2] - prevpos) << 1) | 1);
		prevpos = vm4ip[2];
		vm4ip[2] = 0;
		vm4ip[3] = 0; /* clear out tchn idx */
		}
		else
		{
		zerocnt++;		
		}
	}
if(zerocnt)
	{
	fpos += fstWriterVarint(f, (zerocnt << 1));
	}
#ifdef FST_DEBUG
printf("value chains: %d\n", cnt);
#endif

fstMunmap(vchg_mem, xc->vchn_siz);

fseeko(xc->vchn_handle, 0, SEEK_SET);
fstFtruncate(fileno(xc->vchn_handle), 0);
fputc('!', xc->vchn_handle);
xc->vchn_siz = 1;

endpos = ftello(xc->handle);
fstWriterUint64(xc->handle, endpos-indxpos);		/* write delta index position at very end of block */

/*emit time changes for block */
fflush(xc->tchn_handle);
tlen = ftello(xc->tchn_handle);
fseeko(xc->tchn_handle, 0, SEEK_SET);

tmem = fstMmap(NULL, tlen, PROT_READ|PROT_WRITE, MAP_SHARED, fileno(xc->tchn_handle), 0);
if(tmem)
	{
	unsigned long destlen = tlen;
	unsigned char *dmem = malloc(destlen);
        int rc = compress2(dmem, &destlen, tmem, tlen, 9);

	if((rc == Z_OK) && (destlen < tlen))
		{
		fstFwrite(dmem, destlen, 1, xc->handle);
		}
		else /* comparison between compressed / decompressed len tells if compressed */
		{
		fstFwrite(tmem, tlen, 1, xc->handle);
		destlen = tlen;
		}
	free(dmem);
	fstMunmap(tmem, tlen);
	fstWriterUint64(xc->handle, tlen);		/* uncompressed */
	fstWriterUint64(xc->handle, destlen);		/* compressed */
	fstWriterUint64(xc->handle, xc->tchn_cnt); 	/* number of time items */
	}

xc->tchn_cnt = xc->tchn_idx = 0;
fseeko(xc->tchn_handle, 0, SEEK_SET);
fstFtruncate(fileno(xc->tchn_handle), 0);

/* write block trailer */
endpos = ftello(xc->handle);
fseeko(xc->handle, xc->section_start, SEEK_SET);
fstWriterUint64(xc->handle, endpos - xc->section_start); 	/* write block length */
fseeko(xc->handle, 8, SEEK_CUR);				/* skip begin time */
fstWriterUint64(xc->handle, xc->curtime); 			/* write end time for section */
fstWriterUint64(xc->handle, unc_memreq);			/* amount of buffer memory required in reader for full traversal */
fflush(xc->handle);

fseeko(xc->handle, xc->section_start-1, SEEK_SET);		/* write out FST_BL_VCDATA over FST_BL_SKIP */
fputc(FST_BL_VCDATA, xc->handle);
fflush(xc->handle);

fseeko(xc->handle, endpos, SEEK_SET);				/* seek to end of file */

xc->section_header_truncpos = endpos;				/* cache in case of need to truncate */
if(xc->dump_size_limit)
	{
	if(endpos >= xc->dump_size_limit)
		{
		xc->skip_writing_section_hdr = 1;
		xc->size_limit_locked = 1;
		xc->is_initial_time = 1; /* to trick emit value and emit time change */
#ifdef FST_DEBUG
		printf("<< dump file size limit reached, stopping dumping >>\n");
#endif
		}
	}

if(!xc->skip_writing_section_hdr)
	{
	fstWriterEmitSectionHeader(xc);				/* emit next section header */
	}
fflush(xc->handle);

xc->already_in_flush = 0;
}


/*
 * functions to set miscellaneous header/block information
 */
void fstWriterSetDate(void *ctx, const char *dat)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;
if(xc)
        {
	char s[FST_HDR_DATE_SIZE];
	off_t fpos = ftello(xc->handle);
	int len = strlen(dat);

	fseeko(xc->handle, FST_HDR_OFFS_DATE, SEEK_SET);
	memset(s, 0, FST_HDR_DATE_SIZE);
	memcpy(s, dat, (len < FST_HDR_DATE_SIZE) ? len : FST_HDR_DATE_SIZE);
	fstFwrite(s, FST_HDR_DATE_SIZE, 1, xc->handle);
	fflush(xc->handle);
	fseeko(xc->handle, fpos, SEEK_SET);
	}
}


void fstWriterSetVersion(void *ctx, const char *vers)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;
if(xc && vers)
        {
	char s[FST_HDR_SIM_VERSION_SIZE];
	off_t fpos = ftello(xc->handle);
	int len = strlen(vers);

	fseeko(xc->handle, FST_HDR_OFFS_SIM_VERSION, SEEK_SET);
	memset(s, 0, FST_HDR_SIM_VERSION_SIZE);
	memcpy(s, vers, (len < FST_HDR_SIM_VERSION_SIZE) ? len : FST_HDR_SIM_VERSION_SIZE);
	fstFwrite(s, FST_HDR_SIM_VERSION_SIZE, 1, xc->handle);
	fflush(xc->handle);
	fseeko(xc->handle, fpos, SEEK_SET);
	}
}


void fstWriterSetTimescale(void *ctx, int ts)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;
if(xc)
        {
	off_t fpos = ftello(xc->handle);
	fseeko(xc->handle, FST_HDR_OFFS_TIMESCALE, SEEK_SET);
	fputc(ts & 255, xc->handle);
	fflush(xc->handle);
	fseeko(xc->handle, fpos, SEEK_SET);
	}
}


void fstWriterSetTimescaleFromString(void *ctx, const char *s)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;
if(xc && s)
        {
        int mat = 0;
	int seconds_exp = -9;
	int tv = atoi(s);
	const char *pnt = s;

	while(*pnt)
        	{
                switch(*pnt)
                	{
                        case 'm': seconds_exp = -3; mat = 1; break;
                        case 'u': seconds_exp = -6; mat = 1; break;
                        case 'n': seconds_exp = -9; mat = 1; break;
                        case 'p': seconds_exp = -12; mat = 1; break;
                        case 'f': seconds_exp = -15; mat = 1; break;
                        case 'a': seconds_exp = -18; mat = 1; break;
                        case 'z': seconds_exp = -21; mat = 1; break;
                        case 's': seconds_exp = -0; mat = 1; break;
                        default: break;
                        }

		if(mat) break;
                pnt++;
                }

	if(tv == 10)
        	{
                seconds_exp++;
                } 
        else
        if(tv == 100)
        	{
                seconds_exp+=2;
                }
                              
	fstWriterSetTimescale(ctx, seconds_exp);
        }
}


void fstWriterSetPackType(void *ctx, int typ)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;
if(xc)
	{
	xc->fastpack = (typ != 0);
	}
}


void fstWriterSetRepackOnClose(void *ctx, int enable)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;
if(xc)
	{
	xc->repack_on_close = (enable != 0);
	}
}


void fstWriterSetDumpSizeLimit(void *ctx, uint64_t numbytes)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;
if(xc)
	{
	xc->dump_size_limit = numbytes;
	}
}


int fstWriterGetDumpSizeLimitReached(void *ctx)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;
if(xc)
        {
        return(xc->size_limit_locked != 0);
        }

return(0);
}


/*
 * writer scope/var creation
 */
fstHandle fstWriterCreateVar(void *ctx, enum fstVarType vt, enum fstVarDir vd,
        uint32_t len, const char *nam, fstHandle aliasHandle)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;
int i, nlen, is_real;
                
if(xc && nam)
        {
	if(xc->valpos_mem)
		{
		fstDestroyMmaps(xc, 0);
		}

	fputc(vt, xc->hier_handle);
	fputc(vd, xc->hier_handle);
	nlen = strlen(nam);
	fstFwrite(nam, nlen, 1, xc->hier_handle);
	fputc(0, xc->hier_handle);
	xc->hier_file_len += (nlen+3);

	if((vt == FST_VT_VCD_REAL) || (vt == FST_VT_VCD_REAL_PARAMETER) || (vt == FST_VT_VCD_REALTIME))
		{
		is_real = 1;
		len = 8; /* recast number of bytes to that of what a double is */
		}
		else
		{
		is_real = 0;
		}

	xc->hier_file_len += fstWriterVarint(xc->hier_handle, len);	

	if(aliasHandle > xc->maxhandle) aliasHandle = 0;
	xc->hier_file_len += fstWriterVarint(xc->hier_handle, aliasHandle);	
	xc->numsigs++;
	if(!aliasHandle)
		{
		uint32_t zero = 0;

		fstWriterVarint(xc->geom_handle, !is_real ? len : 0); /* geom section encodes reals as zero byte */

		fstFwrite(&xc->maxvalpos, sizeof(uint32_t), 1, xc->valpos_handle);
		fstFwrite(&len, sizeof(uint32_t), 1, xc->valpos_handle);
		fstFwrite(&zero, sizeof(uint32_t), 1, xc->valpos_handle);
		fstFwrite(&zero, sizeof(uint32_t), 1, xc->valpos_handle);

		if(!is_real)
			{
			for(i=0;i<len;i++)
				{
				fputc('x', xc->curval_handle);
				}
			}
			else
			{
			fstFwrite(&xc->nan, 8, 1, xc->curval_handle); /* initialize doubles to NaN rather than x */
			}			
		
		xc->maxvalpos+=len;
		xc->maxhandle++;
		return(xc->maxhandle);
		}
		else
		{
		return(aliasHandle);
		}
	}

return(0);
}


void fstWriterSetScope(void *ctx, enum fstScopeType scopetype,
                const char *scopename, const char *scopecomp)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;

if(xc && scopename)
	{
	fputc(FST_ST_VCD_SCOPE, xc->hier_handle);
	if((scopetype < FST_ST_VCD_MODULE) || (scopetype > FST_ST_MAX)) { scopetype = FST_ST_VCD_MODULE; }
	fputc(scopetype, xc->hier_handle);
	fprintf(xc->hier_handle, "%s%c%s%c",
		scopename ? scopename : "", 0,
		scopecomp ? scopecomp : "", 0);
	
	if(scopename)
		{
		xc->hier_file_len += strlen(scopename);
		}
	if(scopecomp)
		{
		xc->hier_file_len += strlen(scopecomp);
		}

	xc->hier_file_len += 4; /* FST_ST_VCD_SCOPE + scopetype + two string terminating zeros */
	xc->numscopes++;
	}
}


void fstWriterSetUpscope(void *ctx)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;

if(xc)
	{
	fputc(FST_ST_VCD_UPSCOPE, xc->hier_handle);
	xc->hier_file_len++;
	}
}


/*
 * value and time change emission
 */
void fstWriterEmitValueChange(void *ctx, fstHandle handle, void *val)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;
unsigned char *buf = (unsigned char *)val;
uint32_t offs;
size_t len;

if((xc) && (handle <= xc->maxhandle))
	{
	uint32_t fpos;
	uint32_t *vm4ip;

	if(!xc->valpos_mem)
		{
		xc->vc_emitted = 1;
		fstWriterCreateMmaps(xc);
		}

	handle--; /* move starting at 1 index to starting at 0 */
	vm4ip = &(xc->valpos_mem[4*handle]);
	offs = vm4ip[0];
	len  = vm4ip[1];
	memcpy(xc->curval_mem + offs, buf, len);

	if(!xc->is_initial_time)
		{
		fpos = xc->vchn_siz;
		/* cygwin runs faster if these writes are combined, so the new fstWriterUint32WithVarint function, but should help with regular */
#ifndef FST_USE_FWRITE_COMBINING
                xc->vchn_siz += fstWriterUint32WithVarint(xc->vchn_handle, &vm4ip[2], xc->tchn_idx - vm4ip[3]); /* prev_chg is vm4ip[2] */
                fstFwrite(buf, len, 1, xc->vchn_handle);
                xc->vchn_siz += len;
#else
		xc->vchn_siz += fstWriterUint32WithVarint(xc->vchn_handle, &vm4ip[2], xc->tchn_idx - vm4ip[3], buf, len); /* do one fwrite op only */
#endif
		vm4ip[3] = xc->tchn_idx;
		vm4ip[2] = fpos;
		}
	}
}


void fstWriterEmitTimeChange(void *ctx, uint64_t tim)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;
int i;
int skip = 0;
if(xc)
	{
	if(xc->is_initial_time)
		{
		if(xc->size_limit_locked)	/* this resets xc->is_initial_time to one */
			{
			return;
			}

		if(!xc->valpos_mem)
			{
			fstWriterCreateMmaps(xc);
			}

		skip = 1;

		xc->firsttime = (xc->vc_emitted) ? 0: tim;
		xc->curtime = 0;
		fseeko(xc->vchn_handle, 0, SEEK_SET);
		fstFtruncate(fileno(xc->vchn_handle), 0);
		fputc('!', xc->vchn_handle);
		xc->vchn_siz = 1;
		fstWriterEmitSectionHeader(xc);
		for(i=0;i<xc->maxhandle;i++)
			{
			xc->valpos_mem[4*i+2] = 0; /* zero out offset val */
			xc->valpos_mem[4*i+3] = 0; /* zero out last time change val */
			}
		xc->is_initial_time = 0;
		}
		else
		{
		if(xc->vchn_siz >= FST_BREAK_SIZE)
			{
			fstWriterFlushContext(xc);
			xc->tchn_cnt++;
			fstWriterVarint(xc->tchn_handle, xc->curtime);
			}
		}

	if(!skip)
		{
		xc->tchn_idx++;
		}
	fstWriterVarint(xc->tchn_handle, tim - xc->curtime);
	xc->tchn_cnt++;
	xc->curtime = tim;
	}
}


void fstWriterEmitDumpActive(void *ctx, int enable)
{
struct fstWriterContext *xc = (struct fstWriterContext *)ctx;

if(xc)
	{
	struct fstBlackoutChain *b = calloc(1, sizeof(struct fstBlackoutChain));

	b->tim = xc->curtime;
	b->active = (enable != 0);

	xc->num_blackouts++;
	if(xc->blackout_curr)
		{
		xc->blackout_curr->next = b;
		xc->blackout_curr = b;
		}
		else
		{
		xc->blackout_head = b;
		xc->blackout_curr = b;
		}
	}
}


/***********************/
/***                 ***/
/*** reader function ***/
/***                 ***/
/***********************/

/*
 * private structs
 */
static const char *vartypes[] = {
	"event", "integer", "parameter", "real", "real_parameter",
	"reg", "supply0", "supply1", "time", "tri",
	"triand", "trior", "trireg", "tri0", "tri1", 
	"wand", "wire", "wor", "port", "array", "realtime"
	};

static const char *modtypes[] = {
	"module", "task", "function", "begin", "fork"
	};

struct fstCurrHier
{
struct fstCurrHier *prev;
void *user_info;
int len;
};


struct fstReaderContext
{
/* common entries */

FILE *f, *fh;
#ifdef __MINGW32__
char *fh_name;
#endif

uint64_t start_time, end_time;
uint64_t mem_used_by_writer;
uint64_t scope_count;
uint64_t var_count;
fstHandle maxhandle;
uint64_t num_alias;
uint64_t vc_section_count;

uint32_t *signal_lens;			/* maxhandle sized */
unsigned char *signal_typs;		/* maxhandle sized */
unsigned char *process_mask;		/* maxhandle-based, bitwise sized */
uint32_t longest_signal_value_len;	/* longest len value encountered */
unsigned char *temp_signal_value_buf;	/* malloced for len in longest_signal_value_len */

signed char timescale;
unsigned double_endian_match : 1;
unsigned native_doubles_for_cb : 1;
unsigned contains_geom_section : 1;
unsigned contains_hier_section : 1;	/* valid for hier_pos */
unsigned limit_range_valid : 1;		/* valid for limit_range_start, limit_range_end */

char version[FST_HDR_SIM_VERSION_SIZE + 1];
char date[FST_HDR_DATE_SIZE + 1];

char *filename, *filename_unpacked;
off_t hier_pos;

uint32_t num_blackouts;
uint64_t *blackout_times;
unsigned char *blackout_activity;

uint64_t limit_range_start, limit_range_end;

/* entries specific to read value at time functions */

unsigned rvat_data_valid : 1;
uint64_t *rvat_time_table;
uint64_t rvat_beg_tim, rvat_end_tim;
unsigned char *rvat_frame_data;
uint64_t rvat_frame_maxhandle;
off_t *rvat_chain_table;
uint32_t *rvat_chain_table_lengths;
uint64_t rvat_vc_maxhandle;
off_t rvat_vc_start;
uint32_t *rvat_sig_offs;

uint32_t rvat_chain_len;
unsigned char *rvat_chain_mem;
fstHandle rvat_chain_facidx;

uint32_t rvat_chain_pos_tidx;
uint32_t rvat_chain_pos_idx;  
uint64_t rvat_chain_pos_time;
unsigned rvat_chain_pos_valid : 1;

/* entries specific to hierarchy traversal */

struct fstHier hier;
struct fstCurrHier *curr_hier;
fstHandle current_handle;
char *curr_flat_hier_nam;
int flat_hier_alloc_len;
unsigned do_rewind : 1;
char str_scope_nam[FST_ID_NAM_SIZ+1];
char str_scope_comp[FST_ID_NAM_SIZ+1];

};


/*
 * scope -> flat name handling
 */
static void fstReaderDeallocateScopeData(struct fstReaderContext *xc)
{
struct fstCurrHier *chp;

free(xc->curr_flat_hier_nam); xc->curr_flat_hier_nam = NULL;
while(xc->curr_hier)
	{
	chp = xc->curr_hier->prev;
	free(xc->curr_hier);
	xc->curr_hier = chp;
	}
}


const char *fstReaderGetCurrentFlatScope(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
if(xc)
	{
	return(xc->curr_flat_hier_nam ? xc->curr_flat_hier_nam : "");
	}
	else
	{
	return(NULL);
	}
}


void *fstReaderGetCurrentScopeUserInfo(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
if(xc)
	{
	return(xc->curr_hier ? xc->curr_hier->user_info : NULL);
	}
	else
	{
	return(NULL);
	}
}


const char *fstReaderPopScope(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
if(xc && xc->curr_hier)   
        {
	struct fstCurrHier *ch = xc->curr_hier;
	if(xc->curr_hier->prev)
		{
		xc->curr_flat_hier_nam[xc->curr_hier->prev->len] = 0;
		}
		else
		{
		*xc->curr_flat_hier_nam = 0;
		}
	xc->curr_hier = xc->curr_hier->prev;
	free(ch);
	return(xc->curr_flat_hier_nam ? xc->curr_flat_hier_nam : "");
	}

return(NULL);
}


void fstReaderResetScope(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;

if(xc)
	{
	while(fstReaderPopScope(xc)); /* remove any already-built scoping info */
	}
}


const char *fstReaderPushScope(void *ctx, const char *nam, void *user_info)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
if(xc)
	{
	struct fstCurrHier *ch = malloc(sizeof(struct fstCurrHier));
	int chl = xc->curr_hier ? xc->curr_hier->len : 0;
	int len = chl + 1 + strlen(nam);
	if(len >= xc->flat_hier_alloc_len)
		{
		xc->curr_flat_hier_nam = xc->curr_flat_hier_nam ? realloc(xc->curr_flat_hier_nam, len+1) : malloc(len+1);
		}

	if(chl)
		{
		xc->curr_flat_hier_nam[chl] = '.';
		strcpy(xc->curr_flat_hier_nam + chl + 1, nam);
		}
		else
		{
		strcpy(xc->curr_flat_hier_nam, nam);
		len--;
		}

	ch->len = len;
	ch->prev = xc->curr_hier;
	ch->user_info = user_info;
	xc->curr_hier = ch;
	return(xc->curr_flat_hier_nam);
	}

return(NULL);
}


/*
 * iter mask manipulation util functions
 */
int fstReaderGetFacProcessMask(void *ctx, fstHandle facidx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
                                 
if(xc)
        {      
	facidx--;
	if(facidx<xc->maxhandle)
		{
		int process_idx = facidx/8;
		int process_bit = facidx&7;

		return( (xc->process_mask[process_idx]&(1<<process_bit)) != 0 );
		}
	}
return(0);
}


void fstReaderSetFacProcessMask(void *ctx, fstHandle facidx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
                                 
if(xc)
        { 
	facidx--;
	if(facidx<xc->maxhandle)
		{
		int idx = facidx/8;
		int bitpos = facidx&7;

		xc->process_mask[idx] |= (1<<bitpos);
		}
	}
}


void fstReaderClrFacProcessMask(void *ctx, fstHandle facidx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
                                 
if(xc)
        { 
	facidx--;
	if(facidx<xc->maxhandle)
		{
		int idx = facidx/8;
		int bitpos = facidx&7;

		xc->process_mask[idx] &= (~(1<<bitpos));
		}
	}
}


void fstReaderSetFacProcessMaskAll(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
                                 
if(xc)
        { 
	memset(xc->process_mask, 0xff, (xc->maxhandle+7)/8);
	}
}


void fstReaderClrFacProcessMaskAll(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
                                 
if(xc)
        { 
	memset(xc->process_mask, 0x00, (xc->maxhandle+7)/8);
	}
}


/*
 * various utility read/write functions
 */
signed char fstReaderGetTimescale(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
return(xc ? xc->timescale : 0);
}


uint64_t fstReaderGetStartTime(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
return(xc ? xc->start_time : 0);
}


uint64_t fstReaderGetEndTime(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
return(xc ? xc->end_time : 0);
}


uint64_t fstReaderGetMemoryUsedByWriter(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
return(xc ? xc->mem_used_by_writer : 0);
}


uint64_t fstReaderGetScopeCount(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
return(xc ? xc->scope_count : 0);
}


uint64_t fstReaderGetVarCount(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
return(xc ? xc->var_count : 0);
}


fstHandle fstReaderGetMaxHandle(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
return(xc ? xc->maxhandle : 0);
}


uint64_t fstReaderGetAliasCount(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
return(xc ? xc->num_alias : 0);
}


uint64_t fstReaderGetValueChangeSectionCount(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
return(xc ? xc->vc_section_count : 0);
}


int fstReaderGetDoubleEndianMatchState(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
return(xc ? xc->double_endian_match : 0);
}


const char *fstReaderGetVersionString(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
return(xc ? xc->version : NULL);
}


const char *fstReaderGetDateString(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
return(xc ? xc->date : NULL);
}


uint32_t fstReaderGetNumberDumpActivityChanges(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
return(xc ? xc->num_blackouts : 0);
}


uint64_t fstReaderGetDumpActivityChangeTime(void *ctx, uint32_t idx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;

if(xc && (idx < xc->num_blackouts) && (xc->blackout_times))
	{
	return(xc->blackout_times[idx]);
	}
	else
	{
	return(0);
	}
}


unsigned char fstReaderGetDumpActivityChangeValue(void *ctx, uint32_t idx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;

if(xc && (idx < xc->num_blackouts) && (xc->blackout_activity))
	{
	return(xc->blackout_activity[idx]);
	}
	else
	{
	return(0);
	}
}


void fstReaderSetLimitTimeRange(void *ctx, uint64_t start_time, uint64_t end_time)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;

if(xc)
	{
	xc->limit_range_valid = 1;
	xc->limit_range_start = start_time;
	xc->limit_range_end = end_time;
	}
}


void fstReaderSetUnlimitedTimeRange(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;

if(xc)
	{
	xc->limit_range_valid = 0;
	}
}


void fstReaderIterBlocksSetNativeDoublesOnCallback(void *ctx, int enable)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
if(xc)
	{
	xc->native_doubles_for_cb = (enable != 0);
	}
}

/*
 * hierarchy processing
 */
static char *fstVcdID(int value)
{
static char buf[16];
char *pnt = buf;
int vmod;

/* zero is illegal for a value...it is assumed they start at one */
for(;;)
        {
        if((vmod = (value % 94)))
                {
                *(pnt++) = (char)(vmod + 32);
                } 
                else
                {
                *(pnt++) = '~'; value -= 94;
                }
        value = value / 94;
        if(!value) { break; }
        }

*pnt = 0;
return(buf);
}

static char *fstVcdIDForFwrite(int value, int *len)
{
static char buf[16];
char *pnt = buf;
int vmod;

/* zero is illegal for a value...it is assumed they start at one */
for(;;)
        {
        if((vmod = (value % 94)))
                {
                *(pnt++) = (char)(vmod + 32);
                } 
                else
                {
                *(pnt++) = '~'; value -= 94;
                }
        value = value / 94;
        if(!value) { break; }
        }

*len = pnt-buf;
return(buf);
}


static int fstReaderRecreateHierFile(struct fstReaderContext *xc)
{
int pass_status = 1;

if(!xc->fh)
	{
	off_t offs_cache = ftello(xc->f);
	char *fnam = malloc(strlen(xc->filename) + 6 + 16 + 32 + 1);
	unsigned char *mem = malloc(FST_GZIO_LEN);
	off_t hl, uclen;
	gzFile zhandle;
	int zfd;

	sprintf(fnam, "%s.hier_%d_%p", xc->filename, getpid(), (void *)xc);
	fseeko(xc->f, xc->hier_pos, SEEK_SET);
	uclen = fstReaderUint64(xc->f);
	fflush(xc->f);
	zfd = dup(fileno(xc->f));
	zhandle = gzdopen(zfd, "rb");
	if(!zhandle)
		{
		close(zfd);
		free(mem);
		free(fnam);
		return(0);
		}

	xc->fh = fopen(fnam, "w+b");
        if(!xc->fh)
                {
                xc->fh = tmpfile();  
                free(fnam); fnam = NULL;
                if(!xc->fh)
			{
			free(mem);
			return(0);
			}
                }    

#ifndef __MINGW32__
	if(fnam) unlink(fnam);
#endif

        for(hl = 0; hl < uclen; hl += FST_GZIO_LEN)
		{
                size_t len = ((uclen - hl) > FST_GZIO_LEN) ? FST_GZIO_LEN : (uclen - hl);
		size_t gzreadlen = gzread(zhandle, mem, len); /* rc should equal len... */
		size_t fwlen;

		if(gzreadlen != len)
			{
			pass_status = 0;
			break;
			}

		fwlen = fstFwrite(mem, len, 1, xc->fh);
		if(fwlen != 1)
			{
			pass_status = 0;
			break;
			}
                }
        gzclose(zhandle);
	free(mem);

#ifndef __MINGW32__
	free(fnam);
#else
	xc->fh_name = fnam;
#endif

	fseeko(xc->f, offs_cache, SEEK_SET);
	}

return(pass_status);
}


int fstReaderIterateHierRewind(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
int pass_status = 0;

if(xc)
	{
	pass_status = 1;
	if(!xc->fh)
		{
		pass_status = fstReaderRecreateHierFile(xc);
		}

	xc->do_rewind = 1;
	}

return(pass_status);
}


struct fstHier *fstReaderIterateHier(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
int isfeof;
fstHandle alias;
char *pnt;
int ch;

if(!xc) return(NULL);

if(!xc->fh)
	{
	if(!fstReaderRecreateHierFile(xc))
		{
		return(NULL);
		}
	}

if(xc->do_rewind)
	{
	xc->do_rewind = 0;
	xc->current_handle = 0;
	fseeko(xc->fh, 0, SEEK_SET);
	clearerr(xc->fh);
	}

if(!(isfeof=feof(xc->fh)))
	{
	int tag = fgetc(xc->fh);
	switch(tag)
		{
		case FST_ST_VCD_SCOPE:
			xc->hier.htyp = FST_HT_SCOPE;
			xc->hier.u.scope.typ = fgetc(xc->fh);
			xc->hier.u.scope.name = pnt = xc->str_scope_nam;
			while((ch = fgetc(xc->fh))) 
				{
				*(pnt++) = ch; 
				}; /* scopename */
			*pnt = 0;

			xc->hier.u.scope.component = pnt = xc->str_scope_comp;
			while((ch = fgetc(xc->fh))) 
				{
				*(pnt++) = ch; 
				}; /* scopecomp */
			*pnt = 0;
			break;

		case FST_ST_VCD_UPSCOPE:
			xc->hier.htyp = FST_HT_UPSCOPE;
			break;

		case FST_VT_VCD_EVENT:
		case FST_VT_VCD_INTEGER:
		case FST_VT_VCD_PARAMETER:
		case FST_VT_VCD_REAL:
		case FST_VT_VCD_REAL_PARAMETER:
		case FST_VT_VCD_REG:
		case FST_VT_VCD_SUPPLY0:
		case FST_VT_VCD_SUPPLY1:
		case FST_VT_VCD_TIME:
		case FST_VT_VCD_TRI:
		case FST_VT_VCD_TRIAND:
		case FST_VT_VCD_TRIOR:
		case FST_VT_VCD_TRIREG:
		case FST_VT_VCD_TRI0:
		case FST_VT_VCD_TRI1:
		case FST_VT_VCD_WAND:
		case FST_VT_VCD_WIRE:
		case FST_VT_VCD_WOR:
		case FST_VT_VCD_PORT:
		case FST_VT_VCD_ARRAY:
		case FST_VT_VCD_REALTIME:
			xc->hier.htyp = FST_HT_VAR;

			xc->hier.u.var.typ = tag;
			xc->hier.u.var.direction = fgetc(xc->fh);
			xc->hier.u.var.name = pnt = xc->str_scope_nam;
			while((ch = fgetc(xc->fh))) 
				{
				*(pnt++) = ch; 
				}; /* varname */
			*pnt = 0;
			xc->hier.u.var.length = fstReaderVarint32(xc->fh);
			if(tag == FST_VT_VCD_PORT)
				{
				xc->hier.u.var.length -= 2; /* removal of delimiting spaces */
				xc->hier.u.var.length /= 3; /* port -> signal size adjust */
				}

			alias = fstReaderVarint32(xc->fh);

			if(!alias)
				{
                		xc->current_handle++;
				xc->hier.u.var.handle = xc->current_handle;
				xc->hier.u.var.is_alias = 0;
				}
				else
				{
				xc->hier.u.var.handle = alias;
				xc->hier.u.var.is_alias = 1;
				}
		
			break;

		default:
			isfeof = 1; 
			break;
		}
	}

return(!isfeof ? &xc->hier : NULL);
}


int fstReaderProcessHier(void *ctx, FILE *fv)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
char str[FST_ID_NAM_SIZ+1];
char *pnt;
int ch, scopetype;
int vartype;
uint32_t len, alias;
uint32_t maxvalpos=0;
int num_signal_dyn = 65536;

if(!xc) return(0);

xc->longest_signal_value_len = 32; /* arbitrarily set at 32...this is much longer than an expanded double */

if(!xc->fh)
	{
	if(!fstReaderRecreateHierFile(xc))
		{
		return(0);
		}
	}

if(fv)
	{
	char time_dimension[2] = {0, 0};
	int time_scale = 1;

	fprintf(fv, "$date\n\t%s\n$end\n", xc->date);
	fprintf(fv, "$version\n\t%s\n$end\n", xc->version);
	
        switch(xc->timescale)
                {
                case 0:         break;

                case -1:        time_scale = 100;               time_dimension[0] = 'm'; break;
                case -2:        time_scale = 10;
                case -3:                                        time_dimension[0] = 'm'; break;
         
                case -4:        time_scale = 100;               time_dimension[0] = 'u'; break;
                case -5:        time_scale = 10;
                case -6:                                        time_dimension[0] = 'u'; break;
        
                case -10:       time_scale = 100;               time_dimension[0] = 'p'; break;
                case -11:       time_scale = 10;
                case -12:                                       time_dimension[0] = 'p'; break;
        
                case -13:       time_scale = 100;               time_dimension[0] = 'f'; break;
                case -14:       time_scale = 10;
                case -15:                                       time_dimension[0] = 'f'; break;

                case -16:       time_scale = 100;               time_dimension[0] = 'a'; break;
                case -17:       time_scale = 10;
                case -18:                                       time_dimension[0] = 'a'; break;

                case -19:       time_scale = 100;               time_dimension[0] = 'z'; break;
                case -20:       time_scale = 10;
                case -21:                                       time_dimension[0] = 'z'; break;
        
                case -7:        time_scale = 100;               time_dimension[0] = 'n'; break;
                case -8:        time_scale = 10;
                case -9:
                default:                                        time_dimension[0] = 'n'; break;
                }

	if(fv) fprintf(fv, "$timescale\n\t%d%ss\n$end\n", time_scale, time_dimension);
	}

xc->maxhandle = 0;
xc->num_alias = 0;

free(xc->signal_lens);
xc->signal_lens = malloc(num_signal_dyn*sizeof(uint32_t));

free(xc->signal_typs);
xc->signal_typs = malloc(num_signal_dyn*sizeof(unsigned char));

fseeko(xc->fh, 0, SEEK_SET);
while(!feof(xc->fh))
	{
	int tag = fgetc(xc->fh);
	switch(tag)
		{
		case FST_ST_VCD_SCOPE:
			scopetype = fgetc(xc->fh);
			pnt = str;
			while((ch = fgetc(xc->fh))) 
				{
				*(pnt++) = ch; 
				}; /* scopename */
			*pnt = 0;
			while(fgetc(xc->fh)) { }; /* scopecomp */

			if(fv) fprintf(fv, "$scope %s %s $end\n", modtypes[scopetype], str);
			break;

		case FST_ST_VCD_UPSCOPE:
			if(fv) fprintf(fv, "$upscope $end\n");
			break;

		case FST_VT_VCD_EVENT:
		case FST_VT_VCD_INTEGER:
		case FST_VT_VCD_PARAMETER:
		case FST_VT_VCD_REAL:
		case FST_VT_VCD_REAL_PARAMETER:
		case FST_VT_VCD_REG:
		case FST_VT_VCD_SUPPLY0:
		case FST_VT_VCD_SUPPLY1:
		case FST_VT_VCD_TIME:
		case FST_VT_VCD_TRI:
		case FST_VT_VCD_TRIAND:
		case FST_VT_VCD_TRIOR:
		case FST_VT_VCD_TRIREG:
		case FST_VT_VCD_TRI0:
		case FST_VT_VCD_TRI1:
		case FST_VT_VCD_WAND:
		case FST_VT_VCD_WIRE:
		case FST_VT_VCD_WOR:
		case FST_VT_VCD_PORT:
		case FST_VT_VCD_ARRAY:
		case FST_VT_VCD_REALTIME:
			vartype = tag;
			/* vardir = */ fgetc(xc->fh); /* unused in VCD reader, but need to advance read pointer */
			pnt = str;
			while((ch = fgetc(xc->fh))) 
				{
				*(pnt++) = ch; 
				}; /* varname */
			*pnt = 0;
			len = fstReaderVarint32(xc->fh);
			alias = fstReaderVarint32(xc->fh);

			if(!alias)
				{
				if(xc->maxhandle == num_signal_dyn)
					{
					num_signal_dyn *= 2;
					xc->signal_lens = realloc(xc->signal_lens, num_signal_dyn*sizeof(uint32_t));
					xc->signal_typs = realloc(xc->signal_typs, num_signal_dyn*sizeof(unsigned char));
					}
				xc->signal_lens[xc->maxhandle] = len;
				xc->signal_typs[xc->maxhandle] = vartype;

		                maxvalpos+=len;
				if(len > xc->longest_signal_value_len)
					{
					xc->longest_signal_value_len = len;
					}

				if((vartype == FST_VT_VCD_REAL) || (vartype == FST_VT_VCD_REAL_PARAMETER) || (vartype == FST_VT_VCD_REALTIME))
					{
					len = 64;
					xc->signal_typs[xc->maxhandle] = FST_VT_VCD_REAL;
					}
				if(fv) 
					{
					uint32_t modlen = (vartype != FST_VT_VCD_PORT) ? len : ((len - 2) / 3);
					fprintf(fv, "$var %s %"PRIu32" %s %s $end\n", vartypes[vartype], modlen, fstVcdID(xc->maxhandle+1), str);
					}
                		xc->maxhandle++;
				}
				else
				{
				if((vartype == FST_VT_VCD_REAL) || (vartype == FST_VT_VCD_REAL_PARAMETER) || (vartype == FST_VT_VCD_REALTIME))
					{
					len = 64;
					xc->signal_typs[xc->maxhandle] = FST_VT_VCD_REAL;
					}
				if(fv) 
					{
					uint32_t modlen = (vartype != FST_VT_VCD_PORT) ? len : ((len - 2) / 3);
					fprintf(fv, "$var %s %"PRIu32" %s %s $end\n", vartypes[vartype], modlen, fstVcdID(alias), str);
					}
				xc->num_alias++;
				}
		
			break;

		default:
			break;
		}
	}
if(fv) fprintf(fv, "$enddefinitions $end\n");

xc->signal_lens = realloc(xc->signal_lens, xc->maxhandle*sizeof(uint32_t));
xc->signal_typs = realloc(xc->signal_typs, xc->maxhandle*sizeof(unsigned char));

free(xc->process_mask);
xc->process_mask = calloc(1, (xc->maxhandle+7)/8);

free(xc->temp_signal_value_buf);
xc->temp_signal_value_buf = malloc(xc->longest_signal_value_len + 1);

xc->var_count = xc->maxhandle + xc->num_alias;

return(1);
}


/*
 * reader file open/close functions
 */
int fstReaderInit(struct fstReaderContext *xc)
{
off_t blkpos = 0;
off_t endfile;
uint64_t seclen;
int sectype;
uint64_t vc_section_count_actual = 0;
int hdr_incomplete = 0;
int hdr_seen = 0;
int gzread_pass_status = 1;

sectype = fgetc(xc->f);
if(sectype == FST_BL_ZWRAPPER)
	{
	FILE *fcomp;
	off_t offpnt, uclen;
	char gz_membuf[FST_GZIO_LEN];
	void *zhandle;
	int zfd;
        int flen = strlen(xc->filename);
        char *hf;

	seclen = fstReaderUint64(xc->f);
	uclen = fstReaderUint64(xc->f);

	if(!seclen) return(0); /* not finished compressing, this is a failed read */

        hf = calloc(1, flen + 16 + 32 + 1);

	sprintf(hf, "%s.upk_%d_%p", xc->filename, getpid(), (void *)xc);
	fcomp = fopen(hf, "w+b");
	if(!fcomp)
		{
		fcomp = tmpfile();
		free(hf); hf = NULL;
		if(!fcomp) return(0);
		}

#if defined(FST_MACOSX)
	setvbuf(fcomp, (char *)NULL, _IONBF, 0);   /* keeps gzip from acting weird in tandem with fopen */
#endif

#ifdef __MINGW32__
	setvbuf(fcomp, (char *)NULL, _IONBF, 0);   /* keeps gzip from acting weird in tandem with fopen */
	xc->filename_unpacked = hf;
#else
	if(hf) 
		{
		unlink(hf);
		free(hf);
		}
#endif

	fseeko(xc->f, 1+8+8, SEEK_SET);
	fflush(xc->f);

	zfd = dup(fileno(xc->f));
	zhandle = gzdopen(zfd, "rb");
	if(zhandle)
		{
		for(offpnt = 0; offpnt < uclen; offpnt += FST_GZIO_LEN)
			{
			size_t this_len = ((uclen - offpnt) > FST_GZIO_LEN) ? FST_GZIO_LEN : (uclen - offpnt);
			size_t gzreadlen = gzread(zhandle, gz_membuf, this_len);
			size_t fwlen;

	                if(gzreadlen != this_len)
	                        {
	                        gzread_pass_status = 0;
	                        break;
	                        }
			fwlen = fstFwrite(gz_membuf, this_len, 1, fcomp);
			if(fwlen != 1)
				{
				gzread_pass_status = 0;
				break;
				}
			}
		gzclose(zhandle);
		}
		else
		{
		close(zfd);
		}
	fflush(fcomp);
	fclose(xc->f);
	xc->f = fcomp;
	}

if(gzread_pass_status)
	{
	fseeko(xc->f, 0, SEEK_END);
	endfile = ftello(xc->f);

	while(blkpos < endfile)
		{
		fseeko(xc->f, blkpos, SEEK_SET);
		
		sectype = fgetc(xc->f);
		seclen = fstReaderUint64(xc->f);
	
		if(sectype == EOF) 
			{
			break;
			}
	
		if(!hdr_seen && (sectype != FST_BL_HDR)) 
			{
			break;
			}
	
		blkpos++;
		if(sectype == FST_BL_HDR)
			{
			if(!hdr_seen)
				{
				int ch;
				double dcheck;
	
				xc->start_time = fstReaderUint64(xc->f);
				xc->end_time = fstReaderUint64(xc->f); 
	
				hdr_incomplete = (xc->start_time == 0) && (xc->end_time == 0);
	
				fstFread(&dcheck, 8, 1, xc->f);
				xc->double_endian_match = (dcheck == FST_DOUBLE_ENDTEST);
				if(!xc->double_endian_match)
					{
					union	{
	  					unsigned char rvs_buf[8];
	  					double d;
	  					} vu;
	
					unsigned char *dcheck_alias = (unsigned char *)&dcheck;
					int rvs_idx;
	
					for(rvs_idx=0;rvs_idx<8;rvs_idx++)
						{
						vu.rvs_buf[rvs_idx] = dcheck_alias[7-rvs_idx];
						}
					if(vu.d != FST_DOUBLE_ENDTEST)
						{
						break; /* either corrupt file or wrong architecture (offset +33 also functions as matchword) */
						}
					}
	
				hdr_seen = 1;
	
				xc->mem_used_by_writer = fstReaderUint64(xc->f); 
				xc->scope_count = fstReaderUint64(xc->f); 
				xc->var_count = fstReaderUint64(xc->f); 
				xc->maxhandle = fstReaderUint64(xc->f); 
				xc->num_alias = xc->var_count - xc->maxhandle;
				xc->vc_section_count = fstReaderUint64(xc->f); 
				ch = fgetc(xc->f);
				xc->timescale = (signed char)ch;
				fstFread(xc->version, FST_HDR_SIM_VERSION_SIZE, 1, xc->f);
				xc->version[FST_HDR_SIM_VERSION_SIZE] = 0;
				fstFread(xc->date, FST_HDR_DATE_SIZE, 1, xc->f);
				xc->date[FST_HDR_DATE_SIZE] = 0;
				}
			}
		else if(sectype == FST_BL_VCDATA)
			{
			if(hdr_incomplete)
				{
				uint64_t bt = fstReaderUint64(xc->f);
				xc->end_time = fstReaderUint64(xc->f);
		
				if(!vc_section_count_actual) { xc->start_time = bt; }
				}

			vc_section_count_actual++;
			}
		else if(sectype == FST_BL_GEOM)
			{
			if(!hdr_incomplete)
				{
				uint64_t clen = seclen - 24;
				uint64_t uclen = fstReaderUint64(xc->f);
				unsigned char *ucdata = malloc(uclen);
				unsigned char *pnt = ucdata;
				int i;
	
				xc->contains_geom_section = 1;
				xc->maxhandle = fstReaderUint64(xc->f);
				xc->longest_signal_value_len = 32; /* arbitrarily set at 32...this is much longer than an expanded double */

				free(xc->process_mask);
				xc->process_mask = calloc(1, (xc->maxhandle+7)/8);

				if(clen != uclen)
					{
					unsigned char *cdata = malloc(clen);
				        unsigned long destlen = uclen;
				        unsigned long sourcelen = clen;
					int rc;
	
					fstFread(cdata, clen, 1, xc->f);
					rc = uncompress(ucdata, &destlen, cdata, sourcelen);

					if(rc != Z_OK)
						{
						printf("geom uncompress rc = %d\n", rc);
						exit(255);
						}
					
					free(cdata);
					}
					else
					{
					fstFread(ucdata, uclen, 1, xc->f);
					}
		
				free(xc->signal_lens);
				xc->signal_lens = malloc(sizeof(uint32_t) * xc->maxhandle);
				free(xc->signal_typs);
				xc->signal_typs = malloc(sizeof(unsigned char) * xc->maxhandle);
	
				for(i=0;i<xc->maxhandle;i++)
					{
			                int skiplen;
		               		uint64_t val = fstGetVarint32(pnt, &skiplen);
	
					pnt += skiplen;
	
					if(val)
						{
						xc->signal_lens[i] = val;
						xc->signal_typs[i] = FST_VT_VCD_WIRE;
						if(val > xc->longest_signal_value_len)
	                                        	{
	                                        	xc->longest_signal_value_len = val;
	                                        	}
						}
						else
						{
						xc->signal_lens[i] = 8; /* backpatch in real */
						xc->signal_typs[i] = FST_VT_VCD_REAL;
						/* xc->longest_signal_value_len handled above by overly large init size */
						}
					}

				free(xc->temp_signal_value_buf);
				xc->temp_signal_value_buf = malloc(xc->longest_signal_value_len + 1); 
	
				free(ucdata);
				}
			}
		else if(sectype == FST_BL_HIER)
			{
			xc->contains_hier_section = 1;
			xc->hier_pos = ftello(xc->f);
			}
		else if(sectype == FST_BL_BLACKOUT)
			{
			uint32_t i;
			uint64_t cur_bl = 0;
			uint64_t delta;

			xc->num_blackouts = fstReaderVarint32(xc->f);
			free(xc->blackout_times);
			xc->blackout_times = calloc(xc->num_blackouts, sizeof(uint64_t));
			free(xc->blackout_activity);
			xc->blackout_activity = calloc(xc->num_blackouts, sizeof(unsigned char));

			for(i=0;i<xc->num_blackouts;i++)
				{
				xc->blackout_activity[i] = fgetc(xc->f) != 0;
				delta = fstReaderVarint64(xc->f);
				cur_bl += delta;
				xc->blackout_times[i] = cur_bl;
				}
			}
	
		blkpos += seclen;
		if(!hdr_seen) break;
		}

	if(hdr_seen)
		{
		if(xc->vc_section_count != vc_section_count_actual)
			{
			xc->vc_section_count = vc_section_count_actual;
			}
	
		if(!xc->contains_geom_section)
			{
			fstReaderProcessHier(xc, NULL); /* recreate signal_lens/signal_typs info */
			}
		}
	}

return(hdr_seen);
}


void *fstReaderOpen(const char *nam)
{
struct fstReaderContext *xc = calloc(1, sizeof(struct fstReaderContext));

if((!nam)||(!(xc->f=fopen(nam, "rb"))))
        {
        free(xc);
        xc=NULL;
        }
        else
        {
        int flen = strlen(nam);
        char *hf = calloc(1, flen + 6);
	int rc;

#if defined(__MINGW32__) || defined(FST_MACOSX)
	setvbuf(xc->f, (char *)NULL, _IONBF, 0);   /* keeps gzip from acting weird in tandem with fopen */
#endif

        memcpy(hf, nam, flen);
        strcpy(hf + flen, ".hier");
        xc->fh = fopen(hf, "rb");

	free(hf);
	xc->filename = strdup(nam);
	rc = fstReaderInit(xc);

	if((rc) && (xc->vc_section_count) && (xc->maxhandle) && ((xc->fh)||(xc->contains_hier_section)))
		{
		/* more init */
		xc->do_rewind = 1;
		}
		else
		{
		fstReaderClose(xc);
		xc = NULL;
		}
	}

return(xc);
}


static void fstReaderDeallocateRvatData(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
if(xc)
	{
	free(xc->rvat_chain_mem); xc->rvat_chain_mem = NULL;
	free(xc->rvat_frame_data); xc->rvat_frame_data = NULL;
	free(xc->rvat_time_table); xc->rvat_time_table = NULL;
	free(xc->rvat_chain_table); xc->rvat_chain_table = NULL;
	free(xc->rvat_chain_table_lengths); xc->rvat_chain_table_lengths = NULL;

	xc->rvat_data_valid = 0;
	}
}


void fstReaderClose(void *ctx)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;

if(xc)
	{
	fstReaderDeallocateScopeData(xc);
	fstReaderDeallocateRvatData(xc);
	free(xc->rvat_sig_offs); xc->rvat_sig_offs = NULL;

	free(xc->process_mask); xc->process_mask = NULL;
	free(xc->blackout_times); xc->blackout_times = NULL;
	free(xc->blackout_activity); xc->blackout_activity = NULL;
	free(xc->temp_signal_value_buf); xc->temp_signal_value_buf = NULL;
	free(xc->signal_typs); xc->signal_typs = NULL;
	free(xc->signal_lens); xc->signal_lens = NULL;
	free(xc->filename); xc->filename = NULL;

	if(xc->fh) 
		{ 
		fclose(xc->fh); xc->fh = NULL; 
#ifdef __MINGW32__
		if(xc->fh_name)
			{
			unlink(xc->fh_name);
			free(xc->fh_name); xc->fh_name = NULL;
			}
#endif
		}

	if(xc->f) 
		{ 
		fclose(xc->f); xc->f = NULL; 
		if(xc->filename_unpacked)
			{
			unlink(xc->filename_unpacked);
			free(xc->filename_unpacked);
			}
		}

	free(xc);
	}
}


/*
 * read processing
 */

/* normal read which re-interleaves the value change data */
int fstReaderIterBlocks(void *ctx,
        void (*value_change_callback)(void *user_callback_data_pointer, uint64_t time, fstHandle facidx, const unsigned char *value),
        void *user_callback_data_pointer, FILE *fv)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;

uint64_t previous_time = UINT64_MAX;
uint64_t *time_table = NULL;
uint64_t tsec_nitems;
int secnum = 0;
off_t blkpos = 0;
uint64_t seclen, beg_tim, end_tim;
uint64_t frame_uclen, frame_clen, frame_maxhandle, vc_maxhandle; 
off_t vc_start;
off_t indx_pntr, indx_pos;
off_t *chain_table = NULL;
uint32_t *chain_table_lengths = NULL;
unsigned char *chain_cmem;
unsigned char *pnt;
long chain_clen;
fstHandle idx, pidx=0, i;
uint64_t pval;
uint64_t vc_maxhandle_largest = 0;
uint64_t tsec_uclen = 0, tsec_clen = 0;
int sectype;
uint64_t mem_required_for_traversal;
unsigned char *mem_for_traversal = NULL;
uint32_t traversal_mem_offs;
uint32_t *scatterptr, *headptr, *length_remaining;
uint32_t cur_blackout = 0;
int packtype;

if(!xc) return(0);

scatterptr = calloc(xc->maxhandle, sizeof(uint32_t));
headptr = calloc(xc->maxhandle, sizeof(uint32_t));
length_remaining = calloc(xc->maxhandle, sizeof(uint32_t));

for(;;)
	{
	uint32_t *tc_head = NULL;
	traversal_mem_offs = 0;

	fseeko(xc->f, blkpos, SEEK_SET);
	
	sectype = fgetc(xc->f);
	seclen = fstReaderUint64(xc->f);

	if((sectype == EOF) || (sectype == FST_BL_SKIP))
		{
#ifdef FST_DEBUG
		printf("<< EOF >>\n");
#endif
		break;
		}

	blkpos++;
	if(sectype != FST_BL_VCDATA)
		{
		blkpos += seclen;
		continue;
		}

	if(!seclen) break;

	beg_tim = fstReaderUint64(xc->f);
	end_tim = fstReaderUint64(xc->f);

	if(xc->limit_range_valid)
		{
		if(beg_tim < xc->limit_range_start)
			{
			blkpos += seclen;
			continue;
			}

		if(beg_tim > xc->limit_range_end) /* likely the compare in for(i=0;i<tsec_nitems;i++) below would do this earlier */
			{
			break;
			}
		}


	mem_required_for_traversal = fstReaderUint64(xc->f);
	mem_for_traversal = malloc(mem_required_for_traversal + 66); /* add in potential fastlz overhead */
#ifdef FST_DEBUG
	printf("sec: %d seclen: %d begtim: %d endtim: %d\n",
		secnum, (int)seclen, (int)beg_tim, (int)end_tim);
	printf("\tmem_required_for_traversal: %d\n", (int)mem_required_for_traversal);
#endif
	/* process time block */
	{
	unsigned char *ucdata;
	unsigned char *cdata;
	unsigned long destlen = tsec_uclen;
	unsigned long sourcelen = tsec_clen;
	int rc;
	unsigned char *tpnt;
	uint64_t tpval;
	int ti;

	fseeko(xc->f, blkpos + seclen - 24, SEEK_SET);
	tsec_uclen = fstReaderUint64(xc->f);
	tsec_clen = fstReaderUint64(xc->f);
	tsec_nitems = fstReaderUint64(xc->f);
#ifdef FST_DEBUG
	printf("\ttime section unc: %d, com: %d (%d items)\n", 
		(int)tsec_uclen, (int)tsec_clen, (int)tsec_nitems);
#endif		
	ucdata = malloc(tsec_uclen);
	destlen = tsec_uclen;
	sourcelen = tsec_clen;

	fseeko(xc->f, -24 - ((off_t)tsec_clen), SEEK_CUR);

	if(tsec_uclen != tsec_clen)
		{
		cdata = malloc(tsec_clen);
		fstFread(cdata, tsec_clen, 1, xc->f);
	
		rc = uncompress(ucdata, &destlen, cdata, sourcelen);
	                
		if(rc != Z_OK)
			{
			printf("tsec uncompress rc = %d\n", rc);
			exit(255);
			}
	
		free(cdata);
		}
		else
		{
		fstFread(ucdata, tsec_uclen, 1, xc->f);
		}
	
	free(time_table);
	time_table = calloc(tsec_nitems, sizeof(uint64_t));
	tpnt = ucdata;
	tpval = 0;
	for(ti=0;ti<tsec_nitems;ti++)
		{
		int skiplen;
		uint64_t val = fstGetVarint64(tpnt, &skiplen);
		tpval = time_table[ti] = tpval + val;
		tpnt += skiplen;	
		}

	tc_head = calloc(tsec_nitems, sizeof(uint32_t));
	free(ucdata);
	}

	fseeko(xc->f, blkpos+32, SEEK_SET);

	frame_uclen = fstReaderVarint64(xc->f);
	frame_clen = fstReaderVarint64(xc->f);
	frame_maxhandle = fstReaderVarint64(xc->f);

	if(secnum == 0)
		{
		if(beg_tim != time_table[0])
			{
			unsigned char *mu = malloc(frame_uclen);
			uint32_t sig_offs = 0;

			if(fv)
				{
				if(beg_tim) { fprintf(fv, "#%"PRIu64"\n", beg_tim); }
				if((xc->num_blackouts)&&(cur_blackout != xc->num_blackouts))
					{
					if(beg_tim == xc->blackout_times[cur_blackout])
						{
						fprintf(fv, "$dump%s $end\n", (xc->blackout_activity[cur_blackout++]) ? "on" : "off");
						}
					}
				}

			if(frame_uclen == frame_clen)
				{
				fstFread(mu, frame_uclen, 1, xc->f);
				}
				else
				{
				unsigned char *mc = malloc(frame_clen);
				int rc;

				unsigned long destlen = frame_uclen;
				unsigned long sourcelen = frame_clen;

				fstFread(mc, sourcelen, 1, xc->f);
				rc = uncompress(mu, &destlen, mc, sourcelen);
				if(rc != Z_OK)
					{
					printf("rc: %d\n", rc);
					exit(255);
					}
				free(mc);
				}


			for(idx=0;idx<frame_maxhandle;idx++)
				{
		                int process_idx = idx/8;
		                int process_bit = idx&7;

		                if(xc->process_mask[process_idx]&(1<<process_bit))
					{
					if(xc->signal_lens[idx] == 1)
						{
						unsigned char val = mu[sig_offs];
						if(value_change_callback)
							{
							xc->temp_signal_value_buf[0] = val;
							xc->temp_signal_value_buf[1] = 0;
							value_change_callback(user_callback_data_pointer, beg_tim, idx+1, xc->temp_signal_value_buf);
							}
							else
							{
							if(fv)
								{
								int vcdid_len;
								const char *vcd_id = fstVcdIDForFwrite(idx+1, &vcdid_len);
								fputc(val, fv);
								fstFwrite(vcd_id, vcdid_len, 1, fv);
								fputc('\n', fv);
								}
							}
						}
						else
						{
						if(xc->signal_typs[idx] != FST_VT_VCD_REAL)
							{
							if(value_change_callback)
								{
								memcpy(xc->temp_signal_value_buf, mu+sig_offs, xc->signal_lens[idx]);
								xc->temp_signal_value_buf[xc->signal_lens[idx]] = 0;
								value_change_callback(user_callback_data_pointer, beg_tim, idx+1, xc->temp_signal_value_buf);
								}
								else
								{
								if(fv)
									{
									int vcdid_len;
									const char *vcd_id = fstVcdIDForFwrite(idx+1, &vcdid_len);
									fputc((xc->signal_typs[idx] != FST_VT_VCD_PORT) ? 'b' : 'p', fv);
									fstFwrite(mu+sig_offs, xc->signal_lens[idx], 1, fv);
									fputc(' ', fv);
									fstFwrite(vcd_id, vcdid_len, 1, fv);
									fputc('\n', fv);
									}
								}
							}
							else
							{
							double d;
							unsigned char *clone_d;
							unsigned char *srcdata = mu+sig_offs;
		
							if(value_change_callback)
								{
								if(xc->native_doubles_for_cb)
									{
									if(xc->double_endian_match)
										{
										clone_d = srcdata;
										}
										else
										{
										int j;
		
										clone_d = (unsigned char *)&d;
										for(j=0;j<8;j++)
											{
											clone_d[j] = srcdata[7-j];
											}
										}
									value_change_callback(user_callback_data_pointer, beg_tim, idx+1, clone_d);
									}
									else
									{
									clone_d = (unsigned char *)&d;
									if(xc->double_endian_match)
										{
										memcpy(clone_d, srcdata, 8);
										}
										else
										{
										int j;
		
										for(j=0;j<8;j++)
											{
											clone_d[j] = srcdata[7-j];
											}
										}
									sprintf((char *)xc->temp_signal_value_buf, "%.16g", d);
									value_change_callback(user_callback_data_pointer, beg_tim, idx+1, xc->temp_signal_value_buf);
									}
								}
								else
								{
								if(fv)
									{
									clone_d = (unsigned char *)&d;
									if(xc->double_endian_match)
										{
										memcpy(clone_d, srcdata, 8);
										}
										else
										{
										int j;
		
										for(j=0;j<8;j++)
											{
											clone_d[j] = srcdata[7-j];
											}
										}
						
									fprintf(fv, "r%.16g %s\n", d, fstVcdID(idx+1));
									}
								}
							}
						}
					}	

				sig_offs += xc->signal_lens[idx];
				}

			free(mu);
			fseeko(xc->f, -((off_t)frame_clen), SEEK_CUR);
			}
		}

	fseeko(xc->f, (off_t)frame_clen, SEEK_CUR); /* skip past compressed data */

	vc_maxhandle = fstReaderVarint64(xc->f);
	vc_start = ftello(xc->f);	/* points to '!' character */
	packtype = fgetc(xc->f);

#ifdef FST_DEBUG
	printf("\tframe_uclen: %d, frame_clen: %d, frame_maxhandle: %d\n",
		(int)frame_uclen, (int)frame_clen, (int)frame_maxhandle);
	printf("\tvc_maxhandle: %d, packtype: %c\n", (int)vc_maxhandle, packtype);
#endif

	indx_pntr = blkpos + seclen - 24 -tsec_clen -8;
	fseeko(xc->f, indx_pntr, SEEK_SET);
	chain_clen = fstReaderUint64(xc->f);
	indx_pos = indx_pntr - chain_clen;
#ifdef FST_DEBUG
	printf("\tindx_pos: %d (%d bytes)\n", (int)indx_pos, (int)chain_clen);
#endif
	chain_cmem = malloc(chain_clen);
	fseeko(xc->f, indx_pos, SEEK_SET);
	fstFread(chain_cmem, chain_clen, 1, xc->f);
	
	if(vc_maxhandle > vc_maxhandle_largest)
		{
		free(chain_table);
		free(chain_table_lengths);

		vc_maxhandle_largest = vc_maxhandle;
		chain_table = malloc((vc_maxhandle+1) * sizeof(off_t));
		chain_table_lengths = malloc((vc_maxhandle+1) * sizeof(uint32_t));
		}

	pnt = chain_cmem;
	idx = 0;
	pval = 0;
	do
		{
		int skiplen;
		uint64_t val = fstGetVarint32(pnt, &skiplen);
		
		if(val&1)
			{
			pval = chain_table[idx] = pval + (val >> 1);
			if(idx) { chain_table_lengths[pidx] = pval - chain_table[pidx]; }
			pidx = idx++;
			}
			else
			{
			int loopcnt = val >> 1;
			for(i=0;i<loopcnt;i++)
				{
				chain_table[idx++] = 0;
				}
			}
		
		pnt += skiplen;
		} while (pnt != (chain_cmem + chain_clen));
	chain_table[idx] = indx_pos - vc_start;
	chain_table_lengths[pidx] = chain_table[idx] - chain_table[pidx];
#ifdef FST_DEBUG
	printf("\tdecompressed chain idx len: %"PRIu32"\n", idx);
#endif
	/* check compressed VC data */
	if(idx > xc->maxhandle) idx = xc->maxhandle;
	for(i=0;i<idx;i++)
		{
		if(chain_table[i])
			{
	                int process_idx = i/8;
	                int process_bit = i&7;

	                if(xc->process_mask[process_idx]&(1<<process_bit))
				{
				int rc = Z_OK;
				uint32_t val;
				uint32_t skiplen;
				uint32_t tdelta;
	
				fseeko(xc->f, vc_start + chain_table[i], SEEK_SET);
				val = fstReaderVarint32WithSkip(xc->f, &skiplen);
				if(val)
					{
					unsigned char *mu = mem_for_traversal + traversal_mem_offs;
					unsigned char *mc = malloc(chain_table_lengths[i]);
					unsigned long destlen = val;
					unsigned long sourcelen = chain_table_lengths[i];
	
					fstFread(mc, chain_table_lengths[i], 1, xc->f);
					if(packtype == 'F')
						{
						rc = fastlz_decompress(mc, sourcelen, mu, destlen);
						}
						else
						{
						rc = uncompress(mu, &destlen, mc, sourcelen);
						}
					free(mc);
					/* data to process is for(j=0;j<destlen;j++) in mu[j] */
					headptr[i] = traversal_mem_offs;
					length_remaining[i] = val;
					traversal_mem_offs += val;
					}
					else
					{
					int destlen = chain_table_lengths[i] - skiplen;
					unsigned char *mu = mem_for_traversal + traversal_mem_offs;
					fstFread(mu, destlen, 1, xc->f);
					/* data to process is for(j=0;j<destlen;j++) in mu[j] */
					headptr[i] = traversal_mem_offs;
					length_remaining[i] = destlen;
					traversal_mem_offs += destlen;
					}
	
				if(rc != Z_OK)
					{
					printf("\tclen: %d (rc=%d)\n", (int)val, rc);
					exit(255);
					}
	
				if(xc->signal_lens[i] == 1)
					{
					uint32_t vli = fstGetVarint32NoSkip(mem_for_traversal + headptr[i]);
					uint32_t shcnt = 2 << (vli & 1);
					tdelta = vli >> shcnt;
					}
					else
					{
					uint32_t vli = fstGetVarint32NoSkip(mem_for_traversal + headptr[i]);
					tdelta = vli >> 1;
					}
	
				scatterptr[i] = tc_head[tdelta];
				tc_head[tdelta] = i+1;
				}
			}
		}

	for(i=0;i<tsec_nitems;i++)
		{
		uint32_t tdelta;
		int skiplen;
		uint32_t vli;

		if(fv)
			{
			if(time_table[i] != previous_time)
				{
				if(xc->limit_range_valid)
					{
					if(time_table[i] > xc->limit_range_end)
						{
						break;
						}
					}

				fprintf(fv, "#%"PRIu64"\n", time_table[i]);
				if((xc->num_blackouts)&&(cur_blackout != xc->num_blackouts))
					{
					if(time_table[i] == xc->blackout_times[cur_blackout])
						{
						fprintf(fv, "$dump%s $end\n", (xc->blackout_activity[cur_blackout++]) ? "on" : "off");
						}
					}
				previous_time = time_table[i];
				}
			}
	
		while(tc_head[i])
			{
			idx = tc_head[i] - 1;
			vli = fstGetVarint32(mem_for_traversal + headptr[idx], &skiplen);

			if(xc->signal_lens[idx] == 1)
				{
				unsigned char val;
				if(!(vli & 1))
					{
					tdelta = vli >> 2;
					val = ((vli >> 1) & 1) | '0'; 
					}
					else
					{
					tdelta = vli >> 4;
					val = FST_RCV_STR[((vli >> 1) & 7)];
					}

				if(value_change_callback)
					{
					xc->temp_signal_value_buf[0] = val;
					xc->temp_signal_value_buf[1] = 0;
					value_change_callback(user_callback_data_pointer, time_table[i], idx+1, xc->temp_signal_value_buf);
					}
					else
					{
					if(fv) 
						{
						int vcdid_len;
						const char *vcd_id = fstVcdIDForFwrite(idx+1, &vcdid_len);
						fputc(val, fv);
						fstFwrite(vcd_id, vcdid_len, 1, fv);
						fputc('\n', fv);
						}
					}
				headptr[idx] += skiplen;
				length_remaining[idx] -= skiplen;

				tc_head[i] = scatterptr[idx];
				scatterptr[idx] = 0;
	
				if(length_remaining[idx])
					{
					int shamt;
					vli = fstGetVarint32NoSkip(mem_for_traversal + headptr[idx]);
					shamt = 2 << (vli & 1);
					tdelta = vli >> shamt;

					scatterptr[idx] = tc_head[i+tdelta];
					tc_head[i+tdelta] = idx+1;
					}
				}
				else
				{
				uint32_t len = xc->signal_lens[idx];
				unsigned char *vdata;

				vli = fstGetVarint32(mem_for_traversal + headptr[idx], &skiplen);
				tdelta = vli >> 1;
				vdata = mem_for_traversal + headptr[idx] + skiplen;

				if(xc->signal_typs[idx] != FST_VT_VCD_REAL)
					{
					if(!(vli & 1))
						{
						int byte = 0;
						int bit;
						int j;

						for(j=0;j<len;j++)
							{
							unsigned char ch;
							byte = j/8;
							bit = 7 - (j & 7);
							ch = ((vdata[byte] >> bit) & 1) | '0';
							xc->temp_signal_value_buf[j] = ch;
							}
						xc->temp_signal_value_buf[j] = 0;

						if(value_change_callback)
							{
							value_change_callback(user_callback_data_pointer, time_table[i], idx+1, xc->temp_signal_value_buf);
							}
							else
							{
							if(fv)	{ 
								fputc((xc->signal_typs[idx] != FST_VT_VCD_PORT) ? 'b' : 'p', fv);
								fstFwrite(xc->temp_signal_value_buf, len, 1, fv);
								}
							}

						len = byte+1;
						}
						else
						{
						if(value_change_callback)
							{
							memcpy(xc->temp_signal_value_buf, vdata, len);
							xc->temp_signal_value_buf[len] = 0;
							value_change_callback(user_callback_data_pointer, time_table[i], idx+1, xc->temp_signal_value_buf);
							}
							else
							{
							if(fv)
								{
								fputc((xc->signal_typs[idx] != FST_VT_VCD_PORT) ? 'b' : 'p', fv);
								fstFwrite(vdata, len, 1, fv);
								}
							}
						}
					}
					else
					{
					double d;
					unsigned char *clone_d = (unsigned char *)&d;
					unsigned char buf[8];
					unsigned char *srcdata;

					if(!(vli & 1))	/* very rare case, but possible */
						{
						int bit;
						int j;

						for(j=0;j<8;j++)
							{
							unsigned char ch;
							bit = 7 - (j & 7);
							ch = ((vdata[0] >> bit) & 1) | '0';
							buf[j] = ch;
							}
	
						len = 1;
						srcdata = buf;
						}
						else
						{
						srcdata = vdata;
						}

					if(value_change_callback)
						{
						if(xc->native_doubles_for_cb)
							{
							if(xc->double_endian_match)
								{
								clone_d = srcdata;
								}
								else
								{
								int j;
		
								clone_d = (unsigned char *)&d;
								for(j=0;j<8;j++)
									{
									clone_d[j] = srcdata[7-j];
									}
								}
							value_change_callback(user_callback_data_pointer, time_table[i], idx+1, clone_d);
							}
							else
							{
							clone_d = (unsigned char *)&d;
							if(xc->double_endian_match)
								{
								memcpy(clone_d, srcdata, 8);
								}
								else
								{
								int j;
		
								for(j=0;j<8;j++)
									{
									clone_d[j] = srcdata[7-j];
									}
								}
							sprintf((char *)xc->temp_signal_value_buf, "%.16g", d);
							value_change_callback(user_callback_data_pointer, time_table[i], idx+1, xc->temp_signal_value_buf);
							}
						}
						else
						{
						if(fv)
							{
							clone_d = (unsigned char *)&d;
							if(xc->double_endian_match)
								{
								memcpy(clone_d, srcdata, 8);
								}
								else
								{
								int j;
		
								for(j=0;j<8;j++)
									{
									clone_d[j] = srcdata[7-j];
									}
								}
						
							fprintf(fv, "r%.16g", d);
							}
						}
					}

				if(fv) 
					{
					int vcdid_len;
					const char *vcd_id = fstVcdIDForFwrite(idx+1, &vcdid_len);
					fputc(' ', fv);
					fstFwrite(vcd_id, vcdid_len, 1, fv);
					fputc('\n', fv);
					}

				skiplen += len;
				headptr[idx] += skiplen;
				length_remaining[idx] -= skiplen;

				tc_head[i] = scatterptr[idx];
				scatterptr[idx] = 0;
	
				if(length_remaining[idx])
					{
					vli = fstGetVarint32NoSkip(mem_for_traversal + headptr[idx]);
					tdelta = vli >> 1;

					scatterptr[idx] = tc_head[i+tdelta];
					tc_head[i+tdelta] = idx+1;
					}
				}
			}
		}

	free(tc_head);
	free(chain_cmem);
	free(mem_for_traversal);

	secnum++;
	if(secnum == xc->vc_section_count) break; /* in case file is growing, keep with original block count */
	blkpos += seclen;
	}

free(length_remaining);
free(headptr);
free(scatterptr);

if(chain_table)
	{
	free(chain_table);
	free(chain_table_lengths);
	}

free(time_table);

return(1);
}


/* rvat functions */

static char *fstExtractRvatDataFromFrame(struct fstReaderContext *xc, fstHandle facidx, char *buf)
{
if(facidx >= xc->rvat_frame_maxhandle)
	{
	return(NULL);
	}

if(xc->signal_lens[facidx] == 1)
	{
	buf[0] = (char)xc->rvat_frame_data[xc->rvat_sig_offs[facidx]];
	buf[1] = 0;
	}
	else
	{
	if(xc->signal_typs[facidx] != FST_VT_VCD_REAL)
		{
		memcpy(buf, xc->rvat_frame_data + xc->rvat_sig_offs[facidx], xc->signal_lens[facidx]);
		buf[xc->signal_lens[facidx]] = 0;
		}
		else
		{
		double d;
		unsigned char *clone_d = (unsigned char *)&d;
		unsigned char *srcdata = xc->rvat_frame_data + xc->rvat_sig_offs[facidx];

		if(xc->double_endian_match)
			{
			memcpy(clone_d, srcdata, 8);
			}
			else
			{
			int j;

			for(j=0;j<8;j++)
				{
				clone_d[j] = srcdata[7-j];
				}
			}
						
		sprintf((char *)buf, "%.16g", d);
		}
	}

return(buf);
}


char *fstReaderGetValueFromHandleAtTime(void *ctx, uint64_t tim, fstHandle facidx, char *buf)
{
struct fstReaderContext *xc = (struct fstReaderContext *)ctx;
off_t blkpos = 0, prev_blkpos;
uint64_t beg_tim, end_tim, beg_tim2, end_tim2;
int sectype;
int secnum = 0;
uint64_t seclen;
uint64_t tsec_uclen = 0, tsec_clen = 0;
uint64_t tsec_nitems;
uint64_t frame_uclen, frame_clen;
uint64_t mem_required_for_traversal;
off_t indx_pntr, indx_pos;
long chain_clen;
unsigned char *chain_cmem;
unsigned char *pnt;
fstHandle idx, pidx=0, i;
uint64_t pval;

if((!xc) || (!facidx) || (facidx > xc->maxhandle) || (!buf))
	{
	return(NULL);
	}

if(!xc->rvat_sig_offs)
	{
	uint32_t cur_offs = 0;

	xc->rvat_sig_offs = calloc(xc->maxhandle, sizeof(uint32_t));
	for(i=0;i<xc->maxhandle;i++)
		{
		xc->rvat_sig_offs[i] = cur_offs;
		cur_offs += xc->signal_lens[i];
		}
	}

if(xc->rvat_data_valid)
	{
	if((xc->rvat_beg_tim <= tim) && (tim <= xc->rvat_end_tim))
		{
		goto process_value;
		}

	fstReaderDeallocateRvatData(xc);
	}

xc->rvat_chain_pos_valid = 0;

for(;;)
	{
	fseeko(xc->f, (prev_blkpos = blkpos), SEEK_SET);

	sectype = fgetc(xc->f);
	seclen = fstReaderUint64(xc->f);

	if((sectype == EOF) || (sectype == FST_BL_SKIP) || (!seclen))
		{
		return(NULL); /* if this loop exits on break, it's successful */
		}

	blkpos++;
	if(sectype != FST_BL_VCDATA)
		{
		blkpos += seclen;
		continue;
		}

	beg_tim = fstReaderUint64(xc->f);
	end_tim = fstReaderUint64(xc->f);

	if((beg_tim <= tim) && (tim <= end_tim))
		{
		if((tim == end_tim) && (tim != xc->end_time))
			{
			off_t cached_pos = ftello(xc->f);
			fseeko(xc->f, blkpos, SEEK_SET);

			sectype = fgetc(xc->f);
			seclen = fstReaderUint64(xc->f);

			beg_tim2 = fstReaderUint64(xc->f);
			end_tim2 = fstReaderUint64(xc->f);

			if((sectype != FST_BL_VCDATA) || (!seclen) || (beg_tim2 != tim))
				{
				blkpos = prev_blkpos;
				break;
				}
			beg_tim = beg_tim2;
			end_tim = end_tim2;
			fseeko(xc->f, cached_pos, SEEK_SET);
			}
		break;
		}

	blkpos += seclen;
	secnum++;
	}

xc->rvat_beg_tim = beg_tim;
xc->rvat_end_tim = end_tim;

mem_required_for_traversal = fstReaderUint64(xc->f);
#ifdef FST_DEBUG
printf("rvat sec: %d seclen: %d begtim: %d endtim: %d\n",
	secnum, (int)seclen, (int)beg_tim, (int)end_tim);
printf("\tmem_required_for_traversal: %d\n", (int)mem_required_for_traversal);
#endif

/* process time block */
{
unsigned char *ucdata;
unsigned char *cdata;
unsigned long destlen = tsec_uclen;
unsigned long sourcelen = tsec_clen;
int rc;
unsigned char *tpnt;
uint64_t tpval;
int ti;

fseeko(xc->f, blkpos + seclen - 24, SEEK_SET);
tsec_uclen = fstReaderUint64(xc->f);
tsec_clen = fstReaderUint64(xc->f);
tsec_nitems = fstReaderUint64(xc->f);
#ifdef FST_DEBUG
printf("\ttime section unc: %d, com: %d (%d items)\n", 
	(int)tsec_uclen, (int)tsec_clen, (int)tsec_nitems);
#endif		
ucdata = malloc(tsec_uclen);
destlen = tsec_uclen;
sourcelen = tsec_clen;
	
fseeko(xc->f, -24 - ((off_t)tsec_clen), SEEK_CUR);
if(tsec_uclen != tsec_clen)
	{
	cdata = malloc(tsec_clen);
	fstFread(cdata, tsec_clen, 1, xc->f);
	
	rc = uncompress(ucdata, &destlen, cdata, sourcelen);
	                
	if(rc != Z_OK)
		{
		printf("tsec uncompress rc = %d\n", rc);
		exit(255);
		}
	
	free(cdata);
	}
	else
	{
	fstFread(ucdata, tsec_uclen, 1, xc->f);
	}

xc->rvat_time_table = calloc(tsec_nitems, sizeof(uint64_t));
tpnt = ucdata;
tpval = 0;
for(ti=0;ti<tsec_nitems;ti++)
	{
	int skiplen;
	uint64_t val = fstGetVarint64(tpnt, &skiplen);
	tpval = xc->rvat_time_table[ti] = tpval + val;
	tpnt += skiplen;	
	}

free(ucdata);
}

fseeko(xc->f, blkpos+32, SEEK_SET);

frame_uclen = fstReaderVarint64(xc->f);
frame_clen = fstReaderVarint64(xc->f);
xc->rvat_frame_maxhandle = fstReaderVarint64(xc->f);
xc->rvat_frame_data = malloc(frame_uclen);

if(frame_uclen == frame_clen)
	{
	fstFread(xc->rvat_frame_data, frame_uclen, 1, xc->f);
	}
	else
	{
	unsigned char *mc = malloc(frame_clen);
	int rc;

	unsigned long destlen = frame_uclen;
	unsigned long sourcelen = frame_clen;

	fstFread(mc, sourcelen, 1, xc->f);
	rc = uncompress(xc->rvat_frame_data, &destlen, mc, sourcelen);
	if(rc != Z_OK)
		{
		printf("decompress rc: %d\n", rc);
		exit(255);
		}
	free(mc);
	}

xc->rvat_vc_maxhandle = fstReaderVarint64(xc->f);
xc->rvat_vc_start = ftello(xc->f);	/* points to '!' character */

#ifdef FST_DEBUG
printf("\tframe_uclen: %d, frame_clen: %d, frame_maxhandle: %d\n",
	(int)frame_uclen, (int)frame_clen, (int)xc->rvat_frame_maxhandle);
printf("\tvc_maxhandle: %d\n", (int)xc->rvat_vc_maxhandle);
#endif

indx_pntr = blkpos + seclen - 24 -tsec_clen -8;
fseeko(xc->f, indx_pntr, SEEK_SET);
chain_clen = fstReaderUint64(xc->f);
indx_pos = indx_pntr - chain_clen;
#ifdef FST_DEBUG
printf("\tindx_pos: %d (%d bytes)\n", (int)indx_pos, (int)chain_clen);
#endif
chain_cmem = malloc(chain_clen);
fseeko(xc->f, indx_pos, SEEK_SET);
fstFread(chain_cmem, chain_clen, 1, xc->f);
	
xc->rvat_chain_table = malloc((xc->rvat_vc_maxhandle+1) * sizeof(off_t));
xc->rvat_chain_table_lengths = malloc((xc->rvat_vc_maxhandle+1) * sizeof(uint32_t));

pnt = chain_cmem;
idx = 0;
pval = 0;
do
	{
	int skiplen;
	uint64_t val = fstGetVarint32(pnt, &skiplen);
		
	if(val&1)
		{
		pval = xc->rvat_chain_table[idx] = pval + (val >> 1);
		if(idx) { xc->rvat_chain_table_lengths[pidx] = pval - xc->rvat_chain_table[pidx]; }
		pidx = idx++;
		}
		else
		{
		int loopcnt = val >> 1;
		for(i=0;i<loopcnt;i++)
			{
			xc->rvat_chain_table[idx++] = 0;
			}
		}
		
	pnt += skiplen;
	} while (pnt != (chain_cmem + chain_clen));

free(chain_cmem); 
xc->rvat_chain_table[idx] = indx_pos - xc->rvat_vc_start;
xc->rvat_chain_table_lengths[pidx] = xc->rvat_chain_table[idx] - xc->rvat_chain_table[pidx];

#ifdef FST_DEBUG
printf("\tdecompressed chain idx len: %"PRIu32"\n", idx);
#endif

xc->rvat_data_valid = 1;

/* all data at this point is loaded or resident in fst cache, process and return appropriate value */ 
process_value:
if(facidx > xc->rvat_vc_maxhandle)
	{
	return(NULL);
	}

facidx--; /* scale down for array which starts at zero */


if(((tim == xc->rvat_beg_tim)&&(!xc->rvat_chain_table[facidx])) || (!xc->rvat_chain_table[facidx]))
	{
	return(fstExtractRvatDataFromFrame(xc, facidx, buf));
	}

if(facidx != xc->rvat_chain_facidx)
	{
	if(xc->rvat_chain_mem)
		{
		free(xc->rvat_chain_mem);
		xc->rvat_chain_mem = NULL;

		xc->rvat_chain_pos_valid = 0;
		}
	}

if(!xc->rvat_chain_mem)
	{
	uint32_t skiplen;
	fseeko(xc->f, xc->rvat_vc_start + xc->rvat_chain_table[facidx], SEEK_SET);
	xc->rvat_chain_len = fstReaderVarint32WithSkip(xc->f, &skiplen);
	if(xc->rvat_chain_len)
		{
		unsigned char *mu = malloc(xc->rvat_chain_len);
		unsigned char *mc = malloc(xc->rvat_chain_table_lengths[facidx]);
		unsigned long destlen = xc->rvat_chain_len;
		unsigned long sourcelen = xc->rvat_chain_table_lengths[facidx];
		int rc;
		
		fstFread(mc, xc->rvat_chain_table_lengths[facidx], 1, xc->f);
		rc = uncompress(mu, &destlen, mc, sourcelen);
		free(mc);
	
		if(rc != Z_OK)
			{
			printf("\tclen: %d (rc=%d)\n", (int)xc->rvat_chain_len, rc);
			exit(255);
			}
	
		/* data to process is for(j=0;j<destlen;j++) in mu[j] */
		xc->rvat_chain_mem = mu;
		}
		else
		{
		int destlen = xc->rvat_chain_table_lengths[facidx] - skiplen;
		unsigned char *mu = malloc(xc->rvat_chain_len = destlen);
		fstFread(mu, destlen, 1, xc->f);
		/* data to process is for(j=0;j<destlen;j++) in mu[j] */
		xc->rvat_chain_mem = mu;
		}

	xc->rvat_chain_facidx = facidx;
	}	

/* process value chain here */

{
uint32_t tidx = 0, ptidx = 0;
uint32_t tdelta;
int skiplen;
int iprev = xc->rvat_chain_len;
uint32_t pvli = 0;
int pskip = 0;

if((xc->rvat_chain_pos_valid)&&(tim >= xc->rvat_chain_pos_time))
	{
	i = xc->rvat_chain_pos_idx;
	tidx = xc->rvat_chain_pos_tidx;
	}
	else
	{
	i = 0;
	tidx = 0;
	xc->rvat_chain_pos_time = xc->rvat_beg_tim;
	}

if(xc->signal_lens[facidx] == 1)
	{
	while(i<xc->rvat_chain_len)
		{
	        uint32_t vli = fstGetVarint32(xc->rvat_chain_mem + i, &skiplen);
	        uint32_t shcnt = 2 << (vli & 1);
	        tdelta = vli >> shcnt;

		if(xc->rvat_time_table[tidx + tdelta] <= tim)
			{
			iprev = i;
			pvli = vli;
			ptidx = tidx;
			pskip = skiplen;

			tidx += tdelta;
			i+=skiplen;
			}
			else
			{
			break;
			}
		}
	if(iprev != xc->rvat_chain_len)
		{
		xc->rvat_chain_pos_tidx = ptidx;
		xc->rvat_chain_pos_idx = iprev;
		xc->rvat_chain_pos_time = tim;
		xc->rvat_chain_pos_valid = 1;

		if(!(pvli & 1))
			{
			buf[0] = ((pvli >> 1) & 1) | '0'; 
			}
			else
			{
			buf[0] = FST_RCV_STR[((pvli >> 1) & 7)];
			}
		buf[1] = 0;
		return(buf);
		}
		else
		{
		return(fstExtractRvatDataFromFrame(xc, facidx, buf));
		}
        }
        else
        {
	while(i<xc->rvat_chain_len)
		{
	        uint32_t vli = fstGetVarint32(xc->rvat_chain_mem + i, &skiplen);
	        tdelta = vli >> 1;

		if(xc->rvat_time_table[tidx + tdelta] <= tim)
			{
			iprev = i;
			pvli = vli;
			ptidx = tidx;
			pskip = skiplen;

			tidx += tdelta;
			i+=skiplen;

			if(!(pvli & 1))
				{
				i+=((xc->signal_lens[facidx]+7)/8);
				}
				else
				{
				i+=xc->signal_lens[facidx];
				}
			}
			else
			{
			break;
			}
		}

	if(iprev != xc->rvat_chain_len)
		{
		unsigned char *vdata = xc->rvat_chain_mem + iprev + pskip;

		xc->rvat_chain_pos_tidx = ptidx;
		xc->rvat_chain_pos_idx = iprev;
		xc->rvat_chain_pos_time = tim;
		xc->rvat_chain_pos_valid = 1;

		if(xc->signal_typs[facidx] != FST_VT_VCD_REAL)
			{
			if(!(pvli & 1))
				{
				int byte = 0;
				int bit;
				int j;

				for(j=0;j<xc->signal_lens[facidx];j++)
					{
					unsigned char ch;
					byte = j/8;
					bit = 7 - (j & 7);
					ch = ((vdata[byte] >> bit) & 1) | '0';
					buf[j] = ch;
					}
				buf[j] = 0;

				return(buf);
				}
				else
				{
				memcpy(buf, vdata, xc->signal_lens[facidx]);
				buf[xc->signal_lens[facidx]] = 0;
				return(buf);
				}
			}
			else
			{
			double d;
			unsigned char *clone_d = (unsigned char *)&d;
			unsigned char bufd[8];
			unsigned char *srcdata;

			if(!(pvli & 1))	/* very rare case, but possible */
				{
				int bit;
				int j;

				for(j=0;j<8;j++)
					{
					unsigned char ch;
					bit = 7 - (j & 7);
					ch = ((vdata[0] >> bit) & 1) | '0';
					bufd[j] = ch;
					}
	
				srcdata = bufd;
				}
				else
				{
				srcdata = vdata;
				}

			if(xc->double_endian_match)
				{
				memcpy(clone_d, srcdata, 8);
				}
				else
				{
				int j;

				for(j=0;j<8;j++)
					{
					clone_d[j] = srcdata[7-j];
					}
				}

			sprintf(buf, "r%.16g", d);
			return(buf);
			}
		}
		else
		{
		return(fstExtractRvatDataFromFrame(xc, facidx, buf));
		}
        }               
}

/* return(NULL); */
}