From 0dad9e3adb58838d1fa4d3b8a4e0d1cbecef4f8a Mon Sep 17 00:00:00 2001
From: Cary R <cygcary@yahoo.com>
Date: Tue, 21 Sep 2010 17:41:06 -0700
Subject: [PATCH] Update fstapi.c to the latest from GTKWave-3.3.12

---
 vpi/fstapi.c | 66 +++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 57 insertions(+), 9 deletions(-)

diff --git a/vpi/fstapi.c b/vpi/fstapi.c
index bbb32e737..59211b772 100644
--- a/vpi/fstapi.c
+++ b/vpi/fstapi.c
@@ -42,6 +42,10 @@
 #define FST_MACOSX 
 #endif
 
+#if defined(__CYGWIN__) && defined(__GNUC__)
+#define FST_USE_FWRITE_COMBINING
+#endif
+
 
 /***********************/
 /***                 ***/
@@ -375,7 +379,7 @@ return(rc);
 static int fstWriterVarint(FILE *handle, uint64_t v)
 {
 uint64_t nxt;
-unsigned char buf[32];
+unsigned char buf[10]; /* ceil(64/7) = 10 */
 unsigned char *pnt = buf;
 int len;
 
@@ -391,6 +395,50 @@ 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
 
 /***********************/
 /***                 ***/
@@ -1555,7 +1603,6 @@ size_t len;
 
 if((xc) && (handle <= xc->maxhandle))
 	{
-	uint32_t prev_chg;
 	uint32_t fpos;
 	uint32_t *vm4ip;
 
@@ -1573,14 +1620,15 @@ if((xc) && (handle <= xc->maxhandle))
 
 	if(!xc->is_initial_time)
 		{
-		prev_chg = vm4ip[2];
 		fpos = xc->vchn_siz;
-
-		fstFwrite(&prev_chg, 1, sizeof(uint32_t), xc->vchn_handle);
-		xc->vchn_siz += 4;
-		xc->vchn_siz += fstWriterVarint(xc->vchn_handle, xc->tchn_idx - vm4ip[3]);
-		fstFwrite(buf, len, 1, xc->vchn_handle);
-		xc->vchn_siz += len;
+		/* 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;
 		}