From c6bc7b937e8baeee604dcae77f8a1a8c90631cd8 Mon Sep 17 00:00:00 2001
From: Holger Vogt <holger.vogt@uni-due.de>
Date: Sat, 4 Nov 2017 18:33:29 +0100
Subject: [PATCH] Add function nghash_delete_special() that returns the pointer
 if not successful

---
 src/include/ngspice/hash.h |  5 +++
 src/misc/hash.c            | 88 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 93 insertions(+)

diff --git a/src/include/ngspice/hash.h b/src/include/ngspice/hash.h
index f50ba77a9..26081b55c 100644
--- a/src/include/ngspice/hash.h
+++ b/src/include/ngspice/hash.h
@@ -348,6 +348,11 @@ Function:
     nghash_init_pointer function first.
 */
 
+extern void * nghash_delete_special(NGHASHPTR hashtable, void * user_key);
+/*  if hashtable has been initialized with nghash_init_pointer( int numentries ),
+    use this function.
+    Returns NULL, if successful, otherwise returns user_key */
+
 /* -----------------------------------------------------------------
  * Convenience functions.
 ----------------------------------------------------------------- */
diff --git a/src/misc/hash.c b/src/misc/hash.c
index dd839a84b..1a60acea0 100644
--- a/src/misc/hash.c
+++ b/src/misc/hash.c
@@ -405,6 +405,94 @@ void * nghash_delete(NGHASHPTR hashtable, void * user_key)
 
 } /* end nghash_delete() */
 
+
+/* different return value:
+    NGHASH_FUNC_PTR always returns NULL.
+    This function returns  thepointer, if _not_ successful, otherwise NULL */
+void*
+nghash_delete_special(NGHASHPTR hashtable, void * user_key)
+{
+    int  ret_code;
+    unsigned int hsum;
+    void * user_data_p;
+    NGTABLEPTR curPtr, *prevPtr;
+    NGTABLEPTR *table;
+    
+    /* initialization */
+    table = hashtable->hash_table;
+    DS(hashtable->access++;);
+
+    /* -----------------------------------------------------------------
+     * Process the hash function.
+      ----------------------------------------------------------------- */
+     switch ((intptr_t)hashtable->hash_func) {
+        case NGHASH_FUNC_STR:
+            NGHASH_STR_TO_HASH(user_key, hsum, hashtable->size);
+            break;
+            case NGHASH_FUNC_PTR:
+                NGHASH_PTR_TO_HASH(user_key, hsum, hashtable->size);
+                break;
+                case NGHASH_FUNC_NUM:
+                    NGHASH_NUM_TO_HASH(user_key, hsum, hashtable->size);
+                    break;
+                    default:
+                        hsum = hashtable->hash_func(hashtable, user_key);
+                        
+    }
+
+        /* insert into table only if distinct number */
+        curPtr = table[hsum];
+    if (curPtr) {
+        /* list started at this hash */
+            prevPtr = table + hsum;
+        for (; curPtr; prevPtr = &(curPtr->next), curPtr = curPtr->next) {
+            if (hashtable->compare_func == NGHASH_DEF_CMP(NGHASH_FUNC_STR)) {
+                ret_code = strcmp((char *)curPtr->key, (char *)user_key);
+            }
+            else if (hashtable->compare_func == NGHASH_DEF_CMP(NGHASH_FUNC_PTR) ||
+                hashtable->compare_func == NGHASH_DEF_CMP(NGHASH_FUNC_NUM)) {
+                ret_code = NGHASH_PTR_COMPARE_FUNC(curPtr->key, user_key);
+                
+            }
+            else {
+                ret_code = hashtable->compare_func(curPtr->key, user_key);
+                
+            }
+            if (ret_code == STRINGEQ) {
+                if (curPtr->thread_prev) { /* no sentinel */
+                    curPtr->thread_prev->thread_next = curPtr->thread_next;
+
+                }
+                else {
+                    hashtable->thread = curPtr->thread_next;
+                    
+                }
+                if (curPtr->thread_next) { /* no sentinel */
+                    curPtr->thread_next->thread_prev = curPtr->thread_prev;
+                }
+                else {
+                    hashtable->last_entry = curPtr->thread_prev;
+                }
+                *prevPtr = curPtr->next;
+                if (hashtable->hash_func == NGHASH_DEF_HASH(NGHASH_FUNC_STR)) {
+                /* we allocated this ourselves we can delete it */
+                NGFREE(curPtr->key);
+
+                }
+                user_data_p = curPtr->data;
+                NGFREE(curPtr);
+                hashtable->num_entries--;
+                return(user_data_p);
+
+            }
+
+        }
+
+    }
+    return(user_key); /* didn't find anything to delete */
+    }
+
+
 void * nghash_insert(NGHASHPTR hashtable, void * user_key, void * data)
 {
     int  ret_code ;