Minor cleanup of hash code, to make reduce the likelyhood of bugs in it. Made debug build not use the custom string allocator to allow using valgrind to detect access errors.

[SVN r35154]

historic/jam/src/build.jam

@@ -473,6 +473,10 @@ if $(with-python)
     --defs += HAVE_PYTHON ;
 }
 
+if $(debug)
+{
+    --defs += BJAM_NEWSTR_NO_ALLOCATE ;
+}
 
 
 # The basic symbolic targets...

historic/jam/src/hash.c

@@ -96,6 +96,47 @@ static void hash_mem_free(size_t datalen, void * data);
 static void hash_mem_finalizer(char * key, struct hash * hp);
 #endif
 
+static unsigned int hash_keyval( const unsigned char * key )
+{
+    unsigned int keyval = *key;
+    while( *key )
+        keyval = keyval * 2147059363 + *key++;
+    return keyval;
+}
+
+#define hash_bucket(hp,keyval) ((hp)->tab.base + ( (keyval) % (hp)->tab.nel ))
+
+/*  Find the hash item for the given data. Returns pointer to the
+    item and if given a pointer to the item before the found item.
+    If it's the first item in a bucket, there is no previous item,
+    and zero is returned for the previous item instead.
+*/
+static ITEM * hash_search(
+    struct hash *hp,
+    unsigned int keyval,
+    const unsigned char * keydata,
+    ITEM ** previous )
+{
+    ITEM * i = *hash_bucket(hp,keyval);
+    ITEM * p = 0;
+
+    for ( ; i; i = i->hdr.next )
+    {
+        if( keyval == i->hdr.keyval &&
+            !strcmp( i->data.key, keydata ) )
+        {
+            if (previous)
+            {
+                *previous = p;
+            }
+            return i;
+        }
+        p = i;
+    }
+    
+    return 0;
+}
+
 /*
  * hash_free() - remove the given item from the table if it's there.
  * Returns 1 if found, 0 otherwise.
@@ -104,38 +145,28 @@ static void hash_mem_finalizer(char * key, struct hash * hp);
  */
 int
 hash_free(
-	register struct hash *hp,
-	HASHDATA *data)
+    register struct hash *hp,
+    HASHDATA *data)
 {
-	ITEM **prev;
-	register ITEM **i;
-	unsigned char *b = (unsigned char*)data->key;
-	unsigned int keyval;
-
-	keyval = *b;
-
-	while( *b )
-		keyval = keyval * 2147059363 + *b++;
-
-    prev = hp->tab.base + ( keyval % hp->tab.nel );
-	while(*prev )
+    ITEM * i = 0;
+    ITEM * prev = 0;
+    unsigned int keyval = hash_keyval((unsigned char*)data->key);
+    
+    i = hash_search( hp, keyval, (unsigned char*)data->key, &prev );
+    if (i)
     {
-        register ITEM* i = *prev;
-	    if( keyval == i->hdr.keyval && 
-            !strcmp( i->data.key, data->key ) )
-        {
-            /* unlink the record from the hash chain */
-            *prev = i->hdr.next;
-            /* link it into the freelist */
-            i->hdr.next = hp->items.free;
-            hp->items.free = i;
-            /* mark it free so we skip it during enumeration */
-            i->data.key = 0;
-            /* we have another item */
-            hp->items.more++;
-            return 1;
-        }
-        prev = &i->hdr.next;
+        /* mark it free so we skip it during enumeration */
+        i->data.key = 0;
+        /* unlink the record from the hash chain */
+        if (prev) prev->hdr.next = i->hdr.next;
+        else *hash_bucket(hp,keyval) = i->hdr.next;
+        /* link it into the freelist */
+        i->hdr.next = hp->items.free;
+        hp->items.free = i;
+        /* we have another item */
+        hp->items.more++;
+        
+        return 1;
     }
     return 0;
 }
@@ -150,10 +181,9 @@ hashitem(
 	HASHDATA **data,
 	int enter )
 {
-	ITEM **base;
 	register ITEM *i;
 	unsigned char *b = (unsigned char*)(*data)->key;
-	unsigned int keyval;
+	unsigned int keyval = hash_keyval(b);
     
     #ifdef HASH_DEBUG_PROFILE
     profile_frame prof[1];
@@ -172,28 +202,21 @@ hashitem(
         #endif
 	    return 0;
     }
-
-	keyval = *b;
-
-	while( *b )
-		keyval = keyval * 2147059363 + *b++;
-
-	base = hp->tab.base + ( keyval % hp->tab.nel );
-
-	for( i = *base; i; i = i->hdr.next )
-	    if( keyval == i->hdr.keyval && 
-		!strcmp( i->data.key, (*data)->key ) )
-	{
-		*data = &i->data;
+    
+    i = hash_search( hp, keyval, (unsigned char*)(*data)->key, 0 );
+    if (i)
+    {
+        *data = &i->data;
         #ifdef HASH_DEBUG_PROFILE
-        if ( DEBUG_PROFILE )
-            profile_exit( prof );
+        if ( DEBUG_PROFILE ) profile_exit( prof );
         #endif
-		return !0;
-	}
+        return !0;
+    }
 
-	if( enter ) 
-	{
+    if( enter ) 
+    {
+        ITEM **base = hash_bucket(hp,keyval);
+        
         /* try to grab one from the free list */
         if ( hp->items.free )
         {
@@ -206,19 +229,19 @@ hashitem(
             i = (ITEM *)hp->items.next;
             hp->items.next += hp->items.size;
         }
-		hp->items.more--;
-		memcpy( (char *)&i->data, (char *)*data, hp->items.datalen );
-		i->hdr.keyval = keyval;
-		i->hdr.next = *base;
-		*base = i;
-		*data = &i->data;
+        hp->items.more--;
+        memcpy( (char *)&i->data, (char *)*data, hp->items.datalen );
+        i->hdr.keyval = keyval;
+        i->hdr.next = *base;
+        *base = i;
+        *data = &i->data;
         #ifdef OPT_BOEHM_GC
         if (sizeof(HASHDATA) == hp->items.datalen)
         {
             GC_REGISTER_FINALIZER(i->data.key,&hash_mem_finalizer,hp,0,0);
         }
         #endif
-	}
+    }
 
     #ifdef HASH_DEBUG_PROFILE
     if ( DEBUG_PROFILE )

historic/jam/src/mem.h

@@ -26,7 +26,9 @@ http://www.boost.org/LICENSE_1_0.txt)
     #define bjam_realloc_raw_x(p,s) realloc(p,s)
     #define bjam_free_raw_x(p) free(p)
     
+    #ifndef BJAM_NEWSTR_NO_ALLOCATE
     #define BJAM_NEWSTR_NO_ALLOCATE
+    #endif
 
 #elif defined(OPT_DUMA)
 
@@ -53,7 +55,9 @@ http://www.boost.org/LICENSE_1_0.txt)
     #define bjam_realloc_x(p,s) realloc(p,s)
     #define bjam_free_x(p) free(p)
     
+    #ifndef BJAM_NEWSTR_NO_ALLOCATE
     #define BJAM_NEWSTR_NO_ALLOCATE
+    #endif
 
 #else