Updated buffer-allocator with free-block-list to speed up searches
diff --git a/library/memory_buffer_alloc.c b/library/memory_buffer_alloc.c
index 1a71197..c443920 100644
--- a/library/memory_buffer_alloc.c
+++ b/library/memory_buffer_alloc.c
@@ -50,6 +50,8 @@
size_t alloc;
memory_header *prev;
memory_header *next;
+ memory_header *prev_free;
+ memory_header *next_free;
#if defined(POLARSSL_MEMORY_BACKTRACE)
char **trace;
size_t trace_count;
@@ -62,7 +64,7 @@
unsigned char *buf;
size_t len;
memory_header *first;
- size_t largest_free;
+ memory_header *first_free;
size_t current_alloc_size;
int verify;
#if defined(POLARSSL_MEMORY_DEBUG)
@@ -87,11 +89,14 @@
fprintf( stderr, "HDR: PTR(%10u), PREV(%10u), NEXT(%10u), ALLOC(%u), SIZE(%10u)\n",
(size_t) hdr, (size_t) hdr->prev, (size_t) hdr->next,
hdr->alloc, hdr->size );
+ fprintf( stderr, " FPREV(%10u), FNEXT(%10u)\n",
+ (size_t) hdr->prev_free, (size_t) hdr->next_free );
#if defined(POLARSSL_MEMORY_BACKTRACE)
fprintf( stderr, "TRACE: \n" );
for( i = 0; i < hdr->trace_count; i++ )
fprintf( stderr, "%s\n", hdr->trace[i] );
+ fprintf( stderr, "\n" );
#endif
}
@@ -99,12 +104,21 @@
{
memory_header *cur = heap.first;
+ fprintf( stderr, "\nBlock list\n" );
while( cur != NULL )
{
debug_header( cur );
- fprintf( stderr, "\n" );
cur = cur->next;
}
+
+ fprintf( stderr, "Free list\n" );
+ cur = heap.first_free;
+
+ while( cur != NULL )
+ {
+ debug_header( cur );
+ cur = cur->next_free;
+ }
}
#endif /* POLARSSL_MEMORY_DEBUG */
@@ -134,6 +148,22 @@
return( 1 );
}
+ if( hdr->prev != NULL && hdr->prev == hdr->next )
+ {
+#if defined(POLARSSL_MEMORY_DEBUG)
+ fprintf( stderr, "FATAL: prev == next\n" );
+#endif
+ return( 1 );
+ }
+
+ if( hdr->prev_free != NULL && hdr->prev_free == hdr->next_free )
+ {
+#if defined(POLARSSL_MEMORY_DEBUG)
+ fprintf( stderr, "FATAL: prev_free == next_free\n" );
+#endif
+ return( 1 );
+ }
+
return( 0 );
}
@@ -184,7 +214,7 @@
static void *buffer_alloc_malloc( size_t len )
{
- memory_header *new, *cur = heap.first;
+ memory_header *new, *cur = heap.first_free;
unsigned char *p;
#if defined(POLARSSL_MEMORY_BACKTRACE)
void *trace_buffer[MAX_BT];
@@ -204,15 +234,23 @@
//
while( cur != NULL )
{
- if( cur->alloc == 0 && cur->size >= len )
+ if( cur->size >= len )
break;
- cur = cur->next;
+ cur = cur->next_free;
}
if( cur == NULL )
return( NULL );
+ if( cur->alloc != 0 )
+ {
+#if defined(POLARSSL_MEMORY_DEBUG)
+ fprintf( stderr, "FATAL: block in free_list but allocated data\n" );
+#endif
+ exit( 1 );
+ }
+
#if defined(POLARSSL_MEMORY_DEBUG)
heap.malloc_count++;
#endif
@@ -223,6 +261,19 @@
{
cur->alloc = 1;
+ // Remove from free_list
+ //
+ if( cur->prev_free != NULL )
+ cur->prev_free->next_free = cur->next_free;
+ else
+ heap.first_free = cur->next_free;
+
+ if( cur->next_free != NULL )
+ cur->next_free->prev_free = cur->prev_free;
+
+ cur->prev_free = NULL;
+ cur->next_free = NULL;
+
#if defined(POLARSSL_MEMORY_DEBUG)
heap.total_used += cur->size;
if( heap.total_used > heap.maximum_used)
@@ -257,9 +308,23 @@
if( new->next != NULL )
new->next->prev = new;
+ // Replace cur with new in free_list
+ //
+ new->prev_free = cur->prev_free;
+ new->next_free = cur->next_free;
+ if( new->prev_free != NULL )
+ new->prev_free->next_free = new;
+ else
+ heap.first_free = new;
+
+ if( new->next_free != NULL )
+ new->next_free->prev_free = new;
+
cur->alloc = 1;
cur->size = len;
cur->next = new;
+ cur->prev_free = NULL;
+ cur->next_free = NULL;
#if defined(POLARSSL_MEMORY_DEBUG)
heap.header_count++;
@@ -281,7 +346,7 @@
static void buffer_alloc_free( void *ptr )
{
- memory_header *hdr, *old;
+ memory_header *hdr, *old = NULL;
unsigned char *p = (unsigned char *) ptr;
@@ -349,6 +414,28 @@
old = hdr->next;
hdr->next = hdr->next->next;
+ if( hdr->prev_free != NULL || hdr->next_free != NULL )
+ {
+ if( hdr->prev_free != NULL )
+ hdr->prev_free->next_free = hdr->next_free;
+ else
+ heap.first_free = hdr->next_free;
+
+ if( hdr->next_free != NULL )
+ hdr->next_free->prev_free = hdr->prev_free;
+ }
+
+ hdr->prev_free = old->prev_free;
+ hdr->next_free = old->next_free;
+
+ if( hdr->prev_free != NULL )
+ hdr->prev_free->next_free = hdr;
+ else
+ heap.first_free = hdr;
+
+ if( hdr->next_free != NULL )
+ hdr->next_free->prev_free = hdr;
+
if( hdr->next != NULL )
hdr->next->prev = hdr;
@@ -358,6 +445,16 @@
memset( old, 0, sizeof(memory_header) );
}
+ // Prepend to free_list if we have not merged
+ // (Does not have to stay in same order as prev / next list)
+ //
+ if( old == NULL )
+ {
+ hdr->next_free = heap.first_free;
+ heap.first_free->prev_free = hdr;
+ heap.first_free = hdr;
+ }
+
#if defined(POLARSSL_MEMORY_BACKTRACE)
hdr->trace = NULL;
hdr->trace_count = 0;
@@ -405,9 +502,7 @@
heap.first->size = len - sizeof(memory_header);
heap.first->magic1 = MAGIC1;
heap.first->magic2 = MAGIC2;
-
- heap.largest_free = heap.first->size;
-
+ heap.first_free = heap.first;
return( 0 );
}