[libpng16] Start-up code size improvements, error handler flexibility. These
changes alter how the tricky allocation of the initial png_struct and png_info
structures are handled. png_info is now handled in pretty much the same
way as everything else, except that the allocations handle NULL return
silently. png_struct is changed in a similar way on allocation and on
deallocation a 'safety' error handler is put in place (which should never
be required). The error handler itself is changed to permit mismatches
in the application and libpng error buffer size; however, this means a
silent change to the API to return the jmp_buf if the size doesn't match
the size from the libpng compilation; libpng now allocates the memory and
this may fail. Overall these changes result in slight code size
reductions; however, this is a reduction in code that is always executed
so is particularly valuable. Overall on a 64-bit system the libpng DLL
decreases in code size by 1733 bytes. pngerror.o increases in size by
about 465 bytes because of the new functionality.
diff --git a/pngmem.c b/pngmem.c
index 7f06201..ca905d9 100644
--- a/pngmem.c
+++ b/pngmem.c
@@ -47,7 +47,7 @@
* have the ability to do that.
*/
PNG_FUNCTION(png_voidp,PNGAPI
-png_calloc,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
+png_calloc,(png_const_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
{
png_voidp ret;
@@ -65,7 +65,8 @@
* if the allocation cannot be done (for any reason.)
*/
PNG_FUNCTION(png_voidp /* PRIVATE */,
-png_malloc_base,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
+png_malloc_base,(png_const_structp png_ptr, png_alloc_size_t size),
+ PNG_ALLOCATED)
{
/* Moved to png_malloc_base from png_malloc_default in 1.6.0; the DOS
* allocators have also been removed in 1.6.0, so any 16-bit system now has
@@ -83,7 +84,7 @@
{
#ifdef PNG_USER_MEM_SUPPORTED
if (png_ptr != NULL && png_ptr->malloc_fn != NULL)
- return png_ptr->malloc_fn(png_ptr, size);
+ return png_ptr->malloc_fn(png_constcast(png_structp,png_ptr), size);
else
#endif
@@ -99,7 +100,7 @@
* function png_malloc_default is also provided.
*/
PNG_FUNCTION(png_voidp,PNGAPI
-png_malloc,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
+png_malloc,(png_const_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
{
png_voidp ret;
@@ -116,7 +117,7 @@
#ifdef PNG_USER_MEM_SUPPORTED
PNG_FUNCTION(png_voidp,PNGAPI
-png_malloc_default,(png_structp png_ptr, png_alloc_size_t size),
+png_malloc_default,(png_const_structp png_ptr, png_alloc_size_t size),
PNG_ALLOCATED PNG_DEPRECATED)
{
png_voidp ret;
@@ -139,7 +140,8 @@
* png_error, if it fails to allocate the requested memory.
*/
PNG_FUNCTION(png_voidp,PNGAPI
-png_malloc_warn,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
+png_malloc_warn,(png_const_structp png_ptr, png_alloc_size_t size),
+ PNG_ALLOCATED)
{
if (png_ptr != NULL)
{
@@ -158,21 +160,21 @@
* without taking any action.
*/
void PNGAPI
-png_free(png_structp png_ptr, png_voidp ptr)
+png_free(png_const_structp png_ptr, png_voidp ptr)
{
if (png_ptr == NULL || ptr == NULL)
return;
#ifdef PNG_USER_MEM_SUPPORTED
if (png_ptr->free_fn != NULL)
- png_ptr->free_fn(png_ptr, ptr);
+ png_ptr->free_fn(png_constcast(png_structp,png_ptr), ptr);
else
png_free_default(png_ptr, ptr);
}
PNG_FUNCTION(void,PNGAPI
-png_free_default,(png_structp png_ptr, png_voidp ptr),PNG_DEPRECATED)
+png_free_default,(png_const_structp png_ptr, png_voidp ptr),PNG_DEPRECATED)
{
if (png_ptr == NULL || ptr == NULL)
return;