Check libpng directly into third_party/

third_party/libpng/pngmem.c

+
+/* pngmem.c - stub functions for memory allocation
+ *
+ * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Copyright (c) 1998-2002,2004,2006-2014 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file provides a location for all memory allocation.  Users who
+ * need special memory handling are expected to supply replacement
+ * functions for png_malloc() and png_free(), and to use
+ * png_create_read_struct_2() and png_create_write_struct_2() to
+ * identify the replacement functions.
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+/* Free a png_struct */
+void /* PRIVATE */
+png_destroy_png_struct(png_structrp png_ptr)
+{
+   if (png_ptr != NULL)
+   {
+      /* png_free might call png_error and may certainly call
+       * png_get_mem_ptr, so fake a temporary png_struct to support this.
+       */
+      png_struct dummy_struct = *png_ptr;
+      memset(png_ptr, 0, (sizeof *png_ptr));
+      png_free(&dummy_struct, png_ptr);
+
+#     ifdef PNG_SETJMP_SUPPORTED
+         /* We may have a jmp_buf left to deallocate. */
+         png_free_jmpbuf(&dummy_struct);
+#     endif
+   }
+}
+
+/* Allocate memory.  For reasonable files, size should never exceed
+ * 64K.  However, zlib may allocate more than 64K if you don't tell
+ * it not to.  See zconf.h and png.h for more information.  zlib does
+ * need to allocate exactly 64K, so whatever you call here must
+ * have the ability to do that.
+ */
+PNG_FUNCTION(png_voidp,PNGAPI
+png_calloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
+{
+   png_voidp ret;
+
+   ret = png_malloc(png_ptr, size);
+
+   if (ret != NULL)
+      memset(ret, 0, size);
+
+   return ret;
+}
+
+/* png_malloc_base, an internal function added at libpng 1.6.0, does the work of
+ * allocating memory, taking into account limits and PNG_USER_MEM_SUPPORTED.
+ * Checking and error handling must happen outside this routine; it returns NULL
+ * if the allocation cannot be done (for any reason.)
+ */
+PNG_FUNCTION(png_voidp /* PRIVATE */,
+png_malloc_base,(png_const_structrp 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
+    * to implement a user memory handler.  This checks to be sure it isn't
+    * called with big numbers.
+    */
+#ifndef PNG_USER_MEM_SUPPORTED
+   PNG_UNUSED(png_ptr)
+#endif
+
+   /* Some compilers complain that this is always true.  However, it
+    * can be false when integer overflow happens.
+    */
+   if (size > 0 && size <= PNG_SIZE_MAX
+#     ifdef PNG_MAX_MALLOC_64K
+         && size <= 65536U
+#     endif
+      )
+   {
+#ifdef PNG_USER_MEM_SUPPORTED
+      if (png_ptr != NULL && png_ptr->malloc_fn != NULL)
+         return png_ptr->malloc_fn(png_constcast(png_structrp,png_ptr), size);
+
+      else
+#endif
+         return malloc((size_t)size); /* checked for truncation above */
+   }
+
+   else
+      return NULL;
+}
+
+#if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
+   defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
+/* This is really here only to work round a spurious warning in GCC 4.6 and 4.7
+ * that arises because of the checks in png_realloc_array that are repeated in
+ * png_malloc_array.
+ */
+static png_voidp
+png_malloc_array_checked(png_const_structrp png_ptr, int nelements,
+   size_t element_size)
+{
+   png_alloc_size_t req = nelements; /* known to be > 0 */
+
+   if (req <= PNG_SIZE_MAX/element_size)
+      return png_malloc_base(png_ptr, req * element_size);
+
+   /* The failure case when the request is too large */
+   return NULL;
+}
+
+PNG_FUNCTION(png_voidp /* PRIVATE */,
+png_malloc_array,(png_const_structrp png_ptr, int nelements,
+   size_t element_size),PNG_ALLOCATED)
+{
+   if (nelements <= 0 || element_size == 0)
+      png_error(png_ptr, "internal error: array alloc");
+
+   return png_malloc_array_checked(png_ptr, nelements, element_size);
+}
+
+PNG_FUNCTION(png_voidp /* PRIVATE */,
+png_realloc_array,(png_const_structrp png_ptr, png_const_voidp old_array,
+   int old_elements, int add_elements, size_t element_size),PNG_ALLOCATED)
+{
+   /* These are internal errors: */
+   if (add_elements <= 0 || element_size == 0 || old_elements < 0 ||
+      (old_array == NULL && old_elements > 0))
+      png_error(png_ptr, "internal error: array realloc");
+
+   /* Check for overflow on the elements count (so the caller does not have to
+    * check.)
+    */
+   if (add_elements <= INT_MAX - old_elements)
+   {
+      png_voidp new_array = png_malloc_array_checked(png_ptr,
+         old_elements+add_elements, element_size);
+
+      if (new_array != NULL)
+      {
+         /* Because png_malloc_array worked the size calculations below cannot
+          * overflow.
+          */
+         if (old_elements > 0)
+            memcpy(new_array, old_array, element_size*(unsigned)old_elements);
+
+         memset((char*)new_array + element_size*(unsigned)old_elements, 0,
+            element_size*(unsigned)add_elements);
+
+         return new_array;
+      }
+   }
+
+   return NULL; /* error */
+}
+#endif /* TEXT || sPLT || STORE_UNKNOWN_CHUNKS */
+
+/* Various functions that have different error handling are derived from this.
+ * png_malloc always exists, but if PNG_USER_MEM_SUPPORTED is defined a separate
+ * function png_malloc_default is also provided.
+ */
+PNG_FUNCTION(png_voidp,PNGAPI
+png_malloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
+{
+   png_voidp ret;
+
+   if (png_ptr == NULL)
+      return NULL;
+
+   ret = png_malloc_base(png_ptr, size);
+
+   if (ret == NULL)
+       png_error(png_ptr, "Out of memory"); /* 'm' means png_malloc */
+
+   return ret;
+}
+
+#ifdef PNG_USER_MEM_SUPPORTED
+PNG_FUNCTION(png_voidp,PNGAPI
+png_malloc_default,(png_const_structrp png_ptr, png_alloc_size_t size),
+   PNG_ALLOCATED PNG_DEPRECATED)
+{
+   png_voidp ret;
+
+   if (png_ptr == NULL)
+      return NULL;
+
+   /* Passing 'NULL' here bypasses the application provided memory handler. */
+   ret = png_malloc_base(NULL/*use malloc*/, size);
+
+   if (ret == NULL)
+      png_error(png_ptr, "Out of Memory"); /* 'M' means png_malloc_default */
+
+   return ret;
+}
+#endif /* USER_MEM */
+
+/* This function was added at libpng version 1.2.3.  The png_malloc_warn()
+ * function will issue a png_warning and return NULL instead of issuing a
+ * png_error, if it fails to allocate the requested memory.
+ */
+PNG_FUNCTION(png_voidp,PNGAPI
+png_malloc_warn,(png_const_structrp png_ptr, png_alloc_size_t size),
+   PNG_ALLOCATED)
+{
+   if (png_ptr != NULL)
+   {
+      png_voidp ret = png_malloc_base(png_ptr, size);
+
+      if (ret != NULL)
+         return ret;
+
+      png_warning(png_ptr, "Out of memory");
+   }
+
+   return NULL;
+}
+
+/* Free a pointer allocated by png_malloc().  If ptr is NULL, return
+ * without taking any action.
+ */
+void PNGAPI
+png_free(png_const_structrp 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_constcast(png_structrp,png_ptr), ptr);
+
+   else
+      png_free_default(png_ptr, ptr);
+}
+
+PNG_FUNCTION(void,PNGAPI
+png_free_default,(png_const_structrp png_ptr, png_voidp ptr),PNG_DEPRECATED)
+{
+   if (png_ptr == NULL || ptr == NULL)
+      return;
+#endif /* USER_MEM */
+
+   free(ptr);
+}
+
+#ifdef PNG_USER_MEM_SUPPORTED
+/* This function is called when the application wants to use another method
+ * of allocating and freeing memory.
+ */
+void PNGAPI
+png_set_mem_fn(png_structrp png_ptr, png_voidp mem_ptr, png_malloc_ptr
+  malloc_fn, png_free_ptr free_fn)
+{
+   if (png_ptr != NULL)
+   {
+      png_ptr->mem_ptr = mem_ptr;
+      png_ptr->malloc_fn = malloc_fn;
+      png_ptr->free_fn = free_fn;
+   }
+}
+
+/* This function returns a pointer to the mem_ptr associated with the user
+ * functions.  The application should free any memory associated with this
+ * pointer before png_write_destroy and png_read_destroy are called.
+ */
+png_voidp PNGAPI
+png_get_mem_ptr(png_const_structrp png_ptr)
+{
+   if (png_ptr == NULL)
+      return NULL;
+
+   return png_ptr->mem_ptr;
+}
+#endif /* USER_MEM */
+#endif /* READ || WRITE */