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// Copyright 2012 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// Misc. common utility functions
//
// Author: Skal (pascal.massimino@gmail.com)
#include <stdlib.h>
#include "./utils.h"
// If PRINT_MEM_INFO is defined, extra info (like total memory used, number of
// alloc/free etc) is printed. For debugging/tuning purpose only (it's slow,
// and not multi-thread safe!).
// An interesting alternative is valgrind's 'massif' tool:
// http://valgrind.org/docs/manual/ms-manual.html
// Here is an example command line:
/* valgrind --tool=massif --massif-out-file=massif.out \
--stacks=yes --alloc-fn=WebPSafeAlloc --alloc-fn=WebPSafeCalloc
ms_print massif.out
*/
// In addition:
// * if PRINT_MEM_TRAFFIC is defined, all the details of the malloc/free cycles
// are printed.
// * if MALLOC_FAIL_AT is defined, the global environment variable
// $MALLOC_FAIL_AT is used to simulate a memory error when calloc or malloc
// is called for the nth time. Example usage:
// export MALLOC_FAIL_AT=50 && ./examples/cwebp input.png
// * if MALLOC_LIMIT is defined, the global environment variable $MALLOC_LIMIT
// sets the maximum amount of memory (in bytes) made available to libwebp.
// This can be used to emulate environment with very limited memory.
// Example: export MALLOC_LIMIT=64000000 && ./examples/dwebp picture.webp
// #define PRINT_MEM_INFO
// #define PRINT_MEM_TRAFFIC
// #define MALLOC_FAIL_AT
// #define MALLOC_LIMIT
//------------------------------------------------------------------------------
// Checked memory allocation
#if defined(PRINT_MEM_INFO)
#include <stdio.h>
#include <stdlib.h> // for abort()
static int num_malloc_calls = 0;
static int num_calloc_calls = 0;
static int num_free_calls = 0;
static int countdown_to_fail = 0; // 0 = off
typedef struct MemBlock MemBlock;
struct MemBlock {
void* ptr_;
size_t size_;
MemBlock* next_;
};
static MemBlock* all_blocks = NULL;
static size_t total_mem = 0;
static size_t total_mem_allocated = 0;
static size_t high_water_mark = 0;
static size_t mem_limit = 0;
static int exit_registered = 0;
static void PrintMemInfo(void) {
fprintf(stderr, "\nMEMORY INFO:\n");
fprintf(stderr, "num calls to: malloc = %4d\n", num_malloc_calls);
fprintf(stderr, " calloc = %4d\n", num_calloc_calls);
fprintf(stderr, " free = %4d\n", num_free_calls);
fprintf(stderr, "total_mem: %u\n", (uint32_t)total_mem);
fprintf(stderr, "total_mem allocated: %u\n", (uint32_t)total_mem_allocated);
fprintf(stderr, "high-water mark: %u\n", (uint32_t)high_water_mark);
while (all_blocks != NULL) {
MemBlock* b = all_blocks;
all_blocks = b->next_;
free(b);
}
}
static void Increment(int* const v) {
if (!exit_registered) {
#if defined(MALLOC_FAIL_AT)
{
const char* const malloc_fail_at_str = getenv("MALLOC_FAIL_AT");
if (malloc_fail_at_str != NULL) {
countdown_to_fail = atoi(malloc_fail_at_str);
}
}
#endif
#if defined(MALLOC_LIMIT)
{
const char* const malloc_limit_str = getenv("MALLOC_LIMIT");
if (malloc_limit_str != NULL) {
mem_limit = atoi(malloc_limit_str);
}
}
#endif
(void)countdown_to_fail;
(void)mem_limit;
atexit(PrintMemInfo);
exit_registered = 1;
}
++*v;
}
static void AddMem(void* ptr, size_t size) {
if (ptr != NULL) {
MemBlock* const b = (MemBlock*)malloc(sizeof(*b));
if (b == NULL) abort();
b->next_ = all_blocks;
all_blocks = b;
b->ptr_ = ptr;
b->size_ = size;
total_mem += size;
total_mem_allocated += size;
#if defined(PRINT_MEM_TRAFFIC)
#if defined(MALLOC_FAIL_AT)
fprintf(stderr, "fail-count: %5d [mem=%u]\n",
num_malloc_calls + num_calloc_calls, (uint32_t)total_mem);
#else
fprintf(stderr, "Mem: %u (+%u)\n", (uint32_t)total_mem, (uint32_t)size);
#endif
#endif
if (total_mem > high_water_mark) high_water_mark = total_mem;
}
}
static void SubMem(void* ptr) {
if (ptr != NULL) {
MemBlock** b = &all_blocks;
// Inefficient search, but that's just for debugging.
while (*b != NULL && (*b)->ptr_ != ptr) b = &(*b)->next_;
if (*b == NULL) {
fprintf(stderr, "Invalid pointer free! (%p)\n", ptr);
abort();
}
{
MemBlock* const block = *b;
*b = block->next_;
total_mem -= block->size_;
#if defined(PRINT_MEM_TRAFFIC)
fprintf(stderr, "Mem: %u (-%u)\n",
(uint32_t)total_mem, (uint32_t)block->size_);
#endif
free(block);
}
}
}
#else
#define Increment(v) do {} while (0)
#define AddMem(p, s) do {} while (0)
#define SubMem(p) do {} while (0)
#endif
// Returns 0 in case of overflow of nmemb * size.
static int CheckSizeArgumentsOverflow(uint64_t nmemb, size_t size) {
const uint64_t total_size = nmemb * size;
if (nmemb == 0) return 1;
if ((uint64_t)size > WEBP_MAX_ALLOCABLE_MEMORY / nmemb) return 0;
if (total_size != (size_t)total_size) return 0;
#if defined(PRINT_MEM_INFO) && defined(MALLOC_FAIL_AT)
if (countdown_to_fail > 0 && --countdown_to_fail == 0) {
return 0; // fake fail!
}
#endif
#if defined(MALLOC_LIMIT)
if (mem_limit > 0 && total_mem + total_size >= mem_limit) {
return 0; // fake fail!
}
#endif
return 1;
}
void* WebPSafeMalloc(uint64_t nmemb, size_t size) {
void* ptr;
Increment(&num_malloc_calls);
if (!CheckSizeArgumentsOverflow(nmemb, size)) return NULL;
assert(nmemb * size > 0);
ptr = malloc((size_t)(nmemb * size));
AddMem(ptr, (size_t)(nmemb * size));
return ptr;
}
void* WebPSafeCalloc(uint64_t nmemb, size_t size) {
void* ptr;
Increment(&num_calloc_calls);
if (!CheckSizeArgumentsOverflow(nmemb, size)) return NULL;
assert(nmemb * size > 0);
ptr = calloc((size_t)nmemb, size);
AddMem(ptr, (size_t)(nmemb * size));
return ptr;
}
void WebPSafeFree(void* const ptr) {
if (ptr != NULL) {
Increment(&num_free_calls);
SubMem(ptr);
}
free(ptr);
}
//------------------------------------------------------------------------------
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