blob: 44d0d1a1c433a7653b9ae19cccd3b06ccb2e6562 [file] [log] [blame]
// 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.
// -----------------------------------------------------------------------------
//
// PNG decode.
#include "./pngdec.h"
#ifdef HAVE_CONFIG_H
#include "webp/config.h"
#endif
#include <stdio.h>
#ifdef WEBP_HAVE_PNG
#ifndef PNG_USER_MEM_SUPPORTED
#define PNG_USER_MEM_SUPPORTED // for png_create_read_struct_2
#endif
#include <png.h>
#include <setjmp.h> // note: this must be included *after* png.h
#include <stdlib.h>
#include <string.h>
#include "webp/encode.h"
#include "./imageio_util.h"
#include "./metadata.h"
#define LOCAL_PNG_VERSION ((PNG_LIBPNG_VER_MAJOR << 8) | PNG_LIBPNG_VER_MINOR)
#define LOCAL_PNG_PREREQ(maj, min) \
(LOCAL_PNG_VERSION >= (((maj) << 8) | (min)))
static void PNGAPI error_function(png_structp png, png_const_charp error) {
if (error != NULL) fprintf(stderr, "libpng error: %s\n", error);
longjmp(png_jmpbuf(png), 1);
}
#if LOCAL_PNG_PREREQ(1,4)
typedef png_alloc_size_t LocalPngAllocSize;
#else
typedef png_size_t LocalPngAllocSize;
#endif
static png_voidp MallocFunc(png_structp png_ptr, LocalPngAllocSize size) {
(void)png_ptr;
if (size != (size_t)size) return NULL;
if (!ImgIoUtilCheckSizeArgumentsOverflow(size, 1)) return NULL;
return (png_voidp)malloc((size_t)size);
}
static void FreeFunc(png_structp png_ptr, png_voidp ptr) {
(void)png_ptr;
free(ptr);
}
// Converts the NULL terminated 'hexstring' which contains 2-byte character
// representations of hex values to raw data.
// 'hexstring' may contain values consisting of [A-F][a-f][0-9] in pairs,
// e.g., 7af2..., separated by any number of newlines.
// 'expected_length' is the anticipated processed size.
// On success the raw buffer is returned with its length equivalent to
// 'expected_length'. NULL is returned if the processed length is less than
// 'expected_length' or any character aside from those above is encountered.
// The returned buffer must be freed by the caller.
static uint8_t* HexStringToBytes(const char* hexstring,
size_t expected_length) {
const char* src = hexstring;
size_t actual_length = 0;
uint8_t* const raw_data = (uint8_t*)malloc(expected_length);
uint8_t* dst;
if (raw_data == NULL) return NULL;
for (dst = raw_data; actual_length < expected_length && *src != '\0'; ++src) {
char* end;
char val[3];
if (*src == '\n') continue;
val[0] = *src++;
val[1] = *src;
val[2] = '\0';
*dst++ = (uint8_t)strtol(val, &end, 16);
if (end != val + 2) break;
++actual_length;
}
if (actual_length != expected_length) {
free(raw_data);
return NULL;
}
return raw_data;
}
static int ProcessRawProfile(const char* profile, size_t profile_len,
MetadataPayload* const payload) {
const char* src = profile;
char* end;
int expected_length;
if (profile == NULL || profile_len == 0) return 0;
// ImageMagick formats 'raw profiles' as
// '\n<name>\n<length>(%8lu)\n<hex payload>\n'.
if (*src != '\n') {
fprintf(stderr, "Malformed raw profile, expected '\\n' got '\\x%.2X'\n",
*src);
return 0;
}
++src;
// skip the profile name and extract the length.
while (*src != '\0' && *src++ != '\n') {}
expected_length = (int)strtol(src, &end, 10);
if (*end != '\n') {
fprintf(stderr, "Malformed raw profile, expected '\\n' got '\\x%.2X'\n",
*end);
return 0;
}
++end;
// 'end' now points to the profile payload.
payload->bytes = HexStringToBytes(end, expected_length);
if (payload->bytes == NULL) return 0;
payload->size = expected_length;
return 1;
}
static const struct {
const char* name;
int (*process)(const char* profile, size_t profile_len,
MetadataPayload* const payload);
size_t storage_offset;
} kPNGMetadataMap[] = {
// http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/PNG.html#TextualData
// See also: ExifTool on CPAN.
{ "Raw profile type exif", ProcessRawProfile, METADATA_OFFSET(exif) },
{ "Raw profile type xmp", ProcessRawProfile, METADATA_OFFSET(xmp) },
// Exiftool puts exif data in APP1 chunk, too.
{ "Raw profile type APP1", ProcessRawProfile, METADATA_OFFSET(exif) },
// XMP Specification Part 3, Section 3 #PNG
{ "XML:com.adobe.xmp", MetadataCopy, METADATA_OFFSET(xmp) },
{ NULL, NULL, 0 },
};
// Looks for metadata at both the beginning and end of the PNG file, giving
// preference to the head.
// Returns true on success. The caller must use MetadataFree() on 'metadata' in
// all cases.
static int ExtractMetadataFromPNG(png_structp png,
png_infop const head_info,
png_infop const end_info,
Metadata* const metadata) {
int p;
for (p = 0; p < 2; ++p) {
png_infop const info = (p == 0) ? head_info : end_info;
png_textp text = NULL;
const png_uint_32 num = png_get_text(png, info, &text, NULL);
png_uint_32 i;
// Look for EXIF / XMP metadata.
for (i = 0; i < num; ++i, ++text) {
int j;
for (j = 0; kPNGMetadataMap[j].name != NULL; ++j) {
if (!strcmp(text->key, kPNGMetadataMap[j].name)) {
MetadataPayload* const payload =
(MetadataPayload*)((uint8_t*)metadata +
kPNGMetadataMap[j].storage_offset);
png_size_t text_length;
switch (text->compression) {
#ifdef PNG_iTXt_SUPPORTED
case PNG_ITXT_COMPRESSION_NONE:
case PNG_ITXT_COMPRESSION_zTXt:
text_length = text->itxt_length;
break;
#endif
case PNG_TEXT_COMPRESSION_NONE:
case PNG_TEXT_COMPRESSION_zTXt:
default:
text_length = text->text_length;
break;
}
if (payload->bytes != NULL) {
fprintf(stderr, "Ignoring additional '%s'\n", text->key);
} else if (!kPNGMetadataMap[j].process(text->text, text_length,
payload)) {
fprintf(stderr, "Failed to process: '%s'\n", text->key);
return 0;
}
break;
}
}
}
// Look for an ICC profile.
{
png_charp name;
int comp_type;
#if LOCAL_PNG_PREREQ(1,5)
png_bytep profile;
#else
png_charp profile;
#endif
png_uint_32 len;
if (png_get_iCCP(png, info,
&name, &comp_type, &profile, &len) == PNG_INFO_iCCP) {
if (!MetadataCopy((const char*)profile, len, &metadata->iccp)) return 0;
}
}
}
return 1;
}
typedef struct {
const uint8_t* data;
size_t data_size;
png_size_t offset;
} PNGReadContext;
static void ReadFunc(png_structp png_ptr, png_bytep data, png_size_t length) {
PNGReadContext* const ctx = (PNGReadContext*)png_get_io_ptr(png_ptr);
if (ctx->data_size - ctx->offset < length) {
png_error(png_ptr, "ReadFunc: invalid read length (overflow)!");
}
memcpy(data, ctx->data + ctx->offset, length);
ctx->offset += length;
}
int ReadPNG(const uint8_t* const data, size_t data_size,
struct WebPPicture* const pic,
int keep_alpha, struct Metadata* const metadata) {
volatile png_structp png = NULL;
volatile png_infop info = NULL;
volatile png_infop end_info = NULL;
PNGReadContext context = { NULL, 0, 0 };
int color_type, bit_depth, interlaced;
int has_alpha;
int num_passes;
int p;
volatile int ok = 0;
png_uint_32 width, height, y;
int64_t stride;
uint8_t* volatile rgb = NULL;
if (data == NULL || data_size == 0 || pic == NULL) return 0;
context.data = data;
context.data_size = data_size;
png = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL,
NULL, MallocFunc, FreeFunc);
if (png == NULL) goto End;
png_set_error_fn(png, 0, error_function, NULL);
if (setjmp(png_jmpbuf(png))) {
Error:
MetadataFree(metadata);
goto End;
}
#if LOCAL_PNG_PREREQ(1,5) || \
(LOCAL_PNG_PREREQ(1,4) && PNG_LIBPNG_VER_RELEASE >= 1)
// If it looks like the bitstream is going to need more memory than libpng's
// internal limit (default: 8M), try to (reasonably) raise it.
if (data_size > png_get_chunk_malloc_max(png) && data_size < (1u << 24)) {
png_set_chunk_malloc_max(png, data_size);
}
#endif
info = png_create_info_struct(png);
if (info == NULL) goto Error;
end_info = png_create_info_struct(png);
if (end_info == NULL) goto Error;
png_set_read_fn(png, &context, ReadFunc);
png_read_info(png, info);
if (!png_get_IHDR(png, info,
&width, &height, &bit_depth, &color_type, &interlaced,
NULL, NULL)) goto Error;
png_set_strip_16(png);
png_set_packing(png);
if (color_type == PNG_COLOR_TYPE_PALETTE) {
png_set_palette_to_rgb(png);
}
if (color_type == PNG_COLOR_TYPE_GRAY ||
color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
if (bit_depth < 8) {
png_set_expand_gray_1_2_4_to_8(png);
}
png_set_gray_to_rgb(png);
}
if (png_get_valid(png, info, PNG_INFO_tRNS)) {
png_set_tRNS_to_alpha(png);
has_alpha = 1;
} else {
has_alpha = !!(color_type & PNG_COLOR_MASK_ALPHA);
}
// Apply gamma correction if needed.
{
double image_gamma = 1 / 2.2, screen_gamma = 2.2;
int srgb_intent;
if (png_get_sRGB(png, info, &srgb_intent) ||
png_get_gAMA(png, info, &image_gamma)) {
png_set_gamma(png, screen_gamma, image_gamma);
}
}
if (!keep_alpha) {
png_set_strip_alpha(png);
has_alpha = 0;
}
num_passes = png_set_interlace_handling(png);
png_read_update_info(png, info);
stride = (int64_t)(has_alpha ? 4 : 3) * width * sizeof(*rgb);
if (stride != (int)stride ||
!ImgIoUtilCheckSizeArgumentsOverflow(stride, height)) {
goto Error;
}
rgb = (uint8_t*)malloc((size_t)stride * height);
if (rgb == NULL) goto Error;
for (p = 0; p < num_passes; ++p) {
png_bytep row = rgb;
for (y = 0; y < height; ++y) {
png_read_rows(png, &row, NULL, 1);
row += stride;
}
}
png_read_end(png, end_info);
if (metadata != NULL &&
!ExtractMetadataFromPNG(png, info, end_info, metadata)) {
fprintf(stderr, "Error extracting PNG metadata!\n");
goto Error;
}
pic->width = (int)width;
pic->height = (int)height;
ok = has_alpha ? WebPPictureImportRGBA(pic, rgb, (int)stride)
: WebPPictureImportRGB(pic, rgb, (int)stride);
if (!ok) {
goto Error;
}
End:
if (png != NULL) {
png_destroy_read_struct((png_structpp)&png,
(png_infopp)&info, (png_infopp)&end_info);
}
free(rgb);
return ok;
}
#else // !WEBP_HAVE_PNG
int ReadPNG(const uint8_t* const data, size_t data_size,
struct WebPPicture* const pic,
int keep_alpha, struct Metadata* const metadata) {
(void)data;
(void)data_size;
(void)pic;
(void)keep_alpha;
(void)metadata;
fprintf(stderr, "PNG support not compiled. Please install the libpng "
"development package before building.\n");
return 0;
}
#endif // WEBP_HAVE_PNG
// -----------------------------------------------------------------------------