Merge pull request #7341 from AdmiralCurtiss/simplified-libpng
Use simplified libpng PNG reading API to avoid PNG reading bugs.
This commit is contained in:
Mat M
GitHub
commit
0ed0e513d2
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@ -4,181 +4,37 @@
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#include "Common/Image.h"
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// Versions of libpng older than 1.5 want us to not include setjmp.h before png.h,
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// so let's include png.h first of all headers
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#include <png.h>
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#include <csetjmp>
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#include <cstdlib>
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#include <cstring>
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#include <memory>
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#include <vector>
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#include <png.h>
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#include "Common/CommonTypes.h"
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#include "Common/Logging/Log.h"
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namespace Common
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{
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static int MultiplyAlpha(int alpha, int color)
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{
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const int temp = (alpha * color) + 0x80;
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return ((temp + (temp >> 8)) >> 8);
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}
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static void PremultiplyData(png_structp png, png_row_infop row_info, png_bytep data)
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{
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for (png_size_t i = 0; i < row_info->rowbytes; i += 4, data += 4)
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{
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const png_byte alpha = data[3];
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u32 w;
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if (alpha == 0)
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{
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w = 0;
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}
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else
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{
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png_byte red = data[0];
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png_byte green = data[1];
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png_byte blue = data[2];
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if (alpha != 0xff)
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{
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red = MultiplyAlpha(alpha, red);
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green = MultiplyAlpha(alpha, green);
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blue = MultiplyAlpha(alpha, blue);
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}
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w = (alpha << 24) | (red << 16) | (green << 8) | (blue << 0);
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}
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std::memcpy(data, &w, sizeof(w));
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}
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}
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struct ReadProgress
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{
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const u8* current;
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const u8* end;
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};
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static void ReadCallback(png_structp png, png_bytep data, png_size_t size)
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{
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ReadProgress* progress = static_cast<ReadProgress*>(png_get_io_ptr(png));
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for (size_t i = 0; i < size; ++i)
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{
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if (progress->current >= progress->end)
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png_error(png, "Read beyond end of file"); // This makes us longjmp back to LoadPNG
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data[i] = *(progress->current);
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++(progress->current);
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}
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}
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static void PNGErrorCallback(png_structp png, png_const_charp error_msg)
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{
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ERROR_LOG(COMMON, "PNG loading error: %s", error_msg);
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longjmp(png_jmpbuf(png), 1);
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}
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#ifdef _MSC_VER
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#pragma warning(push)
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#pragma warning(disable : 4611)
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// VS shows the following warning even though no C++ objects are destroyed in LoadPNG:
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// "warning C4611: interaction between '_setjmp' and C++ object destruction is non-portable"
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#endif
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bool LoadPNG(const std::vector<u8>& input, std::vector<u8>* data_out, u32* width_out,
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u32* height_out)
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{
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// The const_cast is only required for libpng versions older than 1.5
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const bool is_png = !png_sig_cmp(const_cast<u8*>(input.data()), 0, input.size());
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if (!is_png)
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// Using the 'Simplified API' of libpng; see section V in the libpng manual.
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// Read header
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png_image png = {};
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png.version = PNG_IMAGE_VERSION;
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if (!png_image_begin_read_from_memory(&png, input.data(), input.size()))
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return false;
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png_struct* png =
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png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, PNGErrorCallback, nullptr);
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if (!png)
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// Prepare output vector
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size_t png_size = PNG_IMAGE_SIZE(png);
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data_out->resize(png_size);
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// Convert to RGBA and write into output vector
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png.format = PNG_FORMAT_RGBA;
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if (!png_image_finish_read(&png, nullptr, data_out->data(), 0, nullptr))
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return false;
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png_info* info = png_create_info_struct(png);
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if (!info)
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{
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png_destroy_read_struct(&png, &info, nullptr);
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return false;
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}
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*width_out = png.width;
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*height_out = png.height;
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// It would've been nice to use std::vector for this, but using setjmp safely
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// means that we have to use this manually managed volatile pointer garbage instead.
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png_byte** volatile row_pointers_volatile = nullptr;
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if (setjmp(png_jmpbuf(png)))
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{
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free(row_pointers_volatile);
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png_destroy_read_struct(&png, &info, nullptr);
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return false;
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}
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ReadProgress read_progress{input.data(), input.data() + input.size()};
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png_set_read_fn(png, &read_progress, ReadCallback);
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png_read_info(png, info);
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png_uint_32 width, height;
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int depth, color_type, interlace;
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png_get_IHDR(png, info, &width, &height, &depth, &color_type, &interlace, nullptr, nullptr);
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if (color_type == PNG_COLOR_TYPE_PALETTE)
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png_set_palette_to_rgb(png);
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else if (color_type == PNG_COLOR_TYPE_GRAY)
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png_set_expand_gray_1_2_4_to_8(png);
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if (png_get_valid(png, info, PNG_INFO_tRNS))
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png_set_tRNS_to_alpha(png);
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if (depth == 16)
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png_set_strip_16(png);
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else if (depth < 8)
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png_set_packing(png);
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if (color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
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png_set_gray_to_rgb(png);
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if (interlace != PNG_INTERLACE_NONE)
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png_set_interlace_handling(png);
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png_set_bgr(png);
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png_set_filler(png, 0xff, PNG_FILLER_AFTER);
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png_set_read_user_transform_fn(png, PremultiplyData);
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png_read_update_info(png, info);
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png_get_IHDR(png, info, &width, &height, &depth, &color_type, &interlace, nullptr, nullptr);
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const size_t stride = width * 4;
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data_out->resize(stride * height);
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png_byte** row_pointers = static_cast<png_byte**>(malloc(height * sizeof(png_byte*)));
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if (!row_pointers)
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{
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png_destroy_read_struct(&png, &info, nullptr);
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return false;
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}
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for (png_uint_32 i = 0; i < height; i++)
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row_pointers[i] = &(*data_out)[i * stride];
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row_pointers_volatile = row_pointers;
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png_read_image(png, row_pointers);
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png_read_end(png, info);
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free(row_pointers);
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png_destroy_read_struct(&png, &info, nullptr);
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*width_out = width;
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*height_out = height;
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return true;
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}
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#ifdef _MSC_VER
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#pragma warning(pop)
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#endif
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} // namespace Common
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