| #pragma once |
| |
| #include <stdlib.h> |
| #include <stdint.h> |
| #include <string.h> |
| |
| #define IMWIDTH 1024 |
| #define IMHEIGHT 1024 |
| |
| extern "C" { |
| # include <png.h> |
| } |
| |
| typedef struct _png_dat { |
| uint8_t *buf; |
| int64_t len; |
| size_t buf_rem; |
| } png_dat; |
| |
| typedef struct _png_parse_dat { |
| uint8_t *cur_pos; |
| } png_parse_dat; |
| |
| /* Write a customized write callback so that we write back to an in-memory buffer. |
| * This allows the testing to not involve disk IO */ |
| static void png_write_cb(png_structp pngp, png_bytep data, png_size_t len) { |
| png_dat *dat = (png_dat*)png_get_io_ptr(pngp); |
| size_t curSize = dat->len + len; |
| |
| /* realloc double the requested buffer size to prevent excessive reallocs */ |
| if (dat->buf_rem < len) { |
| dat->buf = (uint8_t*)realloc(dat->buf, dat->len + dat->buf_rem + 2 * len); |
| |
| if (!dat->buf) { |
| /* Pretty unlikely but we'll put it here just in case */ |
| fprintf(stderr, "realloc failed, exiting\n"); |
| exit(1); |
| } |
| |
| dat->buf_rem += 2 * len; |
| } |
| |
| memcpy(dat->buf + dat->len, data, len); |
| dat->len = curSize; |
| dat->buf_rem -= len; |
| } |
| |
| static void init_compressible(png_bytep buf, size_t num_pix) { |
| /* It doesn't actually matter what we make this, but for |
| * the sake of a reasonable test image, let's make this |
| * be a stripe of R, G, & B, with no alpha channel */ |
| int32_t i = 0; |
| int32_t red_stop = num_pix / 3; |
| int32_t blue_stop = 2 * num_pix / 3; |
| int32_t green_stop = num_pix; |
| |
| for (int32_t x = 0; i < red_stop; x += 3, ++i) { |
| buf[x] = 255; |
| buf[x + 1] = 0; |
| buf[x + 2] = 0; |
| } |
| |
| for (int32_t x = 3 * i; i < blue_stop; x+= 3, ++i) { |
| buf[x] = 0; |
| buf[x + 1] = 255; |
| buf[x + 2] = 0; |
| } |
| |
| for (int32_t x = 3 * i; i < green_stop; x += 3, ++i) { |
| buf[x] = 0; |
| buf[x + 1] = 0; |
| buf[x + 2] = 255; |
| } |
| } |
| |
| static inline void encode_png(png_bytep buf, png_dat *outpng, int32_t comp_level, uint32_t width, uint32_t height) { |
| png_structp png = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); |
| |
| /* Most of this error handling is _likely_ not necessary. Likewise it's likely |
| * a lot of this stuff can be done in the setup function to avoid measuring this |
| * fixed setup time, but for now we'll do it here */ |
| if (!png) abort(); |
| |
| png_infop info = png_create_info_struct(png); |
| if (!info) abort(); |
| |
| png_set_write_fn(png, outpng, png_write_cb, NULL); |
| png_bytep *png_row_ptrs = new png_bytep[height]; |
| for (int i = 0; i < IMHEIGHT; ++i) { |
| png_row_ptrs[i] = (png_bytep)&buf[3*i*width]; |
| } |
| |
| png_set_IHDR(png, info, IMWIDTH, IMHEIGHT, 8, PNG_COLOR_TYPE_RGB, |
| PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, |
| PNG_FILTER_TYPE_DEFAULT); |
| |
| png_write_info(png, info); |
| png_set_compression_level(png, comp_level); |
| png_set_filter(png, 0, PNG_FILTER_NONE); |
| png_write_image(png, (png_bytepp)png_row_ptrs); |
| png_write_end(png, NULL); |
| png_destroy_write_struct(&png, &info); |
| delete[] png_row_ptrs; |
| } |
| |
| static void read_from_pngdat(png_structp png, png_bytep out, png_size_t bytes_to_read) { |
| png_parse_dat *io = (png_parse_dat*)png_get_io_ptr(png); |
| memcpy(out, io->cur_pos, bytes_to_read); |
| io->cur_pos += bytes_to_read; |
| } |
| |
| static inline int decode_png(png_parse_dat *dat, png_bytepp out_bytes, size_t in_size, uint32_t &width, uint32_t &height) { |
| png_structp png = NULL; |
| png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); |
| |
| if (!png) abort(); |
| png_infop info = NULL; |
| info = png_create_info_struct(png); |
| if (!info) abort(); |
| |
| png_set_read_fn(png, dat, read_from_pngdat); |
| png_read_info(png, info); |
| |
| int bit_depth = 0, color_type = -1; |
| png_get_IHDR(png, info, &width, &height, &bit_depth, &color_type, NULL, NULL, NULL); |
| |
| size_t im_size = width * height * bit_depth/8 * 3; |
| if (color_type != PNG_COLOR_TYPE_RGB) { |
| fprintf(stderr, "expected an 8 bpp RGB image\n"); |
| abort(); |
| } |
| |
| if (im_size > in_size) { |
| *out_bytes = (png_bytep)realloc(*out_bytes, im_size); |
| } |
| |
| png_bytep *out_rows = new png_bytep[height]; |
| for (size_t i = 0; i < height; ++i) |
| out_rows[i] = *out_bytes + (width*i*3); |
| |
| png_read_rows(png, out_rows, NULL, height); |
| png_destroy_read_struct(&png, &info, NULL); |
| delete[] out_rows; |
| |
| return im_size; |
| } |