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#ifndef PNG_H
#define PNG_H
#include <stdint.h>
#include <stdio.h>
#include <stdbool.h>
#include <string.h>
#include <stdlib.h>
#include "tinyff/result.h"
#include "tinyff/common.h"
static const unsigned char PNG_SIGNATURE[8] = {
0x89, 'P', 'N', 'G', 0x0D, 0x0A, 0x1A, 0x0A
};
typedef struct {
// Raw file handle
FILE *raw;
// Image dimensions
uint32_t width;
uint32_t height;
// Color information
uint8_t bit_depth;
uint8_t color_type;
// Image data
//
// It's weird because theres actually multiple ways to store it
// we need to be able to have the same fields to hold the data
// or have two seperate fields and a flag pointing to which one is actually
// being used sorta because of palette vs direct color
// so until i find a better way than holding this crappy project together with duct tape
// im just gonna use two fields and a flag
// but again with bit depths and color types this can get really messy really fast
// and i have NO idea what what type direct color data should be stored as.
// god... i hate png
bool valid;
} ff_png_ctx;
typedef struct {
uint32_t length;
const char *type;
uint32_t *data; // length bytes (maximum is uint32_t)
uint32_t crc;
} ff_png_chunk;
// Chunk handling
typedef (*ff_png_chunk_handler_ptr)(uint8_t *buf, size_t len, ff_png_ctx* ctx);
typedef struct {
const char *type;
ff_png_chunk_handler_ptr handler;
} ff_png_chunk_handler;
const ff_png_chunk_handler ff_png_chunk_handlers[] = {
{"IHDR", ff_png_header_handler},
{"IDAT", ff_png_data_handler},
{"IEND", ff_png_end_handler},
{"PLTE", ff_png_palette_handler},
// From now on, the handlers will be for ancillary chunks
{NULL, NULL} // Terminator
};
// Handler declarations
// Massive W.I.P
// Required by definition
ff_result ff_png_header_handler(uint8_t *buf, size_t len, ff_png_ctx* ctx); // IHDR
ff_result ff_png_palette_handler(uint8_t *buf, size_t len, ff_png_ctx* ctx); // PLTE
ff_result ff_png_data_handler(uint8_t *buf, size_t len, ff_png_ctx* ctx); // IDAT
ff_result ff_png_end_handler(uint8_t *buf, size_t len, ff_png_ctx* ctx); // IEND
// PLTE is a funny one
// Its only required for indexed color types
ff_result ff_png_isvalid(FILE *file);
ff_result ff_open_png(const char *filepath, ff_png_ctx **out_ctx);
#endif
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