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/**
* @file png.h
* @brief PNG image format handling for tinyff.
* @author @TazyFoundSoup
*
* This header defines structure and functions for working with PNG images,
* including validation and opening PNG files.
*
* @see src/format/image/png.c
*/
#ifndef PNG_H
#define PNG_H
#include <stdint.h>
#include <stdio.h>
#include <stdbool.h>
#include <string.h>
#include "tinyff/result.h"
/**
* @brief PNG file signature (first 8 bytes)
*
* Used to validate PNG files.
* Will not be used for users directly.
*
* @see ff_png_isvalid
*/
static const unsigned char PNG_SIGNATURE[8] = {
0x89, 'P', 'N', 'G', 0x0D, 0x0A, 0x1A, 0x0A
};
/**
* @brief PNG image context structure
*
* Holds information about a PNG image, including its raw file pointer,
* dimensions, bit depth, color type, pixel data, and validity status.
*/
typedef struct {
FILE *raw;
uint32_t width;
uint32_t height;
uint8_t bit_depth;
uint8_t color_type;
uint8_t *pixels;
size_t count_pixels;
bool valid;
} ff_png_ctx;
/**
* @brief PNG chunk types
*
* Enumerates the different types of PNG chunks.
*
* @details
* - FF_PNG_CHUNK_TYPE_IHDR: Image Header Chunk
* - FF_PNG_CHUNK_TYPE_PLTE: Palette Chunk
* - FF_PNG_CHUNK_TYPE_IDAT: Image Data Chunk
* - FF_PNG_CHUNK_TYPE_IEND: Image End Chunk
*
* @see ff_png_chunk
*/
typedef enum {
FF_PNG_CHUNK_TYPE_IHDR,
FF_PNG_CHUNK_TYPE_PLTE,
FF_PNG_CHUNK_TYPE_IDAT,
FF_PNG_CHUNK_TYPE_IEND,
// There are more,
// but these ones will be
// enough for now
} ff_png_chunk_type;
/**
* @brief PNG chunk structure
*
* Represents a PNG chunk, including its length, type, data, and CRC.
*
* @see ff_png_chunk_type
*/
typedef struct {
uint32_t length;
ff_png_chunk_type type;
uint32_t *data; // length bytes (maximum is uint32_t)
uint32_t crc;
} ff_png_chunk;
/**
* @brief Validate PNG from FILE pointer
*
* Checks necessary validations for PNG files.
*
* @param file An already opened FILE pointer located at start
* @return A result indicating the success/failure of the validation
*
* @warning FILE pointer must be at the start of the file, or unexpected results may occur.
*/
ff_result ff_png_isvalid(FILE *file);
/**
* @brief Open a PNG file and create its context
*
* Opens a PNG file, validates it, and prepares its context for further processing.
*
* @param filepath The path to the PNG file
* @param out_ctx Pointer to store the created PNG context
* @return A result indicating the success/failure of the operation
*
* @todo Implement parsing
* @warning The caller is responsible for freeing the allocated ff_png_ctx and its resources.
*
*
* @see ff_png_ctx
*/
ff_result ff_open_png(const char *filepath, ff_png_ctx **out_ctx);
#endif
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