codec.h

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#pragma once
 
#include <stddef.h>
#include <stdint.h>
 
#include "tinyimg/codec/deflate.h"
#include "tinyimg/image.h"
#include "tinyimg/tinyimg.h"
#include "tinyimg/util.h"
 
#ifdef __cplusplus
extern "C" {
#endif

typedef int (*TinySniffFn)(const uint8_t* buffer, size_t size);

typedef int (*TinyProbeFn)(
    const uint8_t* buffer, size_t size, TinyImageInfo* info
);

typedef int (*TinyDecodeFn)(
    TinyImage* image, const uint8_t* buffer, size_t size,
    const TinyDecodeOpts* opts
);

typedef int (*TinyEncodeFn)(
    const TinyImage* image, const TinyEncodeOpts* opts, TinyWriter* writer
);

typedef struct {
    TinyImageFormat format;
    TinySniffFn sniff;
    TinyProbeFn probe;
    TinyDecodeFn decode;
    TinyEncodeFn encode;
} TinyCodec;

const TinyCodec* tiny_codec_find(TinyImageFormat format);

const TinyCodec* tiny_codec_sniff(const uint8_t* buffer, size_t size);

uint32_t tiny_codec_count(void);

const TinyCodec* tiny_codec_at(uint32_t index);
 
#pragma region shared helpers

int tiny_decode_resolve(
    const TinyDecodeOpts* opts, uint32_t width, uint32_t height,
    TinyDecodeOpts* out, uint32_t* out_width, uint32_t* out_height
);

TinyDeflateLevel tiny_encode_level(const TinyEncodeOpts* opts);

void tiny_pixel_convert(
    uint8_t* dest, uint8_t dest_channels, const uint8_t* src,
    uint8_t src_channels
);

static inline uint8_t tiny_luma(uint8_t r, uint8_t g, uint8_t b) {
    // 13933 + 46871 + 4732 == 65536, so the sum cannot drift off 255
    uint32_t sum = 13933u * r + 46871u * g + 4732u * b;
    return (uint8_t) ((sum + 32768u) >> 16);
}
 
#pragma endregion
 
#ifdef __cplusplus
}
#endif