open-story-teller/software/library/mini_qoi.h

#pragma once

#ifndef MINI_QOI_H
#define MINI_QOI_H

#ifdef __cplusplus
extern "C"
{
#endif

#include <stdint.h>
#include <string.h>
#include <stdbool.h>

#define MQOI_RGB_HASH(px) ((px.r * 3 + px.g * 5 + px.b * 7) & 0b00111111)
#define MQOI_RGBA_HASH(px) ((px.r * 3 + px.g * 5 + px.b * 7 + px.a * 11) & 0b00111111)

#define MQOI_HEADER_SIZE (14)

#define MQOI_MASK_OP_2B (0b11000000)
#define MQOI_MASK_OP_8B (0b11111111)

#define MQOI_MASK_OP_LUMA_DG (0b00111111)
#define MQOI_MASK_OP_RUN (0b00111111)

    // basic types

    typedef enum
    {
        MQOI_DESC_OK = 0,             // The descriptor is valid
        MQOI_DESC_INVALID_MAGIC,      // The magic value isn't correct
        MQOI_DESC_INVALID_CHANNELS,   // The channel number isn't valid
        MQOI_DESC_INVALID_COLORSPACE, // The colorspace isn't valid
    } mqoi_desc_err_t;

    typedef enum
    {
        MQOI_OP2_INDEX = (0b00 << 6),
        MQOI_OP2_DIFF = (0b01 << 6),
        MQOI_OP2_LUMA = (0b10 << 6),
        MQOI_OP2_RUN = (0b11 << 6),
        MQOI_OP8_RUN_RGB = (0b11111110),
        MQOI_OP8_RUN_RGBA = (0b11111111),
    } mqoi_op_t;

    typedef enum
    {
        MQOI_CHANNELS_RGB = 3,
        MQOI_CHANNELS_RGBA,
    } mqoi_channels_t;

    typedef enum
    {
        MQOI_COLORSPACE_SRGB = 0,
        MQOI_COLORSPACE_LINEAR = 1,
    } mqoi_colorspace_t;

    typedef union
    {
        struct
        {
            uint8_t r, g, b;
        };
        uint8_t value[3];
    } mqoi_rgb_t;

    typedef union
    {
        struct
        {
            uint8_t r, g, b, a;
        };
        uint8_t value[4];
    } mqoi_rgba_t;

    typedef struct
    {
        uint8_t head;

        uint8_t magic[4];
        uint8_t width[4];  // big-endian width
        uint8_t height[4]; // big-endian height
        uint8_t channels;
        uint8_t colorspace;
    } mqoi_desc_t;

    // ==== chunks ====

    typedef union
    {
        struct
        {
            uint8_t head;
            union
            {
                mqoi_rgb_t rgb;
                mqoi_rgba_t rgba;
                uint8_t drdb;
            };
        };
        uint8_t value[5];
    } mqoi_chunk_t;

    // ==== codecs ====

    typedef struct
    {
        mqoi_rgba_t hashtable[64];
        mqoi_rgba_t prev_px;
        mqoi_chunk_t working_chunk;
        uint8_t working_chunk_size;
    } mqoi_enc_t;

    typedef struct
    {
        mqoi_rgba_t hashtable[64];
        mqoi_rgba_t prev_px;
        mqoi_chunk_t curr_chunk;
        uint8_t curr_chunk_head : 4;
        uint8_t curr_chunk_size : 4;
        uint32_t pix_left;
    } mqoi_dec_t;

    // ==== mqoi_desc_t ====

    void mqoi_desc_init(mqoi_desc_t *desc);
    void mqoi_desc_push(mqoi_desc_t *desc, uint8_t byte);
    uint8_t *mqoi_desc_pop(mqoi_desc_t *desc);
    uint8_t mqoi_desc_verify(mqoi_desc_t *desc, uint32_t *w, uint32_t *h);
    bool mqoi_desc_done(const mqoi_desc_t *desc);

    /* the encoder is still WIP
    void mqoi_enc_init(mqoi_enc_t * enc);
    void mqoi_enc_push(mqoi_enc_t * enc, mqoi_rgba_t * pix)
    mqoi_chunk_t * mqoi_enc_pop(mqoi_enc_t * enc, uint8_t * size);
    */

    // ==== mqoi_dec_t ====

    void mqoi_dec_init(mqoi_dec_t *dec, uint32_t n_pix);
    void mqoi_dec_push(mqoi_dec_t *dec, uint8_t byte);
    uint8_t mqoi_dec_take(mqoi_dec_t *dec, const uint8_t *bytes);
    mqoi_rgba_t *mqoi_dec_pop(mqoi_dec_t *dec);
    bool mqoi_dec_done(const mqoi_dec_t *dec);

#ifdef __cplusplus
}
#endif

#endif