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refactor encoding and decoding chunk code
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@Aftersol
Aftersol committed Jul 15, 2023
1 parent 09e8823 commit 8b37e1d
Showing 1 changed file with 128 additions and 69 deletions.
197 changes: 128 additions & 69 deletions inc/sQOI.h
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Original file line number Diff line number Diff line change
Expand Up @@ -177,12 +177,26 @@ bool qoi_enc_init(qoi_desc_t* desc, qoi_enc_t* enc, void* data);
bool qoi_enc_done(qoi_enc_t* enc);
void qoi_encode_chunk(qoi_desc_t *desc, qoi_enc_t *enc, void *qoi_pixel_bytes);

static inline void qoi_enc_rgb(qoi_enc_t *enc, qoi_pixel_t px);
static inline void qoi_enc_rgba(qoi_enc_t *enc, qoi_pixel_t px);

static inline void qoi_enc_index(qoi_enc_t *enc, uint8_t index_pos);
static inline void qoi_enc_run(qoi_enc_t *enc);

/* QOI decoder functions */

bool qoi_dec_init(qoi_desc_t* desc, qoi_dec_t* dec, void* data, size_t len);
bool qoi_dec_done(qoi_dec_t* dec);
qoi_pixel_t qoi_decode_chunk(qoi_dec_t* dec);

static inline void qoi_dec_rgb(qoi_dec_t* dec);
static inline void qoi_dec_rgba(qoi_dec_t* dec);

static inline void qoi_dec_index(qoi_dec_t* dec, uint8_t tag);
static inline void qoi_dec_diff(qoi_dec_t* dec, uint8_t tag);
static inline void qoi_dec_luma(qoi_dec_t* dec, uint8_t tag);
static inline void qoi_dec_run(qoi_dec_t* dec, uint8_t tag);

/* Extract a 32-bit big endian integer regardless of endianness */
static inline uint32_t qoi_get_be32(uint32_t value)
{
Expand Down Expand Up @@ -404,6 +418,58 @@ bool qoi_dec_done(qoi_dec_t* dec)
return (dec->offset - dec->data > dec->qoi_len - 8) || (dec->pixel_seek >= dec->img_area); /* Has the decoder decoded all the pixels yet or reached the end of the file? */
}

static inline void qoi_enc_rgb(qoi_enc_t *enc, qoi_pixel_t px)
{
uint8_t tag[4] = {
QOI_OP_RGB,
px.red,
px.green,
px.blue
};

enc->offset[0] = tag[0];
enc->offset[1] = tag[1];
enc->offset[2] = tag[2];
enc->offset[3] = tag[3];

enc->offset += 4;
}

static inline void qoi_enc_rgba(qoi_enc_t *enc, qoi_pixel_t px)
{
uint8_t tag[5] =
{
QOI_OP_RGBA,
px.red,
px.green,
px.blue,
px.alpha
};

enc->offset[0] = tag[0];
enc->offset[1] = tag[1];
enc->offset[2] = tag[2];
enc->offset[3] = tag[3];
enc->offset[4] = tag[4];
enc->offset += 5;
}

static inline void qoi_enc_index(qoi_enc_t *enc, uint8_t index_pos)
{
/* The run-length is stored with a bias of -1 */
uint8_t tag = QOI_OP_INDEX | index_pos;
enc->offset++[0] = tag;
}

static inline void qoi_enc_run(qoi_enc_t *enc)
{
/* The run-length is stored with a bias of -1 */
uint8_t tag = QOI_OP_RUN | (enc->run - 1);
enc->run = 0;

enc->offset++[0] = tag;
}

/*
WARNING: In this function below, you must provide enough memory to put the encoded images
The safest amount of space to store encoded images is the equation below
Expand Down Expand Up @@ -437,11 +503,7 @@ void qoi_encode_chunk(qoi_desc_t *desc, qoi_enc_t *enc, void *qoi_pixel_bytes)
occupied by the QOI_OP_RGB and QOI_OP_RGBA tags. */
if (++enc->run >= 62 || enc->pixel_offset >= enc->len)
{
/* The run-length is stored with a bias of -1 */
uint8_t tag = QOI_OP_RUN | (enc->run - 1);
enc->run = 0;

enc->offset++[0] = tag;
qoi_enc_run(enc);
}
}
else
Expand All @@ -450,19 +512,14 @@ void qoi_encode_chunk(qoi_desc_t *desc, qoi_enc_t *enc, void *qoi_pixel_bytes)
{
/* Write opcode for because there are differences in pixels
The run-length is stored with a bias of -1 */
uint8_t tag = QOI_OP_RUN | (enc->run - 1);
enc->run = 0;

enc->offset++[0] = tag;
qoi_enc_run(enc);

}

/* Check if pixels exist in one of the pixel hash buffers */
if (qoi_cmp_pixel(enc->buffer[index_pos], cur_pixel, 4))
{
uint8_t tag = QOI_OP_INDEX | index_pos;
enc->offset++[0] = tag;

qoi_enc_index(enc, index_pos);
}
else
{
Expand All @@ -471,21 +528,7 @@ void qoi_encode_chunk(qoi_desc_t *desc, qoi_enc_t *enc, void *qoi_pixel_bytes)
/* QOI doesn't have opcodes for alpha values so check alpha values between two pixels first */
if (desc->channels > 3 && cur_pixel.alpha != enc->prev_pixel.alpha)
{
uint8_t tag[5] =
{
QOI_OP_RGBA,
cur_pixel.red,
cur_pixel.green,
cur_pixel.blue,
cur_pixel.alpha
};

enc->offset[0] = tag[0];
enc->offset[1] = tag[1];
enc->offset[2] = tag[2];
enc->offset[3] = tag[3];
enc->offset[4] = tag[4];
enc->offset += 5;
qoi_enc_rgba(enc, cur_pixel);
}
else
{
Expand Down Expand Up @@ -533,19 +576,7 @@ void qoi_encode_chunk(qoi_desc_t *desc, qoi_enc_t *enc, void *qoi_pixel_bytes)
/* otherwise write an RGB tag containting the RGB values of a pixel */
else
{
uint8_t tag[4] = {
QOI_OP_RGB,
cur_pixel.red,
cur_pixel.green,
cur_pixel.blue
};

enc->offset[0] = tag[0];
enc->offset[1] = tag[1];
enc->offset[2] = tag[2];
enc->offset[3] = tag[3];

enc->offset += 4;
qoi_enc_rgb(enc, cur_pixel);
}
}

Expand All @@ -571,6 +602,57 @@ void qoi_encode_chunk(qoi_desc_t *desc, qoi_enc_t *enc, void *qoi_pixel_bytes)
}
}

static inline void qoi_dec_rgb(qoi_dec_t* dec)
{
dec->prev_pixel.red = dec->offset[1];
dec->prev_pixel.green = dec->offset[2];
dec->prev_pixel.blue = dec->offset[3];
dec->offset += 4;
}

static inline void qoi_dec_rgba(qoi_dec_t* dec)
{
dec->prev_pixel.red = dec->offset[1];
dec->prev_pixel.green = dec->offset[2];
dec->prev_pixel.blue = dec->offset[3];
dec->prev_pixel.alpha = dec->offset[4];
dec->offset += 5;
}

static inline void qoi_dec_index(qoi_dec_t* dec, uint8_t tag)
{
dec->prev_pixel = dec->buffer[tag & QOI_TAG_MASK];
dec->offset += 1;
}

static inline void qoi_dec_diff(qoi_dec_t* dec, uint8_t tag)
{
uint8_t diff = tag & QOI_TAG_MASK;

uint8_t red_diff = ((diff >> 4) & 0x03) - 2;
uint8_t green_diff = ((diff >> 2) & 0x03) - 2;
uint8_t blue_diff = (diff & 0x03) - 2;

dec->prev_pixel.red += red_diff;
dec->prev_pixel.green += green_diff;
dec->prev_pixel.blue += blue_diff;
dec->offset += 1;
}

static inline void qoi_dec_luma(qoi_dec_t* dec, uint8_t tag)
{
uint8_t lumaGreen = (tag & QOI_TAG_MASK) - 32;

dec->prev_pixel.red += lumaGreen + ((dec->offset[1] & 0xF0) >> 4) - 8;
dec->prev_pixel.green += lumaGreen;
dec->prev_pixel.blue += lumaGreen + (dec->offset[1] & 0x0F) - 8;

dec->offset += 2;
}
static inline void qoi_dec_run(qoi_dec_t* dec, uint8_t tag){
dec->run = tag & QOI_TAG_MASK;
dec->offset += 1;
}

/*
WARNING: In this function below, you must provide enough memory to put the decoded images
Expand All @@ -596,18 +678,11 @@ qoi_pixel_t qoi_decode_chunk(qoi_dec_t* dec)

if (tag == QOI_OP_RGB) /* RGB pixel */
{
dec->prev_pixel.red = dec->offset[1];
dec->prev_pixel.green = dec->offset[2];
dec->prev_pixel.blue = dec->offset[3];
dec->offset += 4;
qoi_dec_rgb(dec);
}
else if (tag == QOI_OP_RGBA) /* RGBA pixel */
{
dec->prev_pixel.red = dec->offset[1];
dec->prev_pixel.green = dec->offset[2];
dec->prev_pixel.blue = dec->offset[3];
dec->prev_pixel.alpha = dec->offset[4];
dec->offset += 5;
qoi_dec_rgba(dec);
}
else
{
Expand All @@ -617,41 +692,25 @@ qoi_pixel_t qoi_decode_chunk(qoi_dec_t* dec)
{
case QOI_OP_INDEX:
{
dec->prev_pixel = dec->buffer[tag & QOI_TAG_MASK];
dec->offset += 1;
qoi_dec_index(dec, tag);

break;
}
case QOI_OP_DIFF:
{
uint8_t diff = tag & QOI_TAG_MASK;
uint8_t red_diff = ((diff >> 4) & 0x03) - 2;
uint8_t green_diff = ((diff >> 2) & 0x03) - 2;
uint8_t blue_diff = (diff & 0x03) - 2;

dec->prev_pixel.red += red_diff;
dec->prev_pixel.green += green_diff;
dec->prev_pixel.blue += blue_diff;
dec->offset += 1;
qoi_dec_diff(dec, tag);

break;
}
case QOI_OP_LUMA:
{
uint8_t lumaGreen = (tag & QOI_TAG_MASK) - 32;

dec->prev_pixel.red += lumaGreen + ((dec->offset[1] & 0xF0) >> 4) - 8;
dec->prev_pixel.green += lumaGreen;
dec->prev_pixel.blue += lumaGreen + (dec->offset[1] & 0x0F) - 8;

dec->offset += 2;
qoi_dec_luma(dec, tag);

break;
}
case QOI_OP_RUN:
{
dec->run = tag & QOI_TAG_MASK;
dec->offset += 1;
qoi_dec_run(dec, tag);

break;
}
Expand Down

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