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#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include "pm.h"
#include "mallocvar.h"
#include "qoi.h"
#define ZEROARRAY(a) memset((a),0,sizeof(a))
#define QOI_OP_INDEX 0x00 /* 00xxxxxx */
#define QOI_OP_DIFF 0x40 /* 01xxxxxx */
#define QOI_OP_LUMA 0x80 /* 10xxxxxx */
#define QOI_OP_RUN 0xc0 /* 11xxxxxx */
#define QOI_OP_RGB 0xfe /* 11111110 */
#define QOI_OP_RGBA 0xff /* 11111111 */
#define QOI_MASK_2 0xc0 /* 11000000 */
#define QOI_COLOR_HASH(C) (C.rgba.r*3 + C.rgba.g*5 + C.rgba.b*7 + C.rgba.a*11)
#define QOI_MAGIC \
(((unsigned int)'q') << 24 | ((unsigned int)'o') << 16 | \
((unsigned int)'i') << 8 | ((unsigned int)'f'))
#define QOI_HEADER_SIZE 14
/* 2GB is the max file size that this implementation can safely handle. We
guard against anything larger than that, assuming the worst case with 5
bytes per pixel, rounded down to a nice clean value. 400 million pixels
ought to be enough for anybody.
*/
#define QOI_PIXELS_MAX ((unsigned int)400000000)
typedef union {
struct { unsigned char r, g, b, a; } rgba;
unsigned int v;
} Rgba;
static unsigned char const padding[8] = {0,0,0,0,0,0,0,1};
static void
write32(unsigned char * const bytes,
size_t * const cursorP,
unsigned int const v) {
bytes[(*cursorP)++] = (0xff000000 & v) >> 24;
bytes[(*cursorP)++] = (0x00ff0000 & v) >> 16;
bytes[(*cursorP)++] = (0x0000ff00 & v) >> 8;
bytes[(*cursorP)++] = (0x000000ff & v);
}
static unsigned int
read32(const unsigned char * const bytes,
size_t * const cursorP) {
unsigned int a = bytes[(*cursorP)++];
unsigned int b = bytes[(*cursorP)++];
unsigned int c = bytes[(*cursorP)++];
unsigned int d = bytes[(*cursorP)++];
return a << 24 | b << 16 | c << 8 | d;
}
static void
encodeQoiHeader(unsigned char * const bytes,
qoi_Desc const qoiDesc,
size_t * const cursorP) {
write32(bytes, cursorP, QOI_MAGIC);
write32(bytes, cursorP, qoiDesc.width);
write32(bytes, cursorP, qoiDesc.height);
bytes[(*cursorP)++] = qoiDesc.channelCt;
bytes[(*cursorP)++] = qoiDesc.colorspace;
}
static void
encodeNewPixel(Rgba const px,
Rgba const pxPrev,
unsigned char * const bytes,
size_t * const cursorP) {
if (px.rgba.a == pxPrev.rgba.a) {
signed char const vr = px.rgba.r - pxPrev.rgba.r;
signed char const vg = px.rgba.g - pxPrev.rgba.g;
signed char const vb = px.rgba.b - pxPrev.rgba.b;
signed char const vgR = vr - vg;
signed char const vgB = vb - vg;
if (
vr > -3 && vr < 2 &&
vg > -3 && vg < 2 &&
vb > -3 && vb < 2
) {
bytes[(*cursorP)++] = QOI_OP_DIFF |
(vr + 2) << 4 | (vg + 2) << 2 | (vb + 2);
} else if (
vgR > -9 && vgR < 8 &&
vg > -33 && vg < 32 &&
vgB > -9 && vgB < 8
) {
bytes[(*cursorP)++] = QOI_OP_LUMA | (vg + 32);
bytes[(*cursorP)++] = (vgR + 8) << 4 | (vgB + 8);
} else {
bytes[(*cursorP)++] = QOI_OP_RGB;
bytes[(*cursorP)++] = px.rgba.r;
bytes[(*cursorP)++] = px.rgba.g;
bytes[(*cursorP)++] = px.rgba.b;
}
} else {
bytes[(*cursorP)++] = QOI_OP_RGBA;
bytes[(*cursorP)++] = px.rgba.r;
bytes[(*cursorP)++] = px.rgba.g;
bytes[(*cursorP)++] = px.rgba.b;
bytes[(*cursorP)++] = px.rgba.a;
}
}
void
qoi_encode(const unsigned char * const pixels,
const qoi_Desc * const descP,
const unsigned char ** const qoiImageP,
size_t * const outLenP) {
size_t cursor;
unsigned int i, maxSize, run;
unsigned int pxLen, pxEnd, pxPos;
unsigned char * bytes;
Rgba index[64];
Rgba px, pxPrev;
assert(pixels);
assert(descP);
assert(outLenP);
assert(descP->width > 0);
assert(descP->height > 0);
assert(descP->channelCt >= 3 && descP->channelCt <= 4);
assert(descP->colorspace == QOI_SRGB || descP->colorspace == QOI_LINEAR);
if (descP->height >= QOI_PIXELS_MAX / descP->width)
pm_error("Too many pixles for OQI: %u x %u (max is %u",
descP->height, descP->width, QOI_PIXELS_MAX);
maxSize =
descP->width * descP->height * (descP->channelCt + 1) +
QOI_HEADER_SIZE + sizeof(padding);
MALLOCARRAY(bytes, maxSize);
if (!bytes)
pm_error("Cannot allocate %u bytes", maxSize);
cursor = 0;
encodeQoiHeader(bytes, *descP, &cursor);
ZEROARRAY(index);
run = 0;
pxPrev.rgba.r = 0;
pxPrev.rgba.g = 0;
pxPrev.rgba.b = 0;
pxPrev.rgba.a = 255;
px = pxPrev;
pxLen = descP->width * descP->height * descP->channelCt;
pxEnd = pxLen - descP->channelCt;
for (pxPos = 0; pxPos < pxLen; pxPos += descP->channelCt) {
px.rgba.r = pixels[pxPos + 0];
px.rgba.g = pixels[pxPos + 1];
px.rgba.b = pixels[pxPos + 2];
if (descP->channelCt == 4) {
px.rgba.a = pixels[pxPos + 3];
}
if (px.v == pxPrev.v) {
++run;
if (run == 62 || pxPos == pxEnd) {
bytes[cursor++] = QOI_OP_RUN | (run - 1);
run = 0;
}
} else {
unsigned int const indexPos = QOI_COLOR_HASH(px) % 64;
if (run > 0) {
bytes[cursor++] = QOI_OP_RUN | (run - 1);
run = 0;
}
if (index[indexPos].v == px.v) {
bytes[cursor++] = QOI_OP_INDEX | indexPos;
} else {
index[indexPos] = px;
encodeNewPixel(px, pxPrev, bytes, &cursor);
}
}
pxPrev = px;
}
for (i = 0; i < sizeof(padding); ++i)
bytes[cursor++] = padding[i];
*qoiImageP = bytes;
*outLenP = cursor;
}
static void
decodeQoiHeader(const unsigned char * const qoiImage,
qoi_Desc * const qoiDescP,
size_t * const cursorP) {
unsigned int headerMagic;
headerMagic = read32(qoiImage, cursorP);
qoiDescP->width = read32(qoiImage, cursorP);
qoiDescP->height = read32(qoiImage, cursorP);
qoiDescP->channelCt = qoiImage[(*cursorP)++];
qoiDescP->colorspace = qoiImage[(*cursorP)++];
if (qoiDescP->width == 0)
pm_error("Invalid QOI image: width is zero");
if (qoiDescP->height == 0)
pm_error("Invalid QOI image: height is zero");
if (qoiDescP->channelCt != 3 && qoiDescP->channelCt != 4)
pm_error("Invalid QOI image: channel count is %u. "
"Only 3 and 4 are valid", qoiDescP->channelCt);
if (qoiDescP->colorspace != QOI_SRGB && qoiDescP->colorspace != QOI_LINEAR)
pm_error("Invalid QOI image: colorspace code is %u. "
"Only %u (SRGB) and %u (LINEAR) are valid",
qoiDescP->colorspace, QOI_SRGB, QOI_LINEAR);
if (headerMagic != QOI_MAGIC)
pm_error("Invalid QOI image: Where the magic number 0x%04x "
"should be, there is 0x%04x",
QOI_MAGIC, headerMagic);
if (qoiDescP->height >= QOI_PIXELS_MAX / qoiDescP->width)
pm_error ("Invalid QOI image: %u x %u is More than %u pixels",
qoiDescP->width, qoiDescP->height, QOI_PIXELS_MAX);
}
void
qoi_decode(const unsigned char * const qoiImage,
size_t const size,
qoi_Desc * const qoiDescP,
const unsigned char ** const qoiRasterP) {
unsigned int const chunksLen = size - sizeof(padding);
unsigned char * pixels;
Rgba index[64];
Rgba px;
unsigned int pxLen, pxPos;
size_t cursor;
unsigned int run;
assert(qoiImage);
assert(qoiDescP);
assert(size >= QOI_HEADER_SIZE + sizeof(padding));
cursor = 0;
decodeQoiHeader(qoiImage, qoiDescP, &cursor);
pxLen = qoiDescP->width * qoiDescP->height * qoiDescP->channelCt;
MALLOCARRAY(pixels, pxLen);
if (!pixels)
pm_error("Failed to allocate %u bytes for %u x %u x %u QOI raster",
pxLen,
qoiDescP->width, qoiDescP->height, qoiDescP->channelCt);
ZEROARRAY(index);
px.rgba.r = 0;
px.rgba.g = 0;
px.rgba.b = 0;
px.rgba.a = 255;
for (pxPos = 0, run = 0; pxPos < pxLen; pxPos += qoiDescP->channelCt) {
if (run > 0) {
--run;
} else if (cursor < chunksLen) {
unsigned char const b1 = qoiImage[cursor++];
if (b1 == QOI_OP_RGB) {
px.rgba.r = qoiImage[cursor++];
px.rgba.g = qoiImage[cursor++];
px.rgba.b = qoiImage[cursor++];
} else if (b1 == QOI_OP_RGBA) {
px.rgba.r = qoiImage[cursor++];
px.rgba.g = qoiImage[cursor++];
px.rgba.b = qoiImage[cursor++];
px.rgba.a = qoiImage[cursor++];
} else if ((b1 & QOI_MASK_2) == QOI_OP_INDEX) {
px = index[b1];
} else if ((b1 & QOI_MASK_2) == QOI_OP_DIFF) {
px.rgba.r += ((b1 >> 4) & 0x03) - 2;
px.rgba.g += ((b1 >> 2) & 0x03) - 2;
px.rgba.b += ( b1 & 0x03) - 2;
} else if ((b1 & QOI_MASK_2) == QOI_OP_LUMA) {
unsigned char const b2 = qoiImage[cursor++];
unsigned char const vg = (b1 & 0x3f) - 32;
px.rgba.r += vg - 8 + ((b2 >> 4) & 0x0f);
px.rgba.g += vg;
px.rgba.b += vg - 8 + (b2 & 0x0f);
} else if ((b1 & QOI_MASK_2) == QOI_OP_RUN) {
run = (b1 & 0x3f);
}
index[QOI_COLOR_HASH(px) % 64] = px;
}
pixels[pxPos + 0] = px.rgba.r;
pixels[pxPos + 1] = px.rgba.g;
pixels[pxPos + 2] = px.rgba.b;
if (qoiDescP->channelCt == 4)
pixels[pxPos + 3] = px.rgba.a;
}
*qoiRasterP = pixels;
}
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