-- About
-QOI encodes and decodes images in a lossless format. An encoded QOI image is
-usually around 10--30% larger than a decently optimized PNG image.
-
-QOI outperforms simpler PNG encoders in compression ratio and performance. QOI
-images are typically 20% smaller than PNGs written with stbi_image. Encoding is
-25-50x faster and decoding is 3-4x faster than stbi_image or libpng.
+QOI encodes and decodes images in a lossless format. Compared to stb_image and
+stb_image_write QOI offers 20x-50x faster encoding, 3x-4x faster decoding and
+20% better compression.
-- Synopsis
// the input pixel data.
qoi_write("image_new.qoi", rgba_pixels, &(qoi_desc){
.width = 1920,
- .height = 1080,
+ .height = 1080,
.channels = 4,
.colorspace = QOI_SRGB
});
This library uses malloc() and free(). To supply your own malloc implementation
you can define QOI_MALLOC and QOI_FREE before including this library.
+This library uses memset() to zero-initialize the index. To supply your own
+implementation you can define QOI_ZEROARR before including this library.
+
-- Data Format
-A QOI file has a 14 byte header, followed by any number of data "chunks".
+A QOI file has a 14 byte header, followed by any number of data "chunks" and an
+8-byte end marker.
struct qoi_header_t {
char magic[4]; // magic bytes "qoif"
uint32_t width; // image width in pixels (BE)
uint32_t height; // image height in pixels (BE)
- uint8_t channels; // must be 3 (RGB) or 4 (RGBA)
- uint8_t colorspace; // a bitmap 0000rgba where
- // - a zero bit indicates sRGBA,
- // - a one bit indicates linear (user interpreted)
- // colorspace for each channel
+ uint8_t channels; // 3 = RGB, 4 = RGBA
+ uint8_t colorspace; // 0 = sRGB with linear alpha, 1 = all channels linear
};
-The decoder and encoder start with {r: 0, g: 0, b: 0, a: 255} as the previous
-pixel value. Pixels are either encoded as
+Images are encoded row by row, left to right, top to bottom. The decoder and
+encoder start with {r: 0, g: 0, b: 0, a: 255} as the previous pixel value. An
+image is complete when all pixels specified by width * height have been covered.
+
+Pixels are encoded as
- a run of the previous pixel
- - an index into a previously seen pixel
- - a difference to the previous pixel value in r,g,b,a
- - full r,g,b,a values
+ - an index into an array of previously seen pixels
+ - a difference to the previous pixel value in r,g,b
+ - full r,g,b or r,g,b,a values
+
+The color channels are assumed to not be premultiplied with the alpha channel
+("un-premultiplied alpha").
+
+A running array[64] (zero-initialized) of previously seen pixel values is
+maintained by the encoder and decoder. Each pixel that is seen by the encoder
+and decoder is put into this array at the position formed by a hash function of
+the color value. In the encoder, if the pixel value at the index matches the
+current pixel, this index position is written to the stream as QOI_OP_INDEX.
+The hash function for the index is:
+
+ index_position = (r * 3 + g * 5 + b * 7 + a * 11) % 64
+
+Each chunk starts with a 2- or 8-bit tag, followed by a number of data bits. The
+bit length of chunks is divisible by 8 - i.e. all chunks are byte aligned. All
+values encoded in these data bits have the most significant bit on the left.
+
+The 8-bit tags have precedence over the 2-bit tags. A decoder must check for the
+presence of an 8-bit tag first.
-A running array[64] of previously seen pixel values is maintained by the encoder
-and decoder. Each pixel that is seen by the encoder and decoder is put into this
-array at the position (r^g^b^a) % 64. In the encoder, if the pixel value at this
-index matches the current pixel, this index position is written to the stream.
+The byte stream's end is marked with 7 0x00 bytes followed a single 0x01 byte.
-Each chunk starts with a 2, 3 or 4 bit tag, followed by a number of data bits.
-The bit length of chunks is divisible by 8 - i.e. all chunks are byte aligned.
-All values encoded in these data bits have the most significant bit (MSB) on the
-left.
The possible chunks are:
- - QOI_INDEX -------------
+
+.- QOI_OP_INDEX ----------.
| Byte[0] |
| 7 6 5 4 3 2 1 0 |
|-------+-----------------|
| 0 0 | index |
-
+`-------------------------`
2-bit tag b00
6-bit index into the color index array: 0..63
-
- - QOI_RUN_8 -------------
-| Byte[0] |
-| 7 6 5 4 3 2 1 0 |
-|----------+--------------|
-| 0 1 0 | run |
-
-3-bit tag b010
-5-bit run-length repeating the previous pixel: 1..32
+A valid encoder must not issue 2 or more consecutive QOI_OP_INDEX chunks to the
+same index. QOI_OP_RUN should be used instead.
- - QOI_RUN_16 --------------------------------------
-| Byte[0] | Byte[1] |
-| 7 6 5 4 3 2 1 0 | 7 6 5 4 3 2 1 0 |
-|----------+----------------------------------------|
-| 0 1 1 | run |
-
-3-bit tag b011
-13-bit run-length repeating the previous pixel: 33..8224
-
-
- - QOI_DIFF_8 ------------
+.- QOI_OP_DIFF -----------.
| Byte[0] |
| 7 6 5 4 3 2 1 0 |
|-------+-----+-----+-----|
-| 1 0 | dr | db | bg |
-
-2-bit tag b10
+| 0 1 | dr | dg | db |
+`-------------------------`
+2-bit tag b01
2-bit red channel difference from the previous pixel between -2..1
2-bit green channel difference from the previous pixel between -2..1
2-bit blue channel difference from the previous pixel between -2..1
-The difference to the current channel values are using a wraparound operation,
+The difference to the current channel values are using a wraparound operation,
so "1 - 2" will result in 255, while "255 + 1" will result in 0.
+Values are stored as unsigned integers with a bias of 2. E.g. -2 is stored as
+0 (b00). 1 is stored as 3 (b11).
+
+The alpha value remains unchanged from the previous pixel.
- - QOI_DIFF_16 -------------------------------------
+
+.- QOI_OP_LUMA -------------------------------------.
| Byte[0] | Byte[1] |
| 7 6 5 4 3 2 1 0 | 7 6 5 4 3 2 1 0 |
-|----------+--------------|------------ +-----------|
-| 1 1 0 | red diff | green diff | blue diff |
+|-------+-----------------+-------------+-----------|
+| 1 0 | green diff | dr - dg | db - dg |
+`---------------------------------------------------`
+2-bit tag b10
+6-bit green channel difference from the previous pixel -32..31
+4-bit red channel difference minus green channel difference -8..7
+4-bit blue channel difference minus green channel difference -8..7
-3-bit tag b110
-5-bit red channel difference from the previous pixel between -16..15
-4-bit green channel difference from the previous pixel between -8..7
-4-bit blue channel difference from the previous pixel between -8..7
+The green channel is used to indicate the general direction of change and is
+encoded in 6 bits. The red and blue channels (dr and db) base their diffs off
+of the green channel difference and are encoded in 4 bits. I.e.:
+ dr_dg = (cur_px.r - prev_px.r) - (cur_px.g - prev_px.g)
+ db_dg = (cur_px.b - prev_px.b) - (cur_px.g - prev_px.g)
-The difference to the current channel values are using a wraparound operation,
+The difference to the current channel values are using a wraparound operation,
so "10 - 13" will result in 253, while "250 + 7" will result in 1.
+Values are stored as unsigned integers with a bias of 32 for the green channel
+and a bias of 8 for the red and blue channel.
- - QOI_DIFF_24 ---------------------------------------------------------------
-| Byte[0] | Byte[1] | Byte[2] |
-| 7 6 5 4 3 2 1 0 | 7 6 5 4 3 2 1 0 | 7 6 5 4 3 2 1 0 |
-|-------------+----------------+--------------+----------------+--------------|
-| 1 1 1 0 | red diff | green diff | blue diff | alpha diff |
+The alpha value remains unchanged from the previous pixel.
-4-bit tag b1110
-5-bit red channel difference from the previous pixel between -16..15
-5-bit green channel difference from the previous pixel between -16..15
-5-bit blue channel difference from the previous pixel between -16..15
-5-bit alpha channel difference from the previous pixel between -16..15
-The difference to the current channel values are using a wraparound operation,
-so "10 - 13" will result in 253, while "250 + 7" will result in 1.
-
-
- - QOI_COLOR -------------
+.- QOI_OP_RUN ------------.
| Byte[0] |
| 7 6 5 4 3 2 1 0 |
-|-------------+--+--+--+--|
-| 1 1 1 1 |hr|hg|hb|ha|
-
-4-bit tag b1111
-1-bit red byte follows
-1-bit green byte follows
-1-bit blue byte follows
-1-bit alpha byte follows
-
-For each set bit hr, hg, hb and ha another byte follows in this order. If such a
-byte follows, it will replace the current color channel value with the value of
-this byte.
-
-
-The byte stream is padded at the end with 4 zero bytes. Size the longest chunk
-we can encounter is 5 bytes (QOI_COLOR with RGBA set), with this padding we just
-have to check for an overrun once per decode loop iteration.
+|-------+-----------------|
+| 1 1 | run |
+`-------------------------`
+2-bit tag b11
+6-bit run-length repeating the previous pixel: 1..62
+
+The run-length is stored with a bias of -1. Note that the run-lengths 63 and 64
+(b111110 and b111111) are illegal as they are occupied by the QOI_OP_RGB and
+QOI_OP_RGBA tags.
+
+
+.- QOI_OP_RGB ------------------------------------------.
+| Byte[0] | Byte[1] | Byte[2] | Byte[3] |
+| 7 6 5 4 3 2 1 0 | 7 .. 0 | 7 .. 0 | 7 .. 0 |
+|-------------------------+---------+---------+---------|
+| 1 1 1 1 1 1 1 0 | red | green | blue |
+`-------------------------------------------------------`
+8-bit tag b11111110
+8-bit red channel value
+8-bit green channel value
+8-bit blue channel value
+
+The alpha value remains unchanged from the previous pixel.
+
+
+.- QOI_OP_RGBA ---------------------------------------------------.
+| Byte[0] | Byte[1] | Byte[2] | Byte[3] | Byte[4] |
+| 7 6 5 4 3 2 1 0 | 7 .. 0 | 7 .. 0 | 7 .. 0 | 7 .. 0 |
+|-------------------------+---------+---------+---------+---------|
+| 1 1 1 1 1 1 1 1 | red | green | blue | alpha |
+`-----------------------------------------------------------------`
+8-bit tag b11111111
+8-bit red channel value
+8-bit green channel value
+8-bit blue channel value
+8-bit alpha channel value
*/
-// -----------------------------------------------------------------------------
-// Header - Public functions
+/* -----------------------------------------------------------------------------
+Header - Public functions */
#ifndef QOI_H
#define QOI_H
extern "C" {
#endif
-// A pointer to qoi_desc struct has to be supplied to all of qoi's functions. It
-// describes either the input format (for qoi_write, qoi_encode), or is filled
-// with the description read from the file header (for qoi_read, qoi_decode).
+/* A pointer to a qoi_desc struct has to be supplied to all of qoi's functions.
+It describes either the input format (for qoi_write and qoi_encode), or is
+filled with the description read from the file header (for qoi_read and
+qoi_decode).
-// The colorspace in this qoi_desc is a bitmap with 0000rgba where a 0-bit
-// indicates sRGB and a 1-bit indicates linear colorspace for each channel. You
-// may use one of the predefined constants: QOI_SRGB, QOI_SRGB_LINEAR_ALPHA or
-// QOI_LINEAR. The colorspace is purely informative. It will be saved to the
-// file header, but does not affect en-/decoding in any way.
+The colorspace in this qoi_desc is an enum where
+ 0 = sRGB, i.e. gamma scaled RGB channels and a linear alpha channel
+ 1 = all channels are linear
+You may use the constants QOI_SRGB or QOI_LINEAR. The colorspace is purely
+informative. It will be saved to the file header, but does not affect
+how chunks are en-/decoded. */
-#define QOI_SRGB 0x00
-#define QOI_SRGB_LINEAR_ALPHA 0x01
-#define QOI_LINEAR 0x0f
+#define QOI_SRGB 0
+#define QOI_LINEAR 1
typedef struct {
unsigned int width;
#ifndef QOI_NO_STDIO
-// Encode raw RGB or RGBA pixels into a QOI image and write it to the file
-// system. The qoi_desc struct must be filled with the image width, height,
-// number of channels (3 = RGB, 4 = RGBA) and the colorspace.
+/* Encode raw RGB or RGBA pixels into a QOI image and write it to the file
+system. The qoi_desc struct must be filled with the image width, height,
+number of channels (3 = RGB, 4 = RGBA) and the colorspace.
-// The function returns 0 on failure (invalid parameters, or fopen or malloc
-// failed) or the number of bytes written on success.
+The function returns 0 on failure (invalid parameters, or fopen or malloc
+failed) or the number of bytes written on success. */
int qoi_write(const char *filename, const void *data, const qoi_desc *desc);
-// Read and decode a QOI image from the file system. If channels is 0, the
-// number of channels from the file header is used. If channels is 3 or 4 the
-// output format will be forced into this number of channels.
+/* Read and decode a QOI image from the file system. If channels is 0, the
+number of channels from the file header is used. If channels is 3 or 4 the
+output format will be forced into this number of channels.
-// The function either returns NULL on failure (invalid data, or malloc or fopen
-// failed) or a pointer to the decoded pixels. On success, the qoi_desc struct
-// will be filled with the description from the file header.
+The function either returns NULL on failure (invalid data, or malloc or fopen
+failed) or a pointer to the decoded pixels. On success, the qoi_desc struct
+will be filled with the description from the file header.
-// The returned pixel data should be free()d after use.
+The returned pixel data should be free()d after use. */
void *qoi_read(const char *filename, qoi_desc *desc, int channels);
-#endif // QOI_NO_STDIO
+#endif /* QOI_NO_STDIO */
-// Encode raw RGB or RGBA pixels into a QOI image in memory.
+/* Encode raw RGB or RGBA pixels into a QOI image in memory.
-// The function either returns NULL on failure (invalid parameters or malloc
-// failed) or a pointer to the encoded data on success. On success the out_len
-// is set to the size in bytes of the encoded data.
+The function either returns NULL on failure (invalid parameters or malloc
+failed) or a pointer to the encoded data on success. On success the out_len
+is set to the size in bytes of the encoded data.
-// The returned qoi data should be free()d after use.
+The returned qoi data should be free()d after use. */
void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len);
-// Decode a QOI image from memory.
+/* Decode a QOI image from memory.
-// The function either returns NULL on failure (invalid parameters or malloc
-// failed) or a pointer to the decoded pixels. On success, the qoi_desc struct
-// is filled with the description from the file header.
+The function either returns NULL on failure (invalid parameters or malloc
+failed) or a pointer to the decoded pixels. On success, the qoi_desc struct
+is filled with the description from the file header.
-// The returned pixel data should be free()d after use.
+The returned pixel data should be free()d after use. */
void *qoi_decode(const void *data, int size, qoi_desc *desc, int channels);
#ifdef __cplusplus
}
#endif
-#endif // QOI_H
+#endif /* QOI_H */
-// -----------------------------------------------------------------------------
-// Implementation
+/* -----------------------------------------------------------------------------
+Implementation */
#ifdef QOI_IMPLEMENTATION
#include <stdlib.h>
+#include <string.h>
#ifndef QOI_MALLOC
#define QOI_MALLOC(sz) malloc(sz)
#define QOI_FREE(p) free(p)
#endif
+#ifndef QOI_ZEROARR
+ #define QOI_ZEROARR(a) memset((a),0,sizeof(a))
+#endif
-#define QOI_INDEX 0x00 // 00xxxxxx
-#define QOI_RUN_8 0x40 // 010xxxxx
-#define QOI_RUN_16 0x60 // 011xxxxx
-#define QOI_DIFF_8 0x80 // 10xxxxxx
-#define QOI_DIFF_16 0xc0 // 110xxxxx
-#define QOI_DIFF_24 0xe0 // 1110xxxx
-#define QOI_COLOR 0xf0 // 1111xxxx
+#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_MASK_3 0xe0 // 11100000
-#define QOI_MASK_4 0xf0 // 11110000
+#define QOI_MASK_2 0xc0 /* 11000000 */
-#define QOI_COLOR_HASH(C) (C.rgba.r ^ C.rgba.g ^ C.rgba.b ^ C.rgba.a)
+#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
-#define QOI_PADDING 4
+
+/* 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;
} qoi_rgba_t;
-void qoi_write_32(unsigned char *bytes, int *p, unsigned int v) {
+static const unsigned char qoi_padding[8] = {0,0,0,0,0,0,0,1};
+
+static void qoi_write_32(unsigned char *bytes, int *p, unsigned int v) {
bytes[(*p)++] = (0xff000000 & v) >> 24;
bytes[(*p)++] = (0x00ff0000 & v) >> 16;
bytes[(*p)++] = (0x0000ff00 & v) >> 8;
bytes[(*p)++] = (0x000000ff & v);
}
-unsigned int qoi_read_32(const unsigned char *bytes, int *p) {
+static unsigned int qoi_read_32(const unsigned char *bytes, int *p) {
unsigned int a = bytes[(*p)++];
unsigned int b = bytes[(*p)++];
unsigned int c = bytes[(*p)++];
unsigned int d = bytes[(*p)++];
- return (a << 24) | (b << 16) | (c << 8) | d;
+ return a << 24 | b << 16 | c << 8 | d;
}
void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len) {
+ int i, max_size, p, run;
+ int px_len, px_end, px_pos, channels;
+ unsigned char *bytes;
+ const unsigned char *pixels;
+ qoi_rgba_t index[64];
+ qoi_rgba_t px, px_prev;
+
if (
data == NULL || out_len == NULL || desc == NULL ||
desc->width == 0 || desc->height == 0 ||
desc->channels < 3 || desc->channels > 4 ||
- (desc->colorspace & 0xf0) != 0
+ desc->colorspace > 1 ||
+ desc->height >= QOI_PIXELS_MAX / desc->width
) {
return NULL;
}
- int max_size =
- desc->width * desc->height * (desc->channels + 1) +
- QOI_HEADER_SIZE + QOI_PADDING;
+ max_size =
+ desc->width * desc->height * (desc->channels + 1) +
+ QOI_HEADER_SIZE + sizeof(qoi_padding);
- int p = 0;
- unsigned char *bytes = QOI_MALLOC(max_size);
+ p = 0;
+ bytes = (unsigned char *) QOI_MALLOC(max_size);
if (!bytes) {
return NULL;
}
bytes[p++] = desc->colorspace;
- const unsigned char *pixels = (const unsigned char *)data;
+ pixels = (const unsigned char *)data;
+
+ QOI_ZEROARR(index);
- qoi_rgba_t index[64] = {0};
+ run = 0;
+ px_prev.rgba.r = 0;
+ px_prev.rgba.g = 0;
+ px_prev.rgba.b = 0;
+ px_prev.rgba.a = 255;
+ px = px_prev;
- int run = 0;
- qoi_rgba_t px_prev = {.rgba = {.r = 0, .g = 0, .b = 0, .a = 255}};
- qoi_rgba_t px = px_prev;
-
- int px_len = desc->width * desc->height * desc->channels;
- int px_end = px_len - desc->channels;
- int channels = desc->channels;
+ px_len = desc->width * desc->height * desc->channels;
+ px_end = px_len - desc->channels;
+ channels = desc->channels;
- for (int px_pos = 0; px_pos < px_len; px_pos += channels) {
+ for (px_pos = 0; px_pos < px_len; px_pos += channels) {
if (channels == 4) {
px = *(qoi_rgba_t *)(pixels + px_pos);
}
else {
- px.rgba.r = pixels[px_pos];
- px.rgba.g = pixels[px_pos+1];
- px.rgba.b = pixels[px_pos+2];
+ px.rgba.r = pixels[px_pos + 0];
+ px.rgba.g = pixels[px_pos + 1];
+ px.rgba.b = pixels[px_pos + 2];
}
if (px.v == px_prev.v) {
run++;
+ if (run == 62 || px_pos == px_end) {
+ bytes[p++] = QOI_OP_RUN | (run - 1);
+ run = 0;
+ }
}
+ else {
+ int index_pos;
- if (
- run > 0 &&
- (run == 0x2020 || px.v != px_prev.v || px_pos == px_end)
- ) {
- if (run < 33) {
- run -= 1;
- bytes[p++] = QOI_RUN_8 | run;
+ if (run > 0) {
+ bytes[p++] = QOI_OP_RUN | (run - 1);
+ run = 0;
}
- else {
- run -= 33;
- bytes[p++] = QOI_RUN_16 | run >> 8;
- bytes[p++] = run;
- }
- run = 0;
- }
- if (px.v != px_prev.v) {
- int index_pos = QOI_COLOR_HASH(px) % 64;
+ index_pos = QOI_COLOR_HASH(px) % 64;
if (index[index_pos].v == px.v) {
- bytes[p++] = QOI_INDEX | index_pos;
+ bytes[p++] = QOI_OP_INDEX | index_pos;
}
else {
index[index_pos] = px;
- int vr = px.rgba.r - px_prev.rgba.r;
- int vg = px.rgba.g - px_prev.rgba.g;
- int vb = px.rgba.b - px_prev.rgba.b;
- int va = px.rgba.a - px_prev.rgba.a;
-
- if (
- vr > -17 && vr < 16 &&
- vg > -17 && vg < 16 &&
- vb > -17 && vb < 16 &&
- va > -17 && va < 16
- ) {
+ if (px.rgba.a == px_prev.rgba.a) {
+ signed char vr = px.rgba.r - px_prev.rgba.r;
+ signed char vg = px.rgba.g - px_prev.rgba.g;
+ signed char vb = px.rgba.b - px_prev.rgba.b;
+
+ signed char vg_r = vr - vg;
+ signed char vg_b = vb - vg;
+
if (
- va == 0 &&
vr > -3 && vr < 2 &&
- vg > -3 && vg < 2 &&
+ vg > -3 && vg < 2 &&
vb > -3 && vb < 2
) {
- bytes[p++] = QOI_DIFF_8 | ((vr + 2) << 4) | (vg + 2) << 2 | (vb + 2);
+ bytes[p++] = QOI_OP_DIFF | (vr + 2) << 4 | (vg + 2) << 2 | (vb + 2);
}
else if (
- va == 0 &&
- vr > -17 && vr < 16 &&
- vg > -9 && vg < 8 &&
- vb > -9 && vb < 8
+ vg_r > -9 && vg_r < 8 &&
+ vg > -33 && vg < 32 &&
+ vg_b > -9 && vg_b < 8
) {
- bytes[p++] = QOI_DIFF_16 | (vr + 16);
- bytes[p++] = (vg + 8) << 4 | (vb + 8);
+ bytes[p++] = QOI_OP_LUMA | (vg + 32);
+ bytes[p++] = (vg_r + 8) << 4 | (vg_b + 8);
}
else {
- bytes[p++] = QOI_DIFF_24 | (vr + 16) >> 1;
- bytes[p++] = (vr + 16) << 7 | (vg + 16) << 2 | (vb + 16) >> 3;
- bytes[p++] = (vb + 16) << 5 | (va + 16);
+ bytes[p++] = QOI_OP_RGB;
+ bytes[p++] = px.rgba.r;
+ bytes[p++] = px.rgba.g;
+ bytes[p++] = px.rgba.b;
}
}
else {
- bytes[p++] = QOI_COLOR | (vr ? 8 : 0) | (vg ? 4 : 0) | (vb ? 2 : 0) | (va ? 1 : 0);
- if (vr) { bytes[p++] = px.rgba.r; }
- if (vg) { bytes[p++] = px.rgba.g; }
- if (vb) { bytes[p++] = px.rgba.b; }
- if (va) { bytes[p++] = px.rgba.a; }
+ bytes[p++] = QOI_OP_RGBA;
+ bytes[p++] = px.rgba.r;
+ bytes[p++] = px.rgba.g;
+ bytes[p++] = px.rgba.b;
+ bytes[p++] = px.rgba.a;
}
}
}
px_prev = px;
}
- for (int i = 0; i < QOI_PADDING; i++) {
- bytes[p++] = 0;
+ for (i = 0; i < (int)sizeof(qoi_padding); i++) {
+ bytes[p++] = qoi_padding[i];
}
*out_len = p;
}
void *qoi_decode(const void *data, int size, qoi_desc *desc, int channels) {
+ const unsigned char *bytes;
+ unsigned int header_magic;
+ unsigned char *pixels;
+ qoi_rgba_t index[64];
+ qoi_rgba_t px;
+ int px_len, chunks_len, px_pos;
+ int p = 0, run = 0;
+
if (
data == NULL || desc == NULL ||
(channels != 0 && channels != 3 && channels != 4) ||
- size < QOI_HEADER_SIZE + QOI_PADDING
+ size < QOI_HEADER_SIZE + (int)sizeof(qoi_padding)
) {
return NULL;
}
- const unsigned char *bytes = (const unsigned char *)data;
- int p = 0;
+ bytes = (const unsigned char *)data;
- unsigned int header_magic = qoi_read_32(bytes, &p);
+ header_magic = qoi_read_32(bytes, &p);
desc->width = qoi_read_32(bytes, &p);
desc->height = qoi_read_32(bytes, &p);
desc->channels = bytes[p++];
desc->colorspace = bytes[p++];
if (
- desc->width == 0 || desc->height == 0 ||
+ desc->width == 0 || desc->height == 0 ||
desc->channels < 3 || desc->channels > 4 ||
- header_magic != QOI_MAGIC
+ desc->colorspace > 1 ||
+ header_magic != QOI_MAGIC ||
+ desc->height >= QOI_PIXELS_MAX / desc->width
) {
return NULL;
}
channels = desc->channels;
}
- int px_len = desc->width * desc->height * channels;
- unsigned char *pixels = QOI_MALLOC(px_len);
+ px_len = desc->width * desc->height * channels;
+ pixels = (unsigned char *) QOI_MALLOC(px_len);
if (!pixels) {
return NULL;
}
- qoi_rgba_t px = {.rgba = {.r = 0, .g = 0, .b = 0, .a = 255}};
- qoi_rgba_t index[64] = {0};
+ QOI_ZEROARR(index);
+ px.rgba.r = 0;
+ px.rgba.g = 0;
+ px.rgba.b = 0;
+ px.rgba.a = 255;
- int run = 0;
- int chunks_len = size - QOI_PADDING;
- for (int px_pos = 0; px_pos < px_len; px_pos += channels) {
+ chunks_len = size - (int)sizeof(qoi_padding);
+ for (px_pos = 0; px_pos < px_len; px_pos += channels) {
if (run > 0) {
run--;
}
else if (p < chunks_len) {
int b1 = bytes[p++];
- if ((b1 & QOI_MASK_2) == QOI_INDEX) {
- px = index[b1 ^ QOI_INDEX];
+ if (b1 == QOI_OP_RGB) {
+ px.rgba.r = bytes[p++];
+ px.rgba.g = bytes[p++];
+ px.rgba.b = bytes[p++];
}
- else if ((b1 & QOI_MASK_3) == QOI_RUN_8) {
- run = (b1 & 0x1f);
+ else if (b1 == QOI_OP_RGBA) {
+ px.rgba.r = bytes[p++];
+ px.rgba.g = bytes[p++];
+ px.rgba.b = bytes[p++];
+ px.rgba.a = bytes[p++];
}
- else if ((b1 & QOI_MASK_3) == QOI_RUN_16) {
- int b2 = bytes[p++];
- run = (((b1 & 0x1f) << 8) | (b2)) + 32;
+ else if ((b1 & QOI_MASK_2) == QOI_OP_INDEX) {
+ px = index[b1];
}
- else if ((b1 & QOI_MASK_2) == QOI_DIFF_8) {
+ 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_3) == QOI_DIFF_16) {
- int b2 = bytes[p++];
- px.rgba.r += (b1 & 0x1f) - 16;
- px.rgba.g += (b2 >> 4) - 8;
- px.rgba.b += (b2 & 0x0f) - 8;
- }
- else if ((b1 & QOI_MASK_4) == QOI_DIFF_24) {
+ else if ((b1 & QOI_MASK_2) == QOI_OP_LUMA) {
int b2 = bytes[p++];
- int b3 = bytes[p++];
- px.rgba.r += (((b1 & 0x0f) << 1) | (b2 >> 7)) - 16;
- px.rgba.g += ((b2 & 0x7c) >> 2) - 16;
- px.rgba.b += (((b2 & 0x03) << 3) | ((b3 & 0xe0) >> 5)) - 16;
- px.rgba.a += (b3 & 0x1f) - 16;
+ int 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_4) == QOI_COLOR) {
- if (b1 & 8) { px.rgba.r = bytes[p++]; }
- if (b1 & 4) { px.rgba.g = bytes[p++]; }
- if (b1 & 2) { px.rgba.b = bytes[p++]; }
- if (b1 & 1) { px.rgba.a = bytes[p++]; }
+ else if ((b1 & QOI_MASK_2) == QOI_OP_RUN) {
+ run = (b1 & 0x3f);
}
index[QOI_COLOR_HASH(px) % 64] = px;
}
- if (channels == 4) {
+ if (channels == 4) {
*(qoi_rgba_t*)(pixels + px_pos) = px;
}
else {
- pixels[px_pos] = px.rgba.r;
- pixels[px_pos+1] = px.rgba.g;
- pixels[px_pos+2] = px.rgba.b;
+ pixels[px_pos + 0] = px.rgba.r;
+ pixels[px_pos + 1] = px.rgba.g;
+ pixels[px_pos + 2] = px.rgba.b;
}
}
int qoi_write(const char *filename, const void *data, const qoi_desc *desc) {
FILE *f = fopen(filename, "wb");
+ int size;
+ void *encoded;
+
if (!f) {
return 0;
}
- int size;
- void *encoded = qoi_encode(data, desc, &size);
+ encoded = qoi_encode(data, desc, &size);
if (!encoded) {
fclose(f);
return 0;
- }
-
+ }
+
fwrite(encoded, 1, size, f);
fclose(f);
-
+
QOI_FREE(encoded);
return size;
}
void *qoi_read(const char *filename, qoi_desc *desc, int channels) {
FILE *f = fopen(filename, "rb");
+ int size, bytes_read;
+ void *pixels, *data;
+
if (!f) {
return NULL;
}
fseek(f, 0, SEEK_END);
- int size = ftell(f);
+ size = ftell(f);
+ if (size <= 0) {
+ fclose(f);
+ return NULL;
+ }
fseek(f, 0, SEEK_SET);
- void *data = QOI_MALLOC(size);
+ data = QOI_MALLOC(size);
if (!data) {
fclose(f);
return NULL;
}
- int bytes_read = fread(data, 1, size, f);
+ bytes_read = fread(data, 1, size, f);
fclose(f);
- void *pixels = qoi_decode(data, bytes_read, desc, channels);
+ pixels = qoi_decode(data, bytes_read, desc, channels);
QOI_FREE(data);
return pixels;
}
-#endif // QOI_NO_STDIO
-#endif // QOI_IMPLEMENTATION
-
+#endif /* QOI_NO_STDIO */
+#endif /* QOI_IMPLEMENTATION */
projects / fishladder.git / blobdiff