/*
-QOI - The “Quite OK Image” format for fast, lossless image compression
+QOI - The "Quite OK Image" format for fast, lossless image compression
Dominic Szablewski - https://phoboslab.org
-- 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 but 10%
-larger than with libpng. 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
#define QOI_IMPLEMENTATION
#include "qoi.h"
-// Load and decode a QOI image from the file system into a 32bbp RGBA buffer
-int width, height;
-void *rgba_pixels = qoi_read("image.qoi", &width, &height, 4);
+// Encode and store an RGBA buffer to the file system. The qoi_desc describes
+// the input pixel data.
+qoi_write("image_new.qoi", rgba_pixels, &(qoi_desc){
+ .width = 1920,
+ .height = 1080,
+ .channels = 4,
+ .colorspace = QOI_SRGB
+});
+
+// Load and decode a QOI image from the file system into a 32bbp RGBA buffer.
+// The qoi_desc struct will be filled with the width, height, number of channels
+// and colorspace read from the file header.
+qoi_desc desc;
+void *rgba_pixels = qoi_read("image.qoi", &desc, 4);
-// Encode and store an RGBA buffer to the file system
-qoi_write("image_new.qoi", rgba_pixels, width, height, 4);
-- Documentation
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 12 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 [4]; // magic bytes "qoif"
- unsigned short width; // image width in pixels (BE)
- unsigned short height; // image height in pixels (BE)
- unsigned int size; // number of data bytes following this header (BE)
+ 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; // 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
-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 color channels are assumed to not be premultiplied with the alpha channel
+("un-premultiplied alpha").
-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.
+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:
-QOI_INDEX {
- u8 tag : 2; // b00
- u8 idx : 6; // 6-bit index into the color index array: 0..63
-}
+ index_position = (r * 3 + g * 5 + b * 7 + a * 11) % 64
-QOI_RUN_8 {
- u8 tag : 3; // b010
- u8 run : 5; // 5-bit run-length repeating the previous pixel: 1..32
-}
+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.
-QOI_RUN_16 {
- u8 tag : 3; // b011
- u16 run : 13; // 13-bit run-length repeating the previous pixel: 33..8224
-}
+The 8-bit tags have precedence over the 2-bit tags. A decoder must check for the
+presence of an 8-bit tag first.
+
+The byte stream's end is marked with 7 0x00 bytes followed a single 0x01 byte.
+
+
+The possible chunks are:
+
+
+.- 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
+
+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_OP_DIFF -----------.
+| Byte[0] |
+| 7 6 5 4 3 2 1 0 |
+|-------+-----+-----+-----|
+| 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,
+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_OP_LUMA -------------------------------------.
+| Byte[0] | Byte[1] |
+| 7 6 5 4 3 2 1 0 | 7 6 5 4 3 2 1 0 |
+|-------+-----------------+-------------+-----------|
+| 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
+
+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,
+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.
+
+The alpha value remains unchanged from the previous pixel.
+
+
+.- QOI_OP_RUN ------------.
+| Byte[0] |
+| 7 6 5 4 3 2 1 0 |
+|-------+-----------------|
+| 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_DIFF_8 {
- u8 tag : 2; // b10
- u8 dr : 2; // 2-bit red channel difference: -1..2
- u8 dg : 2; // 2-bit green channel difference: -1..2
- u8 db : 2; // 2-bit blue channel difference: -1..2
-}
-QOI_DIFF_16 {
- u8 tag : 3; // b110
- u8 dr : 5; // 5-bit red channel difference: -15..16
- u8 dg : 4; // 4-bit green channel difference: -7.. 8
- u8 db : 4; // 4-bit blue channel difference: -7.. 8
-}
+.- 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
-QOI_DIFF_24 {
- u8 tag : 4; // b1110
- u8 dr : 5; // 5-bit red channel difference: -15..16
- u8 dg : 5; // 5-bit green channel difference: -15..16
- u8 db : 5; // 5-bit blue channel difference: -15..16
- u8 da : 5; // 5-bit alpha channel difference: -15..16
-}
+The alpha value remains unchanged from the previous pixel.
-QOI_COLOR {
- u8 tag : 4; // b1111
- u8 has_r: 1; // red byte follows
- u8 has_g: 1; // green byte follows
- u8 has_b: 1; // blue byte follows
- u8 has_a: 1; // alpha byte follows
- u8 r; // red value if has_r == 1: 0..255
- u8 g; // green value if has_g == 1: 0..255
- u8 b; // blue value if has_b == 1: 0..255
- u8 a; // alpha value if has_a == 1: 0..255
-}
-The byte stream is padded 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.
+.- 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 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 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 0
+#define QOI_LINEAR 1
+
+typedef struct {
+ unsigned int width;
+ unsigned int height;
+ unsigned char channels;
+ unsigned char colorspace;
+} qoi_desc;
+
#ifndef QOI_NO_STDIO
-// Encode raw RGB or RGBA pixels into a QOI image write it to the file system.
-// w and h denote the the width and height of the pixel data. channels must be
-// either 3 for RGB data or 4 for RGBA.
-// The function returns 0 on failure (invalid parameters, or fopen or malloc
-// failed) or the number of bytes written on success.
+/* 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.
-int qoi_write(const char *filename, const void *data, int w, int h, int channels);
+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 into either raw RGB
-// (channels=3) or RGBA (channels=4) pixel data.
-// The function either returns NULL on failure (invalid data, or malloc or fopen
-// failed) or a pointer to the decoded pixels. On success out_w and out_h will
-// be set to the width and height of the decoded image.
-// The returned pixel data should be free()d after use.
-void *qoi_read(const char *filename, int *out_w, int *out_h, int 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.
-#endif // QOI_NO_STDIO
+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. */
-// Encode raw RGB or RGBA pixels into a QOI image in memory. w and h denote the
-// width and height of the pixel data. channels must be either 3 for RGB data
-// or 4 for RGBA.
-// 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 user.
+void *qoi_read(const char *filename, qoi_desc *desc, int channels);
-void *qoi_encode(const void *data, int w, int h, int channels, int *out_len);
+#endif /* QOI_NO_STDIO */
-// Decode a QOI image from memory into either raw RGB (channels=3) or RGBA
-// (channels=4) pixel data.
-// The function either returns NULL on failure (invalid parameters or malloc
-// failed) or a pointer to the decoded pixels. On success out_w and out_h will
-// be set to the width and height of the decoded image.
-// The returned pixel data should be free()d after use.
+/* 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 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.
+
+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. */
+
+void *qoi_decode(const void *data, int size, qoi_desc *desc, int channels);
-void *qoi_decode(const void *data, int size, int *out_w, int *out_h, 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 12
-#define QOI_PADDING 4
+#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;
} qoi_rgba_t;
-void qoi_write_16(unsigned char *bytes, int *p, unsigned short v) {
- bytes[(*p)++] = (0xff00 & v) >> 8;
- bytes[(*p)++] = (0xff & v);
-}
+static const unsigned char qoi_padding[8] = {0,0,0,0,0,0,0,1};
-void qoi_write_32(unsigned char *bytes, int *p, unsigned int v) {
- qoi_write_16(bytes, p, (v & 0xffff0000) >> 16);
- qoi_write_16(bytes, p, (v & 0xffff));
+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_16(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)++];
- return (a << 8) | b;
+ unsigned int c = bytes[(*p)++];
+ unsigned int d = bytes[(*p)++];
+ return a << 24 | b << 16 | c << 8 | d;
}
-unsigned int qoi_read_32(const unsigned char *bytes, int *p) {
- unsigned int a = qoi_read_16(bytes, p);
- unsigned int b = qoi_read_16(bytes, p);
- return (a << 16) | b;
-}
+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;
-void *qoi_encode(const void *data, int w, int h, int channels, int *out_len) {
if (
- data == NULL || out_len == NULL ||
- w <= 0 || w >= (1 << 16) ||
- h <= 0 || h >= (1 << 16) ||
- channels < 3 || channels > 4
+ data == NULL || out_len == NULL || desc == NULL ||
+ desc->width == 0 || desc->height == 0 ||
+ desc->channels < 3 || desc->channels > 4 ||
+ desc->colorspace > 1 ||
+ desc->height >= QOI_PIXELS_MAX / desc->width
) {
return NULL;
}
- int max_size = w * h * (channels + 1) + QOI_HEADER_SIZE + QOI_PADDING;
- int p = 0;
- unsigned char *bytes = QOI_MALLOC(max_size);
+ max_size =
+ desc->width * desc->height * (desc->channels + 1) +
+ QOI_HEADER_SIZE + sizeof(qoi_padding);
+
+ p = 0;
+ bytes = (unsigned char *) QOI_MALLOC(max_size);
if (!bytes) {
return NULL;
}
qoi_write_32(bytes, &p, QOI_MAGIC);
- qoi_write_16(bytes, &p, w);
- qoi_write_16(bytes, &p, h);
- qoi_write_32(bytes, &p, 0); // size, will be set later
+ qoi_write_32(bytes, &p, desc->width);
+ qoi_write_32(bytes, &p, desc->height);
+ bytes[p++] = desc->channels;
+ bytes[p++] = desc->colorspace;
+
- const unsigned char *pixels = (const unsigned char *)data;
+ pixels = (const unsigned char *)data;
- qoi_rgba_t index[64] = {0};
+ QOI_ZEROARR(index);
- int run = 0;
- qoi_rgba_t px_prev = {.rgba = {.r = 0, .g = 0, .b = 0, .a = 255}};
- qoi_rgba_t px = px_prev;
+ 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 px_len = w * h * channels;
- int px_end = px_len - channels;
- for (int px_pos = 0; px_pos < px_len; px_pos += channels) {
+ px_len = desc->width * desc->height * desc->channels;
+ px_end = px_len - desc->channels;
+ channels = desc->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;
- }
- else {
- run -= 33;
- bytes[p++] = QOI_RUN_16 | run >> 8;
- bytes[p++] = run;
+ if (run > 0) {
+ bytes[p++] = QOI_OP_RUN | (run - 1);
+ run = 0;
}
- 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 (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 (
- vr > -16 && vr < 17 && vg > -16 && vg < 17 &&
- vb > -16 && vb < 17 && va > -16 && va < 17
- ) {
if (
- va == 0 && vr > -2 && vr < 3 &&
- vg > -2 && vg < 3 && vb > -2 && vb < 3
+ vr > -3 && vr < 2 &&
+ vg > -3 && vg < 2 &&
+ vb > -3 && vb < 2
) {
- bytes[p++] = QOI_DIFF_8 | ((vr + 1) << 4) | (vg + 1) << 2 | (vb + 1);
+ bytes[p++] = QOI_OP_DIFF | (vr + 2) << 4 | (vg + 2) << 2 | (vb + 2);
}
else if (
- va == 0 && vr > -16 && vr < 17 &&
- vg > -8 && vg < 9 && vb > -8 && vb < 9
+ vg_r > -9 && vg_r < 8 &&
+ vg > -33 && vg < 32 &&
+ vg_b > -9 && vg_b < 8
) {
- bytes[p++] = QOI_DIFF_16 | (vr + 15);
- bytes[p++] = ((vg + 7) << 4) | (vb + 7);
+ bytes[p++] = QOI_OP_LUMA | (vg + 32);
+ bytes[p++] = (vg_r + 8) << 4 | (vg_b + 8);
}
else {
- bytes[p++] = QOI_DIFF_24 | ((vr + 15) >> 1);
- bytes[p++] = ((vr + 15) << 7) | ((vg + 15) << 2) | ((vb + 15) >> 3);
- bytes[p++] = ((vb + 15) << 5) | (va + 15);
+ 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];
}
- int data_len = p - QOI_HEADER_SIZE;
*out_len = p;
-
- p = 8;
- qoi_write_32(bytes, &p, data_len);
return bytes;
}
-void *qoi_decode(const void *data, int size, int *out_w, int *out_h, int channels) {
- if (channels < 3 || channels > 4 || size < QOI_HEADER_SIZE) {
+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 + (int)sizeof(qoi_padding)
+ ) {
return NULL;
}
- const unsigned char *bytes = (const unsigned char *)data;
- int p = 0;
+ bytes = (const unsigned char *)data;
- int magic = qoi_read_32(bytes, &p);
- int w = qoi_read_16(bytes, &p);
- int h = qoi_read_16(bytes, &p);
- int data_len = 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 (
- w == 0 || h == 0 || magic != QOI_MAGIC ||
- size != data_len + QOI_HEADER_SIZE
+ desc->width == 0 || desc->height == 0 ||
+ desc->channels < 3 || desc->channels > 4 ||
+ desc->colorspace > 1 ||
+ header_magic != QOI_MAGIC ||
+ desc->height >= QOI_PIXELS_MAX / desc->width
) {
return NULL;
}
- int px_len = w * h * channels;
- unsigned char *pixels = QOI_MALLOC(px_len);
+ if (channels == 0) {
+ channels = desc->channels;
+ }
+
+ 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) {
- px.rgba.r += ((b1 >> 4) & 0x03) - 1;
- px.rgba.g += ((b1 >> 2) & 0x03) - 1;
- px.rgba.b += ( b1 & 0x03) - 1;
+ 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) {
+ else if ((b1 & QOI_MASK_2) == QOI_OP_LUMA) {
int b2 = bytes[p++];
- px.rgba.r += (b1 & 0x1f) - 15;
- px.rgba.g += (b2 >> 4) - 7;
- px.rgba.b += (b2 & 0x0f) - 7;
+ 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_DIFF_24) {
- int b2 = bytes[p++];
- int b3 = bytes[p++];
- px.rgba.r += (((b1 & 0x0f) << 1) | (b2 >> 7)) - 15;
- px.rgba.g += ((b2 & 0x7c) >> 2) - 15;
- px.rgba.b += (((b2 & 0x03) << 3) | ((b3 & 0xe0) >> 5)) - 15;
- px.rgba.a += (b3 & 0x1f) - 15;
- }
- 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;
}
}
- *out_w = w;
- *out_h = h;
return pixels;
}
#ifndef QOI_NO_STDIO
#include <stdio.h>
-int qoi_write(const char *filename, const void *data, int w, int h, int channels) {
+int qoi_write(const char *filename, const void *data, const qoi_desc *desc) {
+ FILE *f = fopen(filename, "wb");
int size;
- void *encoded = qoi_encode(data, w, h, channels, &size);
- if (!encoded) {
+ void *encoded;
+
+ if (!f) {
return 0;
}
- FILE *f = fopen(filename, "wb");
- if (!f) {
- QOI_FREE(encoded);
+ 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, int *out_w, int *out_h, int channels) {
+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, out_w, out_h, 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