X-Git-Url: https://harrygodden.com/git/?a=blobdiff_plain;f=phoboslab%2Fqoi.h;h=988f9edcb4fe95935746bfaa53c9b97fa3db1e0d;hb=3363633178b1eea582304742ad1202487af0feb1;hp=f12b3af662dc45155835b57fb36d5daf19db2b97;hpb=72e9a469a490e537f2e12464c1b075eb8991a868;p=fishladder.git diff --git a/phoboslab/qoi.h b/phoboslab/qoi.h index f12b3af..988f9ed 100644 --- a/phoboslab/qoi.h +++ b/phoboslab/qoi.h @@ -1,6 +1,6 @@ /* -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 @@ -28,13 +28,9 @@ SOFTWARE. -- 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 @@ -45,12 +41,21 @@ than stbi_image or libpng. #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 @@ -69,91 +74,162 @@ QOI_NO_STDIO before including this library. 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 @@ -162,368 +238,434 @@ to check for an overrun once per decode loop iteration. 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 +#include #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 -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 */