X-Git-Url: https://harrygodden.com/git/?p=fishladder.git;a=blobdiff_plain;f=phoboslab%2Fqoi.h;fp=phoboslab%2Fqoi.h;h=988f9edcb4fe95935746bfaa53c9b97fa3db1e0d;hp=d70e2e8557dff2e54a6a165d63f9ae54c7c853e0;hb=3cb144985169da3cea1c21a7b0bfba8d43c28fdb;hpb=aa435c13e7184bcd2034b8af1b20db1063baf9ec diff --git a/phoboslab/qoi.h b/phoboslab/qoi.h index d70e2e8..988f9ed 100644 --- a/phoboslab/qoi.h +++ b/phoboslab/qoi.h @@ -28,12 +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. 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 @@ -48,7 +45,7 @@ images are typically 20% smaller than PNGs written with stbi_image. Encoding is // the input pixel data. qoi_write("image_new.qoi", rgba_pixels, &(qoi_desc){ .width = 1920, - .height = 1080, + .height = 1080, .channels = 4, .colorspace = QOI_SRGB }); @@ -77,143 +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 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 @@ -222,19 +238,20 @@ have to check for an overrun once per decode loop iteration. 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; @@ -245,49 +262,49 @@ typedef struct { #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); @@ -295,75 +312,91 @@ 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 +#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 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; } @@ -375,105 +408,98 @@ void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len) { 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; @@ -481,27 +507,36 @@ void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len) { } 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; } @@ -510,70 +545,66 @@ void *qoi_decode(const void *data, int size, qoi_desc *desc, int channels) { 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; } } @@ -585,48 +616,56 @@ void *qoi_decode(const void *data, int size, qoi_desc *desc, int channels) { 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 */