From d806c1abb4f4cdc0c8a6558f36ace7eda054ef87 Mon Sep 17 00:00:00 2001 From: iamcheeseman Date: Fri, 8 May 2026 23:17:39 -0400 Subject: move third/ to dc/third --- dc/third/qoi.h | 649 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ third/qoi.h | 649 --------------------------------------------------------- 2 files changed, 649 insertions(+), 649 deletions(-) create mode 100644 dc/third/qoi.h delete mode 100644 third/qoi.h diff --git a/dc/third/qoi.h b/dc/third/qoi.h new file mode 100644 index 0000000..f638dc5 --- /dev/null +++ b/dc/third/qoi.h @@ -0,0 +1,649 @@ +/* + + Copyright (c) 2021, Dominic Szablewski - https://phoboslab.org + SPDX-License-Identifier: MIT + + + QOI - The "Quite OK Image" format for fast, lossless image compression + + -- About + + 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` in *one* C/C++ file before including this +// library to create the implementation. + +#define QOI_IMPLEMENTATION +#include "qoi.h" + +// 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); + + + +-- Documentation + +This library provides the following functions; +- qoi_read -- read and decode a QOI file +- qoi_decode -- decode the raw bytes of a QOI image from memory +- qoi_write -- encode and write a QOI file +- qoi_encode -- encode an rgba buffer into a QOI image in memory + +See the function declaration below for the signature and more information. + +If you don't want/need the qoi_read and qoi_write functions, you can define +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" 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; // 3 = RGB, 4 = RGBA +uint8_t colorspace; // 0 = sRGB with linear alpha, 1 = all channels linear +}; + +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 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. + +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_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 */ + +#ifndef QOI_H +#define QOI_H + +#ifdef __cplusplus + 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 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. */ + + 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. + + 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. */ + + void *qoi_read(const char *filename, qoi_desc *desc, int channels); + +#endif /* QOI_NO_STDIO */ + + + /* 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); + + +#ifdef __cplusplus + } +#endif +#endif /* QOI_H */ + + +/* ----------------------------------------------------------------------------- + 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_OP_INDEX 0x00 /* 00xxxxxx */ +#define QOI_OP_DIFF 0x40 /* 01xxxxxx */ +#define QOI_OP_LUMA 0x80 /* 10xxxxxx */ +#define QOI_OP_RUN 0xc0 /* 11xxxxxx */ +#define QOI_OP_RGB 0xfe /* 11111110 */ +#define QOI_OP_RGBA 0xff /* 11111111 */ + +#define QOI_MASK_2 0xc0 /* 11000000 */ + +#define QOI_COLOR_HASH(C) (C.rgba.r*3 + C.rgba.g*5 + C.rgba.b*7 + C.rgba.a*11) +#define QOI_MAGIC \ + (((unsigned int)'q') << 24 | ((unsigned int)'o') << 16 | \ + ((unsigned int)'i') << 8 | ((unsigned int)'f')) +#define QOI_HEADER_SIZE 14 + +/* 2GB is the max file size that this implementation can safely handle. We guard + against anything larger than that, assuming the worst case with 5 bytes per + pixel, rounded down to a nice clean value. 400 million pixels ought to be + enough for anybody. */ +#define QOI_PIXELS_MAX ((unsigned int)400000000) + +typedef union { + struct { unsigned char r, g, b, a; } rgba; + unsigned int v; +} qoi_rgba_t; + +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); +} + +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; +} + +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 > 1 || + desc->height >= QOI_PIXELS_MAX / desc->width + ) { + return NULL; + } + + 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_32(bytes, &p, desc->width); + qoi_write_32(bytes, &p, desc->height); + bytes[p++] = desc->channels; + bytes[p++] = desc->colorspace; + + + pixels = (const unsigned char *)data; + + QOI_ZEROARR(index); + + 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; + + 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) { + px.rgba.r = pixels[px_pos + 0]; + px.rgba.g = pixels[px_pos + 1]; + px.rgba.b = pixels[px_pos + 2]; + + if (channels == 4) { + px.rgba.a = pixels[px_pos + 3]; + } + + 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) { + bytes[p++] = QOI_OP_RUN | (run - 1); + run = 0; + } + + index_pos = QOI_COLOR_HASH(px) & (64 - 1); + + if (index[index_pos].v == px.v) { + bytes[p++] = QOI_OP_INDEX | index_pos; + } + else { + index[index_pos] = px; + + 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 > -3 && vr < 2 && + vg > -3 && vg < 2 && + vb > -3 && vb < 2 + ) { + bytes[p++] = QOI_OP_DIFF | (vr + 2) << 4 | (vg + 2) << 2 | (vb + 2); + } + else if ( + vg_r > -9 && vg_r < 8 && + vg > -33 && vg < 32 && + vg_b > -9 && vg_b < 8 + ) { + bytes[p++] = QOI_OP_LUMA | (vg + 32); + bytes[p++] = (vg_r + 8) << 4 | (vg_b + 8); + } + else { + bytes[p++] = QOI_OP_RGB; + bytes[p++] = px.rgba.r; + bytes[p++] = px.rgba.g; + bytes[p++] = px.rgba.b; + } + } + else { + 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 (i = 0; i < (int)sizeof(qoi_padding); i++) { + bytes[p++] = qoi_padding[i]; + } + + *out_len = p; + return bytes; +} + +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; + } + + bytes = (const unsigned char *)data; + + 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->channels < 3 || desc->channels > 4 || + desc->colorspace > 1 || + header_magic != QOI_MAGIC || + desc->height >= QOI_PIXELS_MAX / desc->width + ) { + return NULL; + } + + 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_ZEROARR(index); + px.rgba.r = 0; + px.rgba.g = 0; + px.rgba.b = 0; + px.rgba.a = 255; + + 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_OP_RGB) { + px.rgba.r = bytes[p++]; + px.rgba.g = bytes[p++]; + px.rgba.b = bytes[p++]; + } + 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_2) == QOI_OP_INDEX) { + px = index[b1]; + } + else if ((b1 & QOI_MASK_2) == QOI_OP_DIFF) { + px.rgba.r += ((b1 >> 4) & 0x03) - 2; + px.rgba.g += ((b1 >> 2) & 0x03) - 2; + px.rgba.b += ( b1 & 0x03) - 2; + } + else if ((b1 & QOI_MASK_2) == QOI_OP_LUMA) { + int b2 = bytes[p++]; + 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_2) == QOI_OP_RUN) { + run = (b1 & 0x3f); + } + + index[QOI_COLOR_HASH(px) & (64 - 1)] = px; + } + + pixels[px_pos + 0] = px.rgba.r; + pixels[px_pos + 1] = px.rgba.g; + pixels[px_pos + 2] = px.rgba.b; + + if (channels == 4) { + pixels[px_pos + 3] = px.rgba.a; + } + } + + return pixels; +} + +#ifndef QOI_NO_STDIO +#include + +int qoi_write(const char *filename, const void *data, const qoi_desc *desc) { + FILE *f = fopen(filename, "wb"); + int size, err; + void *encoded; + + if (!f) { + return 0; + } + + encoded = qoi_encode(data, desc, &size); + if (!encoded) { + fclose(f); + return 0; + } + + fwrite(encoded, 1, size, f); + fflush(f); + err = ferror(f); + fclose(f); + + QOI_FREE(encoded); + return err ? 0 : 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); + size = ftell(f); + if (size <= 0 || fseek(f, 0, SEEK_SET) != 0) { + fclose(f); + return NULL; + } + + data = QOI_MALLOC(size); + if (!data) { + fclose(f); + return NULL; + } + + bytes_read = fread(data, 1, size, f); + fclose(f); + pixels = (bytes_read != size) ? NULL : qoi_decode(data, bytes_read, desc, channels); + QOI_FREE(data); + return pixels; +} + +#endif /* QOI_NO_STDIO */ +#endif /* QOI_IMPLEMENTATION */ diff --git a/third/qoi.h b/third/qoi.h deleted file mode 100644 index f638dc5..0000000 --- a/third/qoi.h +++ /dev/null @@ -1,649 +0,0 @@ -/* - - Copyright (c) 2021, Dominic Szablewski - https://phoboslab.org - SPDX-License-Identifier: MIT - - - QOI - The "Quite OK Image" format for fast, lossless image compression - - -- About - - 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` in *one* C/C++ file before including this -// library to create the implementation. - -#define QOI_IMPLEMENTATION -#include "qoi.h" - -// 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); - - - --- Documentation - -This library provides the following functions; -- qoi_read -- read and decode a QOI file -- qoi_decode -- decode the raw bytes of a QOI image from memory -- qoi_write -- encode and write a QOI file -- qoi_encode -- encode an rgba buffer into a QOI image in memory - -See the function declaration below for the signature and more information. - -If you don't want/need the qoi_read and qoi_write functions, you can define -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" 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; // 3 = RGB, 4 = RGBA -uint8_t colorspace; // 0 = sRGB with linear alpha, 1 = all channels linear -}; - -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 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. - -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_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 */ - -#ifndef QOI_H -#define QOI_H - -#ifdef __cplusplus - 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 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. */ - - 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. - - 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. */ - - void *qoi_read(const char *filename, qoi_desc *desc, int channels); - -#endif /* QOI_NO_STDIO */ - - - /* 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); - - -#ifdef __cplusplus - } -#endif -#endif /* QOI_H */ - - -/* ----------------------------------------------------------------------------- - 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_OP_INDEX 0x00 /* 00xxxxxx */ -#define QOI_OP_DIFF 0x40 /* 01xxxxxx */ -#define QOI_OP_LUMA 0x80 /* 10xxxxxx */ -#define QOI_OP_RUN 0xc0 /* 11xxxxxx */ -#define QOI_OP_RGB 0xfe /* 11111110 */ -#define QOI_OP_RGBA 0xff /* 11111111 */ - -#define QOI_MASK_2 0xc0 /* 11000000 */ - -#define QOI_COLOR_HASH(C) (C.rgba.r*3 + C.rgba.g*5 + C.rgba.b*7 + C.rgba.a*11) -#define QOI_MAGIC \ - (((unsigned int)'q') << 24 | ((unsigned int)'o') << 16 | \ - ((unsigned int)'i') << 8 | ((unsigned int)'f')) -#define QOI_HEADER_SIZE 14 - -/* 2GB is the max file size that this implementation can safely handle. We guard - against anything larger than that, assuming the worst case with 5 bytes per - pixel, rounded down to a nice clean value. 400 million pixels ought to be - enough for anybody. */ -#define QOI_PIXELS_MAX ((unsigned int)400000000) - -typedef union { - struct { unsigned char r, g, b, a; } rgba; - unsigned int v; -} qoi_rgba_t; - -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); -} - -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; -} - -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 > 1 || - desc->height >= QOI_PIXELS_MAX / desc->width - ) { - return NULL; - } - - 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_32(bytes, &p, desc->width); - qoi_write_32(bytes, &p, desc->height); - bytes[p++] = desc->channels; - bytes[p++] = desc->colorspace; - - - pixels = (const unsigned char *)data; - - QOI_ZEROARR(index); - - 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; - - 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) { - px.rgba.r = pixels[px_pos + 0]; - px.rgba.g = pixels[px_pos + 1]; - px.rgba.b = pixels[px_pos + 2]; - - if (channels == 4) { - px.rgba.a = pixels[px_pos + 3]; - } - - 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) { - bytes[p++] = QOI_OP_RUN | (run - 1); - run = 0; - } - - index_pos = QOI_COLOR_HASH(px) & (64 - 1); - - if (index[index_pos].v == px.v) { - bytes[p++] = QOI_OP_INDEX | index_pos; - } - else { - index[index_pos] = px; - - 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 > -3 && vr < 2 && - vg > -3 && vg < 2 && - vb > -3 && vb < 2 - ) { - bytes[p++] = QOI_OP_DIFF | (vr + 2) << 4 | (vg + 2) << 2 | (vb + 2); - } - else if ( - vg_r > -9 && vg_r < 8 && - vg > -33 && vg < 32 && - vg_b > -9 && vg_b < 8 - ) { - bytes[p++] = QOI_OP_LUMA | (vg + 32); - bytes[p++] = (vg_r + 8) << 4 | (vg_b + 8); - } - else { - bytes[p++] = QOI_OP_RGB; - bytes[p++] = px.rgba.r; - bytes[p++] = px.rgba.g; - bytes[p++] = px.rgba.b; - } - } - else { - 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 (i = 0; i < (int)sizeof(qoi_padding); i++) { - bytes[p++] = qoi_padding[i]; - } - - *out_len = p; - return bytes; -} - -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; - } - - bytes = (const unsigned char *)data; - - 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->channels < 3 || desc->channels > 4 || - desc->colorspace > 1 || - header_magic != QOI_MAGIC || - desc->height >= QOI_PIXELS_MAX / desc->width - ) { - return NULL; - } - - 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_ZEROARR(index); - px.rgba.r = 0; - px.rgba.g = 0; - px.rgba.b = 0; - px.rgba.a = 255; - - 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_OP_RGB) { - px.rgba.r = bytes[p++]; - px.rgba.g = bytes[p++]; - px.rgba.b = bytes[p++]; - } - 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_2) == QOI_OP_INDEX) { - px = index[b1]; - } - else if ((b1 & QOI_MASK_2) == QOI_OP_DIFF) { - px.rgba.r += ((b1 >> 4) & 0x03) - 2; - px.rgba.g += ((b1 >> 2) & 0x03) - 2; - px.rgba.b += ( b1 & 0x03) - 2; - } - else if ((b1 & QOI_MASK_2) == QOI_OP_LUMA) { - int b2 = bytes[p++]; - 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_2) == QOI_OP_RUN) { - run = (b1 & 0x3f); - } - - index[QOI_COLOR_HASH(px) & (64 - 1)] = px; - } - - pixels[px_pos + 0] = px.rgba.r; - pixels[px_pos + 1] = px.rgba.g; - pixels[px_pos + 2] = px.rgba.b; - - if (channels == 4) { - pixels[px_pos + 3] = px.rgba.a; - } - } - - return pixels; -} - -#ifndef QOI_NO_STDIO -#include - -int qoi_write(const char *filename, const void *data, const qoi_desc *desc) { - FILE *f = fopen(filename, "wb"); - int size, err; - void *encoded; - - if (!f) { - return 0; - } - - encoded = qoi_encode(data, desc, &size); - if (!encoded) { - fclose(f); - return 0; - } - - fwrite(encoded, 1, size, f); - fflush(f); - err = ferror(f); - fclose(f); - - QOI_FREE(encoded); - return err ? 0 : 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); - size = ftell(f); - if (size <= 0 || fseek(f, 0, SEEK_SET) != 0) { - fclose(f); - return NULL; - } - - data = QOI_MALLOC(size); - if (!data) { - fclose(f); - return NULL; - } - - bytes_read = fread(data, 1, size, f); - fclose(f); - pixels = (bytes_read != size) ? NULL : qoi_decode(data, bytes_read, desc, channels); - QOI_FREE(data); - return pixels; -} - -#endif /* QOI_NO_STDIO */ -#endif /* QOI_IMPLEMENTATION */ -- cgit v1.3-2-g0d8e