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authorUneven Prankster <unevenprankster@protonmail.com>2023-10-15 21:28:29 -0300
committerUneven Prankster <unevenprankster@protonmail.com>2023-10-15 21:28:29 -0300
commit1c0cc775732201f4c4d3ee0d6772be786b3b4aa1 (patch)
treef5d692d046868261275c7430a624c3ea9ed75d3d /raylib/src/external/qoa.h
parenta89f892640cf12f75c7ce18e6e88c70a8d3965ed (diff)
A lot has certainly happened!
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+/*
+
+Copyright (c) 2023, Dominic Szablewski - https://phoboslab.org
+SPDX-License-Identifier: MIT
+
+QOA - The "Quite OK Audio" format for fast, lossy audio compression
+
+
+-- Data Format
+
+A QOA file has an 8 byte file header, followed by a number of frames. Each frame
+consists of an 8 byte frame header, the current 8 byte en-/decoder state per
+channel and 256 slices per channel. Each slice is 8 bytes wide and encodes 20
+samples of audio data.
+
+Note that the last frame of a file may contain less than 256 slices per channel.
+The last slice (per channel) in the last frame may contain less 20 samples, but
+the slice will still be 8 bytes wide, with the unused samples zeroed out.
+
+The samplerate and number of channels is only stated in the frame headers, but
+not in the file header. A decoder may peek into the first frame of the file to
+find these values.
+
+In a valid QOA file all frames have the same number of channels and the same
+samplerate. These restrictions may be relaxed for streaming. This remains to
+be decided.
+
+All values in a QOA file are BIG ENDIAN. Luckily, EVERYTHING in a QOA file,
+including the headers, is 64 bit aligned, so it's possible to read files with
+just a read_u64() that does the byte swapping if necessary.
+
+In pseudocode, the file layout is as follows:
+
+struct {
+ struct {
+ char magic[4]; // magic bytes 'qoaf'
+ uint32_t samples; // number of samples per channel in this file
+ } file_header; // = 64 bits
+
+ struct {
+ struct {
+ uint8_t num_channels; // number of channels
+ uint24_t samplerate; // samplerate in hz
+ uint16_t fsamples; // sample count per channel in this frame
+ uint16_t fsize; // frame size (including the frame header)
+ } frame_header; // = 64 bits
+
+ struct {
+ int16_t history[4]; // = 64 bits
+ int16_t weights[4]; // = 64 bits
+ } lms_state[num_channels];
+
+ qoa_slice_t slices[256][num_channels]; // = 64 bits each
+ } frames[samples * channels / qoa_max_framesize()];
+} qoa_file;
+
+Wheras the 64bit qoa_slice_t is defined as follows:
+
+.- QOA_SLICE -- 64 bits, 20 samples --------------------------/ /------------.
+| Byte[0] | Byte[1] | Byte[2] \ \ Byte[7] |
+| 7 6 5 4 3 2 1 0 | 7 6 5 4 3 2 1 0 | 7 6 5 / / 2 1 0 |
+|------------+--------+--------+--------+---------+---------+-\ \--+---------|
+| sf_index | r00 | r01 | r02 | r03 | r04 | / / | r19 |
+`-------------------------------------------------------------\ \------------`
+
+`sf_index` defines the scalefactor to use for this slice as an index into the
+qoa_scalefactor_tab[16]
+
+`r00`--`r19` are the residuals for the individual samples, divided by the
+scalefactor and quantized by the qoa_quant_tab[].
+
+In the decoder, a prediction of the next sample is computed by multiplying the
+state (the last four output samples) with the predictor. The residual from the
+slice is then dequantized using the qoa_dequant_tab[] and added to the
+prediction. The result is clamped to int16 to form the final output sample.
+
+*/
+
+
+
+/* -----------------------------------------------------------------------------
+ Header - Public functions */
+
+#ifndef QOA_H
+#define QOA_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define QOA_MIN_FILESIZE 16
+#define QOA_MAX_CHANNELS 8
+
+#define QOA_SLICE_LEN 20
+#define QOA_SLICES_PER_FRAME 256
+#define QOA_FRAME_LEN (QOA_SLICES_PER_FRAME * QOA_SLICE_LEN)
+#define QOA_LMS_LEN 4
+#define QOA_MAGIC 0x716f6166 /* 'qoaf' */
+
+#define QOA_FRAME_SIZE(channels, slices) \
+ (8 + QOA_LMS_LEN * 4 * channels + 8 * slices * channels)
+
+typedef struct {
+ int history[QOA_LMS_LEN];
+ int weights[QOA_LMS_LEN];
+} qoa_lms_t;
+
+typedef struct {
+ unsigned int channels;
+ unsigned int samplerate;
+ unsigned int samples;
+ qoa_lms_t lms[QOA_MAX_CHANNELS];
+ #ifdef QOA_RECORD_TOTAL_ERROR
+ double error;
+ #endif
+} qoa_desc;
+
+unsigned int qoa_encode_header(qoa_desc *qoa, unsigned char *bytes);
+unsigned int qoa_encode_frame(const short *sample_data, qoa_desc *qoa, unsigned int frame_len, unsigned char *bytes);
+void *qoa_encode(const short *sample_data, qoa_desc *qoa, unsigned int *out_len);
+
+unsigned int qoa_max_frame_size(qoa_desc *qoa);
+unsigned int qoa_decode_header(const unsigned char *bytes, int size, qoa_desc *qoa);
+unsigned int qoa_decode_frame(const unsigned char *bytes, unsigned int size, qoa_desc *qoa, short *sample_data, unsigned int *frame_len);
+short *qoa_decode(const unsigned char *bytes, int size, qoa_desc *file);
+
+#ifndef QOA_NO_STDIO
+
+int qoa_write(const char *filename, const short *sample_data, qoa_desc *qoa);
+void *qoa_read(const char *filename, qoa_desc *qoa);
+
+#endif /* QOA_NO_STDIO */
+
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* QOA_H */
+
+
+/* -----------------------------------------------------------------------------
+ Implementation */
+
+#ifdef QOA_IMPLEMENTATION
+#include <stdlib.h>
+
+#ifndef QOA_MALLOC
+ #define QOA_MALLOC(sz) malloc(sz)
+ #define QOA_FREE(p) free(p)
+#endif
+
+typedef unsigned long long qoa_uint64_t;
+
+
+/* The quant_tab provides an index into the dequant_tab for residuals in the
+range of -8 .. 8. It maps this range to just 3bits and becomes less accurate at
+the higher end. Note that the residual zero is identical to the lowest positive
+value. This is mostly fine, since the qoa_div() function always rounds away
+from zero. */
+
+static int qoa_quant_tab[17] = {
+ 7, 7, 7, 5, 5, 3, 3, 1, /* -8..-1 */
+ 0, /* 0 */
+ 0, 2, 2, 4, 4, 6, 6, 6 /* 1.. 8 */
+};
+
+
+/* We have 16 different scalefactors. Like the quantized residuals these become
+less accurate at the higher end. In theory, the highest scalefactor that we
+would need to encode the highest 16bit residual is (2**16)/8 = 8192. However we
+rely on the LMS filter to predict samples accurately enough that a maximum
+residual of one quarter of the 16 bit range is high sufficient. I.e. with the
+scalefactor 2048 times the quant range of 8 we can encode residuals up to 2**14.
+
+The scalefactor values are computed as:
+scalefactor_tab[s] <- round(pow(s + 1, 2.75)) */
+
+static int qoa_scalefactor_tab[16] = {
+ 1, 7, 21, 45, 84, 138, 211, 304, 421, 562, 731, 928, 1157, 1419, 1715, 2048
+};
+
+
+/* The reciprocal_tab maps each of the 16 scalefactors to their rounded
+reciprocals 1/scalefactor. This allows us to calculate the scaled residuals in
+the encoder with just one multiplication instead of an expensive division. We
+do this in .16 fixed point with integers, instead of floats.
+
+The reciprocal_tab is computed as:
+reciprocal_tab[s] <- ((1<<16) + scalefactor_tab[s] - 1) / scalefactor_tab[s] */
+
+static int qoa_reciprocal_tab[16] = {
+ 65536, 9363, 3121, 1457, 781, 475, 311, 216, 156, 117, 90, 71, 57, 47, 39, 32
+};
+
+
+/* The dequant_tab maps each of the scalefactors and quantized residuals to
+their unscaled & dequantized version.
+
+Since qoa_div rounds away from the zero, the smallest entries are mapped to 3/4
+instead of 1. The dequant_tab assumes the following dequantized values for each
+of the quant_tab indices and is computed as:
+float dqt[8] = {0.75, -0.75, 2.5, -2.5, 4.5, -4.5, 7, -7};
+dequant_tab[s][q] <- round(scalefactor_tab[s] * dqt[q]) */
+
+static int qoa_dequant_tab[16][8] = {
+ { 1, -1, 3, -3, 5, -5, 7, -7},
+ { 5, -5, 18, -18, 32, -32, 49, -49},
+ { 16, -16, 53, -53, 95, -95, 147, -147},
+ { 34, -34, 113, -113, 203, -203, 315, -315},
+ { 63, -63, 210, -210, 378, -378, 588, -588},
+ { 104, -104, 345, -345, 621, -621, 966, -966},
+ { 158, -158, 528, -528, 950, -950, 1477, -1477},
+ { 228, -228, 760, -760, 1368, -1368, 2128, -2128},
+ { 316, -316, 1053, -1053, 1895, -1895, 2947, -2947},
+ { 422, -422, 1405, -1405, 2529, -2529, 3934, -3934},
+ { 548, -548, 1828, -1828, 3290, -3290, 5117, -5117},
+ { 696, -696, 2320, -2320, 4176, -4176, 6496, -6496},
+ { 868, -868, 2893, -2893, 5207, -5207, 8099, -8099},
+ {1064, -1064, 3548, -3548, 6386, -6386, 9933, -9933},
+ {1286, -1286, 4288, -4288, 7718, -7718, 12005, -12005},
+ {1536, -1536, 5120, -5120, 9216, -9216, 14336, -14336},
+};
+
+
+/* The Least Mean Squares Filter is the heart of QOA. It predicts the next
+sample based on the previous 4 reconstructed samples. It does so by continuously
+adjusting 4 weights based on the residual of the previous prediction.
+
+The next sample is predicted as the sum of (weight[i] * history[i]).
+
+The adjustment of the weights is done with a "Sign-Sign-LMS" that adds or
+subtracts the residual to each weight, based on the corresponding sample from
+the history. This, surprisingly, is sufficient to get worthwhile predictions.
+
+This is all done with fixed point integers. Hence the right-shifts when updating
+the weights and calculating the prediction. */
+
+static int qoa_lms_predict(qoa_lms_t *lms) {
+ int prediction = 0;
+ for (int i = 0; i < QOA_LMS_LEN; i++) {
+ prediction += lms->weights[i] * lms->history[i];
+ }
+ return prediction >> 13;
+}
+
+static void qoa_lms_update(qoa_lms_t *lms, int sample, int residual) {
+ int delta = residual >> 4;
+ for (int i = 0; i < QOA_LMS_LEN; i++) {
+ lms->weights[i] += lms->history[i] < 0 ? -delta : delta;
+ }
+
+ for (int i = 0; i < QOA_LMS_LEN-1; i++) {
+ lms->history[i] = lms->history[i+1];
+ }
+ lms->history[QOA_LMS_LEN-1] = sample;
+}
+
+
+/* qoa_div() implements a rounding division, but avoids rounding to zero for
+small numbers. E.g. 0.1 will be rounded to 1. Note that 0 itself still
+returns as 0, which is handled in the qoa_quant_tab[].
+qoa_div() takes an index into the .16 fixed point qoa_reciprocal_tab as an
+argument, so it can do the division with a cheaper integer multiplication. */
+
+static inline int qoa_div(int v, int scalefactor) {
+ int reciprocal = qoa_reciprocal_tab[scalefactor];
+ int n = (v * reciprocal + (1 << 15)) >> 16;
+ n = n + ((v > 0) - (v < 0)) - ((n > 0) - (n < 0)); /* round away from 0 */
+ return n;
+}
+
+static inline int qoa_clamp(int v, int min, int max) {
+ return (v < min) ? min : (v > max) ? max : v;
+}
+
+static inline qoa_uint64_t qoa_read_u64(const unsigned char *bytes, unsigned int *p) {
+ bytes += *p;
+ *p += 8;
+ return
+ ((qoa_uint64_t)(bytes[0]) << 56) | ((qoa_uint64_t)(bytes[1]) << 48) |
+ ((qoa_uint64_t)(bytes[2]) << 40) | ((qoa_uint64_t)(bytes[3]) << 32) |
+ ((qoa_uint64_t)(bytes[4]) << 24) | ((qoa_uint64_t)(bytes[5]) << 16) |
+ ((qoa_uint64_t)(bytes[6]) << 8) | ((qoa_uint64_t)(bytes[7]) << 0);
+}
+
+static inline void qoa_write_u64(qoa_uint64_t v, unsigned char *bytes, unsigned int *p) {
+ bytes += *p;
+ *p += 8;
+ bytes[0] = (v >> 56) & 0xff;
+ bytes[1] = (v >> 48) & 0xff;
+ bytes[2] = (v >> 40) & 0xff;
+ bytes[3] = (v >> 32) & 0xff;
+ bytes[4] = (v >> 24) & 0xff;
+ bytes[5] = (v >> 16) & 0xff;
+ bytes[6] = (v >> 8) & 0xff;
+ bytes[7] = (v >> 0) & 0xff;
+}
+
+
+/* -----------------------------------------------------------------------------
+ Encoder */
+
+unsigned int qoa_encode_header(qoa_desc *qoa, unsigned char *bytes) {
+ unsigned int p = 0;
+ qoa_write_u64(((qoa_uint64_t)QOA_MAGIC << 32) | qoa->samples, bytes, &p);
+ return p;
+}
+
+unsigned int qoa_encode_frame(const short *sample_data, qoa_desc *qoa, unsigned int frame_len, unsigned char *bytes) {
+ unsigned int channels = qoa->channels;
+
+ unsigned int p = 0;
+ unsigned int slices = (frame_len + QOA_SLICE_LEN - 1) / QOA_SLICE_LEN;
+ unsigned int frame_size = QOA_FRAME_SIZE(channels, slices);
+
+ /* Write the frame header */
+ qoa_write_u64((
+ (qoa_uint64_t)qoa->channels << 56 |
+ (qoa_uint64_t)qoa->samplerate << 32 |
+ (qoa_uint64_t)frame_len << 16 |
+ (qoa_uint64_t)frame_size
+ ), bytes, &p);
+
+ /* Write the current LMS state */
+ for (int c = 0; c < channels; c++) {
+ qoa_uint64_t weights = 0;
+ qoa_uint64_t history = 0;
+ for (int i = 0; i < QOA_LMS_LEN; i++) {
+ history = (history << 16) | (qoa->lms[c].history[i] & 0xffff);
+ weights = (weights << 16) | (qoa->lms[c].weights[i] & 0xffff);
+ }
+ qoa_write_u64(history, bytes, &p);
+ qoa_write_u64(weights, bytes, &p);
+ }
+
+ /* We encode all samples with the channels interleaved on a slice level.
+ E.g. for stereo: (ch-0, slice 0), (ch 1, slice 0), (ch 0, slice 1), ...*/
+ for (int sample_index = 0; sample_index < frame_len; sample_index += QOA_SLICE_LEN) {
+
+ for (int c = 0; c < channels; c++) {
+ int slice_len = qoa_clamp(QOA_SLICE_LEN, 0, frame_len - sample_index);
+ int slice_start = sample_index * channels + c;
+ int slice_end = (sample_index + slice_len) * channels + c;
+
+ /* Brute for search for the best scalefactor. Just go through all
+ 16 scalefactors, encode all samples for the current slice and
+ meassure the total squared error. */
+ qoa_uint64_t best_error = -1;
+ qoa_uint64_t best_slice;
+ qoa_lms_t best_lms;
+
+ for (int scalefactor = 0; scalefactor < 16; scalefactor++) {
+
+ /* We have to reset the LMS state to the last known good one
+ before trying each scalefactor, as each pass updates the LMS
+ state when encoding. */
+ qoa_lms_t lms = qoa->lms[c];
+ qoa_uint64_t slice = scalefactor;
+ qoa_uint64_t current_error = 0;
+
+ for (int si = slice_start; si < slice_end; si += channels) {
+ int sample = sample_data[si];
+ int predicted = qoa_lms_predict(&lms);
+
+ int residual = sample - predicted;
+ int scaled = qoa_div(residual, scalefactor);
+ int clamped = qoa_clamp(scaled, -8, 8);
+ int quantized = qoa_quant_tab[clamped + 8];
+ int dequantized = qoa_dequant_tab[scalefactor][quantized];
+ int reconstructed = qoa_clamp(predicted + dequantized, -32768, 32767);
+
+ long long error = (sample - reconstructed);
+ current_error += error * error;
+ if (current_error > best_error) {
+ break;
+ }
+
+ qoa_lms_update(&lms, reconstructed, dequantized);
+ slice = (slice << 3) | quantized;
+ }
+
+ if (current_error < best_error) {
+ best_error = current_error;
+ best_slice = slice;
+ best_lms = lms;
+ }
+ }
+
+ qoa->lms[c] = best_lms;
+ #ifdef QOA_RECORD_TOTAL_ERROR
+ qoa->error += best_error;
+ #endif
+
+ /* If this slice was shorter than QOA_SLICE_LEN, we have to left-
+ shift all encoded data, to ensure the rightmost bits are the empty
+ ones. This should only happen in the last frame of a file as all
+ slices are completely filled otherwise. */
+ best_slice <<= (QOA_SLICE_LEN - slice_len) * 3;
+ qoa_write_u64(best_slice, bytes, &p);
+ }
+ }
+
+ return p;
+}
+
+void *qoa_encode(const short *sample_data, qoa_desc *qoa, unsigned int *out_len) {
+ if (
+ qoa->samples == 0 ||
+ qoa->samplerate == 0 || qoa->samplerate > 0xffffff ||
+ qoa->channels == 0 || qoa->channels > QOA_MAX_CHANNELS
+ ) {
+ return NULL;
+ }
+
+ /* Calculate the encoded size and allocate */
+ unsigned int num_frames = (qoa->samples + QOA_FRAME_LEN-1) / QOA_FRAME_LEN;
+ unsigned int num_slices = (qoa->samples + QOA_SLICE_LEN-1) / QOA_SLICE_LEN;
+ unsigned int encoded_size = 8 + /* 8 byte file header */
+ num_frames * 8 + /* 8 byte frame headers */
+ num_frames * QOA_LMS_LEN * 4 * qoa->channels + /* 4 * 4 bytes lms state per channel */
+ num_slices * 8 * qoa->channels; /* 8 byte slices */
+
+ unsigned char *bytes = QOA_MALLOC(encoded_size);
+
+ for (int c = 0; c < qoa->channels; c++) {
+ /* Set the initial LMS weights to {0, 0, -1, 2}. This helps with the
+ prediction of the first few ms of a file. */
+ qoa->lms[c].weights[0] = 0;
+ qoa->lms[c].weights[1] = 0;
+ qoa->lms[c].weights[2] = -(1<<13);
+ qoa->lms[c].weights[3] = (1<<14);
+
+ /* Explicitly set the history samples to 0, as we might have some
+ garbage in there. */
+ for (int i = 0; i < QOA_LMS_LEN; i++) {
+ qoa->lms[c].history[i] = 0;
+ }
+ }
+
+
+ /* Encode the header and go through all frames */
+ unsigned int p = qoa_encode_header(qoa, bytes);
+ #ifdef QOA_RECORD_TOTAL_ERROR
+ qoa->error = 0;
+ #endif
+
+ int frame_len = QOA_FRAME_LEN;
+ for (int sample_index = 0; sample_index < qoa->samples; sample_index += frame_len) {
+ frame_len = qoa_clamp(QOA_FRAME_LEN, 0, qoa->samples - sample_index);
+ const short *frame_samples = sample_data + sample_index * qoa->channels;
+ unsigned int frame_size = qoa_encode_frame(frame_samples, qoa, frame_len, bytes + p);
+ p += frame_size;
+ }
+
+ *out_len = p;
+ return bytes;
+}
+
+
+
+/* -----------------------------------------------------------------------------
+ Decoder */
+
+unsigned int qoa_max_frame_size(qoa_desc *qoa) {
+ return QOA_FRAME_SIZE(qoa->channels, QOA_SLICES_PER_FRAME);
+}
+
+unsigned int qoa_decode_header(const unsigned char *bytes, int size, qoa_desc *qoa) {
+ unsigned int p = 0;
+ if (size < QOA_MIN_FILESIZE) {
+ return 0;
+ }
+
+
+ /* Read the file header, verify the magic number ('qoaf') and read the
+ total number of samples. */
+ qoa_uint64_t file_header = qoa_read_u64(bytes, &p);
+
+ if ((file_header >> 32) != QOA_MAGIC) {
+ return 0;
+ }
+
+ qoa->samples = file_header & 0xffffffff;
+ if (!qoa->samples) {
+ return 0;
+ }
+
+ /* Peek into the first frame header to get the number of channels and
+ the samplerate. */
+ qoa_uint64_t frame_header = qoa_read_u64(bytes, &p);
+ qoa->channels = (frame_header >> 56) & 0x0000ff;
+ qoa->samplerate = (frame_header >> 32) & 0xffffff;
+
+ if (qoa->channels == 0 || qoa->samples == 0 || qoa->samplerate == 0) {
+ return 0;
+ }
+
+ return 8;
+}
+
+unsigned int qoa_decode_frame(const unsigned char *bytes, unsigned int size, qoa_desc *qoa, short *sample_data, unsigned int *frame_len) {
+ unsigned int p = 0;
+ *frame_len = 0;
+
+ if (size < 8 + QOA_LMS_LEN * 4 * qoa->channels) {
+ return 0;
+ }
+
+ /* Read and verify the frame header */
+ qoa_uint64_t frame_header = qoa_read_u64(bytes, &p);
+ int channels = (frame_header >> 56) & 0x0000ff;
+ int samplerate = (frame_header >> 32) & 0xffffff;
+ int samples = (frame_header >> 16) & 0x00ffff;
+ int frame_size = (frame_header ) & 0x00ffff;
+
+ int data_size = frame_size - 8 - QOA_LMS_LEN * 4 * channels;
+ int num_slices = data_size / 8;
+ int max_total_samples = num_slices * QOA_SLICE_LEN;
+
+ if (
+ channels != qoa->channels ||
+ samplerate != qoa->samplerate ||
+ frame_size > size ||
+ samples * channels > max_total_samples
+ ) {
+ return 0;
+ }
+
+
+ /* Read the LMS state: 4 x 2 bytes history, 4 x 2 bytes weights per channel */
+ for (int c = 0; c < channels; c++) {
+ qoa_uint64_t history = qoa_read_u64(bytes, &p);
+ qoa_uint64_t weights = qoa_read_u64(bytes, &p);
+ for (int i = 0; i < QOA_LMS_LEN; i++) {
+ qoa->lms[c].history[i] = ((signed short)(history >> 48));
+ history <<= 16;
+ qoa->lms[c].weights[i] = ((signed short)(weights >> 48));
+ weights <<= 16;
+ }
+ }
+
+
+ /* Decode all slices for all channels in this frame */
+ for (int sample_index = 0; sample_index < samples; sample_index += QOA_SLICE_LEN) {
+ for (int c = 0; c < channels; c++) {
+ qoa_uint64_t slice = qoa_read_u64(bytes, &p);
+
+ int scalefactor = (slice >> 60) & 0xf;
+ int slice_start = sample_index * channels + c;
+ int slice_end = qoa_clamp(sample_index + QOA_SLICE_LEN, 0, samples) * channels + c;
+
+ for (int si = slice_start; si < slice_end; si += channels) {
+ int predicted = qoa_lms_predict(&qoa->lms[c]);
+ int quantized = (slice >> 57) & 0x7;
+ int dequantized = qoa_dequant_tab[scalefactor][quantized];
+ int reconstructed = qoa_clamp(predicted + dequantized, -32768, 32767);
+
+ sample_data[si] = reconstructed;
+ slice <<= 3;
+
+ qoa_lms_update(&qoa->lms[c], reconstructed, dequantized);
+ }
+ }
+ }
+
+ *frame_len = samples;
+ return p;
+}
+
+short *qoa_decode(const unsigned char *bytes, int size, qoa_desc *qoa) {
+ unsigned int p = qoa_decode_header(bytes, size, qoa);
+ if (!p) {
+ return NULL;
+ }
+
+ /* Calculate the required size of the sample buffer and allocate */
+ int total_samples = qoa->samples * qoa->channels;
+ short *sample_data = QOA_MALLOC(total_samples * sizeof(short));
+
+ unsigned int sample_index = 0;
+ unsigned int frame_len;
+ unsigned int frame_size;
+
+ /* Decode all frames */
+ do {
+ short *sample_ptr = sample_data + sample_index * qoa->channels;
+ frame_size = qoa_decode_frame(bytes + p, size - p, qoa, sample_ptr, &frame_len);
+
+ p += frame_size;
+ sample_index += frame_len;
+ } while (frame_size && sample_index < qoa->samples);
+
+ qoa->samples = sample_index;
+ return sample_data;
+}
+
+
+
+/* -----------------------------------------------------------------------------
+ File read/write convenience functions */
+
+#ifndef QOA_NO_STDIO
+#include <stdio.h>
+
+int qoa_write(const char *filename, const short *sample_data, qoa_desc *qoa) {
+ FILE *f = fopen(filename, "wb");
+ unsigned int size;
+ void *encoded;
+
+ if (!f) {
+ return 0;
+ }
+
+ encoded = qoa_encode(sample_data, qoa, &size);
+ if (!encoded) {
+ fclose(f);
+ return 0;
+ }
+
+ fwrite(encoded, 1, size, f);
+ fclose(f);
+
+ QOA_FREE(encoded);
+ return size;
+}
+
+void *qoa_read(const char *filename, qoa_desc *qoa) {
+ FILE *f = fopen(filename, "rb");
+ int size, bytes_read;
+ void *data;
+ short *sample_data;
+
+ if (!f) {
+ return NULL;
+ }
+
+ fseek(f, 0, SEEK_END);
+ size = ftell(f);
+ if (size <= 0) {
+ fclose(f);
+ return NULL;
+ }
+ fseek(f, 0, SEEK_SET);
+
+ data = QOA_MALLOC(size);
+ if (!data) {
+ fclose(f);
+ return NULL;
+ }
+
+ bytes_read = fread(data, 1, size, f);
+ fclose(f);
+
+ sample_data = qoa_decode(data, bytes_read, qoa);
+ QOA_FREE(data);
+ return sample_data;
+}
+
+#endif /* QOA_NO_STDIO */
+#endif /* QOA_IMPLEMENTATION */