mirror of
https://github.com/Relintai/sdl2_frt.git
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150 lines
5.5 KiB
C
150 lines
5.5 KiB
C
/*
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Simple DirectMedia Layer
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Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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#include "../SDL_internal.h"
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/* RIFF WAVE files are little-endian */
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/*******************************************/
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/* Define values for Microsoft WAVE format */
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/*******************************************/
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/* FOURCC */
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#define RIFF 0x46464952 /* "RIFF" */
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#define WAVE 0x45564157 /* "WAVE" */
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#define FACT 0x74636166 /* "fact" */
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#define LIST 0x5453494c /* "LIST" */
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#define BEXT 0x74786562 /* "bext" */
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#define JUNK 0x4B4E554A /* "JUNK" */
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#define FMT 0x20746D66 /* "fmt " */
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#define DATA 0x61746164 /* "data" */
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/* Format tags */
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#define UNKNOWN_CODE 0x0000
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#define PCM_CODE 0x0001
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#define MS_ADPCM_CODE 0x0002
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#define IEEE_FLOAT_CODE 0x0003
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#define ALAW_CODE 0x0006
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#define MULAW_CODE 0x0007
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#define IMA_ADPCM_CODE 0x0011
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#define MPEG_CODE 0x0050
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#define MPEGLAYER3_CODE 0x0055
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#define EXTENSIBLE_CODE 0xFFFE
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/* Stores the WAVE format information. */
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typedef struct WaveFormat
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{
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Uint16 formattag; /* Raw value of the first field in the fmt chunk data. */
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Uint16 encoding; /* Actual encoding, possibly from the extensible header. */
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Uint16 channels; /* Number of channels. */
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Uint32 frequency; /* Sampling rate in Hz. */
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Uint32 byterate; /* Average bytes per second. */
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Uint16 blockalign; /* Bytes per block. */
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Uint16 bitspersample; /* Currently supported are 8, 16, 24, 32, and 4 for ADPCM. */
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/* Extra information size. Number of extra bytes starting at byte 18 in the
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* fmt chunk data. This is at least 22 for the extensible header.
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*/
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Uint16 extsize;
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/* Extensible WAVE header fields */
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Uint16 validsamplebits;
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Uint32 samplesperblock; /* For compressed formats. Can be zero. Actually 16 bits in the header. */
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Uint32 channelmask;
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Uint8 subformat[16]; /* A format GUID. */
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} WaveFormat;
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/* Stores information on the fact chunk. */
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typedef struct WaveFact {
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/* Represents the state of the fact chunk in the WAVE file.
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* Set to -1 if the fact chunk is invalid.
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* Set to 0 if the fact chunk is not present
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* Set to 1 if the fact chunk is present and valid.
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* Set to 2 if samplelength is going to be used as the number of sample frames.
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*/
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Sint32 status;
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/* Version 1 of the RIFF specification calls the field in the fact chunk
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* dwFileSize. The Standards Update then calls it dwSampleLength and specifies
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* that it is 'the length of the data in samples'. WAVE files from Windows
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* with this chunk have it set to the samples per channel (sample frames).
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* This is useful to truncate compressed audio to a specific sample count
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* because a compressed block is usually decoded to a fixed number of
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* sample frames.
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*/
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Uint32 samplelength; /* Raw sample length value from the fact chunk. */
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} WaveFact;
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/* Generic struct for the chunks in the WAVE file. */
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typedef struct WaveChunk
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{
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Uint32 fourcc; /* FOURCC of the chunk. */
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Uint32 length; /* Size of the chunk data. */
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Sint64 position; /* Position of the data in the stream. */
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Uint8 *data; /* When allocated, this points to the chunk data. length is used for the malloc size. */
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size_t size; /* Number of bytes in data that could be read from the stream. Can be smaller than length. */
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} WaveChunk;
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/* Controls how the size of the RIFF chunk affects the loading of a WAVE file. */
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typedef enum WaveRiffSizeHint {
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RiffSizeNoHint,
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RiffSizeForce,
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RiffSizeIgnoreZero,
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RiffSizeIgnore,
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RiffSizeMaximum
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} WaveRiffSizeHint;
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/* Controls how a truncated WAVE file is handled. */
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typedef enum WaveTruncationHint {
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TruncNoHint,
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TruncVeryStrict,
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TruncStrict,
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TruncDropFrame,
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TruncDropBlock
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} WaveTruncationHint;
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/* Controls how the fact chunk affects the loading of a WAVE file. */
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typedef enum WaveFactChunkHint {
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FactNoHint,
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FactTruncate,
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FactStrict,
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FactIgnoreZero,
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FactIgnore
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} WaveFactChunkHint;
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typedef struct WaveFile
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{
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WaveChunk chunk;
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WaveFormat format;
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WaveFact fact;
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/* Number of sample frames that will be decoded. Calculated either with the
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* size of the data chunk or, if the appropriate hint is enabled, with the
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* sample length value from the fact chunk.
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*/
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Sint64 sampleframes;
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void *decoderdata; /* Some decoders require extra data for a state. */
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WaveRiffSizeHint riffhint;
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WaveTruncationHint trunchint;
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WaveFactChunkHint facthint;
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} WaveFile;
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/* vi: set ts=4 sw=4 expandtab: */
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