/*

FLAC audio decoder. Choice of public domain or MIT-0. See license statements at the end of this file.

dr_flac - v0.13.4 - TBD

David Reid - mackron@gmail.com

GitHub: https://github.com/mackron/dr_libs

*/

/*

Introduction

============

dr_flac is a single file library. To use it, do something like the following in one .c file.

    ```c

    #define DR_FLAC_IMPLEMENTATION

    #include "dr_flac.h"

    ```

You can then #include this file in other parts of the program as you would with any other header file. To decode audio data, do something like the following:

    ```c

    drflac* pFlac = drflac_open_file("MySong.flac", NULL);

    if (pFlac == NULL) {

        // Failed to open FLAC file

    }

    drflac_int32* pSamples = malloc(pFlac->totalPCMFrameCount * pFlac->channels * sizeof(drflac_int32));

    drflac_uint64 numberOfInterleavedSamplesActuallyRead = drflac_read_pcm_frames_s32(pFlac, pFlac->totalPCMFrameCount, pSamples);

    ```

The drflac object represents the decoder. It is a transparent type so all the information you need, such as the number of channels and the bits per sample,

should be directly accessible - just make sure you don't change their values. Samples are always output as interleaved signed 32-bit PCM. In the example above

a native FLAC stream was opened, however dr_flac has seamless support for Ogg encapsulated FLAC streams as well.

You do not need to decode the entire stream in one go - you just specify how many samples you'd like at any given time and the decoder will give you as many

samples as it can, up to the amount requested. Later on when you need the next batch of samples, just call it again. Example:

    ```c

    while (drflac_read_pcm_frames_s32(pFlac, chunkSizeInPCMFrames, pChunkSamples) > 0) {

        do_something();

    }

    ```

You can seek to a specific PCM frame with `drflac_seek_to_pcm_frame()`.

If you just want to quickly decode an entire FLAC file in one go you can do something like this:

    ```c

    unsigned int channels;

    unsigned int sampleRate;

    drflac_uint64 totalPCMFrameCount;

    drflac_int32* pSampleData = drflac_open_file_and_read_pcm_frames_s32("MySong.flac", &channels, &sampleRate, &totalPCMFrameCount, NULL);

    if (pSampleData == NULL) {

        // Failed to open and decode FLAC file.

    }

    ...

    drflac_free(pSampleData, NULL);

    ```

You can read samples as signed 16-bit integer and 32-bit floating-point PCM with the *_s16() and *_f32() family of APIs respectively, but note that these

should be considered lossy.

If you need access to metadata (album art, etc.), use `drflac_open_with_metadata()`, `drflac_open_file_with_metdata()` or `drflac_open_memory_with_metadata()`.

The rationale for keeping these APIs separate is that they're slightly slower than the normal versions and also just a little bit harder to use. dr_flac

reports metadata to the application through the use of a callback, and every metadata block is reported before `drflac_open_with_metdata()` returns.

The main opening APIs (`drflac_open()`, etc.) will fail if the header is not present. The presents a problem in certain scenarios such as broadcast style

streams or internet radio where the header may not be present because the user has started playback mid-stream. To handle this, use the relaxed APIs:

    `drflac_open_relaxed()`

    `drflac_open_with_metadata_relaxed()`

It is not recommended to use these APIs for file based streams because a missing header would usually indicate a corrupt or perverse file. In addition, these

APIs can take a long time to initialize because they may need to spend a lot of time finding the first frame.

Build Options

=============

#define these options before including this file.

#define DR_FLAC_NO_STDIO

  Disable `drflac_open_file()` and family.

#define DR_FLAC_NO_OGG

  Disables support for Ogg/FLAC streams.

#define DR_FLAC_BUFFER_SIZE <number>

  Defines the size of the internal buffer to store data from onRead(). This buffer is used to reduce the number of calls back to the client for more data.

  Larger values means more memory, but better performance. My tests show diminishing returns after about 4KB (which is the default). Consider reducing this if

  you have a very efficient implementation of onRead(), or increase it if it's very inefficient. Must be a multiple of 8.

#define DR_FLAC_NO_CRC

  Disables CRC checks. This will offer a performance boost when CRC is unnecessary. This will disable binary search seeking. When seeking, the seek table will

  be used if available. Otherwise the seek will be performed using brute force.

#define DR_FLAC_NO_SIMD

  Disables SIMD optimizations (SSE on x86/x64 architectures, NEON on ARM architectures). Use this if you are having compatibility issues with your compiler.

#define DR_FLAC_NO_WCHAR

  Disables all functions ending with `_w`. Use this if your compiler does not provide wchar.h. Not required if DR_FLAC_NO_STDIO is also defined.

Notes

=====

- dr_flac does not support changing the sample rate nor channel count mid stream.

- dr_flac is not thread-safe, but its APIs can be called from any thread so long as you do your own synchronization.

- When using Ogg encapsulation, a corrupted metadata block will result in `drflac_open_with_metadata()` and `drflac_open()` returning inconsistent samples due

  to differences in corrupted stream recorvery logic between the two APIs.

*/

#ifndef dr_flac_h

#define dr_flac_h

#ifdef __cplusplus

extern "C" {

#endif

#define DRFLAC_STRINGIFY(x)      #x

#define DRFLAC_XSTRINGIFY(x)     DRFLAC_STRINGIFY(x)

#define DRFLAC_VERSION_MAJOR     0

#define DRFLAC_VERSION_MINOR     13

#define DRFLAC_VERSION_REVISION  4

#define DRFLAC_VERSION_STRING    DRFLAC_XSTRINGIFY(DRFLAC_VERSION_MAJOR) "." DRFLAC_XSTRINGIFY(DRFLAC_VERSION_MINOR) "." DRFLAC_XSTRINGIFY(DRFLAC_VERSION_REVISION)

#include <stddef.h> /* For size_t. */

/* Sized Types */

typedef   signed char           drflac_int8;

typedef unsigned char           drflac_uint8;

typedef   signed short          drflac_int16;

typedef unsigned short          drflac_uint16;

typedef   signed int            drflac_int32;

typedef unsigned int            drflac_uint32;

#if defined(_MSC_VER) && !defined(__clang__)

    typedef   signed __int64    drflac_int64;

    typedef unsigned __int64    drflac_uint64;

#else

    #if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)))

        #pragma GCC diagnostic push

        #pragma GCC diagnostic ignored "-Wlong-long"

        #if defined(__clang__)

            #pragma GCC diagnostic ignored "-Wc++11-long-long"

        #endif

    #endif

    typedef   signed long long  drflac_int64;

    typedef unsigned long long  drflac_uint64;

    #if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)))

        #pragma GCC diagnostic pop

    #endif

#endif

#if defined(__LP64__) || defined(_WIN64) || (defined(__x86_64__) && !defined(__ILP32__)) || defined(_M_X64) || defined(__ia64) || defined(_M_IA64) || defined(__aarch64__) || defined(_M_ARM64) || defined(__powerpc64__)

    typedef drflac_uint64       drflac_uintptr;

#else

    typedef drflac_uint32       drflac_uintptr;

#endif

typedef drflac_uint8            drflac_bool8;

typedef drflac_uint32           drflac_bool32;

#define DRFLAC_TRUE             1

#define DRFLAC_FALSE            0

/* End Sized Types */

/* Decorations */

#if !defined(DRFLAC_API)

    #if defined(DRFLAC_DLL)

        #if defined(_WIN32)

            #define DRFLAC_DLL_IMPORT  __declspec(dllimport)

            #define DRFLAC_DLL_EXPORT  __declspec(dllexport)

            #define DRFLAC_DLL_PRIVATE static

        #else

            #if defined(__GNUC__) && __GNUC__ >= 4

                #define DRFLAC_DLL_IMPORT  __attribute__((visibility("default")))

                #define DRFLAC_DLL_EXPORT  __attribute__((visibility("default")))

                #define DRFLAC_DLL_PRIVATE __attribute__((visibility("hidden")))

            #else

                #define DRFLAC_DLL_IMPORT

                #define DRFLAC_DLL_EXPORT

                #define DRFLAC_DLL_PRIVATE static

            #endif

        #endif

        #if defined(DR_FLAC_IMPLEMENTATION) || defined(DRFLAC_IMPLEMENTATION)

            #define DRFLAC_API  DRFLAC_DLL_EXPORT

        #else

            #define DRFLAC_API  DRFLAC_DLL_IMPORT

        #endif

        #define DRFLAC_PRIVATE DRFLAC_DLL_PRIVATE

    #else

        #define DRFLAC_API extern

        #define DRFLAC_PRIVATE static

    #endif

#endif

/* End Decorations */

#if defined(_MSC_VER) && _MSC_VER >= 1700   /* Visual Studio 2012 */

    #define DRFLAC_DEPRECATED       __declspec(deprecated)

#elif (defined(__GNUC__) && __GNUC__ >= 4)  /* GCC 4 */

    #define DRFLAC_DEPRECATED       __attribute__((deprecated))

#elif defined(__has_feature)                /* Clang */

    #if __has_feature(attribute_deprecated)

        #define DRFLAC_DEPRECATED   __attribute__((deprecated))

    #else

        #define DRFLAC_DEPRECATED

    #endif

#else

    #define DRFLAC_DEPRECATED

#endif

DRFLAC_API void drflac_version(drflac_uint32* pMajor, drflac_uint32* pMinor, drflac_uint32* pRevision);

DRFLAC_API const char* drflac_version_string(void);

/* Allocation Callbacks */

typedef struct

{

    void* pUserData;

    void* (* onMalloc)(size_t sz, void* pUserData);

    void* (* onRealloc)(void* p, size_t sz, void* pUserData);

    void  (* onFree)(void* p, void* pUserData);

} drflac_allocation_callbacks;

/* End Allocation Callbacks */

/*

As data is read from the client it is placed into an internal buffer for fast access. This controls the size of that buffer. Larger values means more speed,

but also more memory. In my testing there is diminishing returns after about 4KB, but you can fiddle with this to suit your own needs. Must be a multiple of 8.

*/

#ifndef DR_FLAC_BUFFER_SIZE

#define DR_FLAC_BUFFER_SIZE   4096

#endif

/* Architecture Detection */

#if defined(_WIN64) || defined(_LP64) || defined(__LP64__)

#define DRFLAC_64BIT

#endif

#if defined(__x86_64__) || (defined(_M_X64) && !defined(_M_ARM64EC))

    #define DRFLAC_X64

#elif defined(__i386) || defined(_M_IX86)

    #define DRFLAC_X86

#elif defined(__arm__) || defined(_M_ARM) || defined(__arm64) || defined(__arm64__) || defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)

    #define DRFLAC_ARM

#endif

/* End Architecture Detection */

#ifdef DRFLAC_64BIT

typedef drflac_uint64 drflac_cache_t;

#else

typedef drflac_uint32 drflac_cache_t;

#endif

/* The various metadata block types. */

#define DRFLAC_METADATA_BLOCK_TYPE_STREAMINFO       0

#define DRFLAC_METADATA_BLOCK_TYPE_PADDING          1

#define DRFLAC_METADATA_BLOCK_TYPE_APPLICATION      2

#define DRFLAC_METADATA_BLOCK_TYPE_SEEKTABLE        3

#define DRFLAC_METADATA_BLOCK_TYPE_VORBIS_COMMENT   4

#define DRFLAC_METADATA_BLOCK_TYPE_CUESHEET         5

#define DRFLAC_METADATA_BLOCK_TYPE_PICTURE          6

#define DRFLAC_METADATA_BLOCK_TYPE_INVALID          127

/* The various picture types specified in the PICTURE block. */

#define DRFLAC_PICTURE_TYPE_OTHER                   0

#define DRFLAC_PICTURE_TYPE_FILE_ICON               1

#define DRFLAC_PICTURE_TYPE_OTHER_FILE_ICON         2

#define DRFLAC_PICTURE_TYPE_COVER_FRONT             3

#define DRFLAC_PICTURE_TYPE_COVER_BACK              4

#define DRFLAC_PICTURE_TYPE_LEAFLET_PAGE            5

#define DRFLAC_PICTURE_TYPE_MEDIA                   6

#define DRFLAC_PICTURE_TYPE_LEAD_ARTIST             7

#define DRFLAC_PICTURE_TYPE_ARTIST                  8

#define DRFLAC_PICTURE_TYPE_CONDUCTOR               9

#define DRFLAC_PICTURE_TYPE_BAND                    10

#define DRFLAC_PICTURE_TYPE_COMPOSER                11

#define DRFLAC_PICTURE_TYPE_LYRICIST                12

#define DRFLAC_PICTURE_TYPE_RECORDING_LOCATION      13

#define DRFLAC_PICTURE_TYPE_DURING_RECORDING        14

#define DRFLAC_PICTURE_TYPE_DURING_PERFORMANCE      15

#define DRFLAC_PICTURE_TYPE_SCREEN_CAPTURE          16

#define DRFLAC_PICTURE_TYPE_BRIGHT_COLORED_FISH     17

#define DRFLAC_PICTURE_TYPE_ILLUSTRATION            18

#define DRFLAC_PICTURE_TYPE_BAND_LOGOTYPE           19

#define DRFLAC_PICTURE_TYPE_PUBLISHER_LOGOTYPE      20

typedef enum

{

    drflac_container_native,

    drflac_container_ogg,

    drflac_container_unknown

} drflac_container;

typedef enum

{

    DRFLAC_SEEK_SET,

    DRFLAC_SEEK_CUR,

    DRFLAC_SEEK_END

} drflac_seek_origin;

/* The order of members in this structure is important because we map this directly to the raw data within the SEEKTABLE metadata block. */

typedef struct

{

    drflac_uint64 firstPCMFrame;

    drflac_uint64 flacFrameOffset;   /* The offset from the first byte of the header of the first frame. */

    drflac_uint16 pcmFrameCount;

} drflac_seekpoint;

typedef struct

{

    drflac_uint16 minBlockSizeInPCMFrames;

    drflac_uint16 maxBlockSizeInPCMFrames;

    drflac_uint32 minFrameSizeInPCMFrames;

    drflac_uint32 maxFrameSizeInPCMFrames;

    drflac_uint32 sampleRate;

    drflac_uint8  channels;

    drflac_uint8  bitsPerSample;

    drflac_uint64 totalPCMFrameCount;

    drflac_uint8  md5[16];

} drflac_streaminfo;

typedef struct

{

    /*

    The metadata type. Use this to know how to interpret the data below. Will be set to one of the

    DRFLAC_METADATA_BLOCK_TYPE_* tokens.

    */

    drflac_uint32 type;

    /* The size in bytes of the block and the buffer pointed to by pRawData if it's non-NULL. */

    drflac_uint32 rawDataSize;

    /* The offset in the stream of the raw data. */

    drflac_uint64 rawDataOffset;

    /*

    A pointer to the raw data. This points to a temporary buffer so don't hold on to it. It's best to

    not modify the contents of this buffer. Use the structures below for more meaningful and structured

    information about the metadata. It's possible for this to be null.

    */

    const void* pRawData;

    union

    {

        drflac_streaminfo streaminfo;

        struct

        {

            int unused;

        } padding;

        struct

        {

            drflac_uint32 id;

            const void* pData;

            drflac_uint32 dataSize;

        } application;

        struct

        {

            drflac_uint32 seekpointCount;

            const drflac_seekpoint* pSeekpoints;

        } seektable;

        struct

        {

            drflac_uint32 vendorLength;

            const char* vendor;

            drflac_uint32 commentCount;

            const void* pComments;

        } vorbis_comment;

        struct

        {

            char catalog[128];

            drflac_uint64 leadInSampleCount;

            drflac_bool32 isCD;

            drflac_uint8 trackCount;

            const void* pTrackData;

        } cuesheet;

        struct

        {

            drflac_uint32 type;

            drflac_uint32 mimeLength;

            const char* mime;

            drflac_uint32 descriptionLength;

            const char* description;

            drflac_uint32 width;

            drflac_uint32 height;

            drflac_uint32 colorDepth;

            drflac_uint32 indexColorCount;

            drflac_uint32 pictureDataSize;

            drflac_uint64 pictureDataOffset;  /* Offset from the start of the stream. */

            const drflac_uint8* pPictureData;

        } picture;

    } data;

} drflac_metadata;

/*

Callback for when data needs to be read from the client.

Parameters

----------

pUserData (in)

    The user data that was passed to drflac_open() and family.

pBufferOut (out)

    The output buffer.

bytesToRead (in)

    The number of bytes to read.

Return Value

------------

The number of bytes actually read.

Remarks

-------

A return value of less than bytesToRead indicates the end of the stream. Do _not_ return from this callback until either the entire bytesToRead is filled or

you have reached the end of the stream.

*/

typedef size_t (* drflac_read_proc)(void* pUserData, void* pBufferOut, size_t bytesToRead);

/*

Callback for when data needs to be seeked.

Parameters

----------

pUserData (in)

    The user data that was passed to drflac_open() and family.

offset (in)

    The number of bytes to move, relative to the origin. Will never be negative.

origin (in)

    The origin of the seek - the current position, the start of the stream, or the end of the stream.

Return Value

------------

Whether or not the seek was successful.

Remarks

-------

Seeking relative to the start and the current position must always be supported. If seeking from the end of the stream is not supported, return DRFLAC_FALSE.

When seeking to a PCM frame using drflac_seek_to_pcm_frame(), dr_flac may call this with an offset beyond the end of the FLAC stream. This needs to be detected

and handled by returning DRFLAC_FALSE.

*/

typedef drflac_bool32 (* drflac_seek_proc)(void* pUserData, int offset, drflac_seek_origin origin);

/*

Callback for when the current position in the stream needs to be retrieved.

Parameters

----------

pUserData (in)

    The user data that was passed to drflac_open() and family.

pCursor (out)

    A pointer to a variable to receive the current position in the stream.

Return Value

------------

Whether or not the operation was successful.

*/

typedef drflac_bool32 (* drflac_tell_proc)(void* pUserData, drflac_int64* pCursor);

/*

Callback for when a metadata block is read.

Parameters

----------

pUserData (in)

    The user data that was passed to drflac_open() and family.

pMetadata (in)

    A pointer to a structure containing the data of the metadata block.

Remarks

-------

Use pMetadata->type to determine which metadata block is being handled and how to read the data. This

will be set to one of the DRFLAC_METADATA_BLOCK_TYPE_* tokens.

*/

typedef void (* drflac_meta_proc)(void* pUserData, drflac_metadata* pMetadata);

/* Structure for internal use. Only used for decoders opened with drflac_open_memory. */

typedef struct

{

    const drflac_uint8* data;

    size_t dataSize;

    size_t currentReadPos;

} drflac__memory_stream;

/* Structure for internal use. Used for bit streaming. */

typedef struct

{

    /* The function to call when more data needs to be read. */

    drflac_read_proc onRead;

    /* The function to call when the current read position needs to be moved. */

    drflac_seek_proc onSeek;

    /* The function to call when the current read position needs to be retrieved. */

    drflac_tell_proc onTell;

    /* The user data to pass around to onRead and onSeek. */

    void* pUserData;

    /*

    The number of unaligned bytes in the L2 cache. This will always be 0 until the end of the stream is hit. At the end of the

    stream there will be a number of bytes that don't cleanly fit in an L1 cache line, so we use this variable to know whether

    or not the bistreamer needs to run on a slower path to read those last bytes. This will never be more than sizeof(drflac_cache_t).

    */

    size_t unalignedByteCount;

    /* The content of the unaligned bytes. */

    drflac_cache_t unalignedCache;

    /* The index of the next valid cache line in the "L2" cache. */

    drflac_uint32 nextL2Line;

    /* The number of bits that have been consumed by the cache. This is used to determine how many valid bits are remaining. */

    drflac_uint32 consumedBits;

    /*

    The cached data which was most recently read from the client. There are two levels of cache. Data flows as such:

    Client -> L2 -> L1. The L2 -> L1 movement is aligned and runs on a fast path in just a few instructions.

    */

    drflac_cache_t cacheL2[DR_FLAC_BUFFER_SIZE/sizeof(drflac_cache_t)];

    drflac_cache_t cache;

    /*

    CRC-16. This is updated whenever bits are read from the bit stream. Manually set this to 0 to reset the CRC. For FLAC, this

    is reset to 0 at the beginning of each frame.

    */

    drflac_uint16 crc16;

    drflac_cache_t crc16Cache;              /* A cache for optimizing CRC calculations. This is filled when when the L1 cache is reloaded. */

    drflac_uint32 crc16CacheIgnoredBytes;   /* The number of bytes to ignore when updating the CRC-16 from the CRC-16 cache. */

} drflac_bs;

typedef struct

{

    /* The type of the subframe: SUBFRAME_CONSTANT, SUBFRAME_VERBATIM, SUBFRAME_FIXED or SUBFRAME_LPC. */

    drflac_uint8 subframeType;

    /* The number of wasted bits per sample as specified by the sub-frame header. */

    drflac_uint8 wastedBitsPerSample;

    /* The order to use for the prediction stage for SUBFRAME_FIXED and SUBFRAME_LPC. */

    drflac_uint8 lpcOrder;

    /* A pointer to the buffer containing the decoded samples in the subframe. This pointer is an offset from drflac::pExtraData. */

    drflac_int32* pSamplesS32;

} drflac_subframe;

typedef struct

{

    /*

    If the stream uses variable block sizes, this will be set to the index of the first PCM frame. If fixed block sizes are used, this will

    always be set to 0. This is 64-bit because the decoded PCM frame number will be 36 bits.

    */

    drflac_uint64 pcmFrameNumber;

    /*

    If the stream uses fixed block sizes, this will be set to the frame number. If variable block sizes are used, this will always be 0. This

    is 32-bit because in fixed block sizes, the maximum frame number will be 31 bits.

    */

    drflac_uint32 flacFrameNumber;

    /* The sample rate of this frame. */

    drflac_uint32 sampleRate;

    /* The number of PCM frames in each sub-frame within this frame. */

    drflac_uint16 blockSizeInPCMFrames;

    /*

    The channel assignment of this frame. This is not always set to the channel count. If interchannel decorrelation is being used this

    will be set to DRFLAC_CHANNEL_ASSIGNMENT_LEFT_SIDE, DRFLAC_CHANNEL_ASSIGNMENT_RIGHT_SIDE or DRFLAC_CHANNEL_ASSIGNMENT_MID_SIDE.

    */

    drflac_uint8 channelAssignment;

    /* The number of bits per sample within this frame. */

    drflac_uint8 bitsPerSample;

    /* The frame's CRC. */

    drflac_uint8 crc8;

} drflac_frame_header;

typedef struct

{

    /* The header. */

    drflac_frame_header header;

    /*

    The number of PCM frames left to be read in this FLAC frame. This is initially set to the block size. As PCM frames are read,

    this will be decremented. When it reaches 0, the decoder will see this frame as fully consumed and load the next frame.

    */

    drflac_uint32 pcmFramesRemaining;

    /* The list of sub-frames within the frame. There is one sub-frame for each channel, and there's a maximum of 8 channels. */

    drflac_subframe subframes[8];

} drflac_frame;

typedef struct

{

    /* The function to call when a metadata block is read. */

    drflac_meta_proc onMeta;

    /* The user data posted to the metadata callback function. */

    void* pUserDataMD;

    /* Memory allocation callbacks. */

    drflac_allocation_callbacks allocationCallbacks;

    /* The sample rate. Will be set to something like 44100. */

    drflac_uint32 sampleRate;

    /*

    The number of channels. This will be set to 1 for monaural streams, 2 for stereo, etc. Maximum 8. This is set based on the

    value specified in the STREAMINFO block.

    */

    drflac_uint8 channels;

    /* The bits per sample. Will be set to something like 16, 24, etc. */

    drflac_uint8 bitsPerSample;

    /* The maximum block size, in samples. This number represents the number of samples in each channel (not combined). */

    drflac_uint16 maxBlockSizeInPCMFrames;

    /*

    The total number of PCM Frames making up the stream. Can be 0 in which case it's still a valid stream, but just means

    the total PCM frame count is unknown. Likely the case with streams like internet radio.

    */

    drflac_uint64 totalPCMFrameCount;

    /* The container type. This is set based on whether or not the decoder was opened from a native or Ogg stream. */

    drflac_container container;

    /* The number of seekpoints in the seektable. */

    drflac_uint32 seekpointCount;

    /* Information about the frame the decoder is currently sitting on. */

    drflac_frame currentFLACFrame;

    /* The index of the PCM frame the decoder is currently sitting on. This is only used for seeking. */

    drflac_uint64 currentPCMFrame;

    /* The position of the first FLAC frame in the stream. This is only ever used for seeking. */

    drflac_uint64 firstFLACFramePosInBytes;

    /* A hack to avoid a malloc() when opening a decoder with drflac_open_memory(). */

    drflac__memory_stream memoryStream;

    /* A pointer to the decoded sample data. This is an offset of pExtraData. */

    drflac_int32* pDecodedSamples;

    /* A pointer to the seek table. This is an offset of pExtraData, or NULL if there is no seek table. */

    drflac_seekpoint* pSeekpoints;

    /* Internal use only. Only used with Ogg containers. Points to a drflac_oggbs object. This is an offset of pExtraData. */

    void* _oggbs;

    /* Internal use only. Used for profiling and testing different seeking modes. */

    drflac_bool32 _noSeekTableSeek    : 1;

    drflac_bool32 _noBinarySearchSeek : 1;

    drflac_bool32 _noBruteForceSeek   : 1;

    /* The bit streamer. The raw FLAC data is fed through this object. */

    drflac_bs bs;

    /* Variable length extra data. We attach this to the end of the object so we can avoid unnecessary mallocs. */

    drflac_uint8 pExtraData[1];

} drflac;

/*

Opens a FLAC decoder.

Parameters

----------

onRead (in)

    The function to call when data needs to be read from the client.

onSeek (in)

    The function to call when the read position of the client data needs to move.

onTell (in)

    The function to call when the read position of the client needs to be queried.

pUserData (in, optional)

    A pointer to application defined data that will be passed to onRead and onSeek.

pAllocationCallbacks (in, optional)

    A pointer to application defined callbacks for managing memory allocations.

Return Value

------------

Returns a pointer to an object representing the decoder.

Remarks

-------

Close the decoder with `drflac_close()`.

`pAllocationCallbacks` can be NULL in which case it will use `DRFLAC_MALLOC`, `DRFLAC_REALLOC` and `DRFLAC_FREE`.

This function will automatically detect whether or not you are attempting to open a native or Ogg encapsulated FLAC, both of which should work seamlessly

without any manual intervention. Ogg encapsulation also works with multiplexed streams which basically means it can play FLAC encoded audio tracks in videos.

This is the lowest level function for opening a FLAC stream. You can also use `drflac_open_file()` and `drflac_open_memory()` to open the stream from a file or

from a block of memory respectively.

The STREAMINFO block must be present for this to succeed. Use `drflac_open_relaxed()` to open a FLAC stream where the header may not be present.

Use `drflac_open_with_metadata()` if you need access to metadata.

Seek Also

---------

drflac_open_file()

drflac_open_memory()

drflac_open_with_metadata()

drflac_close()

*/

DRFLAC_API drflac* drflac_open(drflac_read_proc onRead, drflac_seek_proc onSeek, drflac_tell_proc onTell, void* pUserData, const drflac_allocation_callbacks* pAllocationCallbacks);

/*

Opens a FLAC stream with relaxed validation of the header block.

Parameters

----------

onRead (in)

    The function to call when data needs to be read from the client.

onSeek (in)

    The function to call when the read position of the client data needs to move.

onTell (in)

    The function to call when the read position of the client needs to be queried.

container (in)

    Whether or not the FLAC stream is encapsulated using standard FLAC encapsulation or Ogg encapsulation.

pUserData (in, optional)

    A pointer to application defined data that will be passed to onRead and onSeek.

pAllocationCallbacks (in, optional)

    A pointer to application defined callbacks for managing memory allocations.

Return Value

------------

A pointer to an object representing the decoder.

Remarks

-------

The same as drflac_open(), except attempts to open the stream even when a header block is not present.

Because the header is not necessarily available, the caller must explicitly define the container (Native or Ogg). Do not set this to `drflac_container_unknown`

as that is for internal use only.

Opening in relaxed mode will continue reading data from onRead until it finds a valid frame. If a frame is never found it will continue forever. To abort,

force your `onRead` callback to return 0, which dr_flac will use as an indicator that the end of the stream was found.

Use `drflac_open_with_metadata_relaxed()` if you need access to metadata.

*/

DRFLAC_API drflac* drflac_open_relaxed(drflac_read_proc onRead, drflac_seek_proc onSeek, drflac_tell_proc onTell, drflac_container container, void* pUserData, const drflac_allocation_callbacks* pAllocationCallbacks);

/*

Opens a FLAC decoder and notifies the caller of the metadata chunks (album art, etc.).

Parameters

----------

onRead (in)

    The function to call when data needs to be read from the client.

onSeek (in)

    The function to call when the read position of the client data needs to move.

onTell (in)

    The function to call when the read position of the client needs to be queried.

onMeta (in)

    The function to call for every metadata block.

pUserData (in, optional)

    A pointer to application defined data that will be passed to onRead, onSeek and onMeta.

pAllocationCallbacks (in, optional)

    A pointer to application defined callbacks for managing memory allocations.

Return Value

------------

A pointer to an object representing the decoder.

Remarks

-------

Close the decoder with `drflac_close()`.

`pAllocationCallbacks` can be NULL in which case it will use `DRFLAC_MALLOC`, `DRFLAC_REALLOC` and `DRFLAC_FREE`.

This is slower than `drflac_open()`, so avoid this one if you don't need metadata. Internally, this will allocate and free memory on the heap for every

metadata block except for STREAMINFO and PADDING blocks.

The caller is notified of the metadata via the `onMeta` callback. All metadata blocks will be handled before the function returns. This callback takes a

pointer to a `drflac_metadata` object which is a union containing the data of all relevant metadata blocks. Use the `type` member to discriminate against

the different metadata types.

The STREAMINFO block must be present for this to succeed. Use `drflac_open_with_metadata_relaxed()` to open a FLAC stream where the header may not be present.

Note that this will behave inconsistently with `drflac_open()` if the stream is an Ogg encapsulated stream and a metadata block is corrupted. This is due to

the way the Ogg stream recovers from corrupted pages. When `drflac_open_with_metadata()` is being used, the open routine will try to read the contents of the

metadata block, whereas `drflac_open()` will simply seek past it (for the sake of efficiency). This inconsistency can result in different samples being

returned depending on whether or not the stream is being opened with metadata.

Seek Also

---------

drflac_open_file_with_metadata()

drflac_open_memory_with_metadata()

drflac_open()

drflac_close()

*/

DRFLAC_API drflac* drflac_open_with_metadata(drflac_read_proc onRead, drflac_seek_proc onSeek, drflac_tell_proc onTell, drflac_meta_proc onMeta, void* pUserData, const drflac_allocation_callbacks* pAllocationCallbacks);

/*

The same as drflac_open_with_metadata(), except attempts to open the stream even when a header block is not present.

See Also

--------

drflac_open_with_metadata()

drflac_open_relaxed()

*/

DRFLAC_API drflac* drflac_open_with_metadata_relaxed(drflac_read_proc onRead, drflac_seek_proc onSeek, drflac_tell_proc onTell, drflac_meta_proc onMeta, drflac_container container, void* pUserData, const drflac_allocation_callbacks* pAllocationCallbacks);

/*

Closes the given FLAC decoder.

Parameters

----------

pFlac (in)

    The decoder to close.

Remarks

-------

This will destroy the decoder object.

See Also

--------

drflac_open()

drflac_open_with_metadata()

drflac_open_file()

drflac_open_file_w()

drflac_open_file_with_metadata()

drflac_open_file_with_metadata_w()

drflac_open_memory()

drflac_open_memory_with_metadata()

*/

DRFLAC_API void drflac_close(drflac* pFlac);

/*

Reads sample data from the given FLAC decoder, output as interleaved signed 32-bit PCM.

Parameters

----------

pFlac (in)

    The decoder.

framesToRead (in)

    The number of PCM frames to read.

pBufferOut (out, optional)

    A pointer to the buffer that will receive the decoded samples.

Return Value

------------

Returns the number of PCM frames actually read. If the return value is less than `framesToRead` it has reached the end.

Remarks

-------

pBufferOut can be null, in which case the call will act as a seek, and the return value will be the number of frames seeked.

*/

DRFLAC_API drflac_uint64 drflac_read_pcm_frames_s32(drflac* pFlac, drflac_uint64 framesToRead, drflac_int32* pBufferOut);

/*

Reads sample data from the given FLAC decoder, output as interleaved signed 16-bit PCM.

Parameters

----------

pFlac (in)

    The decoder.

framesToRead (in)

    The number of PCM frames to read.

pBufferOut (out, optional)

    A pointer to the buffer that will receive the decoded samples.

Return Value

------------

Returns the number of PCM frames actually read. If the return value is less than `framesToRead` it has reached the end.

Remarks

-------

pBufferOut can be null, in which case the call will act as a seek, and the return value will be the number of frames seeked.

Note that this is lossy for streams where the bits per sample is larger than 16.

*/

DRFLAC_API drflac_uint64 drflac_read_pcm_frames_s16(drflac* pFlac, drflac_uint64 framesToRead, drflac_int16* pBufferOut);

/*

Reads sample data from the given FLAC decoder, output as interleaved 32-bit floating point PCM.

Parameters

----------

pFlac (in)

    The decoder.

framesToRead (in)

    The number of PCM frames to read.

pBufferOut (out, optional)

    A pointer to the buffer that will receive the decoded samples.

Return Value

------------

Returns the number of PCM frames actually read. If the return value is less than `framesToRead` it has reached the end.

Remarks

-------

pBufferOut can be null, in which case the call will act as a seek, and the return value will be the number of frames seeked.

Note that this should be considered lossy due to the nature of floating point numbers not being able to exactly represent every possible number.

*/

DRFLAC_API drflac_uint64 drflac_read_pcm_frames_f32(drflac* pFlac, drflac_uint64 framesToRead, float* pBufferOut);

/*

Seeks to the PCM frame at the given index.

Parameters

----------

pFlac (in)

    The decoder.

pcmFrameIndex (in)

    The index of the PCM frame to seek to. See notes below.

Return Value

-------------

`DRFLAC_TRUE` if successful; `DRFLAC_FALSE` otherwise.

*/

DRFLAC_API drflac_bool32 drflac_seek_to_pcm_frame(drflac* pFlac, drflac_uint64 pcmFrameIndex);

#ifndef DR_FLAC_NO_STDIO

/*

Opens a FLAC decoder from the file at the given path.

Parameters

----------

pFileName (in)

    The path of the file to open, either absolute or relative to the current directory.

pAllocationCallbacks (in, optional)

    A pointer to application defined callbacks for managing memory allocations.

Return Value

------------

A pointer to an object representing the decoder.

Remarks

-------

Close the decoder with drflac_close().

Remarks

-------

This will hold a handle to the file until the decoder is closed with drflac_close(). Some platforms will restrict the number of files a process can have open

at any given time, so keep this mind if you have many decoders open at the same time.

See Also

--------

drflac_open_file_with_metadata()

drflac_open()

drflac_close()

*/

DRFLAC_API drflac* drflac_open_file(const char* pFileName, const drflac_allocation_callbacks* pAllocationCallbacks);

DRFLAC_API drflac* drflac_open_file_w(const wchar_t* pFileName, const drflac_allocation_callbacks* pAllocationCallbacks);

/*

Opens a FLAC decoder from the file at the given path and notifies the caller of the metadata chunks (album art, etc.)

Parameters

----------

pFileName (in)

    The path of the file to open, either absolute or relative to the current directory.

pAllocationCallbacks (in, optional)

    A pointer to application defined callbacks for managing memory allocations.

onMeta (in)

    The callback to fire for each metadata block.

pUserData (in)

    A pointer to the user data to pass to the metadata callback.

pAllocationCallbacks (in)

    A pointer to application defined callbacks for managing memory allocations.

Remarks

-------

Look at the documentation for drflac_open_with_metadata() for more information on how metadata is handled.

See Also

--------

drflac_open_with_metadata()

drflac_open()

drflac_close()

*/

DRFLAC_API drflac* drflac_open_file_with_metadata(const char* pFileName, drflac_meta_proc onMeta, void* pUserData, const drflac_allocation_callbacks* pAllocationCallbacks);

DRFLAC_API drflac* drflac_open_file_with_metadata_w(const wchar_t* pFileName, drflac_meta_proc onMeta, void* pUserData, const drflac_allocation_callbacks* pAllocationCallbacks);

#endif

/*

Opens a FLAC decoder from a pre-allocated block of memory

Parameters

----------

pData (in)

    A pointer to the raw encoded FLAC data.

dataSize (in)

    The size in bytes of `data`.

pAllocationCallbacks (in)

    A pointer to application defined callbacks for managing memory allocations.

Return Value

------------

A pointer to an object representing the decoder.

Remarks

-------

This does not create a copy of the data. It is up to the application to ensure the buffer remains valid for the lifetime of the decoder.

See Also

--------

drflac_open()

drflac_close()

*/

DRFLAC_API drflac* drflac_open_memory(const void* pData, size_t dataSize, const drflac_allocation_callbacks* pAllocationCallbacks);

/*

Opens a FLAC decoder from a pre-allocated block of memory and notifies the caller of the metadata chunks (album art, etc.)

Parameters

----------

pData (in)

    A pointer to the raw encoded FLAC data.

dataSize (in)

    The size in bytes of `data`.

onMeta (in)

    The callback to fire for each metadata block.

pUserData (in)

    A pointer to the user data to pass to the metadata callback.

pAllocationCallbacks (in)

    A pointer to application defined callbacks for managing memory allocations.

Remarks