module stb.vorbis;

extern (C):
//////////////////////////////////////////////////////////////////////////////
//
//  HEADER BEGINS HERE
//

import std.c.stdio;

///////////   THREAD SAFETY

// Individual stb_vorbis* handles are not thread-safe; you cannot decode from
// them from multiple threads at the same time. However, you can have multiple
// stb_vorbis* handles and decode from them independently in multiple thrads.


///////////   MEMORY ALLOCATION

// normally stb_vorbis uses malloc() to allocate memory at startup,
// and alloca() to allocate temporary memory during a frame on the
// stack. (Memory consumption will depend on the amount of setup
// data in the file and how you set the compile flags for speed
// vs. size. In my test files the maximal-size usage is ~150KB.)
//
// You can modify the wrapper functions in the source (setup_malloc,
// setup_temp_malloc, temp_malloc) to change this behavior, or you
// can use a simpler allocation model: you pass in a buffer from
// which stb_vorbis will allocate _all_ its memory (including the
// temp memory). "open" may fail with a VORBIS_outofmem if you
// do not pass in enough data; there is no way to determine how
// much you do need except to succeed (at which point you can
// query get_info to find the exact amount required. yes I know
// this is lame).
//
// If you pass in a non-NULL buffer of the type below, allocation
// will occur from it as described above. Otherwise just pass NULL
// to use malloc()/alloca()

struct stb_vorbis;

struct stb_vorbis_alloc
{
   byte *alloc_buffer;
   int   alloc_buffer_length_in_bytes;
}


///////////   FUNCTIONS USEABLE WITH ALL INPUT MODES

struct stb_vorbis_info
{
   uint sample_rate;
   int channels;

   uint setup_memory_required;
   uint setup_temp_memory_required;
   uint temp_memory_required;

   int max_frame_size;
}

// get general information about the file
stb_vorbis_info stb_vorbis_get_info(stb_vorbis *f);

// get the last error detected (clears it, too)
int stb_vorbis_get_error(stb_vorbis *f);

// close an ogg vorbis file and free all memory in use
void stb_vorbis_close(stb_vorbis *f);

// this function returns the offset (in samples) from the beginning of the
// file that will be returned by the next decode, if it is known, or -1
// otherwise. after a flush_pushdata() call, this may take a while before
// it becomes valid again.
// NOT WORKING YET after a seek with PULLDATA API
int stb_vorbis_get_sample_offset(stb_vorbis *f);

// returns the current seek point within the file, or offset from the beginning
// of the memory buffer. In pushdata mode it returns 0.
uint stb_vorbis_get_file_offset(stb_vorbis *f);

///////////   PUSHDATA API

// this API allows you to get blocks of data from any source and hand
// them to stb_vorbis. you have to buffer them; stb_vorbis will tell
// you how much it used, and you have to give it the rest next time;
// and stb_vorbis may not have enough data to work with and you will
// need to give it the same data again PLUS more. Note that the Vorbis
// specification does not bound the size of an individual frame.

stb_vorbis *stb_vorbis_open_pushdata(
         ubyte *datablock, int datablock_length_in_bytes,
         int *datablock_memory_consumed_in_bytes,
         int *error,
         stb_vorbis_alloc *alloc_buffer);
// create a vorbis decoder by passing in the initial data block containing
//    the ogg&vorbis headers (you don't need to do parse them, just provide
//    the first N bytes of the file--you're told if it's not enough, see below)
// on success, returns an stb_vorbis *, does not set error, returns the amount of
//    data parsed/consumed on this call in *datablock_memory_consumed_in_bytes;
// on failure, returns NULL on error and sets *error, does not change *datablock_memory_consumed
// if returns NULL and *error is VORBIS_need_more_data, then the input block was
//       incomplete and you need to pass in a larger block from the start of the file

int stb_vorbis_decode_frame_pushdata(
         stb_vorbis *f, ubyte *datablock, int datablock_length_in_bytes,
         int *channels,             // place to write number of float * buffers
         float ***output,           // place to write float ** array of float * buffers
         int *samples               // place to write number of output samples
     );
// decode a frame of audio sample data if possible from the passed-in data block
//
// return value: number of bytes we used from datablock
// possible cases:
//     0 bytes used, 0 samples output (need more data)
//     N bytes used, 0 samples output (resynching the stream, keep going)
//     N bytes used, M samples output (one frame of data)
// note that after opening a file, you will ALWAYS get one N-bytes,0-sample
// frame, because Vorbis always "discards" the first frame.
//
// Note that on resynch, stb_vorbis will rarely consume all of the buffer,
// instead only datablock_length_in_bytes-3 or less. This is because it wants
// to avoid missing parts of a page header if they cross a datablock boundary,
// without writing state-machiney code to record a partial detection.
//
// The number of channels returned are stored in *channels (which can be
// NULL--it is always the same as the number of channels reported by
// get_info). *output will contain an array of float* buffers, one per
// channel. In other words, (*output)[0][0] contains the first sample from
// the first channel, and (*output)[1][0] contains the first sample from
// the second channel.

void stb_vorbis_flush_pushdata(stb_vorbis *f);
// inform stb_vorbis that your next datablock will not be contiguous with
// previous ones (e.g. you've seeked in the data); future attempts to decode
// frames will cause stb_vorbis to resynchronize (as noted above), and
// once it sees a valid Ogg page (typically 4-8KB, as large as 64KB), it
// will begin decoding the _next_ frame.
//
// if you want to seek using pushdata, you need to seek in your file, then
// call stb_vorbis_flush_pushdata(), then start calling decoding, then once
// decoding is returning you data, call stb_vorbis_get_sample_offset, and
// if you don't like the result, seek your file again and repeat.


//////////   PULLING INPUT API

// This API assumes stb_vorbis is allowed to pull data from a source--
// either a block of memory containing the _entire_ vorbis stream, or a
// FILE * that you or it create, or possibly some other reading mechanism
// if you go modify the source to replace the FILE * case with some kind
// of callback to your code. (But if you don't support seeking, you may
// just want to go ahead and use pushdata.)

int stb_vorbis_decode_filename(char *filename, int *channels, short **output);
int stb_vorbis_decode_memory(ubyte *mem, int len, int *channels, short **output);
// decode an entire file and output the data interleaved into a malloc()ed
// buffer stored in *output. The return value is the number of samples
// decoded, or -1 if the file could not be opened or was not an ogg vorbis file.
// When you're done with it, just free() the pointer returned in *output.

stb_vorbis * stb_vorbis_open_memory(ubyte *data, int len,
                                  int *error, stb_vorbis_alloc *alloc_buffer);
// create an ogg vorbis decoder from an ogg vorbis stream in memory (note
// this must be the entire stream!). on failure, returns NULL and sets *error

stb_vorbis * stb_vorbis_open_filename(char *filename,
                                  int *error, stb_vorbis_alloc *alloc_buffer);
// create an ogg vorbis decoder from a filename via fopen(). on failure,
// returns NULL and sets *error (possibly to VORBIS_file_open_failure).

stb_vorbis * stb_vorbis_open_file(FILE *f, int close_handle_on_close,
                                  int *error, stb_vorbis_alloc *alloc_buffer);
// create an ogg vorbis decoder from an open FILE *, looking for a stream at
// the _current_ seek point (ftell). on failure, returns NULL and sets *error.
// note that stb_vorbis must "own" this stream; if you seek it in between
// calls to stb_vorbis, it will become confused. Morever, if you attempt to
// perform stb_vorbis_seek_*() operations on this file, it will assume it
// owns the _entire_ rest of the file after the start point. Use the next
// function, stb_vorbis_open_file_section(), to limit it.

stb_vorbis * stb_vorbis_open_file_section(FILE *f, int close_handle_on_close,
                int *error, stb_vorbis_alloc *alloc_buffer, uint len);
// create an ogg vorbis decoder from an open FILE *, looking for a stream at
// the _current_ seek point (ftell); the stream will be of length 'len' bytes.
// on failure, returns NULL and sets *error. note that stb_vorbis must "own"
// this stream; if you seek it in between calls to stb_vorbis, it will become
// confused.

int stb_vorbis_seek_frame(stb_vorbis *f, uint sample_number);
int stb_vorbis_seek(stb_vorbis *f, uint sample_number);
// NOT WORKING YET
// these functions seek in the Vorbis file to (approximately) 'sample_number'.
// after calling seek_frame(), the next call to get_frame_*() will include
// the specified sample. after calling stb_vorbis_seek(), the next call to
// stb_vorbis_get_samples_* will start with the specified sample. If you
// do not need to seek to EXACTLY the target sample when using get_samples_*,
// you can also use seek_frame().

void stb_vorbis_seek_start(stb_vorbis *f);
// this function is equivalent to stb_vorbis_seek(f,0), but it
// actually works

uint stb_vorbis_stream_length_in_samples(stb_vorbis *f);
float        stb_vorbis_stream_length_in_seconds(stb_vorbis *f);
// these functions return the total length of the vorbis stream

int stb_vorbis_get_frame_float(stb_vorbis *f, int *channels, float ***output);
// decode the next frame and return the number of samples. the number of
// channels returned are stored in *channels (which can be NULL--it is always
// the same as the number of channels reported by get_info). *output will
// contain an array of float* buffers, one per channel. These outputs will
// be overwritten on the next call to stb_vorbis_get_frame_*.
//
// You generally should not intermix calls to stb_vorbis_get_frame_*()
// and stb_vorbis_get_samples_*(), since the latter calls the former.

int stb_vorbis_get_frame_short_interleaved(stb_vorbis *f, int num_c, short *buffer, int num_shorts);
int stb_vorbis_get_frame_short            (stb_vorbis *f, int num_c, short **buffer, int num_samples);
// decode the next frame and return the number of samples per channel. the
// data is coerced to the number of channels you request according to the
// channel coercion rules (see below). You must pass in the size of your
// buffer(s) so that stb_vorbis will not overwrite the end of the buffer.
// The maximum buffer size needed can be gotten from get_info(); however,
// the Vorbis I specification implies an absolute maximum of 4096 samples
// per channel. Note that for interleaved data, you pass in the number of
// shorts (the size of your array), but the return value is the number of
// samples per channel, not the total number of samples.

// Channel coercion rules:
//    Let M be the number of channels requested, and N the number of channels present,
//    and Cn be the nth channel; let stereo L be the sum of all L and center channels,
//    and stereo R be the sum of all R and center channels (channel assignment from the
//    vorbis spec).
//        M    N       output
//        1    k      sum(Ck) for all k
//        2    *      stereo L, stereo R
//        k    l      k > l, the first l channels, then 0s
//        k    l      k <= l, the first k channels
//    Note that this is not _good_ surround etc. mixing at all! It's just so
//    you get something useful.

int stb_vorbis_get_samples_float_interleaved(stb_vorbis *f, int channels, float *buffer, int num_floats);
int stb_vorbis_get_samples_float(stb_vorbis *f, int channels, float **buffer, int num_samples);
// gets num_samples samples, not necessarily on a frame boundary--this requires
// buffering so you have to supply the buffers. DOES NOT APPLY THE COERCION RULES.
// Returns the number of samples stored per channel; it may be less than requested
// at the end of the file. If there are no more samples in the file, returns 0.

int stb_vorbis_get_samples_short_interleaved(stb_vorbis *f, int channels, short *buffer, int num_shorts);
int stb_vorbis_get_samples_short(stb_vorbis *f, int channels, short **buffer, int num_samples);
// gets num_samples samples, not necessarily on a frame boundary--this requires
// buffering so you have to supply the buffers. Applies the coercion rules above
// to produce 'channels' channels. Returns the number of samples stored per channel;
// it may be less than requested at the end of the file. If there are no more
// samples in the file, returns 0.

////////   ERROR CODES

enum STBVorbisError
{
   VORBIS__no_error,

   VORBIS_need_more_data=1,             // not a real error

   VORBIS_invalid_api_mixing,           // can't mix API modes
   VORBIS_outofmem,                     // not enough memory
   VORBIS_feature_not_supported,        // uses floor 0
   VORBIS_too_many_channels,            // STB_VORBIS_MAX_CHANNELS is too small
   VORBIS_file_open_failure,            // fopen() failed
   VORBIS_seek_without_length,          // can't seek in unknown-length file

   VORBIS_unexpected_eof=10,            // file is truncated?
   VORBIS_seek_invalid,                 // seek past EOF

   // decoding errors (corrupt/invalid stream) -- you probably
   // don't care about the exact details of these

   // vorbis errors:
   VORBIS_invalid_setup=20,
   VORBIS_invalid_stream,

   // ogg errors:
   VORBIS_missing_capture_pattern=30,
   VORBIS_invalid_stream_structure_version,
   VORBIS_continued_packet_flag_invalid,
   VORBIS_incorrect_stream_serial_number,
   VORBIS_invalid_first_page,
   VORBIS_bad_packet_type,
   VORBIS_cant_find_last_page,
   VORBIS_seek_failed,
}

//
//  HEADER ENDS HERE
//
//////////////////////////////////////////////////////////////////////////////

