/*

** Copyright (C) 2002-2017 Erik de Castro Lopo <erikd@mega-nerd.com>

**

** This program is free software; you can redistribute it and/or modify

** it under the terms of the GNU Lesser General Public License as published by

** the Free Software Foundation; either version 2.1 of the License, or

** (at your option) any later version.

**

** This program is distributed in the hope that it will be useful,

** but WITHOUT ANY WARRANTY; without even the implied warranty of

** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

** GNU Lesser General Public License for more details.

**

** You should have received a copy of the GNU Lesser General Public License

** along with this program; if not, write to the Free Software

** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

*/

#include  "sfconfig.h"

#include  <stdio.h>

#include  <fcntl.h>

#include  <string.h>

#include  <ctype.h>

#include  "sndfile.h"

#include  "sfendian.h"

#include  "common.h"

/*------------------------------------------------------------------------------

** Macros to handle big/little endian issues.

*/

#define SFE_HTK_BAD_FILE_LEN  1666

#define SFE_HTK_NOT_WAVEFORM  1667

/*------------------------------------------------------------------------------

** Private static functions.

*/

static  int   htk_close   (SF_PRIVATE *psf) ;

static int    htk_write_header (SF_PRIVATE *psf, int calc_length) ;

static int    htk_read_header (SF_PRIVATE *psf) ;

/*------------------------------------------------------------------------------

** Public function.

*/

int

htk_open  (SF_PRIVATE *psf)

{ int   subformat ;

  int   error = 0 ;

  if (psf->is_pipe)

    return SFE_HTK_NO_PIPE ;

  if (psf->file.mode == SFM_READ || (psf->file.mode == SFM_RDWR && psf->filelength > 0))

  { if ((error = htk_read_header (psf)))

      return error ;

    } ;

  subformat = SF_CODEC (psf->sf.format) ;

  if (psf->file.mode == SFM_WRITE || psf->file.mode == SFM_RDWR)

  { if ((SF_CONTAINER (psf->sf.format)) != SF_FORMAT_HTK)

      return  SFE_BAD_OPEN_FORMAT ;

    psf->endian = SF_ENDIAN_BIG ;

    if (htk_write_header (psf, SF_FALSE))

      return psf->error ;

    psf->write_header = htk_write_header ;

    } ;

  psf->container_close = htk_close ;

  psf->blockwidth = psf->bytewidth * psf->sf.channels ;

  switch (subformat)

  { case SF_FORMAT_PCM_16 : /* 16-bit linear PCM. */

        error = pcm_init (psf) ;

        break ;

    default : break ;

    } ;

  return error ;

} /* htk_open */

/*------------------------------------------------------------------------------

*/

static int

htk_close (SF_PRIVATE *psf)

{

  if (psf->file.mode == SFM_WRITE || psf->file.mode == SFM_RDWR)

    htk_write_header (psf, SF_TRUE) ;

  return 0 ;

} /* htk_close */

static int

htk_write_header (SF_PRIVATE *psf, int calc_length)

{ sf_count_t  current ;

  int     sample_count, sample_period ;

  current = psf_ftell (psf) ;

  if (calc_length)

    psf->filelength = psf_get_filelen (psf) ;

  /* Reset the current header length to zero. */

  psf->header.ptr [0] = 0 ;

  psf->header.indx = 0 ;

  psf_fseek (psf, 0, SEEK_SET) ;

  if (psf->filelength > 12)

    sample_count = (psf->filelength - 12) / 2 ;

  else

    sample_count = 0 ;

  sample_period = 10000000 / psf->sf.samplerate ;

  psf_binheader_writef (psf, "E444", BHW4 (sample_count), BHW4 (sample_period), BHW4 (0x20000)) ;

  /* Header construction complete so write it out. */

  psf_fwrite (psf->header.ptr, psf->header.indx, 1, psf) ;

  if (psf->error)

    return psf->error ;

  psf->dataoffset = psf->header.indx ;

  if (current > 0)

    psf_fseek (psf, current, SEEK_SET) ;

  return psf->error ;

} /* htk_write_header */

/*

** Found the following info in a comment block within Bill Schottstaedt's

** sndlib library.

**

** HTK format files consist of a contiguous sequence of samples preceded by a

** header. Each sample is a vector of either 2-byte integers or 4-byte floats.

** 2-byte integers are used for compressed forms as described below and for

** vector quantised data as described later in section 5.11. HTK format data

** files can also be used to store speech waveforms as described in section 5.8.

**

** The HTK file format header is 12 bytes long and contains the following data

**   nSamples   -- number of samples in file (4-byte integer)

**   sampPeriod -- sample period in 100ns units (4-byte integer)

**   sampSize   -- number of bytes per sample (2-byte integer)

**   parmKind   -- a code indicating the sample kind (2-byte integer)

**

** The parameter kind  consists of a 6 bit code representing the basic

** parameter kind plus additional bits for each of the possible qualifiers.

** The basic parameter kind codes are

**

**  0    WAVEFORM    sampled waveform

**  1    LPC         linear prediction filter coefficients

**  2    LPREFC      linear prediction reflection coefficients

**  3    LPCEPSTRA   LPC cepstral coefficients

**  4    LPDELCEP    LPC cepstra plus delta coefficients

**  5    IREFC       LPC reflection coef in 16 bit integer format

**  6    MFCC        mel-frequency cepstral coefficients

**  7    FBANK       log mel-filter bank channel outputs

**  8    MELSPEC     linear mel-filter bank channel outputs

**  9    USER        user defined sample kind

**  10   DISCRETE    vector quantised data

**

** and the bit-encoding for the qualifiers (in octal) is

**   _E   000100      has energy

**   _N   000200      absolute energy suppressed

**   _D   000400      has delta coefficients

**   _A   001000      has acceleration coefficients

**   _C   002000      is compressed

**   _Z   004000      has zero mean static coef.

**   _K   010000      has CRC checksum

**   _O   020000      has 0'th cepstral coef.

*/

static int

htk_read_header (SF_PRIVATE *psf)

{ int   sample_count, sample_period, marker ;

  psf_binheader_readf (psf, "pE444", 0, &sample_count, &sample_period, &marker) ;

  if (2 * sample_count + 12 != psf->filelength)

    return SFE_HTK_BAD_FILE_LEN ;

  if (marker != 0x20000)

    return SFE_HTK_NOT_WAVEFORM ;

  psf->sf.channels = 1 ;

  if (sample_period > 0)

  { psf->sf.samplerate = 10000000 / sample_period ;

    psf_log_printf (psf, "HTK Waveform file\n  Sample Count  : %d\n  Sample Period : %d => %d Hz\n",

          sample_count, sample_period, psf->sf.samplerate) ;

    }

  else

  { psf->sf.samplerate = 16000 ;

    psf_log_printf (psf, "HTK Waveform file\n  Sample Count  : %d\n  Sample Period : %d (should be > 0) => Guessed sample rate %d Hz\n",

          sample_count, sample_period, psf->sf.samplerate) ;

    } ;

  psf->sf.format = SF_FORMAT_HTK | SF_FORMAT_PCM_16 ;

  psf->bytewidth = 2 ;

  /* HTK always has a 12 byte header. */

  psf->dataoffset = 12 ;

  psf->endian = SF_ENDIAN_BIG ;

  psf->datalength = psf->filelength - psf->dataoffset ;

  psf->blockwidth = psf->sf.channels * psf->bytewidth ;

  if (! psf->sf.frames && psf->blockwidth)

    psf->sf.frames = (psf->filelength - psf->dataoffset) / psf->blockwidth ;

  return 0 ;

} /* htk_read_header */