/* libSoX lpc-10 format. * * Copyright 2007 Reuben Thomas <rrt@sc3d.org> * * This library 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 library 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 library; if not, write to the Free Software Foundation, * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA */ #include "sox_i.h" #include <lpc10.h> /* Private data */typedef struct {  struct lpc10_encoder_state *encst;  float speech[LPC10_SAMPLES_PER_FRAME];  unsigned samples;  struct lpc10_decoder_state *decst;} priv_t; /*  Write the bits in bits[0] through bits[len-1] to file f, in "packed"  format.   bits is expected to be an array of len integer values, where each  integer is 0 to represent a 0 bit, and any other value represents a  1 bit. This bit string is written to the file f in the form of  several 8 bit characters. If len is not a multiple of 8, then the  last character is padded with 0 bits -- the padding is in the least  significant bits of the last byte. The 8 bit characters are "filled"  in order from most significant bit to least significant.*/static void write_bits(sox_format_t * ft, INT32 *bits, int len){  int i;  uint8_t mask; /* The next bit position within the variable "data" to                   place the next bit. */  uint8_t data; /* The contents of the next byte to place in the                   output. */   /* Fill in the array bits.   * The first compressed output bit will be the most significant   * bit of the byte, so initialize mask to 0x80.  The next byte of   * compressed data is initially 0, and the desired bits will be   * turned on below.   */  mask = 0x80;  data = 0;   for (i = 0; i < len; i++) {    /* Turn on the next bit of output data, if necessary. */    if (bits[i]) {      data |= mask;    }    /*     * If the byte data is full, determined by mask becoming 0,     * then write the byte to the output file, and reinitialize     * data and mask for the next output byte.  Also add the byte     * if (i == len-1), because if len is not a multiple of 8,     * then mask won't yet be 0.  */    mask >>= 1;    if ((mask == 0) || (i == len-1)) {      lsx_writeb(ft, data);      data = 0;      mask = 0x80;    }  }} /*  Read bits from file f into bits[0] through bits[len-1], in "packed"  format.   Read ceiling(len/8) characters from file f, if that many are  available to read, otherwise read to the end of the file. The first  character's 8 bits, in order from MSB to LSB, are used to fill  bits[0] through bits[7]. The second character's bits are used to  fill bits[8] through bits[15], and so on. If ceiling(len/8)  characters are available to read, and len is not a multiple of 8,  then some of the least significant bits of the last character read  are completely ignored. Every entry of bits[] that is modified is  changed to either a 0 or a 1.   The number of bits successfully read is returned, and is always in  the range 0 to len, inclusive. If it is less than len, it will  always be a multiple of 8.*/static int read_bits(sox_format_t * ft, INT32 *bits, int len){  int i;  uint8_t c = 0;   /* Unpack the array bits into coded_frame. */  for (i = 0; i < len; i++) {    if (i % 8 == 0) {      lsx_read_b_buf(ft, &c, (size_t) 1);      if (lsx_eof(ft)) {        return (i);      }    }    if (c & (0x80 >> (i & 7))) {      bits[i] = 1;    } else {      bits[i] = 0;    }  }  return (len);} static int startread(sox_format_t * ft){  priv_t * lpc = (priv_t *)ft->priv;   if ((lpc->decst = create_lpc10_decoder_state()) == NULL) {    fprintf(stderr, "lpc10 could not allocate decoder state");    return SOX_EOF;  }  lpc->samples = LPC10_SAMPLES_PER_FRAME;  return lsx_check_read_params(ft, 1, 8000., SOX_ENCODING_LPC10, 0, (uint64_t)0, sox_false);} static int startwrite(sox_format_t * ft){  priv_t * lpc = (priv_t *)ft->priv;   if ((lpc->encst = create_lpc10_encoder_state()) == NULL) {    fprintf(stderr, "lpc10 could not allocate encoder state");    return SOX_EOF;  }  lpc->samples = 0;   return SOX_SUCCESS;} static size_t read_samples(sox_format_t * ft, sox_sample_t *buf, size_t len){  priv_t * lpc = (priv_t *)ft->priv;  size_t nread = 0;   while (nread < len) {    SOX_SAMPLE_LOCALS;    /* Read more data if buffer is empty */    if (lpc->samples == LPC10_SAMPLES_PER_FRAME) {      INT32 bits[LPC10_BITS_IN_COMPRESSED_FRAME];       if (read_bits(ft, bits, LPC10_BITS_IN_COMPRESSED_FRAME) !=          LPC10_BITS_IN_COMPRESSED_FRAME)        break;      lpc10_decode(bits, lpc->speech, lpc->decst);      lpc->samples = 0;    }     while (nread < len && lpc->samples < LPC10_SAMPLES_PER_FRAME)      buf[nread++] = SOX_FLOAT_32BIT_TO_SAMPLE(lpc->speech[lpc->samples++], ft->clips);  }   return nread;} static size_t write_samples(sox_format_t * ft, const sox_sample_t *buf, size_t len){  priv_t * lpc = (priv_t *)ft->priv;  size_t nwritten = 0;   while (len > 0) {    while (len > 0 && lpc->samples < LPC10_SAMPLES_PER_FRAME) {      SOX_SAMPLE_LOCALS;      lpc->speech[lpc->samples++] = SOX_SAMPLE_TO_FLOAT_32BIT(buf[nwritten++], ft->clips);      len--;    }     if (lpc->samples == LPC10_SAMPLES_PER_FRAME) {      INT32 bits[LPC10_BITS_IN_COMPRESSED_FRAME];       lpc10_encode(lpc->speech, bits, lpc->encst);      write_bits(ft, bits, LPC10_BITS_IN_COMPRESSED_FRAME);      lpc->samples = 0;    }  }   return nwritten;} static int stopread(sox_format_t * ft){  priv_t * lpc = (priv_t *)ft->priv;   free(lpc->decst);   return SOX_SUCCESS;} static int stopwrite(sox_format_t * ft){  priv_t * lpc = (priv_t *)ft->priv;   free(lpc->encst);   return SOX_SUCCESS;} LSX_FORMAT_HANDLER(lpc10){  static char const * const names[] = {"lpc10", "lpc", NULL};  static sox_rate_t   const write_rates[] = {8000, 0};  static unsigned     const write_encodings[] = {SOX_ENCODING_LPC10, 0, 0};  static sox_format_handler_t handler = {SOX_LIB_VERSION_CODE,    "Low bandwidth, robotic sounding speech compression", names, SOX_FILE_MONO,    startread, read_samples, stopread,    startwrite, write_samples, stopwrite,    NULL, write_encodings, write_rates, sizeof(priv_t)  };  return &handler;}