/*---------------------------------------------------------------------------*\

  FILE........: generate_codebook.c
  AUTHOR......: Bruce Perens
  DATE CREATED: 29 Sep 2010

  Generate header files containing quantisers, runs at compile time.

\*---------------------------------------------------------------------------*/

/*
  All rights reserved.

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License version 2.1, as
  published by the Free Software Foundation.  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 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, see <http://www.gnu.org/licenses/>.
*/

#include <ctype.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>

static const char usage[] =
    "Usage: %s filename array_name [filename ...]\n"
    "\tCreate C code for codebook tables.\n";

static const char format[] =
    "The table format must be:\n"
    "\tTwo integers describing the dimensions of the codebook.\n"
    "\tThen, enough numbers to fill the specified dimensions.\n";

static const char header[] =
    "/* THIS IS A GENERATED FILE. Edit generate_codebook.c and its input */\n\n"
    "/*\n"
    " * This intermediary file and the files that used to create it are under "
    "\n"
    " * The LGPL. See the file COPYING.\n"
    " */\n\n"
    "#include \"defines.h\"\n\n";

struct codebook {
  unsigned int k;
  unsigned int log2m;
  unsigned int m;
  float *cb;
};

static void dump_array(const struct codebook *b, int index) {
  int limit = b->k * b->m;
  int i;

  printf("#ifdef __EMBEDDED__\n");
  printf("static const float codes%d[] = {\n", index);
  printf("#else\n");
  printf("static float codes%d[] = {\n", index);
  printf("#endif\n");
  for (i = 0; i < limit; i++) {
    printf("  %g", b->cb[i]);
    if (i < limit - 1) printf(",");

    /* organise VQs by rows, looks prettier */
    if (((i + 1) % b->k) == 0) printf("\n");
  }
  printf("};\n");
}

static void dump_structure(const struct codebook *b, int index) {
  printf("  {\n");
  printf("    %d,\n", b->k);
  printf("    %d,\n", (int)roundf(log(b->m) / log(2)));
  printf("    %d,\n", b->m);
  printf("    codes%d\n", index);
  printf("  }");
}

float get_float(FILE *in, const char *name, char **cursor, char *buffer,
                int size) {
  for (;;) {
    char *s = *cursor;
    char c;

    while ((c = *s) != '\0' && !isdigit(c) && c != '-' && c != '.') s++;

    /* Comments start with "#" and continue to the end of the line. */
    if (c != '\0' && c != '#') {
      char *end = 0;
      float f = 0;

      f = strtod(s, &end);

      if (end != s) *cursor = end;
      return f;
    }

    if (fgets(buffer, size, in) == NULL) {
      fprintf(stderr, "%s: Format error. %s\n", name, format);
      exit(1);
    }
    *cursor = buffer;
  }
}

static struct codebook *load(FILE *file, const char *name) {
  char line[1024];
  char *cursor = line;
  struct codebook *b = malloc(sizeof(struct codebook));
  int i;
  int size;

  *cursor = '\0';

  b->k = (int)get_float(file, name, &cursor, line, sizeof(line));
  b->m = (int)get_float(file, name, &cursor, line, sizeof(line));
  size = b->k * b->m;

  b->cb = (float *)malloc(size * sizeof(float));

  for (i = 0; i < size; i++)
    b->cb[i] = get_float(file, name, &cursor, line, sizeof(line));

  return b;
}

int main(int argc, char **argv) {
  struct codebook **cb = malloc(argc * sizeof(struct codebook *));
  int i;

  if (argc < 2) {
    fprintf(stderr, usage, argv[0]);
    fprintf(stderr, format);
    exit(1);
  }

  for (i = 0; i < argc - 2; i++) {
    FILE *in = fopen(argv[i + 2], "r");

    if (in == NULL) {
      perror(argv[i + 2]);
      exit(1);
    }

    cb[i] = load(in, argv[i + 2]);

    fclose(in);
  }

  printf(header);
  for (i = 0; i < argc - 2; i++) {
    printf("  /* %s */\n", argv[i + 2]);
    dump_array(cb[i], i);
  }
  printf("\nconst struct lsp_codebook %s[] = {\n", argv[1]);
  for (i = 0; i < argc - 2; i++) {
    printf("  /* %s */\n", argv[i + 2]);
    dump_structure(cb[i], i);
    printf(",\n");
  }
  printf("  { 0, 0, 0, 0 }\n");
  printf("};\n");
  for (i = 0; i < argc - 2; i++) {
    free(cb[i]->cb);
    free(cb[i]);
  }
  free(cb);
  return 0;
}
