text: /*
   * Copyright (c) 2012 Stefano Sabatini
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg 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.
   *
   * FFmpeg 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 FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include "config.h"
  #if HAVE_UNISTD_H
  #include <unistd.h>             /* getopt */
  #endif
  
  #include "libavutil/eval.h"
  #include "libavutil/mem.h"
  
  #if !HAVE_GETOPT
  #include "compat/getopt.c"
  #endif
  
  /**
   * @file
   * simple arithmetic expression evaluator
   */
  
  static void usage(void)
  {
      printf("Simple expression evalutor, please *don't* turn me to a feature-complete language interpreter\n");
      printf("usage: ffeval [OPTIONS]\n");
      printf("\n"
             "Options:\n"
             "-e                echo each input line on output\n"
             "-h                print this help\n"
             "-i INFILE         set INFILE as input file, stdin if omitted\n"
             "-o OUTFILE        set OUTFILE as output file, stdout if omitted\n"
             "-p PROMPT         set output prompt\n");
  }
  
  int main(int argc, char **argv)
  {
      int buf_size = 0;
      char *buf = NULL;
      const char *outfilename = NULL, *infilename = NULL;
      FILE *outfile = NULL, *infile = NULL;
      const char *prompt = "=> ";
      int count = 0, echo = 0;
      int c;
  
  #define GROW_ARRAY()                                                    \
      do {                                                                \
          if (!av_dynarray2_add((void **)&buf, &buf_size, 1, NULL)) {     \
              av_log(NULL, AV_LOG_ERROR,                                  \
                     "Memory allocation problem occurred\n");             \
              return 1;                                                   \
          }                                                               \
      } while (0)
  
      GROW_ARRAY();
      while ((c = getopt(argc, argv, "ehi:o:p:")) != -1) {
          switch (c) {
          case 'e':
              echo = 1;
              break;
          case 'h':
              usage();
              return 0;
          case 'i':
              infilename = optarg;
              break;
          case 'o':
              outfilename = optarg;
              break;
          case 'p':
              prompt = optarg;
              break;
          case '?':
              return 1;
          }
      }
  
      if (!infilename || !strcmp(infilename, "-")) {
          infilename = "stdin";
          infile = stdin;
      } else {
          infile = fopen(infilename, "r");
      }
      if (!infile) {
          fprintf(stderr, "Impossible to open input file '%s': %s\n", infilename, strerror(errno));
          return 1;
      }
  
      if (!outfilename || !strcmp(outfilename, "-")) {
          outfilename = "stdout";
          outfile = stdout;
      } else {
          outfile = fopen(outfilename, "w");
      }
      if (!outfile) {
          fprintf(stderr, "Impossible to open output file '%s': %s\n", outfilename, strerror(errno));
          return 1;
      }
  
      while ((c = fgetc(infile)) != EOF) {
          if (c == '\n') {
              double d;
  
              buf[count] = 0;
              if (buf[0] != '#') {
                  int ret = av_expr_parse_and_eval(&d, buf,
                                                   NULL, NULL,
                                                   NULL, NULL, NULL, NULL, NULL, 0, NULL);
                  if (echo)
                      fprintf(outfile, "%s ", buf);
                  if (ret >= 0) fprintf(outfile, "%s%f\n", prompt, d);
                  else          fprintf(outfile, "%s%s\n", prompt, av_err2str(ret));
              }
              count = 0;
          } else {
              if (count >= buf_size-1)
                  GROW_ARRAY();
              buf[count++] = c;
          }
      }
  
      av_free(buf);
      return 0;
  }
  