/*
  * 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 <unistd.h>             /* getopt */
 #include "libavutil/eval.h"
 
 /**
  * @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");
 }
 
 #define MAX_BLOCK_SIZE SIZE_MAX
 
 int main(int argc, char **argv)
 {
     size_t buf_size = 256;
     char *buf = av_malloc(buf_size);
     const char *outfilename = NULL, *infilename = NULL;
     FILE *outfile = NULL, *infile = NULL;
     const char *prompt = "=> ";
     int count = 0, echo = 0;
     char c;
 
     av_max_alloc(MAX_BLOCK_SIZE);
 
     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 = "/dev/stdin";
     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 = "/dev/stdout";
     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] != '#') {
                 av_expr_parse_and_eval(&d, buf,
                                        NULL, NULL,
                                        NULL, NULL, NULL, NULL, NULL, 0, NULL);
                 if (echo)
                     fprintf(outfile, "%s ", buf);
                 fprintf(outfile, "%s%f\n", prompt, d);
             }
             count = 0;
         } else {
             if (count >= buf_size-1) {
                 if (buf_size == MAX_BLOCK_SIZE) {
                     av_log(NULL, AV_LOG_ERROR, "Memory allocation problem, "
                            "max block size '%zd' reached\n", MAX_BLOCK_SIZE);
                     return 1;
                 }
                 buf_size = FFMIN(buf_size, MAX_BLOCK_SIZE / 2) * 2;
                 buf = av_realloc_f((void *)buf, buf_size, 1);
                 if (!buf) {
                     av_log(NULL, AV_LOG_ERROR, "Memory allocation problem occurred\n");
                     return 1;
                 }
             }
             buf[count++] = c;
         }
     }
 
     av_free(buf);
     return 0;
 }