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	 24860a913c
			
		
	
	24860a913c
	
	
	
		
			
			The tool is useful for testing the internal arithmetic evaluation engine (indeed I plan to use it in FATE), and provides a handy calculator when you can't rely on bc ;-).
		
			
				
	
	
		
			129 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			129 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2012 Stefano Sabatini
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|  *
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|  * This file is part of FFmpeg.
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|  *
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|  * FFmpeg is free software; you can redistribute it and/or
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|  * modify it under the terms of the GNU Lesser General Public
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|  * License as published by the Free Software Foundation; either
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|  * version 2.1 of the License, or (at your option) any later version.
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|  *
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|  * FFmpeg is distributed in the hope that it will be useful,
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|  * but WITHOUT ANY WARRANTY; without even the implied warranty of
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|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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|  * Lesser General Public License for more details.
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|  *
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|  * You should have received a copy of the GNU Lesser General Public
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|  * License along with FFmpeg; if not, write to the Free Software
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|  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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|  */
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| 
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| #include <unistd.h>             /* getopt */
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| #include "libavutil/eval.h"
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| 
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| /**
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|  * @file
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|  * simple arithmetic expression evaluator
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|  */
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| 
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| static void usage(void)
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| {
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|     printf("Simple expression evalutor, please *don't* turn me to a feature-complete language interpreter\n");
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|     printf("usage: ffeval [OPTIONS]\n");
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|     printf("\n"
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|            "Options:\n"
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|            "-e                echo each input line on output\n"
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|            "-h                print this help\n"
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|            "-i INFILE         set INFILE as input file, stdin if omitted\n"
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|            "-o OUTFILE        set OUTFILE as output file, stdout if omitted\n"
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|            "-p PROMPT         set output prompt\n");
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| }
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| 
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| #define MAX_BLOCK_SIZE SIZE_MAX
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| 
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| int main(int argc, char **argv)
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| {
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|     size_t buf_size = 256;
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|     char *buf = av_malloc(buf_size);
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|     const char *outfilename = NULL, *infilename = NULL;
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|     FILE *outfile = NULL, *infile = NULL;
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|     const char *prompt = "=> ";
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|     int count = 0, echo = 0;
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|     char c;
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| 
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|     av_max_alloc(MAX_BLOCK_SIZE);
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| 
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|     while ((c = getopt(argc, argv, "ehi:o:p:")) != -1) {
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|         switch (c) {
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|         case 'e':
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|             echo = 1;
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|             break;
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|         case 'h':
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|             usage();
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|             return 0;
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|         case 'i':
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|             infilename = optarg;
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|             break;
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|         case 'o':
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|             outfilename = optarg;
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|             break;
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|         case 'p':
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|             prompt = optarg;
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|             break;
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|         case '?':
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|             return 1;
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|         }
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|     }
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| 
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|     if (!infilename || !strcmp(infilename, "-"))
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|         infilename = "/dev/stdin";
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|     infile = fopen(infilename, "r");
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|     if (!infile) {
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|         fprintf(stderr, "Impossible to open input file '%s': %s\n", infilename, strerror(errno));
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|         return 1;
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|     }
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| 
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|     if (!outfilename || !strcmp(outfilename, "-"))
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|         outfilename = "/dev/stdout";
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|     outfile = fopen(outfilename, "w");
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|     if (!outfile) {
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|         fprintf(stderr, "Impossible to open output file '%s': %s\n", outfilename, strerror(errno));
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|         return 1;
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|     }
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| 
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|     while ((c = fgetc(infile)) != EOF) {
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|         if (c == '\n') {
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|             double d;
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| 
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|             buf[count] = 0;
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|             if (buf[0] != '#') {
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|                 av_expr_parse_and_eval(&d, buf,
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|                                        NULL, NULL,
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|                                        NULL, NULL, NULL, NULL, NULL, 0, NULL);
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|                 if (echo)
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|                     fprintf(outfile, "%s ", buf);
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|                 fprintf(outfile, "%s%f\n", prompt, d);
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|             }
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|             count = 0;
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|         } else {
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|             if (count >= buf_size-1) {
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|                 if (buf_size == MAX_BLOCK_SIZE) {
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|                     av_log(NULL, AV_LOG_ERROR, "Memory allocation problem, "
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|                            "max block size '%zd' reached\n", MAX_BLOCK_SIZE);
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|                     return 1;
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|                 }
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|                 buf_size = FFMIN(buf_size, MAX_BLOCK_SIZE / 2) * 2;
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|                 buf = av_realloc_f((void *)buf, buf_size, 1);
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|                 if (!buf) {
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|                     av_log(NULL, AV_LOG_ERROR, "Memory allocation problem occurred\n");
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|                     return 1;
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|                 }
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|             }
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|             buf[count++] = c;
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|         }
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|     }
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| 
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|     av_free(buf);
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|     return 0;
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| }
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