143 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			143 lines
		
	
	
		
			4.1 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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#include "config.h"
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#if HAVE_UNISTD_H
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#include <unistd.h>             /* getopt */
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#endif
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#include "libavutil/eval.h"
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#if !HAVE_GETOPT
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#include "compat/getopt.c"
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#endif
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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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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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#define MAX_BLOCK_SIZE SIZE_MAX
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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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    int c;
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    av_max_alloc(MAX_BLOCK_SIZE);
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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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    if (!infilename || !strcmp(infilename, "-")) {
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        infilename = "stdin";
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        infile = stdin;
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    } else {
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        infile = fopen(infilename, "r");
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    }
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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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    if (!outfilename || !strcmp(outfilename, "-")) {
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        outfilename = "stdout";
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        outfile = stdout;
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    } else {
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        outfile = fopen(outfilename, "w");
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    }
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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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    while ((c = fgetc(infile)) != EOF) {
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        if (c == '\n') {
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            double d;
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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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    av_free(buf);
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    return 0;
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}
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