mirror of https://git.ffmpeg.org/ffmpeg.git
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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#include <unistd.h> /* getopt */
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#include "libavutil/eval.h"
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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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char 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 = "/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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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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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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