blind

suckless command-line video editing utility
git clone git://git.suckless.org/blind
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blind-read-head.c (991B)

      1 /* See LICENSE file for copyright and license details. */
      2 #include "common.h"
      3 
      4 USAGE("")
      5 
      6 int
      7 main(int argc, char *argv[])
      8 {
      9 	char buf[STREAM_HEAD_MAX];
     10 	char magic[] = {'\0', 'u', 'i', 'v', 'f'};
     11 	char b, *p;
     12 	size_t i, ptr;
     13 
     14 	UNOFLAGS(argc);
     15 
     16 	for (ptr = 0; ptr < sizeof(buf);) {
     17 		if (!eread(STDIN_FILENO, buf + ptr, 1, "<stdin>"))
     18 			goto bad_format;
     19 		if (buf[ptr++] == '\n')
     20 			break;
     21 	}
     22 	if (ptr == sizeof(buf))
     23 		goto bad_format;
     24 
     25 	p = buf;
     26 	for (i = 0; i < ELEMENTSOF(magic); i++)
     27 		if (!eread(STDIN_FILENO, &b, 1, "<stdin>") || b != magic[i])
     28 			goto bad_format;
     29 
     30 	for (i = 0; i < 3; i++) {
     31 		if (!isdigit(*p))
     32 			goto bad_format;
     33 		while (isdigit(*p)) p++;
     34 		if (*p++ != ' ')
     35 			goto bad_format;
     36 	}
     37 	while (isalnum(*p) || *p == ' ') {
     38 		if (p[0] == ' ' && p[-1] == ' ')
     39 			goto bad_format;
     40 		p++;
     41 	}
     42 	if (p[-1] == ' ' || p[0] != '\n')
     43 		goto bad_format;
     44 
     45 	ewriteall(STDOUT_FILENO, buf, ptr, "<stdout>");
     46 
     47 	return 0;
     48 bad_format:
     49 	eprintf("<stdin>: file format not supported\n");
     50 }