git/t/helper/test-genrandom.c

35 lines
760 B
C

/*
* Simple random data generator used to create reproducible test files.
* This is inspired from POSIX.1-2001 implementation example for rand().
* Copyright (C) 2007 by Nicolas Pitre, licensed under the GPL version 2.
*/
#include "test-tool.h"
#include "git-compat-util.h"
int cmd__genrandom(int argc, const char **argv)
{
unsigned long count, next = 0;
unsigned char *c;
if (argc < 2 || argc > 3) {
fprintf(stderr, "usage: %s <seed_string> [<size>]\n", argv[0]);
return 1;
}
c = (unsigned char *) argv[1];
do {
next = next * 11 + *c;
} while (*c++);
count = (argc == 3) ? strtoul(argv[2], NULL, 0) : -1L;
while (count--) {
next = next * 1103515245 + 12345;
if (putchar((next >> 16) & 0xff) == EOF)
return -1;
}
return 0;
}