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struct result_buf {
unsigned long array[24*1024*1024];
int len;
};
struct result_buf rbuf;
int read(int fd, void *buf, unsigned long len);
void *malloc(unsigned long);
long strlen(char *);
int open(char *, int flags, long mode);
int printf(char *, ...);
void exit(int);
int strncmp(char *, char *, unsigned long);
void rabin_karp(char *p, int plen, char *t, int tlen)
{
unsigned long d = 129;
unsigned long h = 1, p_h = 0, t_h = 0;
int i;
for (i = 0; i < plen - 1; ++i)
h = (h * d);
for (i = 0; i < plen; ++i) {
p_h = (d*p_h + p[i]);
t_h = (d*t_h + t[i]);
}
for (i = 0; i <= tlen - plen; ++i) {
if (p_h == t_h && strncmp(t + i, p, plen) == 0) {
rbuf.array[rbuf.len] = i;
++rbuf.len;
}
if (i < tlen - plen) {
t_h = (d*(t_h - t[i]*h)) + t[i + plen];
}
}
}
void *read_file(int fd, int *len)
{
int size = 1500 * 1024 * 1024;
unsigned char *arr = malloc(size);
int i;
for (i = 0; ;) {
int rd = read(fd, arr + i, size - i);
if (rd < 0)
exit(2);
if (rd == 0)
break;
i += rd;
}
*len = i;
return arr;
}
int main(int argc, char **argv)
{
int i, slen;
long sum = 0;
int fd;
char *buf;
char *needle = argv[2];
fd = open(argv[1], 0, 0);
if (fd == -1)
return 1;
buf = read_file(fd, &slen);
printf("len: %d\n", slen);
rabin_karp(needle, strlen(needle), buf, slen);
for (i = 0; i < rbuf.len; ++i)
sum += rbuf.array[i];
printf("%ld\n", sum);
return 0;
}
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