micro-utils/src/grep.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <regex.h>

typedef struct {
	char *pattern;
	regex_t rgex;
} PATTERN;
static PATTERN *regexs;
static size_t r_size;

static char i_flag;
static char F_flag;
static char H_flag;

static int addpattern(char *str) {
	if (regexs == NULL) {
		regexs = malloc(sizeof(PATTERN));
		if (regexs == NULL) {
			fprintf(stderr, "grep: malloc failed\n");
			return 1;
		}
	}

	PATTERN *regexs_tmp = realloc(regexs, (r_size + 1) * sizeof(PATTERN));
	if (regexs_tmp == NULL) {
		free(regexs);

		fprintf(stderr, "grep: realloc failed\n");
		return 1;
	}
	regexs = regexs_tmp;

	/* Add new pattern */
	regexs[r_size].pattern = str;
	
	r_size++;
	return 0;
}

int main(int argc, char **argv) {
	int opt;
	while ((opt = getopt(argc, argv, "e:iFH")) != -1) {
		switch (opt) {
			case 'e':
				if (addpattern(optarg))
					return 1;

				break;

			case 'i':
				i_flag = 1;
				break;

			case 'F':
				F_flag = 1;
				break;

			case 'H':
				H_flag = 1;
				break;

			default:
				printf("grep [eiFH] [FILE]\n\t-e PTRN Pattern to match\n\t-i Ignore case\n\t-H Add 'filename:' prefix\n\t-F PATTERN is a literal (not regexp)\n");
				return 0;
		}
	}

	argv += optind;
	argc -= optind;
	if (r_size == 0) {
		fprintf(stderr, "grep: no patterns specified\n");
		return 1;
	}

	free(regexs);
	return 0;
}