59 lines
1.2 KiB
C
59 lines
1.2 KiB
C
#include <string.h>
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#include <stdlib.h>
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#include "lfstring.h"
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int find_substrings(const char* haystack, const char* needle, size_t *num_substrings, size_t **substrings) {
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if (*substrings != NULL) {
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return 1;
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}
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size_t sz_h = strlen(haystack);
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size_t sz_n = strlen(needle);
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if ((int)sz_h - (int)sz_n < 0) {
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return 0;
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}
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*num_substrings = 0;
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for (size_t i = 0; i <= sz_h - sz_n; ++i) {
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if (strncmp(haystack + i, needle, sz_n) == 0) {
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++(*num_substrings);
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}
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}
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if (*num_substrings == 0) {
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return 0;
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}
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*substrings = malloc(sizeof(size_t) * *num_substrings);
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if (*substrings == NULL) {
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return -1;
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}
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size_t idx = 0;
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for (size_t i = 0; i <= sz_h - sz_n; ++i) {
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if (strncmp(haystack + i, needle, sz_n) == 0) {
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(*substrings)[idx++] = i;
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}
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}
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return 0;
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}
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char* substr(const char* str, size_t idx, size_t len) {
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size_t sz_str = strlen(str);
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if (sz_str < len || idx + len > sz_str) {
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return NULL;
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}
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char *substr = malloc(sizeof(char) * len + 1);
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if (substr == NULL) {
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return NULL;
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}
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memcpy(substr, str + idx, len);
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substr[len] = '\0';
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return substr;
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}
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