mdtex/str_split.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

size_t split_count(char* a_str, const char a_delim) {
    char* tmp = a_str;
    char* last_comma = 0;
    size_t count = 0;
    while (*tmp) {
        if (a_delim == *tmp) {
            count++;
            last_comma = tmp;
        }
        tmp++;
    }

    // Add space for trailing token.
    count += last_comma < (a_str + strlen(a_str) - 1);

    // Add space for terminating null string.
    count++;

    return count;
}

/* Adapted from http://stackoverflow.com/a/9210560 */
char** str_split(char* a_str, const char a_delim) {
    char delim[2];
    delim[0] = a_delim;
    delim[1] = 0;
    size_t count = split_count(a_str, a_delim);
    char** result = malloc(sizeof(char*) * count);
    if(!result) {
        fprintf(stderr, "Failed to allocate memory when splitting string '%s'.\n", a_str);
        return NULL;
    }
    if(result) {
        size_t idx  = 0;
        char* token = strtok(a_str, delim);
        while (token) {
            assert(idx < count);
            *(result + idx++) = strdup(token);
            token = strtok(0, delim);
        }
        assert(idx == count - 1);
        *(result + idx) = 0;
    }
    return result;
}

void substring(char* substr, const char* string, size_t start, size_t end) {
    if(end > strlen(string)) {
        end = strlen(string);
    }
    if(start < 0) {
        start = 0;
    }
    if(end < start) {
        return NULL;
    }
    size_t nchars = end - start + 1; // Need +1 because substring should include both ends.
    memcpy(substr, &string[start], nchars);
    substr[nchars] = '\0';
}

/* Adapted from http://stackoverflow.com/a/12890107 */
char* replace(const char *src, char ch, const char *repl) {
    int count = 0;
    const char *tmp;
    for(tmp=src; *tmp; tmp++)
        count += (*tmp == ch);

    size_t rlen = strlen(repl);
    char *res = malloc(strlen(src) + (rlen-1)*count + 1);
    char *ptr = res;
    for(tmp=src; *tmp; tmp++) {
        if(*tmp == ch) {
            memcpy(ptr, repl, rlen);
            ptr += rlen;
        } else {
            *ptr++ = *tmp;
        }
    }
    *ptr = 0;
    return res;
}