Manual implemenation of a split() function in C

main.c

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

#define bool short
#define false 0
#define true 1

bool my_contains(char *charset, char c) {
    for (int i = 0; charset[i] != '\0'; i++) {
        if (charset[i] == c) {
            return true;
        }
    }
    return false;
}


void my_strcpy(char *dst, char *src, int length) {
    for (int i = 0; i < length; i++) {
        dst[i] = src[i];
    }
}

int my_strlen(char *str) {
    int l = 0;
    while (str[l] != '\0') {
        l++;
    }
    return l;
}

char **ft_split(char *str, char *charset) {
    char **output = (char **)malloc(sizeof(char *) * my_strlen(str));
    int outputIndex = 0;

    int inputStartIndex = 0;
    int inputEndIndex = 0;

    while (1==1) {
        if (my_contains(charset, str[inputEndIndex]) || str[inputEndIndex] == '\0') { // check if separator or end of string

            // only append to output if non-zero length
            if(inputEndIndex - inputStartIndex > 0) {
                // append to output
                output[outputIndex] = (char *)malloc(sizeof(char) * (inputEndIndex - inputStartIndex + 1));
                my_strcpy(output[outputIndex], str + inputStartIndex, inputEndIndex - inputStartIndex);
                output[outputIndex][inputEndIndex - inputStartIndex] = 0;
                outputIndex++;
            } 

            inputStartIndex = inputEndIndex+1;
        }

        // break at the end of the string
        if(str[inputEndIndex] == '\0') {
            break;
        }

        inputEndIndex++;
    }

    // reallocate to only use the minimum memory necessary
    char **newOutput = (char **)malloc(sizeof(char *) * (outputIndex));
    for (int i = 0; i < outputIndex; i++) {
        newOutput[i] = output[i];
    }
    newOutput[outputIndex] = 0;

    free(output);
    return newOutput;
}

int main() {
    char *str = "Hello, world!world!world!world!hey";
    char *charset = ", !";

    char **output = ft_split(str, charset);

    for (int i = 0; output[i] != NULL; i++) {
        printf("PART=%s\n", output[i]);
    }
}