Test.c

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

char* get_repeated_single_quotes(char* x, int has_previous) {
    char* p;
    char* result;
    size_t result_length;
    size_t i;

    for (p = x; *p == '\''; ++p)
    {
    }

    result_length = (p - x) + (has_previous && *(x - 1) == '\'');
    result = (char*) malloc(result_length + 1);
    for (i = 0; i < result_length; ++i)
    {
        result[i] = '\'';
    }
    result[result_length] = '\0';

    return result;
}

int is_closing_quote(char *template, int is_literal_string, int has_previous)
{
    char* repeated_single_quotes;
    int result_on_single;

    if (!is_literal_string)
    {
	// is not \"
	return
	    (!has_previous || *(template - 1) != '\\') &&
	    (*template == '"');
    }
    // is not ''

    if (*template != '\'')
    {
        return 0;
    }

    if (!has_previous && *(template + 1) == '\'')
    {
        return 0;
    }
    else if (has_previous && *(template - 1) == '\'' && *(template + 1) != '\'')
    {
        return 0;
    }
    return 1;
}

int main(void) {
    char* x = get_repeated_single_quotes("'''", 0);
    printf("%s\n", x);
    char* y = get_repeated_single_quotes(x + 1, 1);
    printf("%s\n", y);

    printf("double\n");
    char* str = "ho-ya! \\\"\"";
    printf("%d\n", is_closing_quote(str, 0, 0) == 0);
    printf("%d\n", is_closing_quote(str + 8, 0, 1) == 0);
    printf("%d\n", is_closing_quote(str + 9, 0, 1) == 1);

    printf("single\n");
    char* lit = "ho-ya! '''";
    printf("%d\n", is_closing_quote(lit, 1, 0) == 0);
    printf("%d\n", is_closing_quote(lit + 7, 1, 1) == 0);
    printf("%d\n", is_closing_quote(lit + 8, 1, 1) == 0);
    printf("%d\n", is_closing_quote(lit + 9, 1, 1) == 1);

    printf("single2\n");
    char* whole = "'I''ll come with you.'";
    char* to = whole + 2;
    printf("%d\n", is_closing_quote(to, 1, 1) == 0);
    printf("%d\n", is_closing_quote(to + 19, 1, 1) == 1);
}