safe_strn

safe_strn is a C library for safe string operation. It includes some basic string functions to prevent buffer overflow.

Run

Firstly, compile the code with following command:

$ gcc lib/*.h lib/*.c test/*.h test/*.c example/*

Then, run the executable file.

$ ./a.out

Usage

Add lib/ folder under your workspace and include the library as follows. You may need to give the relative path depending on where you put location.

#include "safe_string.h"

int main() {
    
    char *src = "hello world";
    char *new_str = (char *) malloc(sizeof(char) * 12); // Allocate memory for string
    str_cpy(src, new_str, 11);  // Copy src to new_str
    
    int len = str_len(new_str); // Length of new_str
    
    char *str1 = "abc";
    char *str2 = "abc";
    int res = str_cmp(str1, str2, 3, 3);
    
    if (res < 0) {
        printf("str1 less than str2\n"): 
    } else if (res > 0){
        printf("str2 less than str1.\n");
    } else {
        printf("str1 and str2 are equal.\n");    // Prints "str1 and str2 are equal."
    }
    
    char *str = str_mk("create a new string.", 50); // Create a null-terminated string with maximum 50 length.
}

Documentation

str_mk

Creates string by preventing potential buffer overflow. Guarantees putting null-terminator at the end of the string. Also, prevents buffer overflow which is caused by integer overflow.

char *str_mk(const char *str, size_t str_len);

str_cpy

Copies the string from src to dst. You need to pass length of the string that you want to copy.

int str_cpy(const char *src, char *dst, size_t n));

str_len

Returns the length of the string.

int str_len(const char *s);

str_cat

Concatenates the given strings. Returns the new length of the src.

int str_cat(char *src, const char *append, size_t src_size, size_t app_size);

str_cmp

Compares the two given strings. If str1 less than str2, returns -1. If str2 less than str1, returns 1. And str1 and str2 are equal, then returns 0.

int str_cmp(const char *str1, const char *str2, size_t str1_size, size_t str2_size);

LICENSE

GNU General Public License v3.0