xlibc/x_string/src/x_string.c

72 lines
1.3 KiB
C

#include <stdio.h>
#include <stdlib.h>
// return the length of string to the null terminator
int x_strlen(char* str){
char* ptr = str;
while(*ptr != '\0'){
ptr++;
}
return ptr - str;
}
// copy one string to another destination
// must include the size of the destination
void x_strcpy(char* dest, char* src, const int size_dest){
char* dest_ptr = dest;
char* src_ptr = src;
int i = 0;
while(*src_ptr != '\0'){
if (i >= size_dest){
fprintf(stderr, "Error: x_strcpy\nSource string exeeds destination memory\n");
exit(1);
}
*dest_ptr = *src_ptr;
dest_ptr++;
src_ptr++;
i++;
}
}
// compare two strings
// return 0 if equal to eachother
// return -1 if not
int x_strcmp (char* str1, char* str2){
char* ptr1 = str1;
char* ptr2 = str2;
while(*ptr1 != '\0' && *ptr2 != '\0'){
if(*ptr1 != *ptr2){
return -1;
}
ptr1++;
ptr2++;
}
// if havent reached the end of one of the strings
if (*ptr1 != '\0' || *ptr2 != '\0'){
return -1;
}
return 0;
}
// concatinate two strings
char* x_strconcat(char* str1, char* str2){
char* new_string;
int len1 = x_strlen(str1);
int len2 = x_strlen(str2);
int new_length = len1 + len2;
new_string = malloc( sizeof(*new_string) * new_length );
x_strcpy(new_string, str1, new_length);
x_strcpy(&new_string[len1], str2, new_length - len1);
return new_string;
}