osdev/stdlib/string.c at master · cstack/osdev · GitHub

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#include "string.h"

Returns an integral value indicating the relationship between the strings:

return value indicates

<0 the first character that does not match has a lower value in ptr1 than in ptr2

0 the contents of both strings are equal

>0 the first character that does not match has a greater value in ptr1 than in ptr2

int strcmp(const char * str1, const char * str2) {

while (*str1 != 0 && *str2 != 0) {

int diff = *str1 - *str2;

if (diff != 0) {

return diff;

}

str1++;

str2++;

}

// One of these points to 0

return *str1 - *str2;

}

int strncmp (const char * str1, const char * str2, uint32_t num) {

while (*str1 != 0 && *str2 != 0 && num > 1) {

int diff = *str1 - *str2;

if (diff != 0) {

return diff;

}

str1++;

str2++;

num--;

}

return *str1 - *str2;

}

void* memcpy (void* dest, const void* src, uint32_t count) {

char* dest_byte = (char*) dest;

char* src_byte = (char*) src;

for (uint32_t i = 0; i < count; i++) {

*dest_byte = *src_byte;

dest_byte++;

src_byte++;

}

return dest;

}

osdev/stdlib/string.c at master · cstack/osdev · GitHub

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