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#include <string.h>
size_t strlen(const char* string)
{
size_t length = 0;
while (string[length])
length++;
return length;
}
int strcmp(const char* a, const char* b)
{
while (*a && *a == *b)
{
a++;
b++;
}
return (int)(unsigned char)*a - (int)(unsigned char)*b;
}
int strncmp(const char* a, const char* b, size_t length)
{
for (size_t i = 0; i < length; i++)
{
unsigned char ca = (unsigned char)a[i];
unsigned char cb = (unsigned char)b[i];
if (ca != cb)
return (int)ca - (int)cb;
if (ca == 0)
return 0;
}
return 0;
}
char* strcpy(char* destination, const char* source)
{
char* out = destination;
while ((*out++ = *source++))
;
return destination;
}
char* strncpy(char* destination, const char* source, size_t length)
{
size_t i = 0;
for (; i < length && source[i]; i++)
destination[i] = source[i];
for (; i < length; i++)
destination[i] = 0;
return destination;
}
void* memcpy(void* destination, const void* source, size_t length)
{
unsigned char* out = destination;
const unsigned char* in = source;
for (size_t i = 0; i < length; i++)
out[i] = in[i];
return destination;
}
void* memmove(void* destination, const void* source, size_t length)
{
unsigned char* out = destination;
const unsigned char* in = source;
if (out < in)
for (size_t i = 0; i < length; i++)
out[i] = in[i];
else
for (size_t i = length; i > 0; i--)
out[i - 1] = in[i - 1];
return destination;
}
void* memset(void* destination, int value, size_t length)
{
unsigned char* out = destination;
for (size_t i = 0; i < length; i++)
out[i] = (unsigned char)value;
return destination;
}
int memcmp(const void* a, const void* b, size_t length)
{
const unsigned char* aa = a;
const unsigned char* bb = b;
for (size_t i = 0; i < length; i++)
if (aa[i] != bb[i])
return (int)aa[i] - (int)bb[i];
return 0;
}
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