ROSE/dosfs/tmpstring.c

100 lines
1.9 KiB
C
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#pragma once
#include <stdint.h>
#include <stddef.h>
void *memcpy(void *restrict dest, const void *restrict src, size_t n)
{
unsigned char *d = dest;
const unsigned char *s = src;
for (; n; n--) *d++ = *s++;
return dest;
}
void *memset(void *dest, int c, size_t n)
{
unsigned char *s = dest;
size_t k;
/* Fill head and tail with minimal branching. Each
* conditional ensures that all the subsequently used
* offsets are well-defined and in the dest region. */
if (!n) return dest;
s[0] = c;
s[n-1] = c;
if (n <= 2) return dest;
s[1] = c;
s[2] = c;
s[n-2] = c;
s[n-3] = c;
if (n <= 6) return dest;
s[3] = c;
s[n-4] = c;
if (n <= 8) return dest;
/* Advance pointer to align it at a 4-byte boundary,
* and truncate n to a multiple of 4. The previous code
* already took care of any head/tail that get cut off
* by the alignment. */
k = -(uintptr_t)s & 3;
s += k;
n -= k;
n &= -4;
/* Pure C fallback with no aliasing violations. */
for (; n; n--, s++) *s = c;
return dest;
}
size_t strlen(const char *s)
{
const char *a = s;
for (; *s; s++);
return s-a;
}
int memcmp(const void *vl, const void *vr, size_t n)
{
const unsigned char *l=vl, *r=vr;
for (; n && *l == *r; n--, l++, r++);
return n ? *l-*r : 0;
}
char *strncpy(char *restrict d, const char *restrict s, size_t n)
{
for (; n && (*d=*s); n--, s++, d++);
memset(d, 0, n);
return d;
}
char *strcpy(char *restrict dest, const char *restrict src)
{
char *restrict d = dest;
const char *restrict s = src;
for (; (*d=*s); s++, d++);
return d;
}
int strcmp(const char *l, const char *r)
{
for (; *l==*r && *l; l++, r++);
return *(unsigned char *)l - *(unsigned char *)r;
}
/* STDLIB DIV FUNCTIONS */
typedef struct { int32_t quot, rem; } div_t;
typedef struct { int64_t quot, rem; } ldiv_t;
div_t div(int num, int den)
{
return (div_t){ num/den, num%den };
}
ldiv_t ldiv(long num, long den)
{
return (ldiv_t){ num/den, num%den };
}