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circuitpython/lib/libc/string0.c

223 lines
5.9 KiB

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdint.h>
#include <string.h>
#define likely(x) __builtin_expect((x), 1)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-align"
void *memcpy(void *dst, const void *src, size_t n) {
if (likely(!(((uintptr_t)dst) & 3) && !(((uintptr_t)src) & 3))) {
// pointers aligned
uint32_t *d = dst;
const uint32_t *s = src;
// copy words first
for (size_t i = (n >> 2); i; i--) {
*d++ = *s++;
}
if (n & 2) {
// copy half-word
*(uint16_t*)d = *(const uint16_t*)s;
d = (uint32_t*)((uint16_t*)d + 1);
s = (const uint32_t*)((const uint16_t*)s + 1);
}
if (n & 1) {
// copy byte
*((uint8_t*)d) = *((const uint8_t*)s);
}
} else {
// unaligned access, copy bytes
uint8_t *d = dst;
const uint8_t *s = src;
for (; n; n--) {
*d++ = *s++;
}
}
return dst;
}
void *memmove(void *dest, const void *src, size_t n) {
if (src < dest && (uint8_t*)dest < (const uint8_t*)src + n) {
// need to copy backwards
uint8_t *d = (uint8_t*)dest + n - 1;
const uint8_t *s = (const uint8_t*)src + n - 1;
for (; n > 0; n--) {
*d-- = *s--;
}
return dest;
} else {
// can use normal memcpy
return memcpy(dest, src, n);
}
}
void *memset(void *s, int c, size_t n) {
if (c == 0 && ((uintptr_t)s & 3) == 0) {
// aligned store of 0
uint32_t *s32 = s;
for (size_t i = n >> 2; i > 0; i--) {
*s32++ = 0;
}
if (n & 2) {
*((uint16_t*)s32) = 0;
s32 = (uint32_t*)((uint16_t*)s32 + 1);
}
if (n & 1) {
*((uint8_t*)s32) = 0;
}
} else {
uint8_t *s2 = s;
for (; n > 0; n--) {
*s2++ = c;
}
}
return s;
}
#pragma GCC diagnostic pop
int memcmp(const void *s1, const void *s2, size_t n) {
const uint8_t *s1_8 = s1;
const uint8_t *s2_8 = s2;
while (n--) {
char c1 = *s1_8++;
char c2 = *s2_8++;
if (c1 < c2) return -1;
else if (c1 > c2) return 1;
}
return 0;
}
void *memchr(const void *s, int c, size_t n) {
if (n != 0) {
const unsigned char *p = s;
do {
if (*p++ == c)
return ((void *)(p - 1));
} while (--n != 0);
}
return 0;
}
size_t strlen(const char *str) {
int len = 0;
for (const char *s = str; *s; s++) {
len += 1;
}
return len;
}
int strcmp(const char *s1, const char *s2) {
while (*s1 && *s2) {
char c1 = *s1++; // XXX UTF8 get char, next char
char c2 = *s2++; // XXX UTF8 get char, next char
if (c1 < c2) return -1;
else if (c1 > c2) return 1;
}
if (*s2) return -1;
else if (*s1) return 1;
else return 0;
}
int strncmp(const char *s1, const char *s2, size_t n) {
while (*s1 && *s2 && n > 0) {
char c1 = *s1++; // XXX UTF8 get char, next char
char c2 = *s2++; // XXX UTF8 get char, next char
n--;
if (c1 < c2) return -1;
else if (c1 > c2) return 1;
}
if (n == 0) return 0;
else if (*s2) return -1;
else if (*s1) return 1;
else return 0;
}
char *strcpy(char *dest, const char *src) {
char *d = dest;
while (*src) {
*d++ = *src++;
}
*d = '\0';
return dest;
}
// needed because gcc optimises strcpy + strcat to this
char *stpcpy(char *dest, const char *src) {
while (*src) {
*dest++ = *src++;
}
*dest = '\0';
return dest;
}
char *strcat(char *dest, const char *src) {
char *d = dest;
while (*d) {
d++;
}
while (*src) {
*d++ = *src++;
}
*d = '\0';
return dest;
}
// Public Domain implementation of strchr from:
// http://en.wikibooks.org/wiki/C_Programming/Strings#The_strchr_function
char *strchr(const char *s, int c)
{
/* Scan s for the character. When this loop is finished,
s will either point to the end of the string or the
character we were looking for. */
while (*s != '\0' && *s != (char)c)
s++;
return ((*s == c) ? (char *) s : 0);
}
// Public Domain implementation of strstr from:
// http://en.wikibooks.org/wiki/C_Programming/Strings#The_strstr_function
char *strstr(const char *haystack, const char *needle)
{
size_t needlelen;
/* Check for the null needle case. */
if (*needle == '\0')
return (char *) haystack;
needlelen = strlen(needle);
for (; (haystack = strchr(haystack, *needle)) != 0; haystack++)
if (strncmp(haystack, needle, needlelen) == 0)
return (char *) haystack;
return 0;
}