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Diffstat (limited to 'lib/stdlib/mem.c')
-rw-r--r-- | lib/stdlib/mem.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/lib/stdlib/mem.c b/lib/stdlib/mem.c new file mode 100644 index 0000000..f1f335a --- /dev/null +++ b/lib/stdlib/mem.c @@ -0,0 +1,121 @@ +/* + * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * Redistributions of source code must retain the above copyright notice, this + * list of conditions and the following disclaimer. + * + * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * Neither the name of ARM nor the names of its contributors may be used + * to endorse or promote products derived from this software without specific + * prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#include <stddef.h> /* size_t */ + +/* + * Fill @count bytes of memory pointed to by @dst with @val + */ +void *memset(void *dst, int val, size_t count) +{ + char *ptr = dst; + + while (count--) + *ptr++ = val; + + return dst; +} + +/* + * Compare @len bytes of @s1 and @s2 + */ +int memcmp(const void *s1, const void *s2, size_t len) +{ + const char *s = s1; + const char *d = s2; + char dc; + char sc; + + while (len--) { + sc = *s++; + dc = *d++; + if (sc - dc) + return (sc - dc); + } + + return 0; +} + +/* + * Copy @len bytes from @src to @dst + */ +void *memcpy(void *dst, const void *src, size_t len) +{ + const char *s = src; + char *d = dst; + + while (len--) + *d++ = *s++; + + return dst; +} + +/* + * Move @len bytes from @src to @dst + */ +void *memmove(void *dst, const void *src, size_t len) +{ + /* + * The following test makes use of unsigned arithmetic overflow to + * more efficiently test the condition !(src <= dst && dst < str+len). + * It also avoids the situation where the more explicit test would give + * incorrect results were the calculation str+len to overflow (though + * that issue is probably moot as such usage is probably undefined + * behaviour and a bug anyway. + */ + if ((size_t)dst - (size_t)src >= len) { + /* destination not in source data, so can safely use memcpy */ + return memcpy(dst, src, len); + } else { + /* copy backwards... */ + const char *end = dst; + const char *s = (const char *)src + len; + char *d = (char *)dst + len; + while (d != end) + *--d = *--s; + } + return dst; +} + +/* + * Scan @len bytes of @src for value @c + */ +void *memchr(const void *src, int c, size_t len) +{ + const char *s = src; + + while (len--) { + if (*s == c) + return (void *) s; + s++; + } + + return NULL; +} |