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December 17, 2021 08:29
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fast_strlcpy
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/* Copyright (c) 1998, 2015 Todd C. Miller <millert@openbsd.org> | |
* (c) 2021 Andrii Makukha | |
* | |
* Permission to use, copy, modify, and distribute this software for any | |
* purpose with or without fee is hereby granted, provided that the above | |
* copyright notice and this permission notice appear in all copies. | |
* | |
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES | |
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF | |
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR | |
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES | |
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN | |
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF | |
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. | |
*/ | |
/* | |
* @brief Copy string src to buffer dst of size dsize. At most dsize-1 chars | |
* will be copied. Always NUL-terminates (unless dsize == 0). | |
* | |
* @return dsize if truncation occured | |
* zero if dsize is zero | |
* othersize - length of string copied | |
* | |
* Based on https://github.com/libressl-portable/openbsd/blob/master/src/lib/libc/string/strlcpy.c | |
*/ | |
size_t fast_strlcpy(char *dst, const char *src, size_t dsize) | |
{ | |
const char *osrc = src; | |
size_t nleft = dsize; | |
// Copy as many bytes as will fit. | |
if (nleft != 0) { | |
while (--nleft != 0) { | |
if ((*dst++ = *src++) == '\0') | |
break; | |
} | |
} | |
// Not enough room in dst, add NUL. | |
if (nleft == 0) { | |
if (dsize != 0) | |
*dst = '\0'; // NUL-terminate dst | |
//while (*src++); // Original strlcpy from OpenBSD - this is slow and unsafe | |
src++; // Change in this "fast" version | |
} | |
// Count does not include NUL | |
return (src - osrc - 1); | |
} |
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