__memrchr gblic 源码分析

/* memrchr -- find the last occurrence of a byte in a memory block Copyright (C) 1991, 93, 96, 97, 99, 2000 Free Software Foundation, Inc. This file is part of the GNU C Library. Based on strlen implementation by Torbjorn Granlund (tege@sics.se), with help from Dan Sahlin (dan@sics.se) and commentary by Jim Blandy (jimb@ai.mit.edu); adaptation to memchr suggested by Dick Karpinski (dick@cca.ucsf.edu), and implemented by Roland McGrath (roland@ai.mit.edu). The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #include <stdlib.h> #ifdef HAVE_CONFIG_H # include <config.h> #endif #undef __ptr_t #if defined __cplusplus || (defined __STDC__ && __STDC__) # define __ptr_t void * #else /* Not C++ or ANSI C. */ # define __ptr_t char * #endif /* C++ or ANSI C. */ #if defined _LIBC # include <string.h> # include <memcopy.h> #else # define reg_char char #endif #if defined HAVE_LIMITS_H || defined _LIBC # include <limits.h> #endif #define LONG_MAX_32_BITS 2147483647 #ifndef LONG_MAX # define LONG_MAX LONG_MAX_32_BITS #endif #include <sys/types.h> #undef _