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/* Copyright (c) 2007 Dmitry Xmelkov
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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* Neither the name of the copyright holders nor the names of
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE. */
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/* $Id: strcasestr.S,v 1.2.2.1 2007/03/31 13:23:16 dmix Exp $ */
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/** \ingroup avr_string
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\fn char *strcasestr(const char *s1, const char *s2)
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The strcasestr() function finds the first occurrence of the
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substring \p s2 in the string \p s1. This is like strstr(), except
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that it ignores case of alphabetic symbols in searching for the
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substring. (Glibc, GNU extension.)
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\return The strcasestr() function returns a pointer to the beginning
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of the substring, or \c NULL if the substring is not found. If \p s2
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points to a string of zero length, the function returns \p s1. */
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/** \ingroup avr_pgmspace
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\fn char *strcasestr_P(const char *s1, PGM_P s2)
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This funtion is similar to strcasestr() except that \p s2 is pointer
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to a string in program space. */
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#if !defined(__DOXYGEN__)
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#define beg2 r21 /* begin of s2 (cashed): s2[0] */
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#define ctmp r20 /* scratch arg of .Lcmp() */
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#define csvd r0 /* second arg of .Lcmp(), nochanged */
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# define strcasestr strcasestr_P
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# define LOAD X_lpm /* may scratch r0 */
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tst beg2 ; is str2 empty?
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breq .L_ret ; return original string (req'd by standard)
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X_movw s2_lo, ZL ; save: address of second s2 byte
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mov csvd, beg2 ; Find first char
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breq .L_nomatch ; end of s1
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X_movw s1_lo, XL ; store return value (decrement is needed)
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3: LOAD csvd, Z+ ; compare strings (csvd is r0)
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breq .L_match ; end of s2
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cpse ctmp, __zero_reg__ ; now Z==0
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; (ctmp==0 && Z==0) || - end of s1
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; (ctmp!=0 && Z==0) || - chars are not equal
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; (Z==1) - chars are equal
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X_movw ZL, s2_lo ; restore s2+1
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; (ctmp==0 && Z==0) || - end of s2
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; (ctmp!=0 && Z==0) - chars are not equal
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cpse ctmp, __zero_reg__ ; if equal, then tail(s1) is less
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rjmp 1b ; then strlen(s2)
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sbiw s1_lo, 1 ; restore after post-increment
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/* Compare 2 bytes ignoring a case of symbols.
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Return: if (bytes are equal) Z==1, else (Z==0 && ctmp != 0)
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.if ('a'-'A' - 0x20) | ('Z'-'A' - 25) | ('z'-'a' - 25)
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.Lcmp: eor ctmp, csvd
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breq 1f ; OK, bytes are equal
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brne 1f ; bytes are different more than alpha case
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; now caseless comparison
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or ctmp, csvd ; ctmp = tolower(csvd)
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subi ctmp, -(255 - 'z') ; shift a..z to 230..255
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subi ctmp, 255 - ('z' - 'a')
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brlo 1f ; branch, if not an alpha
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#endif /* not __DOXYGEN__ */
added
removed
libc/string/strcasestr.S
