83 lines
2.2 KiB
C
83 lines
2.2 KiB
C
/*
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FUNCTION
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<<tolower>>, <<tolower_l>>---translate characters to lowercase
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INDEX
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tolower
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INDEX
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tolower_l
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INDEX
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_tolower
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SYNOPSIS
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#include <ctype.h>
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int tolower(int <[c]>);
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int _tolower(int <[c]>);
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#include <ctype.h>
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int tolower_l(int <[c]>, locale_t <[locale]>);
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DESCRIPTION
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<<tolower>> is a macro which converts uppercase characters to lowercase,
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leaving all other characters unchanged. It is only defined when
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<[c]> is an integer in the range <<EOF>> to <<255>>.
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<<tolower_l>> is like <<tolower>> but performs the function based on the
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locale specified by the locale object locale. If <[locale]> is
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LC_GLOBAL_LOCALE or not a valid locale object, the behaviour is undefined.
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You can use a compiled subroutine instead of the macro definition by
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undefining this macro using `<<#undef tolower>>' or `<<#undef tolower_l>>'.
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<<_tolower>> performs the same conversion as <<tolower>>, but should
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only be used when <[c]> is known to be an uppercase character (<<A>>--<<Z>>).
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RETURNS
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<<tolower>>, <<tolower_l>> return the lowercase equivalent of <[c]> when
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<[c]> is an uppercase character, and <[c]> otherwise.
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<<_tolower>> returns the lowercase equivalent of <[c]> when it is a
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character between <<A>> and <<Z>>. If <[c]> is not one of these
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characters, the behaviour of <<_tolower>> is undefined.
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PORTABILITY
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<<tolower>> is ANSI C. <<_tolower>> is not recommended for portable programs.
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<<tolower_l>> is POSIX-1.2008.
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No supporting OS subroutines are required.
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*/
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#include <_ansi.h>
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#include <ctype.h>
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#if defined (_MB_EXTENDED_CHARSETS_ISO) || defined (_MB_EXTENDED_CHARSETS_WINDOWS)
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <wctype.h>
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#include <wchar.h>
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#endif
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#undef tolower
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int
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tolower (int c)
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{
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#if defined (_MB_EXTENDED_CHARSETS_ISO) || defined (_MB_EXTENDED_CHARSETS_WINDOWS)
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if ((unsigned char) c <= 0x7f)
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return isupper (c) ? c - 'A' + 'a' : c;
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else if (c != EOF && MB_CUR_MAX == 1 && isupper (c))
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{
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char s[MB_LEN_MAX] = { c, '\0' };
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wchar_t wc;
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if (mbtowc (&wc, s, 1) >= 0
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&& wctomb (s, (wchar_t) towlower ((wint_t) wc)) == 1)
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c = (unsigned char) s[0];
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}
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return c;
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#else
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return isupper(c) ? (c) - 'A' + 'a' : c;
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#endif
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}
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