From fa095a4504cbe668e4244547e2c141597bea4ecf Mon Sep 17 00:00:00 2001 From: Andreas Rottmann Date: Mon, 14 Sep 2009 12:32:44 +0200 Subject: Imported Upstream version 0.9.1 --- lib/unistr/u16-prev.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 lib/unistr/u16-prev.c (limited to 'lib/unistr/u16-prev.c') diff --git a/lib/unistr/u16-prev.c b/lib/unistr/u16-prev.c new file mode 100644 index 0000000..3beecf0 --- /dev/null +++ b/lib/unistr/u16-prev.c @@ -0,0 +1,53 @@ +/* Iterate over previous character in UTF-16 string. + Copyright (C) 2002, 2006-2007 Free Software Foundation, Inc. + Written by Bruno Haible , 2002. + + This program 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 3 of the License, or + (at your option) any later version. + + This program 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 this program. If not, see . */ + +#include + +/* Specification. */ +#include "unistr.h" + +const uint16_t * +u16_prev (ucs4_t *puc, const uint16_t *s, const uint16_t *start) +{ + /* Keep in sync with unistr.h and utf16-ucs4.c. */ + if (s != start) + { + uint16_t c_1 = s[-1]; + + if (c_1 < 0xd800 || c_1 >= 0xe000) + { + *puc = c_1; + return s - 1; + } +#if CONFIG_UNICODE_SAFETY + if (c_1 >= 0xdc00) +#endif + if (s - 1 != start) + { + uint16_t c_2 = s[-2]; + +#if CONFIG_UNICODE_SAFETY + if (c_2 >= 0xd800 && c_2 < 0xdc00) +#endif + { + *puc = 0x10000 + ((c_2 - 0xd800) << 10) + (c_1 - 0xdc00); + return s - 2; + } + } + } + return NULL; +} -- cgit v1.2.3