/* Compare pieces of UTF-16 strings. Copyright (C) 1999, 2002, 2006 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 Library General Public License as published by the Free Software Foundation; either version 2, 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 Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #include /* Specification. */ #include "unistr.h" int u16_cmp (const uint16_t *s1, const uint16_t *s2, size_t n) { /* Note that the UTF-16 encoding does NOT preserve lexicographic order. Namely, if uc1 is a 16-bit character and [uc2a,uc2b] is a surrogate pair, we must enforce uc1 < [uc2a,uc2b], even if uc1 > uc2a. */ for (; n > 0;) { uint16_t c1 = *s1++; uint16_t c2 = *s2++; if (c1 == c2) { n--; continue; } if (c1 < 0xd800 || c1 >= 0xe000) { if (!(c2 < 0xd800 || c2 >= 0xe000)) /* c2 is a surrogate, but c1 is not. */ return -1; } else { if (c2 < 0xd800 || c2 >= 0xe000) /* c1 is a surrogate, but c2 is not. */ return 1; } return (int)c1 - (int)c2; /* > 0 if c1 > c2, < 0 if c1 < c2. */ } return 0; }