grub/lib/charset.c
Vladimir 'phcoder' Serbinenko 1d3c6f1de7 Manually reimported XNU branch
2009-11-09 18:43:53 +01:00

116 lines
3 KiB
C

/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2006,2007,2008,2009 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
/* Convert a (possibly null-terminated) UTF-8 string of at most SRCSIZE
bytes (if SRCSIZE is -1, it is ignored) in length to a UTF-16 string.
Return the number of characters converted. DEST must be able to hold
at least DESTSIZE characters. If an invalid sequence is found, return -1.
If SRCEND is not NULL, then *SRCEND is set to the next byte after the
last byte used in SRC. */
#include <grub/charset.h>
grub_ssize_t
grub_utf8_to_utf16 (grub_uint16_t *dest, grub_size_t destsize,
const grub_uint8_t *src, grub_size_t srcsize,
const grub_uint8_t **srcend)
{
grub_uint16_t *p = dest;
int count = 0;
grub_uint32_t code = 0;
if (srcend)
*srcend = src;
while (srcsize && destsize)
{
grub_uint32_t c = *src++;
if (srcsize != (grub_size_t)-1)
srcsize--;
if (count)
{
if ((c & GRUB_UINT8_2_LEADINGBITS) != GRUB_UINT8_1_LEADINGBIT)
{
/* invalid */
return -1;
}
else
{
code <<= 6;
code |= (c & GRUB_UINT8_6_TRAILINGBITS);
count--;
}
}
else
{
if (c == 0)
break;
if ((c & GRUB_UINT8_1_LEADINGBIT) == 0)
code = c;
else if ((c & GRUB_UINT8_3_LEADINGBITS) == GRUB_UINT8_2_LEADINGBITS)
{
count = 1;
code = c & GRUB_UINT8_5_TRAILINGBITS;
}
else if ((c & GRUB_UINT8_4_LEADINGBITS) == GRUB_UINT8_3_LEADINGBITS)
{
count = 2;
code = c & GRUB_UINT8_4_TRAILINGBITS;
}
else if ((c & GRUB_UINT8_5_LEADINGBITS) == GRUB_UINT8_4_LEADINGBITS)
{
count = 3;
code = c & GRUB_UINT8_3_TRAILINGBITS;
}
else if ((c & GRUB_UINT8_6_LEADINGBITS) == GRUB_UINT8_5_LEADINGBITS)
{
count = 4;
code = c & GRUB_UINT8_2_TRAILINGBITS;
}
else if ((c & GRUB_UINT8_7_LEADINGBITS) == GRUB_UINT8_6_LEADINGBITS)
{
count = 5;
code = c & GRUB_UINT8_1_TRAILINGBIT;
}
else
return -1;
}
if (count == 0)
{
if (destsize < 2 && code >= GRUB_UCS2_LIMIT)
break;
if (code >= GRUB_UCS2_LIMIT)
{
*p++ = GRUB_UTF16_UPPER_SURROGATE (code);
*p++ = GRUB_UTF16_LOWER_SURROGATE (code);
destsize -= 2;
}
else
{
*p++ = code;
destsize--;
}
}
}
if (srcend)
*srcend = src;
return p - dest;
}