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Added a simple utf8 encoder in the kernel.

This commit is contained in:
Jonas 'Sortie' Termansen 2012-01-18 22:06:10 +01:00
parent ac51e98cb8
commit 1f3f85b609
3 changed files with 114 additions and 0 deletions
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1
sortix/Makefile
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@ -66,6 +66,7 @@ descriptor_tables.o \
interrupt.o \
time.o \
log.o \
utf8.o \
panic.o \
keyboard.o \
scheduler.o \

76
sortix/utf8.cpp Normal file
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@ -0,0 +1,76 @@
/******************************************************************************
COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2012.
This file is part of Sortix.
Sortix 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.
Sortix 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 Sortix. If not, see <http://www.gnu.org/licenses/>.
utf8.cpp
Encodes UTF-32 strings in UTF-8.
******************************************************************************/
#include "platform.h"
#include <libmaxsi/error.h>
#include "utf8.h"
using namespace Maxsi;
namespace Sortix
{
namespace UTF8
{
unsigned Encode(uint32_t unicode, char* dest)
{
uint8_t* buf = (uint8_t*) dest;
unsigned bytes = 1;
unsigned bits = 7;
if ( (1U<<7U) <= unicode ) { bytes = 2; bits = 11; }
if ( (1U<<11U) <= unicode ) { bytes = 3; bits = 16; }
if ( (1U<<16U) <= unicode ) { bytes = 4; bits = 21; }
if ( (1U<<21U) <= unicode ) { bytes = 5; bits = 26; }
if ( (1U<<26U) <= unicode ) { bytes = 6; bits = 31; }
if ( (1U<<31U) <= unicode ) { Error::Set(EINVAL); return 0; }
uint8_t prefix;
unsigned prefixavai;
switch ( bytes )
{
case 1: prefixavai = 7; prefix = 0b0U << prefixavai; break;
case 2: prefixavai = 5; prefix = 0b110U << prefixavai; break;
case 3: prefixavai = 4; prefix = 0b1110U << prefixavai; break;
case 4: prefixavai = 3; prefix = 0b11110U << prefixavai; break;
case 5: prefixavai = 2; prefix = 0b111110U << prefixavai; break;
case 6: prefixavai = 1; prefix = 0b1111110U << prefixavai; break;
}
// Put the first bits in the unused area of the prefix.
prefix |= unicode >> (bits - prefixavai);
*buf++ = prefix;
unsigned bitsleft = bits - prefixavai;
while ( bitsleft )
{
bitsleft -= 6;
uint8_t elembits = (unicode>>bitsleft) & ((1U<<6U)-1U);
uint8_t elem = (0b10U<<6U) | elembits;
*buf++ = elem;
}
return bytes;
}
}
}

37
sortix/utf8.h Normal file
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@ -0,0 +1,37 @@
/******************************************************************************
COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2012.
This file is part of Sortix.
Sortix 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.
Sortix 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 Sortix. If not, see <http://www.gnu.org/licenses/>.
utf8.h
Encodes UTF-32 strings in UTF-8.
******************************************************************************/
#ifndef SORTIX_UTF8_H
#define SORTIX_UTF8_H
namespace Sortix
{
namespace UTF8
{
unsigned Encode(uint32_t unicode, char* dest);
}
}
#endif