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/***************************************************************************
*
* $Id: utf8.c 93 2009-08-24 20:57:31Z Michael.McTernan $
*
* UTF8 decode routine.
* Copyright (C) 2008 Michael C McTernan, Michael.McTernan.2001@cs.bris.ac.uk
*
* This program 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 2
* 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 General Public License for more details.
*
* You should have received a copy of the GNU 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
**************************************************************************/
/**************************************************************************
* Includes
**************************************************************************/
#include "mscgen_utf8.h"
/**************************************************************************
* Manifest Constants
**************************************************************************/
/**************************************************************************
* Macros
**************************************************************************/
/**************************************************************************
* Types
**************************************************************************/
/**************************************************************************
* Local Variables
**************************************************************************/
/**************************************************************************
* Local Functions
**************************************************************************/
/** Count leading ones from the MSB.
*/
static unsigned int clo(char c)
{
unsigned int t = 0;
while((c & (0x80 >> t)) != 0 && t < 8)
{
t++;
}
return t;
}
/**************************************************************************
* Global Functions
**************************************************************************/
Boolean Utf8Decode(const char *s, unsigned int *r, unsigned int *bytes)
{
if((*s & 0x80) == 0)
{
return FALSE;
}
else
{
unsigned int t;
/* Set default return values */
*bytes = clo(*s);
*r = 0;
/* Loop through string, checking for null termination */
for(t = 0; t < *bytes && s[t] != '\0'; t++)
{
/* Shift up previous bits */
*r <<= 6;
/* Add the required bits */
if(t == 0)
{
*r |= s[t] & (0xff >> (*bytes + 1));
}
else
{
*r |= s[t] & 0x3f;
}
}
/* Success if no NULL was encountered */
return t == *bytes;
}
}
/* END OF FILE */
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