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yap-6.3/packages/sgml/utf8.c

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/* $Id$
Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: jan@swi.psy.uva.nl
WWW: http://www.swi-prolog.org
Copyright (C): 1985-2002, University of Amsterdam
This library 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 2.1 of the License, or (at your option) any later version.
This library 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 library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <stdio.h>
#include "utf8.h"
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
UTF-8 Decoding, based on http://www.cl.cam.ac.uk/~mgk25/unicode.html
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
#define CONT(i) ((in[i]&0xc0) == 0x80)
#define VAL(i, s) ((in[i]&0x3f) << s)
char *
sgml__utf8_get_char(const char *in, int *chr)
{ /* 2-byte, 0x80-0x7ff */
if ( (in[0]&0xe0) == 0xc0 && CONT(1) )
{ *chr = ((in[0]&0x1f) << 6)|VAL(1,0);
return (char *)in+2;
}
/* 3-byte, 0x800-0xffff */
if ( (in[0]&0xf0) == 0xe0 && CONT(1) && CONT(2) )
{ *chr = ((in[0]&0xf) << 12)|VAL(1,6)|VAL(2,0);
return (char *)in+3;
}
/* 4-byte, 0x10000-0x1FFFFF */
if ( (in[0]&0xf8) == 0xf0 && CONT(1) && CONT(2) && CONT(3) )
{ *chr = ((in[0]&0x7) << 18)|VAL(1,12)|VAL(2,6)|VAL(3,0);
return (char *)in+4;
}
/* 5-byte, 0x200000-0x3FFFFFF */
if ( (in[0]&0xfc) == 0xf8 && CONT(1) && CONT(2) && CONT(3) && CONT(4) )
{ *chr = ((in[0]&0x3) << 24)|VAL(1,18)|VAL(2,12)|VAL(3,6)|VAL(4,0);
return (char *)in+5;
}
/* 6-byte, 0x400000-0x7FFFFFF */
if ( (in[0]&0xfe) == 0xfc && CONT(1) && CONT(2) && CONT(3) && CONT(4) && CONT(5) )
{ *chr = ((in[0]&0x1) << 30)|VAL(1,24)|VAL(2,18)|VAL(3,12)|VAL(4,6)|VAL(5,0);
return (char *)in+4;
}
*chr = *in;
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return (char *)in+1;
}
char *
sgml_utf8_put_char(char *out, int chr)
{ if ( chr < 0x80 )
{ *out++ = chr;
} else if ( chr < 0x800 )
{ *out++ = 0xc0|((chr>>6)&0x1f);
*out++ = 0x80|(chr&0x3f);
} else if ( chr < 0x10000 )
{ *out++ = 0xe0|((chr>>12)&0x0f);
*out++ = 0x80|((chr>>6)&0x3f);
*out++ = 0x80|(chr&0x3f);
} else if ( chr < 0x200000 )
{ *out++ = 0xf0|((chr>>18)&0x07);
*out++ = 0x80|((chr>>12)&0x3f);
*out++ = 0x80|((chr>>6)&0x3f);
*out++ = 0x80|(chr&0x3f);
} else if ( chr < 0x4000000 )
{ *out++ = 0xf8|((chr>>24)&0x03);
*out++ = 0x80|((chr>>18)&0x3f);
*out++ = 0x80|((chr>>12)&0x3f);
*out++ = 0x80|((chr>>6)&0x3f);
*out++ = 0x80|(chr&0x3f);
} else if ( (unsigned)chr < 0x80000000 )
{ *out++ = 0xfc|((chr>>30)&0x01);
*out++ = 0x80|((chr>>24)&0x3f);
*out++ = 0x80|((chr>>18)&0x3f);
*out++ = 0x80|((chr>>12)&0x3f);
*out++ = 0x80|((chr>>6)&0x3f);
*out++ = 0x80|(chr&0x3f);
}
return out;
}
size_t
sgml_utf8_strlen(const char *s, size_t len)
{ const char *e = &s[len];
unsigned int l = 0;
while(s<e)
{ int chr;
s = utf8_get_char(s, &chr);
l++;
}
return l;
}