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/*
File: utfsize.c
Copyright (C) 2021 Christophe GRENIER <grenier@cgsecurity.org>
This software 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 the Free Software Foundation, Inc., 51
Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_txt) || defined(SINGLE_FORMAT_win)
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <stdio.h>
#include "log.h"
#include "utfsize.h"
int UTFsize(const unsigned char *buffer, const unsigned int buf_len)
{
const unsigned char *p=buffer; /* pointers to actual position in source buffer */
unsigned int i=0;
/*@
@ loop invariant 0 <= i < buf_len + 3;
@ loop invariant p == buffer + i;
@ loop assigns i, p;
@ loop variant buf_len - 1 - i;
@*/
while(i<buf_len)
{
/*@ assert i < buf_len; */
/*@ assert p == buffer + i; */
const unsigned char c=*p;
if(c=='\0')
return i;
/* Reject some invalid UTF-8 sequences */
if(c==0xc0 || c==0xc1 || c==0xf7 || c>=0xfd)
return i;
/*@ assert i + 1 >= buf_len || \valid_read(p+1); */
/*@ assert i + 2 >= buf_len || \valid_read(p+2); */
if((c & 0xf0)==0xe0 &&
(i+1 >= buf_len || (*(p+1) & 0xc0)==0x80) &&
(i+2 >= buf_len || (*(p+2) & 0xc0)==0x80))
{ /* UTF8 l=3 */
#ifdef DEBUG_TXT
log_info("UTFsize i=%u l=3\n", i);
#endif
p+=3;
i+=3;
}
else if((c & 0xe0)==0xc0 &&
(i+1 >= buf_len || (*(p+1) & 0xc0)==0x80))
{ /* UTF8 l=2 */
#ifdef DEBUG_TXT
log_info("UTFsize i=%u l=2\n", i);
#endif
p+=2;
i+=2;
}
else
{ /* Ascii UCS */
#ifdef DEBUG_TXT
log_info("UTFsize i=%u l=1 ? *p=%c\n", i, c);
#endif
switch(c)
{
case 0x00:
case 0x01:
case 0x02:
case 0x03:
case 0x04:
case 0x05:
case 0x06:
case 0x07:
case 0x0b:
case 0x0c:
case 0x10:
case 0x11:
case 0x12:
case 0x13:
case 0x14:
case 0x15:
case 0x16:
case 0x17:
case 0x18:
case 0x19:
case 0x1a:
case 0x1b:
case 0x1c:
case 0x1d:
case 0x1e:
case 0x1f:
case 0x7f:
return i;
}
p++;
i++;
}
}
return (i<buf_len?i:buf_len);
}
#endif
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