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/* Time-stamp: <2005-10-25 17:40:48 poser>
*
* Copyright (C) 2004 William J. Poser (billposer@alum.mit.edu)
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
* or go to the web page: http://www.gnu.org/licenses/gpl.txt.
*
* Given a bad UTF-8 sequence, explain why it is bad.
*
* Author: Bill Poser (wjposer@unagi.cis.upenn.edu)
*
*/
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "unicode.h"
#define FALSE 0
#define TRUE 1
/*
* Index into the table below with the first byte of a UTF-8 sequence to
* get the number of bytes that should follow.
*/
static const char TrailingBytesForUTF8[256] = {
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, 3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5
};
/*
* Magic values subtracted from a buffer value during UTF8 conversion.
* This table contains as many values as there might be trailing bytes
* in a UTF-8 sequence.
*/
static const UTF32 OffsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL,
0x03C82080UL, 0xFA082080UL, 0x82082080UL };
void
ExplicateBadUTF8(FILE *fp, unsigned char *c){
int BytesNeeded;
int i;
unsigned char *cptr;
extern char * binfmtc(unsigned char);
cptr = c;
if( (c[0] & 0xC0) == 0x80){
fprintf(fp,"The first byte, value 0x%02X, with bit pattern %s,\nis not a valid first byte of a UTF-8 sequence because its high bits are 10.\nA valid first byte must be of the form 0nnnnnnn or 11nnnnnn.\n",c[0],binfmtc(c[0]));
return;
}
BytesNeeded = (int) TrailingBytesForUTF8[c[0]];
for (i = 1; i <= BytesNeeded; i++){
if (( c[i] & 0xC0) != 0x80){
fprintf(fp,"The sequence is not a valid UTF-8 character because\nthe first byte, value 0x%02X, bit pattern %s,\nrequires %d continuation bytes, but of the immediately\nfollowing bytes, byte %d, value 0x%02X, bit pattern\n%s is not a valid continuation byte, since\nits high bits are not 10.\n",c[0],binfmtc(c[0]),BytesNeeded,i,c[i],binfmtc(c[i]));
return;
}
}
}
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