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/*
kmime_charfreq.cpp
KMime, the KDE internet mail/usenet news message library.
Copyright (c) 2001-2002 Marc Mutz <[email protected]>
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; version 2 of the License.
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, US
*/
#include "kmime_charfreq.h"
namespace KMime {
CharFreq::CharFreq( const TQByteArray & buf )
: NUL(0),
CTL(0),
CR(0), LF(0),
CRLF(0),
printable(0),
eightBit(0),
total(0),
lineMin(0xffffffff),
lineMax(0),
mTrailingWS(false),
mLeadingFrom(false)
{
if ( !buf.isEmpty() )
count( buf.data(), buf.size() );
}
CharFreq::CharFreq( const char * buf, size_t len )
: NUL(0),
CTL(0),
CR(0), LF(0),
CRLF(0),
printable(0),
eightBit(0),
total(0),
lineMin(0xffffffff),
lineMax(0),
mTrailingWS(false),
mLeadingFrom(false)
{
if ( buf && len > 0 )
count( buf, len );
}
static inline bool isWS( char ch ) { return ( ch == '\t' || ch == ' ' ); }
void CharFreq::count( const char * it, size_t len ) {
const char * end = it + len;
uint currentLineLength = 0;
// initialize the prevChar with LF so that From_ detection works w/o
// special-casing:
char prevChar = '\n';
char prevPrevChar = 0;
for ( ; it != end ; ++it ) {
++currentLineLength;
switch ( *it ) {
case '\0': ++NUL; break;
case '\r': ++CR; break;
case '\n': ++LF;
if ( prevChar == '\r' ) { --currentLineLength; ++CRLF; }
if ( currentLineLength >= lineMax ) lineMax = currentLineLength-1;
if ( currentLineLength <= lineMin ) lineMin = currentLineLength-1;
if ( !mTrailingWS )
if ( isWS( prevChar ) || ( prevChar == '\r' && isWS( prevPrevChar ) ) )
mTrailingWS = true;
currentLineLength = 0;
break;
case 'F': // check for lines starting with From_ if not found already:
if ( !mLeadingFrom )
if ( prevChar == '\n' && end - it >= 5 && !tqstrncmp( "From ", it, 5 ) )
mLeadingFrom = true;
++printable;
break;
default:
{
uchar c = *it;
if ( (c == '\t') || ((c >= ' ') && (c <= '~')) )
++printable;
else if ( (c == 127) || (c < ' ') )
++CTL;
else
++eightBit;
}
}
prevPrevChar = prevChar;
prevChar = *it;
}
// consider the length of the last line
if ( currentLineLength >= lineMax ) lineMax = currentLineLength;
if ( currentLineLength <= lineMin ) lineMin = currentLineLength;
// check whether the last character is tab or space
if ( isWS( prevChar ) )
mTrailingWS = true;
total = len;
}
bool CharFreq::isEightBitData() const {
return type() == EightBitData;
}
bool CharFreq::isEightBitText() const {
return type() == EightBitText;
}
bool CharFreq::isSevenBitData() const {
return type() == SevenBitData;
}
bool CharFreq::isSevenBitText() const {
return type() == SevenBitText;
}
bool CharFreq::hasTrailingWhitespace() const {
return mTrailingWS;
}
bool CharFreq::hasLeadingFrom() const {
return mLeadingFrom;
}
CharFreq::Type CharFreq::type() const {
#if 0
tqDebug( "Total: %d; NUL: %d; CTL: %d;\n"
"CR: %d; LF: %d; CRLF: %d;\n"
"lineMin: %d; lineMax: %d;\n"
"printable: %d; eightBit: %d;\n"
"trailing whitespace: %s;\n"
"leading 'From ': %s;\n",
total, NUL, CTL, CR, LF, CRLF, lineMin, lineMax,
printable, eightBit,
mTrailingWS ? "yes" : "no" , mLeadingFrom ? "yes" : "no" );
#endif
if ( NUL ) // must be binary
return Binary;
// doesn't contain NUL's:
if ( eightBit ) {
if ( lineMax > 988 ) return EightBitData; // not allowed in 8bit
if ( CR != CRLF || controlCodesRatio() > 0.2 ) return EightBitData;
return EightBitText;
}
// doesn't contain NUL's, nor 8bit chars:
if ( lineMax > 988 ) return SevenBitData;
if ( CR != CRLF || controlCodesRatio() > 0.2 ) return SevenBitData;
// no NUL, no 8bit chars, no excessive CTLs and no lines > 998 chars:
return SevenBitText;
}
float CharFreq::printableRatio() const {
if ( total ) return float(printable) / float(total);
else return 0;
}
float CharFreq::controlCodesRatio() const {
if ( total ) return float(CTL) / float(total);
else return 0;
}
} // namespace KMime
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