vectorscan/src/util/dump_charclass.cpp
2024-04-29 15:09:55 +03:00

261 lines
7.3 KiB
C++

/*
* Copyright (c) 2015-2018, Intel Corporation
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Intel Corporation nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/** \file
* \brief Dump code for character classes (expressed as CharReach objects).
*/
#include "config.h"
// Everything in this file is dump code
#if defined(DUMP_SUPPORT)
#include "charreach.h"
#include "dump_charclass.h"
#include <cctype>
#include <iomanip>
#include <ostream>
#include <sstream>
using std::string;
using std::ostream;
namespace ue2 {
static
void describeChar(ostream &os, char c, enum cc_output_t out_type) {
// these characters must always be escaped
static const string escaped("^-[].");
static const string dot_single_escaped("\"\'");
const string backslash((out_type == CC_OUT_DOT ? 2 : 1), '\\');
if (isgraph(c) && c != '\\') {
if (escaped.find(c) != string::npos) {
os << backslash << c;
} else if (out_type == CC_OUT_DOT
&& dot_single_escaped.find(c) != string::npos) {
os << '\\' << c;
} else {
os << c;
}
} else if (c == 0x09) {
os << backslash << 't';
} else if (c == 0x0a) {
os << backslash << 'n';
} else if (c == 0x0d) {
os << backslash << 'r';
} else {
auto fmt(os.flags());
os << backslash << 'x' << std::hex << std::setw(2)
<< std::setfill('0') << (unsigned)(c & 0xff);
os.flags(fmt);
}
}
static
void describeRange(ostream &os, unsigned char c1, unsigned char c2, enum cc_output_t out_type) {
assert(c1 <= c2);
if (c1 == c2) {
describeChar(os, (char)c1, out_type);
}
else if (c2 - c1 < 4) {
// render as individual chars
do {
describeChar(os, (char)c1, out_type);
} while (c1++ != c2);
} else {
// range
describeChar(os, (char)c1, out_type);
os << '-';
describeChar(os, (char)c2, out_type);
}
}
static
bool extractMnemonic(ostream &os, CharReach &cr, enum cc_output_t out_type) {
const string backslash((out_type == CC_OUT_DOT ? 2 : 1), '\\');
// \w (word characters: any letter, digit, or underscore)
static const CharReach words(string("_0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWYXZ"));
if (words == (cr & words)) {
cr &= ~words;
os << backslash << 'w';
return true;
}
// \d (digits)
static const CharReach digits(string("0123456789"));
if (digits == (cr & digits)) {
cr &= ~digits;
os << backslash << 'd';
return true;
}
// \s (whitespace)
static const CharReach whitespace(string("\x09\x0a\x0b\x0c\x0d\x20", 6));
if (whitespace == (cr & whitespace)) {
cr &= ~whitespace;
os << backslash << 's';
return true;
}
return false;
}
static
bool isContiguous(const CharReach &cr, size_t &first, size_t &last) {
first = cr.find_first();
size_t c = first;
while (c != CharReach::npos) {
last = c;
c = cr.find_next(c);
if (c == CharReach::npos) {
break;
}
if (c != last + 1) {
return false;
}
}
return true;
}
static
size_t describeClassInt(ostream &os, const CharReach &incr, size_t maxLength,
enum cc_output_t out_type) {
// Approx size of output
size_t i = 0;
// one we can break
CharReach cr(incr);
// If we can be rendered as a single range, do it
size_t first = 0, last = 0;
if (isContiguous(cr, first, last)) {
describeRange(os, first, last, out_type);
i = 2;
return i;
}
// Extract any mnemonics
while (extractMnemonic(os, cr, out_type)) {
if (++i == maxLength) {
os << "...]";
return maxLength;
}
}
if (cr.none()) {
// all mnemonics, all the time
return i;
}
// Render charclass as a series of ranges
size_t c_start = cr.find_first();
size_t c = c_start;
while (c != CharReach::npos) {
size_t c_last = c;
c = cr.find_next(c);
if (c != c_last + 1 || c_last == 0xff) {
describeRange(os, c_start, c_last, out_type);
c_start = c;
if (++i == maxLength && c != CharReach::npos) {
os << "...]";
return maxLength;
}
}
}
return i;
}
////
//// Functions exported outside this unit.
////
// C++ iostreams interface
void describeClass(ostream &os, const CharReach &incr, size_t maxLength,
enum cc_output_t out_type) {
if (incr.all()) {
os << "<any>";
return;
}
if (incr.none()) {
os << "<empty>";
return;
}
if (incr.count() == 1) {
describeChar(os, (char)incr.find_first(), out_type);
return;
}
if ((~incr).count() == 1) {
os << "[^";
describeChar(os, (char)(~incr).find_first(), out_type);
os << ']';
return;
}
// build up a normal string and a negated one, and see which is shorter
std::ostringstream out;
int out_count = describeClassInt(out, incr, maxLength, out_type);
std::ostringstream neg;
UNUSED int neg_count = describeClassInt(neg, ~incr, maxLength, out_type);
if (out.tellp() <= neg.tellp()) {
if (out_count > 1) {
os << '[' << out.str() << ']';
} else {
os << out.str();
}
} else {
// TODO: negated single mnemonics
os << "[^" << neg.str() << ']';
}
}
// Version that returns a string, for convenience.
string describeClass(const CharReach &cr, size_t maxLength,
enum cc_output_t out_type) {
std::ostringstream oss;
describeClass(oss, cr, maxLength, out_type);
return oss.str();
}
// C stdio wrapper
void describeClass(FILE *f, const CharReach &cr, size_t maxLength,
enum cc_output_t out_type) {
fprintf(f, "%s", describeClass(cr, maxLength, out_type).c_str());
}
} // namespace ue2
#endif // DUMP_SUPPORT