aria2/src/bencode2.cc

331 lines
8.8 KiB
C++

/* <!-- copyright */
/*
* aria2 - The high speed download utility
*
* Copyright (C) 2010 Tatsuhiro Tsujikawa
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
/* copyright --> */
#include "bencode2.h"
#include <sstream>
#include "fmt.h"
#include "DlAbortEx.h"
#include "error_code.h"
#include "BufferedFile.h"
#include "util.h"
namespace aria2 {
namespace bencode2 {
namespace {
template<typename InputIterator>
std::pair<SharedHandle<ValueBase>, InputIterator>
decodeiter
(InputIterator first,
InputIterator last,
size_t depth);
} // namespace
namespace {
template<typename InputIterator>
std::pair<std::pair<InputIterator, InputIterator>, InputIterator>
decoderawstring(InputIterator first, InputIterator last)
{
InputIterator i = first;
int32_t len;
for(; i != last && *i != ':'; ++i);
if(i == last || i == first ||
!util::parseIntNoThrow(len, std::string(first, i)) ||
len < 0) {
throw DL_ABORT_EX2("Bencode decoding failed:"
" A positive integer expected but none found.",
error_code::BENCODE_PARSE_ERROR);
}
++i;
if(last-i < len) {
throw DL_ABORT_EX2
(fmt("Bencode decoding failed:"
" Expected %d bytes of data, but only %d read.",
len, static_cast<int>(last-i)),
error_code::BENCODE_PARSE_ERROR);
}
return std::make_pair(std::make_pair(i, i+len), i+len);
}
} // namespace
namespace {
template<typename InputIterator>
std::pair<SharedHandle<ValueBase>, InputIterator>
decodestring(InputIterator first, InputIterator last)
{
std::pair<std::pair<InputIterator, InputIterator>, InputIterator> r =
decoderawstring(first, last);
return std::make_pair(String::g(r.first.first, r.first.second), r.second);
}
} // namespace
namespace {
template<typename InputIterator>
std::pair<SharedHandle<ValueBase>, InputIterator>
decodeinteger(InputIterator first, InputIterator last)
{
InputIterator i = first;
for(; i != last && *i != 'e'; ++i);
Integer::ValueType iv;
if(i == last || !util::parseLLIntNoThrow(iv, std::string(first, i))) {
throw DL_ABORT_EX2("Bencode decoding failed:"
" Integer expected but none found",
error_code::BENCODE_PARSE_ERROR);
}
return std::make_pair(Integer::g(iv), ++i);
}
} // namespace
namespace {
template<typename InputIterator>
std::pair<SharedHandle<ValueBase>, InputIterator>
decodedict
(InputIterator first,
InputIterator last,
size_t depth)
{
SharedHandle<Dict> dict = Dict::g();
while(first != last) {
if(*first == 'e') {
return std::make_pair(dict, ++first);
} else {
std::pair<std::pair<InputIterator, InputIterator>, InputIterator> keyp =
decoderawstring(first, last);
std::pair<SharedHandle<ValueBase>, InputIterator> r =
decodeiter(keyp.second, last, depth);
dict->put(std::string(keyp.first.first, keyp.first.second), r.first);
first = r.second;
}
}
throw DL_ABORT_EX2("Bencode decoding failed:"
" Unexpected EOF in dict context. 'e' expected.",
error_code::BENCODE_PARSE_ERROR);
}
} // namespace
namespace {
template<typename InputIterator>
std::pair<SharedHandle<ValueBase>, InputIterator>
decodelist
(InputIterator first,
InputIterator last,
size_t depth)
{
SharedHandle<List> list = List::g();
while(first != last) {
if(*first == 'e') {
return std::make_pair(list, ++first);
} else {
std::pair<SharedHandle<ValueBase>, InputIterator> r =
decodeiter(first, last, depth);
list->append(r.first);
first = r.second;
}
}
throw DL_ABORT_EX2("Bencode decoding failed:"
" Unexpected EOF in list context. 'e' expected.",
error_code::BENCODE_PARSE_ERROR);
}
} // namespace
namespace {
void checkDepth(size_t depth)
{
if(depth >= MAX_STRUCTURE_DEPTH) {
throw DL_ABORT_EX2("Bencode decoding failed: Structure is too deep.",
error_code::BENCODE_PARSE_ERROR);
}
}
} // namespace
namespace {
template<typename InputIterator>
std::pair<SharedHandle<ValueBase>, InputIterator>
decodeiter
(InputIterator first,
InputIterator last,
size_t depth)
{
checkDepth(depth);
if(first == last) {
throw DL_ABORT_EX2("Bencode decoding failed:"
" Unexpected EOF in term context."
" 'd', 'l', 'i' or digit is expected.",
error_code::BENCODE_PARSE_ERROR);
}
if(*first == 'd') {
return decodedict(++first, last, depth+1);
} else if(*first == 'l') {
return decodelist(++first, last, depth+1);
} else if(*first == 'i') {
return decodeinteger(++first, last);
} else {
return decodestring(first, last);
}
}
} // namespace
namespace {
template<typename InputIterator>
SharedHandle<ValueBase> decodegen
(InputIterator first,
InputIterator last,
size_t& end)
{
if(first == last) {
return SharedHandle<ValueBase>();
}
std::pair<SharedHandle<ValueBase>, InputIterator> p =
decodeiter(first, last, 0);
end = p.second-first;
return p.first;
}
} // namespace
SharedHandle<ValueBase> decode
(std::string::const_iterator first,
std::string::const_iterator last)
{
size_t end;
return decodegen(first, last, end);
}
SharedHandle<ValueBase> decode
(std::string::const_iterator first,
std::string::const_iterator last,
size_t& end)
{
return decodegen(first, last, end);
}
SharedHandle<ValueBase> decode
(const unsigned char* first,
const unsigned char* last)
{
size_t end;
return decodegen(first, last, end);
}
SharedHandle<ValueBase> decode
(const unsigned char* first,
const unsigned char* last,
size_t& end)
{
return decodegen(first, last, end);
}
SharedHandle<ValueBase> decodeFromFile(const std::string& filename)
{
BufferedFile fp(filename, BufferedFile::READ);
if(fp) {
std::stringstream ss;
fp.transfer(ss);
fp.close();
const std::string s = ss.str();
size_t end;
return decodegen(s.begin(), s.end(), end);
} else {
throw DL_ABORT_EX2
(fmt("Bencode decoding failed: Cannot open file '%s'.",
filename.c_str()),
error_code::BENCODE_PARSE_ERROR);
}
}
std::string encode(const ValueBase* vlb)
{
class BencodeValueBaseVisitor:public ValueBaseVisitor {
private:
std::ostringstream out_;
public:
virtual void visit(const String& string)
{
const std::string& s = string.s();
out_ << s.size() << ":";
out_.write(s.data(), s.size());
}
virtual void visit(const Integer& integer)
{
out_ << "i" << integer.i() << "e";
}
virtual void visit(const Bool& v) {}
virtual void visit(const Null& v) {}
virtual void visit(const List& list)
{
out_ << "l";
for(List::ValueType::const_iterator i = list.begin(), eoi = list.end();
i != eoi; ++i){
(*i)->accept(*this);
}
out_ << "e";
}
virtual void visit(const Dict& dict)
{
out_ << "d";
for(Dict::ValueType::const_iterator i = dict.begin(), eoi = dict.end();
i != eoi; ++i){
const std::string& key = (*i).first;
out_ << key.size() << ":";
out_.write(key.data(), key.size());
(*i).second->accept(*this);
}
out_ << "e";
}
std::string getResult() const
{
return out_.str();
}
};
BencodeValueBaseVisitor visitor;
vlb->accept(visitor);
return visitor.getResult();
}
std::string encode(const SharedHandle<ValueBase>& vlb)
{
return encode(vlb.get());
}
} // namespace bencode2
} // namespace aria2