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/*
* libjingle
* Copyright 2004--2005, Google Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
#ifndef _TALK_BASE_CRYPTSTRING_H_
#define _TALK_BASE_CRYPTSTRING_H_
#include <string.h>
#include <string>
#include "talk/base/linked_ptr.h"
#include "talk/base/scoped_ptr.h"
namespace talk_base {
class CryptStringImpl {
public:
virtual ~CryptStringImpl() {}
virtual size_t GetLength() const = 0;
virtual void CopyTo(char * dest, bool nullterminate) const = 0;
virtual std::string UrlEncode() const = 0;
virtual CryptStringImpl * Copy() const = 0;
};
class EmptyCryptStringImpl : public CryptStringImpl {
public:
virtual ~EmptyCryptStringImpl() {}
virtual size_t GetLength() const { return 0; }
virtual void CopyTo(char * dest, bool nullterminate) const {
if (nullterminate) {
*dest = '\0';
}
}
virtual std::string UrlEncode() const { return ""; }
virtual CryptStringImpl * Copy() const { return new EmptyCryptStringImpl(); }
};
class CryptString {
public:
CryptString() : impl_(new EmptyCryptStringImpl()) {}
size_t GetLength() const { return impl_->GetLength(); }
void CopyTo(char * dest, bool nullterminate) const { impl_->CopyTo(dest, nullterminate); }
CryptString(const CryptString & other) : impl_(other.impl_->Copy()) {}
explicit CryptString(const CryptStringImpl & impl) : impl_(impl.Copy()) {}
CryptString & operator=(const CryptString & other) {
if (this != &other) {
impl_.reset(other.impl_->Copy());
}
return *this;
}
void Clear() { impl_.reset(new EmptyCryptStringImpl()); }
std::string UrlEncode() const { return impl_->UrlEncode(); }
private:
scoped_ptr<const CryptStringImpl> impl_;
};
// Used for constructing strings where a password is involved and we
// need to ensure that we zero memory afterwards
class FormatCryptString {
public:
FormatCryptString() {
storage_ = new char[32];
capacity_ = 32;
length_ = 0;
storage_[0] = 0;
}
void Append(const std::string & text) {
Append(text.data(), text.length());
}
void Append(const char * data, size_t length) {
EnsureStorage(length_ + length + 1);
memcpy(storage_ + length_, data, length);
length_ += length;
storage_[length_] = '\0';
}
void Append(const CryptString * password) {
size_t len = password->GetLength();
EnsureStorage(length_ + len + 1);
password->CopyTo(storage_ + length_, true);
length_ += len;
}
size_t GetLength() {
return length_;
}
const char * GetData() {
return storage_;
}
// Ensures storage of at least n bytes
void EnsureStorage(size_t n) {
if (capacity_ >= n) {
return;
}
size_t old_capacity = capacity_;
char * old_storage = storage_;
for (;;) {
capacity_ *= 2;
if (capacity_ >= n)
break;
}
storage_ = new char[capacity_];
if (old_capacity) {
memcpy(storage_, old_storage, length_);
// zero memory in a way that an optimizer won't optimize it out
old_storage[0] = 0;
for (size_t i = 1; i < old_capacity; i++) {
old_storage[i] = old_storage[i - 1];
}
delete[] old_storage;
}
}
~FormatCryptString() {
if (capacity_) {
storage_[0] = 0;
for (size_t i = 1; i < capacity_; i++) {
storage_[i] = storage_[i - 1];
}
}
delete[] storage_;
}
private:
char * storage_;
size_t capacity_;
size_t length_;
};
class InsecureCryptStringImpl : public CryptStringImpl {
public:
std::string& password() { return password_; }
const std::string& password() const { return password_; }
virtual ~InsecureCryptStringImpl() {}
virtual size_t GetLength() const { return password_.size(); }
virtual void CopyTo(char * dest, bool nullterminate) const {
memcpy(dest, password_.data(), password_.size());
if (nullterminate) dest[password_.size()] = 0;
}
virtual std::string UrlEncode() const { return password_; }
virtual CryptStringImpl * Copy() const {
InsecureCryptStringImpl * copy = new InsecureCryptStringImpl;
copy->password() = password_;
return copy;
}
private:
std::string password_;
};
}
#endif // _TALK_BASE_CRYPTSTRING_H_
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