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/*
* SecureQueue
* (C) 1999-2007 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#include <botan/secqueue.h>
#include <algorithm>
namespace Botan {
/**
* A node in a SecureQueue
*/
class SecureQueueNode
{
public:
SecureQueueNode() : buffer(DEFAULT_BUFFERSIZE)
{ next = 0; start = end = 0; }
~SecureQueueNode() { next = 0; start = end = 0; }
u32bit write(const byte input[], u32bit length)
{
u32bit copied = std::min<u32bit>(length, buffer.size() - end);
copy_mem(&buffer[end], input, copied);
end += copied;
return copied;
}
u32bit read(byte output[], u32bit length)
{
u32bit copied = std::min(length, end - start);
copy_mem(output, &buffer[start], copied);
start += copied;
return copied;
}
u32bit peek(byte output[], u32bit length, u32bit offset = 0)
{
const u32bit left = end - start;
if(offset >= left) return 0;
u32bit copied = std::min(length, left - offset);
copy_mem(output, &buffer[start + offset], copied);
return copied;
}
u32bit size() const { return (end - start); }
private:
friend class SecureQueue;
SecureQueueNode* next;
SecureVector<byte> buffer;
u32bit start, end;
};
/*
* Create a SecureQueue
*/
SecureQueue::SecureQueue()
{
set_next(0, 0);
head = tail = new SecureQueueNode;
}
/*
* Copy a SecureQueue
*/
SecureQueue::SecureQueue(const SecureQueue& input) :
Fanout_Filter(), DataSource()
{
set_next(0, 0);
head = tail = new SecureQueueNode;
SecureQueueNode* temp = input.head;
while(temp)
{
write(&temp->buffer[temp->start], temp->end - temp->start);
temp = temp->next;
}
}
/*
* Destroy this SecureQueue
*/
void SecureQueue::destroy()
{
SecureQueueNode* temp = head;
while(temp)
{
SecureQueueNode* holder = temp->next;
delete temp;
temp = holder;
}
head = tail = 0;
}
/*
* Copy a SecureQueue
*/
SecureQueue& SecureQueue::operator=(const SecureQueue& input)
{
destroy();
head = tail = new SecureQueueNode;
SecureQueueNode* temp = input.head;
while(temp)
{
write(&temp->buffer[temp->start], temp->end - temp->start);
temp = temp->next;
}
return (*this);
}
/*
* Add some bytes to the queue
*/
void SecureQueue::write(const byte input[], u32bit length)
{
if(!head)
head = tail = new SecureQueueNode;
while(length)
{
const u32bit n = tail->write(input, length);
input += n;
length -= n;
if(length)
{
tail->next = new SecureQueueNode;
tail = tail->next;
}
}
}
/*
* Read some bytes from the queue
*/
u32bit SecureQueue::read(byte output[], u32bit length)
{
u32bit got = 0;
while(length && head)
{
const u32bit n = head->read(output, length);
output += n;
got += n;
length -= n;
if(head->size() == 0)
{
SecureQueueNode* holder = head->next;
delete head;
head = holder;
}
}
return got;
}
/*
* Read data, but do not remove it from queue
*/
u32bit SecureQueue::peek(byte output[], u32bit length, u32bit offset) const
{
SecureQueueNode* current = head;
while(offset && current)
{
if(offset >= current->size())
{
offset -= current->size();
current = current->next;
}
else
break;
}
u32bit got = 0;
while(length && current)
{
const u32bit n = current->peek(output, length, offset);
offset = 0;
output += n;
got += n;
length -= n;
current = current->next;
}
return got;
}
/*
* Return how many bytes the queue holds
*/
u32bit SecureQueue::size() const
{
SecureQueueNode* current = head;
u32bit count = 0;
while(current)
{
count += current->size();
current = current->next;
}
return count;
}
/*
* Test if the queue has any data in it
*/
bool SecureQueue::end_of_data() const
{
return (size() == 0);
}
}
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