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/*
* Buffering Filter
* (C) 1999-2007 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#include <botan/buf_filt.h>
#include <botan/exceptn.h>
#include <algorithm>
namespace Botan {
/*
* Buffering_Filter Constructor
*/
Buffering_Filter::Buffering_Filter(u32bit b, u32bit i) : INITIAL_BLOCK_SIZE(i),
BLOCK_SIZE(b)
{
initial_block_pos = block_pos = 0;
initial.create(INITIAL_BLOCK_SIZE);
block.create(BLOCK_SIZE);
}
/*
* Reset the Buffering Filter
*/
void Buffering_Filter::end_msg()
{
if(initial_block_pos != INITIAL_BLOCK_SIZE)
throw Exception("Buffering_Filter: Not enough data for first block");
final_block(block, block_pos);
initial_block_pos = block_pos = 0;
initial.clear();
block.clear();
}
/*
* Buffer input into blocks
*/
void Buffering_Filter::write(const byte input[], u32bit length)
{
if(initial_block_pos != INITIAL_BLOCK_SIZE)
{
u32bit copied = std::min(INITIAL_BLOCK_SIZE - initial_block_pos, length);
initial.copy(initial_block_pos, input, copied);
input += copied;
length -= copied;
initial_block_pos += copied;
if(initial_block_pos == INITIAL_BLOCK_SIZE)
initial_block(initial);
}
block.copy(block_pos, input, length);
if(block_pos + length >= BLOCK_SIZE)
{
main_block(block);
input += (BLOCK_SIZE - block_pos);
length -= (BLOCK_SIZE - block_pos);
while(length >= BLOCK_SIZE)
{
main_block(input);
input += BLOCK_SIZE;
length -= BLOCK_SIZE;
}
block.copy(input, length);
block_pos = 0;
}
block_pos += length;
}
}
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