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/*
* Compression Utils
* (C) 2014,2016 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/internal/compress_utils.h>
#include <botan/exceptn.h>
namespace Botan {
void* Compression_Alloc_Info::do_malloc(size_t n, size_t size)
{
const size_t total_size = n * size;
BOTAN_ASSERT_EQUAL(total_size / size, n, "Overflow check");
// TODO maximum length check here?
void* ptr = std::malloc(total_size);
/*
* Return null rather than throwing here as we are being called by a
* C library and it may not be possible for an exception to unwind
* the call stack from here. The compression library is expecting a
* function written in C and a null return on error, which it will
* send upwards to the compression wrappers.
*/
if(ptr)
{
std::memset(ptr, 0, total_size);
m_current_allocs[ptr] = total_size;
}
return ptr;
}
void Compression_Alloc_Info::do_free(void* ptr)
{
if(ptr)
{
auto i = m_current_allocs.find(ptr);
if(i == m_current_allocs.end())
throw Exception("Compression_Alloc_Info::free got pointer not allocated by us");
secure_scrub_memory(ptr, i->second);
std::free(ptr);
m_current_allocs.erase(i);
}
}
void Stream_Compression::clear()
{
m_stream.reset();
}
void Stream_Compression::start(size_t level)
{
m_stream.reset(make_stream(level));
}
void Stream_Compression::process(secure_vector<uint8_t>& buf, size_t offset, uint32_t flags)
{
BOTAN_ASSERT(m_stream, "Initialized");
BOTAN_ASSERT(buf.size() >= offset, "Offset is sane");
if(m_buffer.size() < buf.size() + offset)
m_buffer.resize(buf.size() + offset);
// If the output buffer has zero length, .data() might return nullptr. This would
// make some compression algorithms (notably those provided by zlib) fail.
// Any small positive value works fine, but we choose 32 as it is the smallest power
// of two that is large enough to hold all the headers and trailers of the common
// formats, preventing further resizings to make room for output data.
if(m_buffer.size() == 0)
m_buffer.resize(32);
m_stream->next_in(buf.data() + offset, buf.size() - offset);
m_stream->next_out(m_buffer.data() + offset, m_buffer.size() - offset);
while(true)
{
m_stream->run(flags);
if(m_stream->avail_out() == 0)
{
const size_t added = 8 + m_buffer.size();
m_buffer.resize(m_buffer.size() + added);
m_stream->next_out(m_buffer.data() + m_buffer.size() - added, added);
}
else if(m_stream->avail_in() == 0)
{
m_buffer.resize(m_buffer.size() - m_stream->avail_out());
break;
}
}
copy_mem(m_buffer.data(), buf.data(), offset);
buf.swap(m_buffer);
}
void Stream_Compression::update(secure_vector<uint8_t>& buf, size_t offset, bool flush)
{
BOTAN_ASSERT(m_stream, "Initialized");
process(buf, offset, flush ? m_stream->flush_flag() : m_stream->run_flag());
}
void Stream_Compression::finish(secure_vector<uint8_t>& buf, size_t offset)
{
BOTAN_ASSERT(m_stream, "Initialized");
process(buf, offset, m_stream->finish_flag());
clear();
}
void Stream_Decompression::clear()
{
m_stream.reset();
}
void Stream_Decompression::start()
{
m_stream.reset(make_stream());
}
void Stream_Decompression::process(secure_vector<uint8_t>& buf, size_t offset, uint32_t flags)
{
BOTAN_ASSERT(m_stream, "Initialized");
BOTAN_ASSERT(buf.size() >= offset, "Offset is sane");
if(m_buffer.size() < buf.size() + offset)
m_buffer.resize(buf.size() + offset);
m_stream->next_in(buf.data() + offset, buf.size() - offset);
m_stream->next_out(m_buffer.data() + offset, m_buffer.size() - offset);
while(true)
{
const bool stream_end = m_stream->run(flags);
if(stream_end)
{
if(m_stream->avail_in() == 0) // all data consumed?
{
m_buffer.resize(m_buffer.size() - m_stream->avail_out());
clear();
break;
}
// More data follows: try to process as a following stream
const size_t read = (buf.size() - offset) - m_stream->avail_in();
start();
m_stream->next_in(buf.data() + offset + read, buf.size() - offset - read);
}
if(m_stream->avail_out() == 0)
{
const size_t added = 8 + m_buffer.size();
m_buffer.resize(m_buffer.size() + added);
m_stream->next_out(m_buffer.data() + m_buffer.size() - added, added);
}
else if(m_stream->avail_in() == 0)
{
m_buffer.resize(m_buffer.size() - m_stream->avail_out());
break;
}
}
copy_mem(m_buffer.data(), buf.data(), offset);
buf.swap(m_buffer);
}
void Stream_Decompression::update(secure_vector<uint8_t>& buf, size_t offset)
{
process(buf, offset, m_stream->run_flag());
}
void Stream_Decompression::finish(secure_vector<uint8_t>& buf, size_t offset)
{
if(buf.size() != offset || m_stream.get())
process(buf, offset, m_stream->finish_flag());
if(m_stream.get())
throw Exception(name() + " finished but not at stream end");
}
}
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