128 lines
2.8 KiB
C++
128 lines
2.8 KiB
C++
#include "CStreamBuffer.h"
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#include <assert.h>
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//
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// CStreamBuffer
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//
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const UInt32 CStreamBuffer::kChunkSize = 4096;
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CStreamBuffer::CStreamBuffer() : m_size(0)
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{
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// do nothing
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}
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CStreamBuffer::~CStreamBuffer()
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{
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// do nothing
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}
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const void* CStreamBuffer::peek(UInt32 n)
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{
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assert(n <= m_size);
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// reserve space in first chunk
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ChunkList::iterator head = m_chunks.begin();
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head->reserve(n);
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// consolidate chunks into the first chunk until it has n bytes
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ChunkList::iterator scan = head;
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++scan;
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while (head->size() < n && scan != m_chunks.end()) {
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head->insert(head->end(), scan->begin(), scan->end());
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scan = m_chunks.erase(scan);
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}
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return reinterpret_cast<const void*>(head->begin());
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}
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void CStreamBuffer::pop(UInt32 n)
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{
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// discard all chunks if n is greater than or equal to m_size
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if (n >= m_size) {
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m_size = 0;
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m_chunks.clear();
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return;
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}
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// update size
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m_size -= n;
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// discard chunks until more than n bytes would've been discarded
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ChunkList::iterator scan = m_chunks.begin();
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assert(scan != m_chunks.end());
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while (scan->size() <= n) {
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n -= scan->size();
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scan = m_chunks.erase(scan);
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assert(scan != m_chunks.end());
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}
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assert(n > 0);
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// remove left over bytes from the head chunk
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scan->erase(scan->begin(), scan->begin() + n);
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}
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#include "CLog.h"
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void CStreamBuffer::write(
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const void* vdata, UInt32 n)
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{
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assert(vdata != NULL);
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// ignore if no data, otherwise update size
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if (n == 0) {
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return;
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}
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log((CLOG_DEBUG "### %p buffering %d bytes onto %d bytes", this, n, m_size));
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m_size += n;
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// cast data to bytes
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const UInt8* data = reinterpret_cast<const UInt8*>(vdata);
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if (n > 1000)
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log((CLOG_DEBUG "### %p src: %u %u %u %u %u %u %u %u", this,
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data[0], data[1], data[2], data[3], data[4], data[5], data[6], data[7]));
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// point to last chunk if it has space, otherwise append an empty chunk
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ChunkList::iterator scan = m_chunks.end();
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if (scan != m_chunks.begin()) {
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log((CLOG_DEBUG "### %p at least one chunk", this));
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--scan;
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if (scan->size() >= kChunkSize)
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{
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log((CLOG_DEBUG "### %p last chunk full", this));
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++scan;
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}
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}
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if (scan == m_chunks.end()) {
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log((CLOG_DEBUG "### %p append chunk", this));
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scan = m_chunks.insert(scan, Chunk());
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}
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// append data in chunks
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while (n > 0) {
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// choose number of bytes for next chunk
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assert(scan->size() <= kChunkSize);
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UInt32 count = kChunkSize - scan->size();
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if (count > n)
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count = n;
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// transfer data
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log((CLOG_DEBUG "### %p append %d bytes onto last chunk", this, count));
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scan->insert(scan->end(), data, data + count);
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n -= count;
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data += count;
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// append another empty chunk if we're not done yet
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if (n > 0) {
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++scan;
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scan = m_chunks.insert(scan, Chunk());
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log((CLOG_DEBUG "### %p append chunk2", this));
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}
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}
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}
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UInt32 CStreamBuffer::getSize() const
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{
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return m_size;
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}
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