108 lines
2.1 KiB
C++
108 lines
2.1 KiB
C++
#include "CStreamBuffer.h"
|
|
#include <assert.h>
|
|
|
|
//
|
|
// CStreamBuffer
|
|
//
|
|
|
|
const UInt32 CStreamBuffer::kChunkSize = 4096;
|
|
|
|
CStreamBuffer::CStreamBuffer() : m_size(0)
|
|
{
|
|
// do nothing
|
|
}
|
|
|
|
CStreamBuffer::~CStreamBuffer()
|
|
{
|
|
// do nothing
|
|
}
|
|
|
|
const void* CStreamBuffer::peek(UInt32 n)
|
|
{
|
|
assert(n <= m_size);
|
|
|
|
// reserve space in first chunk
|
|
ChunkList::iterator head = m_chunks.begin();
|
|
head->reserve(n);
|
|
|
|
// consolidate chunks into the first chunk until it has n bytes
|
|
ChunkList::iterator scan = head;
|
|
++scan;
|
|
while (head->size() < n && scan != m_chunks.end()) {
|
|
head->insert(head->end(), scan->begin(), scan->end());
|
|
scan = m_chunks.erase(scan);
|
|
}
|
|
|
|
return reinterpret_cast<const void*>(head->begin());
|
|
}
|
|
|
|
void CStreamBuffer::pop(UInt32 n)
|
|
{
|
|
m_size -= n;
|
|
|
|
// discard chunks until more than n bytes would've been discarded
|
|
ChunkList::iterator scan = m_chunks.begin();
|
|
while (scan->size() <= n && scan != m_chunks.end()) {
|
|
n -= scan->size();
|
|
scan = m_chunks.erase(scan);
|
|
}
|
|
|
|
// if there's anything left over then remove it from the head chunk.
|
|
// if there's no head chunk then we're already empty.
|
|
if (scan == m_chunks.end()) {
|
|
m_size = 0;
|
|
}
|
|
else if (n > 0) {
|
|
scan->erase(scan->begin(), scan->begin() + n);
|
|
}
|
|
}
|
|
|
|
void CStreamBuffer::write(
|
|
const void* vdata, UInt32 n)
|
|
{
|
|
assert(vdata != NULL);
|
|
|
|
if (n == 0) {
|
|
return;
|
|
}
|
|
m_size += n;
|
|
|
|
// cast data to bytes
|
|
const UInt8* data = reinterpret_cast<const UInt8*>(vdata);
|
|
|
|
// point to last chunk if it has space, otherwise append an empty chunk
|
|
ChunkList::iterator scan = m_chunks.end();
|
|
if (scan != m_chunks.begin()) {
|
|
--scan;
|
|
if (scan->size() >= kChunkSize)
|
|
++scan;
|
|
}
|
|
if (scan == m_chunks.end()) {
|
|
scan = m_chunks.insert(scan);
|
|
}
|
|
|
|
// append data in chunks
|
|
while (n > 0) {
|
|
// choose number of bytes for next chunk
|
|
UInt32 count = kChunkSize - scan->size();
|
|
if (count > n)
|
|
count = n;
|
|
|
|
// transfer data
|
|
scan->insert(scan->end(), data, data + count);
|
|
n -= count;
|
|
data += count;
|
|
|
|
// append another empty chunk if we're not done yet
|
|
if (n > 0) {
|
|
scan = m_chunks.insert(scan);
|
|
}
|
|
}
|
|
}
|
|
|
|
UInt32 CStreamBuffer::getSize() const
|
|
{
|
|
return m_size;
|
|
}
|
|
|