icinga2/base/fifo.cpp

116 lines
2.0 KiB
C++

#include "i2-base.h"
using namespace icinga;
FIFO::FIFO(void)
{
m_Buffer = NULL;
m_BufferSize = 0;
m_Offset = 0;
}
FIFO::~FIFO(void)
{
Memory::Free(m_Buffer);
}
char *FIFO::ResizeBuffer(char *buffer, size_t oldSize, size_t newSize)
{
if (oldSize != 0)
oldSize += FIFO::BlockSize - (oldSize % FIFO::BlockSize);
size_t ceilNewSize = newSize + FIFO::BlockSize - (newSize % FIFO::BlockSize);
size_t oldBlocks = oldSize / FIFO::BlockSize;
size_t newBlocks = ceilNewSize / FIFO::BlockSize;
if (oldBlocks == newBlocks)
return buffer;
if (newSize == 0) {
Memory::Free(buffer);
return NULL;
} else {
return (char *)Memory::Reallocate(buffer, newBlocks * FIFO::BlockSize);
}
}
void FIFO::Optimize(void)
{
char *newBuffer;
if (m_Offset == 0 || m_Offset < m_BufferSize / 5)
return;
if (m_BufferSize - m_Offset == 0) {
free(m_Buffer);
m_Buffer = 0;
m_BufferSize = 0;
m_Offset = 0;
return;
}
newBuffer = (char *)ResizeBuffer(NULL, 0, m_BufferSize - m_Offset);
if (newBuffer == NULL)
return;
memcpy(newBuffer, m_Buffer + m_Offset, m_BufferSize - m_Offset);
free(m_Buffer);
m_Buffer = newBuffer;
m_BufferSize -= m_Offset;
m_Offset = 0;
}
size_t FIFO::GetSize(void) const
{
return m_BufferSize - m_Offset;
}
const void *FIFO::GetReadBuffer(void) const
{
return m_Buffer + m_Offset;
}
size_t FIFO::Read(void *buffer, size_t count)
{
count = (count <= m_BufferSize) ? count : m_BufferSize;
if (buffer != NULL)
memcpy(buffer, m_Buffer + m_Offset, count);
m_Offset += count;
Optimize();
return count;
}
void *FIFO::GetWriteBuffer(size_t count)
{
char *new_buffer;
new_buffer = ResizeBuffer(m_Buffer, m_BufferSize, m_BufferSize + count);
if (new_buffer == NULL)
throw exception(/*"Out of memory."*/);
m_Buffer = new_buffer;
return new_buffer + m_Offset + m_BufferSize;
}
size_t FIFO::Write(const void *buffer, size_t count)
{
if (buffer != NULL) {
void *target_buffer = GetWriteBuffer(count);
memcpy(target_buffer, buffer, count);
}
m_BufferSize += count;
return count;
}