55 lines
2.2 KiB
C++
55 lines
2.2 KiB
C++
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/*
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* Created by Brett on 29/01/23.
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* Licensed under GNU General Public License V3.0
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* See LICENSE file for license detail
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*/
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#include <blt/fs/filesystem.h>
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#include <cstring>
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#include "blt/std/logging.h"
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blt::fs::fstream_block_reader::fstream_block_reader(std::fstream& stream, size_t bufferSize) :
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block_reader(bufferSize), m_stream(stream), m_buffer(new char[bufferSize]) {
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if (!m_stream.good() || m_stream.fail())
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BLT_WARN("Provided std::fstream is not good! Clearing!");
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m_stream.clear();
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}
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int blt::fs::fstream_block_reader::read(char* buffer, size_t bytes) {
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if (readIndex == 0)
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m_stream.read(m_buffer, (long) m_bufferSize);
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if (readIndex + bytes >= m_bufferSize) {
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// copy out all the data from the current buffer
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auto bytesLeft = m_bufferSize - readIndex;
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memcpy(buffer, m_buffer + readIndex, bytesLeft);
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readIndex = 0;
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// now to prevent large scale reading in small blocks, we should just read the entire thing into the buffer.
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m_stream.read(buffer + bytesLeft, (long) (bytes - bytesLeft));
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} else {
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// but in the case that the size of the data read is small, we should read in blocks and copy from that buffer
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// that should be quicker since file operations are slow.
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std::memcpy(buffer, m_buffer + readIndex, bytes);
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readIndex += bytes;
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}
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return 0;
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}
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int blt::fs::fstream_block_writer::write(char* buffer, size_t bytes) {
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if (writeIndex + bytes >= m_bufferSize) {
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// in an attempt to stay efficient we write out the old buffer and the new buffer
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// since there is a good chance there is more than a buffer's worth of data being written
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// otherwise the buffer is almost full and can be written anyway. (this might be bad for performance especially if the FS wants round numbers)
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m_stream.write(m_buffer, (long) writeIndex);
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writeIndex = 0;
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m_stream.write(buffer, (long) bytes);
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} else {
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std::memcpy(m_buffer + writeIndex, buffer, bytes);
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writeIndex += bytes;
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}
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return 0;
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}
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void blt::fs::fstream_block_writer::flush_internal() {
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m_stream.write(m_buffer, (long) writeIndex);
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writeIndex = 0;
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}
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