#include <snappy.h>
+#include <iostream>
+
#include <assert.h>
#include <string.h>
//read in the initial buffer if we're reading
if (m_stream.is_open() && mode == File::Read) {
+ m_stream.seekg(0, std::ios::end);
+ m_endPos = m_stream.tellg();
+ m_stream.seekg(0, std::ios::beg);
+
// read the snappy file identifier
unsigned char byte1, byte2;
m_stream >> byte1;
assert(m_cachePtr == m_cache);
}
-void SnappyFile::flushReadCache()
+void SnappyFile::flushReadCache(size_t skipLength)
{
//assert(m_cachePtr == m_cache + m_cacheSize);
+ m_currentOffset.chunk = m_stream.tellg();
size_t compressedLength;
compressedLength = readCompressedLength();
::snappy::GetUncompressedLength(m_compressedCache, compressedLength,
&m_cacheSize);
createCache(m_cacheSize);
- ::snappy::RawUncompress(m_compressedCache, compressedLength,
- m_cache);
+ if (skipLength < m_cacheSize) {
+ ::snappy::RawUncompress(m_compressedCache, compressedLength,
+ m_cache);
+ }
} else {
createCache(0);
}
}
return length;
}
+
+bool SnappyFile::supportsOffsets() const
+{
+ return true;
+}
+
+File::Offset SnappyFile::currentOffset()
+{
+ m_currentOffset.offsetInChunk = m_cachePtr - m_cache;
+ return m_currentOffset;
+}
+
+void SnappyFile::setCurrentOffset(const File::Offset &offset)
+{
+ // to remove eof bit
+ m_stream.clear();
+ // seek to the start of a chunk
+ m_stream.seekg(offset.chunk, std::ios::beg);
+ // load the chunk
+ flushReadCache();
+ assert(m_cacheSize >= offset.offsetInChunk);
+ // seek within our cache to the correct location within the chunk
+ m_cachePtr = m_cache + offset.offsetInChunk;
+
+}
+
+bool SnappyFile::rawSkip(size_t length)
+{
+ if (endOfData()) {
+ return false;
+ }
+
+ if (freeCacheSize() >= length) {
+ m_cachePtr += length;
+ } else {
+ size_t sizeToRead = length;
+ while (sizeToRead) {
+ size_t chunkSize = std::min(freeCacheSize(), sizeToRead);
+ m_cachePtr += chunkSize;
+ sizeToRead -= chunkSize;
+ if (sizeToRead > 0) {
+ flushReadCache(sizeToRead);
+ }
+ if (!m_cacheSize) {
+ break;
+ }
+ }
+ }
+
+ return true;
+}
+
+int SnappyFile::rawPercentRead()
+{
+ return 100 * (double(m_stream.tellg()) / double(m_endPos));
+}