+#include "trace_snappyfile.hpp"
+
+#include <snappy.h>
+
+#include <assert.h>
+#include <string.h>
+
+using namespace Trace;
+
+SnappyFile::SnappyFile(const std::string &filename,
+ File::Mode mode)
+ : File(),
+ m_cache(0),
+ m_cachePtr(0),
+ m_cacheSize(0)
+{
+ m_compressedCache = new char[SNAPPY_CHUNK_SIZE];
+}
+
+SnappyFile::~SnappyFile()
+{
+ delete [] m_compressedCache;
+}
+
+bool SnappyFile::rawOpen(const std::string &filename, File::Mode mode)
+{
+ std::ios_base::openmode fmode = std::fstream::binary;
+ if (mode == File::Write) {
+ fmode |= (std::fstream::out | std::fstream::trunc);
+ createCache(SNAPPY_CHUNK_SIZE);
+ } else if (mode == File::Read) {
+ fmode |= std::fstream::in;
+ }
+
+ m_stream.open(filename.c_str(), fmode);
+
+ //read in the initial buffer if we're reading
+ if (m_stream.is_open() && mode == File::Read) {
+ // read the snappy file identifier
+ unsigned char byte1, byte2;
+ m_stream >> byte1;
+ m_stream >> byte2;
+ assert(byte1 == SNAPPY_BYTE1 && byte2 == SNAPPY_BYTE2);
+
+ flushCache();
+ } else if (m_stream.is_open() && mode == File::Write) {
+ // write the snappy file identifier
+ m_stream << SNAPPY_BYTE1;
+ m_stream << SNAPPY_BYTE2;
+ }
+ return m_stream.is_open();
+}
+
+bool SnappyFile::rawWrite(const void *buffer, int length)
+{
+ if (freeCacheSize() > length) {
+ memcpy(m_cachePtr, buffer, length);
+ m_cachePtr += length;
+ } else if (freeCacheSize() == length) {
+ memcpy(m_cachePtr, buffer, length);
+ m_cachePtr += length;
+ flushCache();
+ } else {
+ int sizeToWrite = length;
+
+ while (sizeToWrite >= freeCacheSize()) {
+ int endSize = freeCacheSize();
+ int offset = length - sizeToWrite;
+ memcpy(m_cachePtr, (char*)buffer + offset, endSize);
+ sizeToWrite -= endSize;
+ m_cachePtr += endSize;
+ flushCache();
+ }
+ if (sizeToWrite) {
+ int offset = length - sizeToWrite;
+ memcpy(m_cachePtr, (char*)buffer + offset, sizeToWrite);
+ m_cachePtr += sizeToWrite;
+ }
+ }
+
+ return true;
+}
+
+bool SnappyFile::rawRead(void *buffer, int length)
+{
+ if (m_stream.eof()) {
+ return false;
+ }
+ if (freeCacheSize() > length) {
+ memcpy(buffer, m_cachePtr, length);
+ m_cachePtr += length;
+ } else if (freeCacheSize() == length) {
+ memcpy(buffer, m_cachePtr, length);
+ m_cachePtr += length;
+ flushCache();
+ } else {
+ int sizeToRead = length;
+ int offset = 0;
+ while (sizeToRead) {
+ int chunkSize = std::min(freeCacheSize(), sizeToRead);
+ offset = length - sizeToRead;
+ memcpy((char*)buffer + offset, m_cachePtr, chunkSize);
+ m_cachePtr += chunkSize;
+ sizeToRead -= chunkSize;
+ if (sizeToRead > 0)
+ flushCache();
+ if (!m_cacheSize)
+ break;
+ }
+ }
+
+ return true;
+}
+
+int SnappyFile::rawGetc()
+{
+ int c = 0;
+ if (!rawRead(&c, 1))
+ return -1;
+ return c;
+}
+
+void SnappyFile::rawClose()
+{
+ flushCache();
+ m_stream.close();
+ delete [] m_cache;
+ m_cache = NULL;
+ m_cachePtr = NULL;
+}
+
+void SnappyFile::rawFlush(FlushType type)
+{
+ if (type == FlushDeep) {
+ flushCache();
+ }
+ m_stream.flush();
+}
+
+void SnappyFile::flushCache()
+{
+ if (m_mode == File::Write) {
+ size_t compressedLength;
+
+ ::snappy::RawCompress(m_cache, SNAPPY_CHUNK_SIZE - freeCacheSize(),
+ m_compressedCache, &compressedLength);
+
+ m_stream << compressedLength;
+ m_stream.write(m_compressedCache, compressedLength);
+ m_cachePtr = m_cache;
+ } else if (m_mode == File::Read) {
+ if (m_stream.eof())
+ return;
+ //assert(m_cachePtr == m_cache + m_cacheSize);
+ size_t compressedLength;
+ m_stream >> compressedLength;
+ m_stream.read((char*)m_compressedCache, compressedLength);
+ ::snappy::GetUncompressedLength(m_compressedCache, compressedLength,
+ &m_cacheSize);
+ if (m_cache)
+ delete [] m_cache;
+ createCache(m_cacheSize);
+ ::snappy::RawUncompress(m_compressedCache, compressedLength,
+ m_cache);
+ }
+}
+
+void SnappyFile::createCache(size_t size)
+{
+ m_cache = new char[size];
+ m_cachePtr = m_cache;
+ m_cacheSize = size;
+}