uncompressed_stream.cpp

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#include "rosbag/chunked_file.h"

#include <iostream>
#include <cstring>

#include <boost/format.hpp>

using std::string;
using boost::format;
using ros::Exception;

namespace rosbag {

UncompressedStream::UncompressedStream(ChunkedFile* file) : Stream(file) { }

CompressionType UncompressedStream::getCompressionType() const {
    return compression::Uncompressed;
}

void UncompressedStream::write(void* ptr, size_t size) {
    size_t result = fwrite(ptr, 1, size, getFilePointer());
    if (result != size)
        throw BagIOException((format("Error writing to file: writing %1% bytes, wrote %2% bytes") % size % result).str());

    advanceOffset(size);
}

void UncompressedStream::read(void* ptr, size_t size) {
    size_t nUnused = (size_t) getUnusedLength();
    char* unused = getUnused();

    if (nUnused > 0) {
        // We have unused data from the last compressed read
        if (nUnused == size) {
            // Copy the unused data into the buffer
            memcpy(ptr, unused, nUnused);

            clearUnused();
        }
        else if (nUnused < size) {
            // Copy the unused data into the buffer
            memcpy(ptr, unused, nUnused);

            // Still have data to read
            size -= nUnused;

            // Read the remaining data from the file
            int result = fread((char*) ptr + nUnused, 1, size, getFilePointer());
            if ((size_t) result != size)
                throw BagIOException((format("Error reading from file + unused: wanted %1% bytes, read %2% bytes") % size % result).str());

            advanceOffset(size);

            clearUnused();
        }
        else {
            // nUnused_ > size
            memcpy(ptr, unused, size);

            setUnused(unused + size);
            setUnusedLength(nUnused - size);
        }
    }
    
    // No unused data - read from stream
    int result = fread(ptr, 1, size, getFilePointer());
    if ((size_t) result != size)
        throw BagIOException((format("Error reading from file: wanted %1% bytes, read %2% bytes") % size % result).str());

    advanceOffset(size);
}

void UncompressedStream::decompress(uint8_t* dest, unsigned int dest_len, uint8_t* source, unsigned int source_len) {
    if (dest_len < source_len)
        throw BagException("dest_len not large enough");

    memcpy(dest, source, source_len);
}

} // namespace rosbag