Support lz4_legacy archive with multiple magic

Multiple lz4_legacy archives can be directly concatenated
This commit is contained in:
topjohnwu 2022-02-10 23:49:17 -08:00
parent 12093a3dad
commit 7fcb63230f

View File

@ -454,7 +454,7 @@ private:
class LZ4_decoder : public chunk_out_stream {
public:
explicit LZ4_decoder(stream_ptr &&base) :
chunk_out_stream(std::move(base), LZ4_COMPRESSED, sizeof(block_sz) + 4),
chunk_out_stream(std::move(base), LZ4_COMPRESSED, sizeof(block_sz)),
out_buf(new char[LZ4_UNCOMPRESSED]), block_sz(0) {}
~LZ4_decoder() override {
@ -471,12 +471,14 @@ protected:
auto in = reinterpret_cast<const char *>(buf);
if (block_sz == 0) {
if (chunk_sz == sizeof(block_sz) + 4) {
// Skip the first 4 bytes, which is magic
memcpy(&block_sz, in + 4, sizeof(block_sz));
} else {
memcpy(&block_sz, in, sizeof(block_sz));
if (block_sz == 0x184C2102) {
// This is actually the lz4 magic, read the next 4 bytes
block_sz = 0;
chunk_sz = sizeof(block_sz);
return true;
}
// Read the next block chunk
chunk_sz = block_sz;
return true;
} else {