| // Copyright 2022 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef SRC_LIB_ZXDUMP_DUMP_FILE_ZSTD_H_ |
| #define SRC_LIB_ZXDUMP_DUMP_FILE_ZSTD_H_ |
| |
| #include <forward_list> |
| |
| #include <zstd/zstd.h> |
| |
| #include "dump-file.h" |
| |
| namespace zxdump::internal { |
| |
| static_assert(kHeaderProbeSize >= ZSTD_FRAMEHEADERSIZE_MAX); |
| |
| // A virtual dump file via streaming decompression from another dump file. |
| class DumpFile::Zstd : public DumpFile { |
| public: |
| Zstd() = delete; |
| |
| Zstd(DumpFile& file, FileRange where) |
| : file_{&file}, file_pos_{where.offset, 0}, ctx_{ZSTD_createDCtx()} {} |
| |
| Zstd(Zstd&&) = default; |
| Zstd& operator=(Zstd&&) = default; |
| |
| size_t size() const override; |
| |
| fit::result<Error, ByteView> ReadProbe(FileRange where) override; |
| |
| fit::result<Error, ByteView> ReadEphemeral(FileRange where) override; |
| |
| fit::result<Error, ByteView> ReadPermanent(FileRange where) override; |
| |
| fit::result<Error, Buffer<>> ReadMemory(FileRange where) override; |
| |
| void shrink_to_fit() override; |
| |
| // Put some data through the decompressor. |
| fit::result<Error, bool> Pump(ByteView compressed, size_t skip); |
| |
| private: |
| struct FreeCtx { |
| void operator()(ZSTD_DCtx* ctx) const { ZSTD_freeDCtx(ctx); } |
| }; |
| |
| fit::result<Error, ByteView> Read(FileRange where, bool permanent, bool probe); |
| |
| // The read state of the underlying stream: the offset of what's |
| // already been read; and the size of what to read next. When the size |
| // is zero that means the decompressor has finished and there is no |
| // more to read. |
| DumpFile* file_; |
| FileRange file_pos_{}; |
| |
| std::unique_ptr<ZSTD_DCtx, FreeCtx> ctx_; // Decompressor state. |
| |
| // Decompression writes into this buffer, corresponding to a range of the |
| // uncompressed file image. This acts as the ephemeral buffer too. |
| ByteVector buffer_; |
| FileRange buffer_range_{}; |
| |
| // ReadPermanent results are kept here. |
| std::forward_list<ByteVector> keepalive_; |
| |
| // Occasionally a dangling ephemeral buffer has to be kept alive |
| // temporarily when a new buffer is allocated. |
| std::forward_list<ByteVector> ephemeral_; |
| }; |
| |
| } // namespace zxdump::internal |
| |
| #endif // SRC_LIB_ZXDUMP_DUMP_FILE_ZSTD_H_ |