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+// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
+// This source code is licensed under both the GPLv2 (found in the
+// COPYING file in the root directory) and Apache 2.0 License
+// (found in the LICENSE.Apache file in the root directory).
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+//
+#pragma once
+
+#include <algorithm>
+#include <limits>
+#ifdef ROCKSDB_MALLOC_USABLE_SIZE
+#ifdef OS_FREEBSD
+#include <malloc_np.h>
+#else // OS_FREEBSD
+#include <malloc.h>
+#endif // OS_FREEBSD
+#endif // ROCKSDB_MALLOC_USABLE_SIZE
+#include <string>
+
+#include "memory/memory_allocator.h"
+#include "rocksdb/options.h"
+#include "rocksdb/table.h"
+#include "util/coding.h"
+#include "util/compression_context_cache.h"
+#include "util/string_util.h"
+
+#ifdef SNAPPY
+#include <snappy.h>
+#endif
+
+#ifdef ZLIB
+#include <zlib.h>
+#endif
+
+#ifdef BZIP2
+#include <bzlib.h>
+#endif
+
+#if defined(LZ4)
+#include <lz4.h>
+#include <lz4hc.h>
+#endif
+
+#if defined(ZSTD)
+#include <zstd.h>
+#if ZSTD_VERSION_NUMBER >= 10103 // v1.1.3+
+#include <zdict.h>
+#endif // ZSTD_VERSION_NUMBER >= 10103
+namespace ROCKSDB_NAMESPACE {
+// Need this for the context allocation override
+// On windows we need to do this explicitly
+#if (ZSTD_VERSION_NUMBER >= 500)
+#if defined(ROCKSDB_JEMALLOC) && defined(OS_WIN) && \
+ defined(ZSTD_STATIC_LINKING_ONLY)
+#define ROCKSDB_ZSTD_CUSTOM_MEM
+namespace port {
+ZSTD_customMem GetJeZstdAllocationOverrides();
+} // namespace port
+#endif // defined(ROCKSDB_JEMALLOC) && defined(OS_WIN) &&
+ // defined(ZSTD_STATIC_LINKING_ONLY)
+
+// We require `ZSTD_sizeof_DDict` and `ZSTD_createDDict_byReference` to use
+// `ZSTD_DDict`. The former was introduced in v1.0.0 and the latter was
+// introduced in v1.1.3. But an important bug fix for `ZSTD_sizeof_DDict` came
+// in v1.1.4, so that is the version we require. As of today's latest version
+// (v1.3.8), they are both still in the experimental API, which means they are
+// only exported when the compiler flag `ZSTD_STATIC_LINKING_ONLY` is set.
+#if defined(ZSTD_STATIC_LINKING_ONLY) && ZSTD_VERSION_NUMBER >= 10104
+#define ROCKSDB_ZSTD_DDICT
+#endif // defined(ZSTD_STATIC_LINKING_ONLY) && ZSTD_VERSION_NUMBER >= 10104
+
+// Cached data represents a portion that can be re-used
+// If, in the future we have more than one native context to
+// cache we can arrange this as a tuple
+class ZSTDUncompressCachedData {
+ public:
+ using ZSTDNativeContext = ZSTD_DCtx*;
+ ZSTDUncompressCachedData() {}
+ // Init from cache
+ ZSTDUncompressCachedData(const ZSTDUncompressCachedData& o) = delete;
+ ZSTDUncompressCachedData& operator=(const ZSTDUncompressCachedData&) = delete;
+ ZSTDUncompressCachedData(ZSTDUncompressCachedData&& o) ROCKSDB_NOEXCEPT
+ : ZSTDUncompressCachedData() {
+ *this = std::move(o);
+ }
+ ZSTDUncompressCachedData& operator=(ZSTDUncompressCachedData&& o)
+ ROCKSDB_NOEXCEPT {
+ assert(zstd_ctx_ == nullptr);
+ std::swap(zstd_ctx_, o.zstd_ctx_);
+ std::swap(cache_idx_, o.cache_idx_);
+ return *this;
+ }
+ ZSTDNativeContext Get() const { return zstd_ctx_; }
+ int64_t GetCacheIndex() const { return cache_idx_; }
+ void CreateIfNeeded() {
+ if (zstd_ctx_ == nullptr) {
+#ifdef ROCKSDB_ZSTD_CUSTOM_MEM
+ zstd_ctx_ =
+ ZSTD_createDCtx_advanced(port::GetJeZstdAllocationOverrides());
+#else // ROCKSDB_ZSTD_CUSTOM_MEM
+ zstd_ctx_ = ZSTD_createDCtx();
+#endif // ROCKSDB_ZSTD_CUSTOM_MEM
+ cache_idx_ = -1;
+ }
+ }
+ void InitFromCache(const ZSTDUncompressCachedData& o, int64_t idx) {
+ zstd_ctx_ = o.zstd_ctx_;
+ cache_idx_ = idx;
+ }
+ ~ZSTDUncompressCachedData() {
+ if (zstd_ctx_ != nullptr && cache_idx_ == -1) {
+ ZSTD_freeDCtx(zstd_ctx_);
+ }
+ }
+
+ private:
+ ZSTDNativeContext zstd_ctx_ = nullptr;
+ int64_t cache_idx_ = -1; // -1 means this instance owns the context
+};
+#endif // (ZSTD_VERSION_NUMBER >= 500)
+} // namespace ROCKSDB_NAMESPACE
+#endif // ZSTD
+
+#if !(defined ZSTD) || !(ZSTD_VERSION_NUMBER >= 500)
+namespace ROCKSDB_NAMESPACE {
+class ZSTDUncompressCachedData {
+ void* padding; // unused
+ public:
+ using ZSTDNativeContext = void*;
+ ZSTDUncompressCachedData() {}
+ ZSTDUncompressCachedData(const ZSTDUncompressCachedData&) {}
+ ZSTDUncompressCachedData& operator=(const ZSTDUncompressCachedData&) = delete;
+ ZSTDUncompressCachedData(ZSTDUncompressCachedData&&)
+ ROCKSDB_NOEXCEPT = default;
+ ZSTDUncompressCachedData& operator=(ZSTDUncompressCachedData&&)
+ ROCKSDB_NOEXCEPT = default;
+ ZSTDNativeContext Get() const { return nullptr; }
+ int64_t GetCacheIndex() const { return -1; }
+ void CreateIfNeeded() {}
+ void InitFromCache(const ZSTDUncompressCachedData&, int64_t) {}
+ private:
+ void ignore_padding__() { padding = nullptr; }
+};
+} // namespace ROCKSDB_NAMESPACE
+#endif
+
+#if defined(XPRESS)
+#include "port/xpress.h"
+#endif
+
+namespace ROCKSDB_NAMESPACE {
+
+// Holds dictionary and related data, like ZSTD's digested compression
+// dictionary.
+struct CompressionDict {
+#if ZSTD_VERSION_NUMBER >= 700
+ ZSTD_CDict* zstd_cdict_ = nullptr;
+#endif // ZSTD_VERSION_NUMBER >= 700
+ std::string dict_;
+
+ public:
+#if ZSTD_VERSION_NUMBER >= 700
+ CompressionDict(std::string dict, CompressionType type, int level) {
+#else // ZSTD_VERSION_NUMBER >= 700
+ CompressionDict(std::string dict, CompressionType /*type*/, int /*level*/) {
+#endif // ZSTD_VERSION_NUMBER >= 700
+ dict_ = std::move(dict);
+#if ZSTD_VERSION_NUMBER >= 700
+ zstd_cdict_ = nullptr;
+ if (!dict_.empty() && (type == kZSTD || type == kZSTDNotFinalCompression)) {
+ if (level == CompressionOptions::kDefaultCompressionLevel) {
+ // 3 is the value of ZSTD_CLEVEL_DEFAULT (not exposed publicly), see
+ // https://github.com/facebook/zstd/issues/1148
+ level = 3;
+ }
+ // Should be safe (but slower) if below call fails as we'll use the
+ // raw dictionary to compress.
+ zstd_cdict_ = ZSTD_createCDict(dict_.data(), dict_.size(), level);
+ assert(zstd_cdict_ != nullptr);
+ }
+#endif // ZSTD_VERSION_NUMBER >= 700
+ }
+
+ ~CompressionDict() {
+#if ZSTD_VERSION_NUMBER >= 700
+ size_t res = 0;
+ if (zstd_cdict_ != nullptr) {
+ res = ZSTD_freeCDict(zstd_cdict_);
+ }
+ assert(res == 0); // Last I checked they can't fail
+ (void)res; // prevent unused var warning
+#endif // ZSTD_VERSION_NUMBER >= 700
+ }
+
+#if ZSTD_VERSION_NUMBER >= 700
+ const ZSTD_CDict* GetDigestedZstdCDict() const { return zstd_cdict_; }
+#endif // ZSTD_VERSION_NUMBER >= 700
+
+ Slice GetRawDict() const { return dict_; }
+
+ static const CompressionDict& GetEmptyDict() {
+ static CompressionDict empty_dict{};
+ return empty_dict;
+ }
+
+ CompressionDict() = default;
+ // Disable copy/move
+ CompressionDict(const CompressionDict&) = delete;
+ CompressionDict& operator=(const CompressionDict&) = delete;
+ CompressionDict(CompressionDict&&) = delete;
+ CompressionDict& operator=(CompressionDict&&) = delete;
+};
+
+// Holds dictionary and related data, like ZSTD's digested uncompression
+// dictionary.
+struct UncompressionDict {
+ // Block containing the data for the compression dictionary in case the
+ // constructor that takes a string parameter is used.
+ std::string dict_;
+
+ // Block containing the data for the compression dictionary in case the
+ // constructor that takes a Slice parameter is used and the passed in
+ // CacheAllocationPtr is not nullptr.
+ CacheAllocationPtr allocation_;
+
+ // Slice pointing to the compression dictionary data. Can point to
+ // dict_, allocation_, or some other memory location, depending on how
+ // the object was constructed.
+ Slice slice_;
+
+#ifdef ROCKSDB_ZSTD_DDICT
+ // Processed version of the contents of slice_ for ZSTD compression.
+ ZSTD_DDict* zstd_ddict_ = nullptr;
+#endif // ROCKSDB_ZSTD_DDICT
+
+#ifdef ROCKSDB_ZSTD_DDICT
+ UncompressionDict(std::string dict, bool using_zstd)
+#else // ROCKSDB_ZSTD_DDICT
+ UncompressionDict(std::string dict, bool /* using_zstd */)
+#endif // ROCKSDB_ZSTD_DDICT
+ : dict_(std::move(dict)), slice_(dict_) {
+#ifdef ROCKSDB_ZSTD_DDICT
+ if (!slice_.empty() && using_zstd) {
+ zstd_ddict_ = ZSTD_createDDict_byReference(slice_.data(), slice_.size());
+ assert(zstd_ddict_ != nullptr);
+ }
+#endif // ROCKSDB_ZSTD_DDICT
+ }
+
+#ifdef ROCKSDB_ZSTD_DDICT
+ UncompressionDict(Slice slice, CacheAllocationPtr&& allocation,
+ bool using_zstd)
+#else // ROCKSDB_ZSTD_DDICT
+ UncompressionDict(Slice slice, CacheAllocationPtr&& allocation,
+ bool /* using_zstd */)
+#endif // ROCKSDB_ZSTD_DDICT
+ : allocation_(std::move(allocation)), slice_(std::move(slice)) {
+#ifdef ROCKSDB_ZSTD_DDICT
+ if (!slice_.empty() && using_zstd) {
+ zstd_ddict_ = ZSTD_createDDict_byReference(slice_.data(), slice_.size());
+ assert(zstd_ddict_ != nullptr);
+ }
+#endif // ROCKSDB_ZSTD_DDICT
+ }
+
+ UncompressionDict(UncompressionDict&& rhs)
+ : dict_(std::move(rhs.dict_)),
+ allocation_(std::move(rhs.allocation_)),
+ slice_(std::move(rhs.slice_))
+#ifdef ROCKSDB_ZSTD_DDICT
+ ,
+ zstd_ddict_(rhs.zstd_ddict_)
+#endif
+ {
+#ifdef ROCKSDB_ZSTD_DDICT
+ rhs.zstd_ddict_ = nullptr;
+#endif
+ }
+
+ ~UncompressionDict() {
+#ifdef ROCKSDB_ZSTD_DDICT
+ size_t res = 0;
+ if (zstd_ddict_ != nullptr) {
+ res = ZSTD_freeDDict(zstd_ddict_);
+ }
+ assert(res == 0); // Last I checked they can't fail
+ (void)res; // prevent unused var warning
+#endif // ROCKSDB_ZSTD_DDICT
+ }
+
+ UncompressionDict& operator=(UncompressionDict&& rhs) {
+ if (this == &rhs) {
+ return *this;
+ }
+
+ dict_ = std::move(rhs.dict_);
+ allocation_ = std::move(rhs.allocation_);
+ slice_ = std::move(rhs.slice_);
+
+#ifdef ROCKSDB_ZSTD_DDICT
+ zstd_ddict_ = rhs.zstd_ddict_;
+ rhs.zstd_ddict_ = nullptr;
+#endif
+
+ return *this;
+ }
+
+ // The object is self-contained if the string constructor is used, or the
+ // Slice constructor is invoked with a non-null allocation. Otherwise, it
+ // is the caller's responsibility to ensure that the underlying storage
+ // outlives this object.
+ bool own_bytes() const { return !dict_.empty() || allocation_; }
+
+ const Slice& GetRawDict() const { return slice_; }
+
+#ifdef ROCKSDB_ZSTD_DDICT
+ const ZSTD_DDict* GetDigestedZstdDDict() const { return zstd_ddict_; }
+#endif // ROCKSDB_ZSTD_DDICT
+
+ static const UncompressionDict& GetEmptyDict() {
+ static UncompressionDict empty_dict{};
+ return empty_dict;
+ }
+
+ size_t ApproximateMemoryUsage() const {
+ size_t usage = sizeof(struct UncompressionDict);
+ usage += dict_.size();
+ if (allocation_) {
+ auto allocator = allocation_.get_deleter().allocator;
+ if (allocator) {
+ usage += allocator->UsableSize(allocation_.get(), slice_.size());
+ } else {
+ usage += slice_.size();
+ }
+ }
+#ifdef ROCKSDB_ZSTD_DDICT
+ usage += ZSTD_sizeof_DDict(zstd_ddict_);
+#endif // ROCKSDB_ZSTD_DDICT
+ return usage;
+ }
+
+ UncompressionDict() = default;
+ // Disable copy
+ UncompressionDict(const CompressionDict&) = delete;
+ UncompressionDict& operator=(const CompressionDict&) = delete;
+};
+
+class CompressionContext {
+ private:
+#if defined(ZSTD) && (ZSTD_VERSION_NUMBER >= 500)
+ ZSTD_CCtx* zstd_ctx_ = nullptr;
+ void CreateNativeContext(CompressionType type) {
+ if (type == kZSTD || type == kZSTDNotFinalCompression) {
+#ifdef ROCKSDB_ZSTD_CUSTOM_MEM
+ zstd_ctx_ =
+ ZSTD_createCCtx_advanced(port::GetJeZstdAllocationOverrides());
+#else // ROCKSDB_ZSTD_CUSTOM_MEM
+ zstd_ctx_ = ZSTD_createCCtx();
+#endif // ROCKSDB_ZSTD_CUSTOM_MEM
+ }
+ }
+ void DestroyNativeContext() {
+ if (zstd_ctx_ != nullptr) {
+ ZSTD_freeCCtx(zstd_ctx_);
+ }
+ }
+
+ public:
+ // callable inside ZSTD_Compress
+ ZSTD_CCtx* ZSTDPreallocCtx() const {
+ assert(zstd_ctx_ != nullptr);
+ return zstd_ctx_;
+ }
+
+#else // ZSTD && (ZSTD_VERSION_NUMBER >= 500)
+ private:
+ void CreateNativeContext(CompressionType /* type */) {}
+ void DestroyNativeContext() {}
+#endif // ZSTD && (ZSTD_VERSION_NUMBER >= 500)
+ public:
+ explicit CompressionContext(CompressionType type) {
+ CreateNativeContext(type);
+ }
+ ~CompressionContext() { DestroyNativeContext(); }
+ CompressionContext(const CompressionContext&) = delete;
+ CompressionContext& operator=(const CompressionContext&) = delete;
+};
+
+class CompressionInfo {
+ const CompressionOptions& opts_;
+ const CompressionContext& context_;
+ const CompressionDict& dict_;
+ const CompressionType type_;
+ const uint64_t sample_for_compression_;
+
+ public:
+ CompressionInfo(const CompressionOptions& _opts,
+ const CompressionContext& _context,
+ const CompressionDict& _dict, CompressionType _type,
+ uint64_t _sample_for_compression)
+ : opts_(_opts),
+ context_(_context),
+ dict_(_dict),
+ type_(_type),
+ sample_for_compression_(_sample_for_compression) {}
+
+ const CompressionOptions& options() const { return opts_; }
+ const CompressionContext& context() const { return context_; }
+ const CompressionDict& dict() const { return dict_; }
+ CompressionType type() const { return type_; }
+ uint64_t SampleForCompression() const { return sample_for_compression_; }
+};
+
+class UncompressionContext {
+ private:
+ CompressionContextCache* ctx_cache_ = nullptr;
+ ZSTDUncompressCachedData uncomp_cached_data_;
+
+ public:
+ struct NoCache {};
+ // Do not use context cache, used by TableBuilder
+ UncompressionContext(NoCache, CompressionType /* type */) {}
+
+ explicit UncompressionContext(CompressionType type) {
+ if (type == kZSTD || type == kZSTDNotFinalCompression) {
+ ctx_cache_ = CompressionContextCache::Instance();
+ uncomp_cached_data_ = ctx_cache_->GetCachedZSTDUncompressData();
+ }
+ }
+ ~UncompressionContext() {
+ if (uncomp_cached_data_.GetCacheIndex() != -1) {
+ assert(ctx_cache_ != nullptr);
+ ctx_cache_->ReturnCachedZSTDUncompressData(
+ uncomp_cached_data_.GetCacheIndex());
+ }
+ }
+ UncompressionContext(const UncompressionContext&) = delete;
+ UncompressionContext& operator=(const UncompressionContext&) = delete;
+
+ ZSTDUncompressCachedData::ZSTDNativeContext GetZSTDContext() const {
+ return uncomp_cached_data_.Get();
+ }
+};
+
+class UncompressionInfo {
+ const UncompressionContext& context_;
+ const UncompressionDict& dict_;
+ const CompressionType type_;
+
+ public:
+ UncompressionInfo(const UncompressionContext& _context,
+ const UncompressionDict& _dict, CompressionType _type)
+ : context_(_context), dict_(_dict), type_(_type) {}
+
+ const UncompressionContext& context() const { return context_; }
+ const UncompressionDict& dict() const { return dict_; }
+ CompressionType type() const { return type_; }
+};
+
+inline bool Snappy_Supported() {
+#ifdef SNAPPY
+ return true;
+#else
+ return false;
+#endif
+}
+
+inline bool Zlib_Supported() {
+#ifdef ZLIB
+ return true;
+#else
+ return false;
+#endif
+}
+
+inline bool BZip2_Supported() {
+#ifdef BZIP2
+ return true;
+#else
+ return false;
+#endif
+}
+
+inline bool LZ4_Supported() {
+#ifdef LZ4
+ return true;
+#else
+ return false;
+#endif
+}
+
+inline bool XPRESS_Supported() {
+#ifdef XPRESS
+ return true;
+#else
+ return false;
+#endif
+}
+
+inline bool ZSTD_Supported() {
+#ifdef ZSTD
+ // ZSTD format is finalized since version 0.8.0.
+ return (ZSTD_versionNumber() >= 800);
+#else
+ return false;
+#endif
+}
+
+inline bool ZSTDNotFinal_Supported() {
+#ifdef ZSTD
+ return true;
+#else
+ return false;
+#endif
+}
+
+inline bool CompressionTypeSupported(CompressionType compression_type) {
+ switch (compression_type) {
+ case kNoCompression:
+ return true;
+ case kSnappyCompression:
+ return Snappy_Supported();
+ case kZlibCompression:
+ return Zlib_Supported();
+ case kBZip2Compression:
+ return BZip2_Supported();
+ case kLZ4Compression:
+ return LZ4_Supported();
+ case kLZ4HCCompression:
+ return LZ4_Supported();
+ case kXpressCompression:
+ return XPRESS_Supported();
+ case kZSTDNotFinalCompression:
+ return ZSTDNotFinal_Supported();
+ case kZSTD:
+ return ZSTD_Supported();
+ default:
+ assert(false);
+ return false;
+ }
+}
+
+inline std::string CompressionTypeToString(CompressionType compression_type) {
+ switch (compression_type) {
+ case kNoCompression:
+ return "NoCompression";
+ case kSnappyCompression:
+ return "Snappy";
+ case kZlibCompression:
+ return "Zlib";
+ case kBZip2Compression:
+ return "BZip2";
+ case kLZ4Compression:
+ return "LZ4";
+ case kLZ4HCCompression:
+ return "LZ4HC";
+ case kXpressCompression:
+ return "Xpress";
+ case kZSTD:
+ return "ZSTD";
+ case kZSTDNotFinalCompression:
+ return "ZSTDNotFinal";
+ case kDisableCompressionOption:
+ return "DisableOption";
+ default:
+ assert(false);
+ return "";
+ }
+}
+
+inline std::string CompressionOptionsToString(
+ CompressionOptions& compression_options) {
+ std::string result;
+ result.reserve(512);
+ result.append("window_bits=")
+ .append(ToString(compression_options.window_bits))
+ .append("; ");
+ result.append("level=")
+ .append(ToString(compression_options.level))
+ .append("; ");
+ result.append("strategy=")
+ .append(ToString(compression_options.strategy))
+ .append("; ");
+ result.append("max_dict_bytes=")
+ .append(ToString(compression_options.max_dict_bytes))
+ .append("; ");
+ result.append("zstd_max_train_bytes=")
+ .append(ToString(compression_options.zstd_max_train_bytes))
+ .append("; ");
+ result.append("enabled=")
+ .append(ToString(compression_options.enabled))
+ .append("; ");
+ return result;
+}
+
+// compress_format_version can have two values:
+// 1 -- decompressed sizes for BZip2 and Zlib are not included in the compressed
+// block. Also, decompressed sizes for LZ4 are encoded in platform-dependent
+// way.
+// 2 -- Zlib, BZip2 and LZ4 encode decompressed size as Varint32 just before the
+// start of compressed block. Snappy format is the same as version 1.
+
+inline bool Snappy_Compress(const CompressionInfo& /*info*/, const char* input,
+ size_t length, ::std::string* output) {
+#ifdef SNAPPY
+ output->resize(snappy::MaxCompressedLength(length));
+ size_t outlen;
+ snappy::RawCompress(input, length, &(*output)[0], &outlen);
+ output->resize(outlen);
+ return true;
+#else
+ (void)input;
+ (void)length;
+ (void)output;
+ return false;
+#endif
+}
+
+inline bool Snappy_GetUncompressedLength(const char* input, size_t length,
+ size_t* result) {
+#ifdef SNAPPY
+ return snappy::GetUncompressedLength(input, length, result);
+#else
+ (void)input;
+ (void)length;
+ (void)result;
+ return false;
+#endif
+}
+
+inline bool Snappy_Uncompress(const char* input, size_t length, char* output) {
+#ifdef SNAPPY
+ return snappy::RawUncompress(input, length, output);
+#else
+ (void)input;
+ (void)length;
+ (void)output;
+ return false;
+#endif
+}
+
+namespace compression {
+// returns size
+inline size_t PutDecompressedSizeInfo(std::string* output, uint32_t length) {
+ PutVarint32(output, length);
+ return output->size();
+}
+
+inline bool GetDecompressedSizeInfo(const char** input_data,
+ size_t* input_length,
+ uint32_t* output_len) {
+ auto new_input_data =
+ GetVarint32Ptr(*input_data, *input_data + *input_length, output_len);
+ if (new_input_data == nullptr) {
+ return false;
+ }
+ *input_length -= (new_input_data - *input_data);
+ *input_data = new_input_data;
+ return true;
+}
+} // namespace compression
+
+// compress_format_version == 1 -- decompressed size is not included in the
+// block header
+// compress_format_version == 2 -- decompressed size is included in the block
+// header in varint32 format
+// @param compression_dict Data for presetting the compression library's
+// dictionary.
+inline bool Zlib_Compress(const CompressionInfo& info,
+ uint32_t compress_format_version, const char* input,
+ size_t length, ::std::string* output) {
+#ifdef ZLIB
+ if (length > std::numeric_limits<uint32_t>::max()) {
+ // Can't compress more than 4GB
+ return false;
+ }
+
+ size_t output_header_len = 0;
+ if (compress_format_version == 2) {
+ output_header_len = compression::PutDecompressedSizeInfo(
+ output, static_cast<uint32_t>(length));
+ }
+ // Resize output to be the plain data length.
+ // This may not be big enough if the compression actually expands data.
+ output->resize(output_header_len + length);
+
+ // The memLevel parameter specifies how much memory should be allocated for
+ // the internal compression state.
+ // memLevel=1 uses minimum memory but is slow and reduces compression ratio.
+ // memLevel=9 uses maximum memory for optimal speed.
+ // The default value is 8. See zconf.h for more details.
+ static const int memLevel = 8;
+ int level;
+ if (info.options().level == CompressionOptions::kDefaultCompressionLevel) {
+ level = Z_DEFAULT_COMPRESSION;
+ } else {
+ level = info.options().level;
+ }
+ z_stream _stream;
+ memset(&_stream, 0, sizeof(z_stream));
+ int st = deflateInit2(&_stream, level, Z_DEFLATED, info.options().window_bits,
+ memLevel, info.options().strategy);
+ if (st != Z_OK) {
+ return false;
+ }
+
+ Slice compression_dict = info.dict().GetRawDict();
+ if (compression_dict.size()) {
+ // Initialize the compression library's dictionary
+ st = deflateSetDictionary(
+ &_stream, reinterpret_cast<const Bytef*>(compression_dict.data()),
+ static_cast<unsigned int>(compression_dict.size()));
+ if (st != Z_OK) {
+ deflateEnd(&_stream);
+ return false;
+ }
+ }
+
+ // Compress the input, and put compressed data in output.
+ _stream.next_in = (Bytef*)input;
+ _stream.avail_in = static_cast<unsigned int>(length);
+
+ // Initialize the output size.
+ _stream.avail_out = static_cast<unsigned int>(length);
+ _stream.next_out = reinterpret_cast<Bytef*>(&(*output)[output_header_len]);
+
+ bool compressed = false;
+ st = deflate(&_stream, Z_FINISH);
+ if (st == Z_STREAM_END) {
+ compressed = true;
+ output->resize(output->size() - _stream.avail_out);
+ }
+ // The only return value we really care about is Z_STREAM_END.
+ // Z_OK means insufficient output space. This means the compression is
+ // bigger than decompressed size. Just fail the compression in that case.
+
+ deflateEnd(&_stream);
+ return compressed;
+#else
+ (void)info;
+ (void)compress_format_version;
+ (void)input;
+ (void)length;
+ (void)output;
+ return false;
+#endif
+}
+
+// compress_format_version == 1 -- decompressed size is not included in the
+// block header
+// compress_format_version == 2 -- decompressed size is included in the block
+// header in varint32 format
+// @param compression_dict Data for presetting the compression library's
+// dictionary.
+inline CacheAllocationPtr Zlib_Uncompress(
+ const UncompressionInfo& info, const char* input_data, size_t input_length,
+ int* decompress_size, uint32_t compress_format_version,
+ MemoryAllocator* allocator = nullptr, int windowBits = -14) {
+#ifdef ZLIB
+ uint32_t output_len = 0;
+ if (compress_format_version == 2) {
+ if (!compression::GetDecompressedSizeInfo(&input_data, &input_length,
+ &output_len)) {
+ return nullptr;
+ }
+ } else {
+ // Assume the decompressed data size will 5x of compressed size, but round
+ // to the page size
+ size_t proposed_output_len = ((input_length * 5) & (~(4096 - 1))) + 4096;
+ output_len = static_cast<uint32_t>(
+ std::min(proposed_output_len,
+ static_cast<size_t>(std::numeric_limits<uint32_t>::max())));
+ }
+
+ z_stream _stream;
+ memset(&_stream, 0, sizeof(z_stream));
+
+ // For raw inflate, the windowBits should be -8..-15.
+ // If windowBits is bigger than zero, it will use either zlib
+ // header or gzip header. Adding 32 to it will do automatic detection.
+ int st =
+ inflateInit2(&_stream, windowBits > 0 ? windowBits + 32 : windowBits);
+ if (st != Z_OK) {
+ return nullptr;
+ }
+
+ const Slice& compression_dict = info.dict().GetRawDict();
+ if (compression_dict.size()) {
+ // Initialize the compression library's dictionary
+ st = inflateSetDictionary(
+ &_stream, reinterpret_cast<const Bytef*>(compression_dict.data()),
+ static_cast<unsigned int>(compression_dict.size()));
+ if (st != Z_OK) {
+ return nullptr;
+ }
+ }
+
+ _stream.next_in = (Bytef*)input_data;
+ _stream.avail_in = static_cast<unsigned int>(input_length);
+
+ auto output = AllocateBlock(output_len, allocator);
+
+ _stream.next_out = (Bytef*)output.get();
+ _stream.avail_out = static_cast<unsigned int>(output_len);
+
+ bool done = false;
+ while (!done) {
+ st = inflate(&_stream, Z_SYNC_FLUSH);
+ switch (st) {
+ case Z_STREAM_END:
+ done = true;
+ break;
+ case Z_OK: {
+ // No output space. Increase the output space by 20%.
+ // We should never run out of output space if
+ // compress_format_version == 2
+ assert(compress_format_version != 2);
+ size_t old_sz = output_len;
+ uint32_t output_len_delta = output_len / 5;
+ output_len += output_len_delta < 10 ? 10 : output_len_delta;
+ auto tmp = AllocateBlock(output_len, allocator);
+ memcpy(tmp.get(), output.get(), old_sz);
+ output = std::move(tmp);
+
+ // Set more output.
+ _stream.next_out = (Bytef*)(output.get() + old_sz);
+ _stream.avail_out = static_cast<unsigned int>(output_len - old_sz);
+ break;
+ }
+ case Z_BUF_ERROR:
+ default:
+ inflateEnd(&_stream);
+ return nullptr;
+ }
+ }
+
+ // If we encoded decompressed block size, we should have no bytes left
+ assert(compress_format_version != 2 || _stream.avail_out == 0);
+ *decompress_size = static_cast<int>(output_len - _stream.avail_out);
+ inflateEnd(&_stream);
+ return output;
+#else
+ (void)info;
+ (void)input_data;
+ (void)input_length;
+ (void)decompress_size;
+ (void)compress_format_version;
+ (void)allocator;
+ (void)windowBits;
+ return nullptr;
+#endif
+}
+
+// compress_format_version == 1 -- decompressed size is not included in the
+// block header
+// compress_format_version == 2 -- decompressed size is included in the block
+// header in varint32 format
+inline bool BZip2_Compress(const CompressionInfo& /*info*/,
+ uint32_t compress_format_version, const char* input,
+ size_t length, ::std::string* output) {
+#ifdef BZIP2
+ if (length > std::numeric_limits<uint32_t>::max()) {
+ // Can't compress more than 4GB
+ return false;
+ }
+ size_t output_header_len = 0;
+ if (compress_format_version == 2) {
+ output_header_len = compression::PutDecompressedSizeInfo(
+ output, static_cast<uint32_t>(length));
+ }
+ // Resize output to be the plain data length.
+ // This may not be big enough if the compression actually expands data.
+ output->resize(output_header_len + length);
+
+ bz_stream _stream;
+ memset(&_stream, 0, sizeof(bz_stream));
+
+ // Block size 1 is 100K.
+ // 0 is for silent.
+ // 30 is the default workFactor
+ int st = BZ2_bzCompressInit(&_stream, 1, 0, 30);
+ if (st != BZ_OK) {
+ return false;
+ }
+
+ // Compress the input, and put compressed data in output.
+ _stream.next_in = (char*)input;
+ _stream.avail_in = static_cast<unsigned int>(length);
+
+ // Initialize the output size.
+ _stream.avail_out = static_cast<unsigned int>(length);
+ _stream.next_out = reinterpret_cast<char*>(&(*output)[output_header_len]);
+
+ bool compressed = false;
+ st = BZ2_bzCompress(&_stream, BZ_FINISH);
+ if (st == BZ_STREAM_END) {
+ compressed = true;
+ output->resize(output->size() - _stream.avail_out);
+ }
+ // The only return value we really care about is BZ_STREAM_END.
+ // BZ_FINISH_OK means insufficient output space. This means the compression
+ // is bigger than decompressed size. Just fail the compression in that case.
+
+ BZ2_bzCompressEnd(&_stream);
+ return compressed;
+#else
+ (void)compress_format_version;
+ (void)input;
+ (void)length;
+ (void)output;
+ return false;
+#endif
+}
+
+// compress_format_version == 1 -- decompressed size is not included in the
+// block header
+// compress_format_version == 2 -- decompressed size is included in the block
+// header in varint32 format
+inline CacheAllocationPtr BZip2_Uncompress(
+ const char* input_data, size_t input_length, int* decompress_size,
+ uint32_t compress_format_version, MemoryAllocator* allocator = nullptr) {
+#ifdef BZIP2
+ uint32_t output_len = 0;
+ if (compress_format_version == 2) {
+ if (!compression::GetDecompressedSizeInfo(&input_data, &input_length,
+ &output_len)) {
+ return nullptr;
+ }
+ } else {
+ // Assume the decompressed data size will 5x of compressed size, but round
+ // to the next page size
+ size_t proposed_output_len = ((input_length * 5) & (~(4096 - 1))) + 4096;
+ output_len = static_cast<uint32_t>(
+ std::min(proposed_output_len,
+ static_cast<size_t>(std::numeric_limits<uint32_t>::max())));
+ }
+
+ bz_stream _stream;
+ memset(&_stream, 0, sizeof(bz_stream));
+
+ int st = BZ2_bzDecompressInit(&_stream, 0, 0);
+ if (st != BZ_OK) {
+ return nullptr;
+ }
+
+ _stream.next_in = (char*)input_data;
+ _stream.avail_in = static_cast<unsigned int>(input_length);
+
+ auto output = AllocateBlock(output_len, allocator);
+
+ _stream.next_out = (char*)output.get();
+ _stream.avail_out = static_cast<unsigned int>(output_len);
+
+ bool done = false;
+ while (!done) {
+ st = BZ2_bzDecompress(&_stream);
+ switch (st) {
+ case BZ_STREAM_END:
+ done = true;
+ break;
+ case BZ_OK: {
+ // No output space. Increase the output space by 20%.
+ // We should never run out of output space if
+ // compress_format_version == 2
+ assert(compress_format_version != 2);
+ uint32_t old_sz = output_len;
+ output_len = output_len * 1.2;
+ auto tmp = AllocateBlock(output_len, allocator);
+ memcpy(tmp.get(), output.get(), old_sz);
+ output = std::move(tmp);
+
+ // Set more output.
+ _stream.next_out = (char*)(output.get() + old_sz);
+ _stream.avail_out = static_cast<unsigned int>(output_len - old_sz);
+ break;
+ }
+ default:
+ BZ2_bzDecompressEnd(&_stream);
+ return nullptr;
+ }
+ }
+
+ // If we encoded decompressed block size, we should have no bytes left
+ assert(compress_format_version != 2 || _stream.avail_out == 0);
+ *decompress_size = static_cast<int>(output_len - _stream.avail_out);
+ BZ2_bzDecompressEnd(&_stream);
+ return output;
+#else
+ (void)input_data;
+ (void)input_length;
+ (void)decompress_size;
+ (void)compress_format_version;
+ (void)allocator;
+ return nullptr;
+#endif
+}
+
+// compress_format_version == 1 -- decompressed size is included in the
+// block header using memcpy, which makes database non-portable)
+// compress_format_version == 2 -- decompressed size is included in the block
+// header in varint32 format
+// @param compression_dict Data for presetting the compression library's
+// dictionary.
+inline bool LZ4_Compress(const CompressionInfo& info,
+ uint32_t compress_format_version, const char* input,
+ size_t length, ::std::string* output) {
+#ifdef LZ4
+ if (length > std::numeric_limits<uint32_t>::max()) {
+ // Can't compress more than 4GB
+ return false;
+ }
+
+ size_t output_header_len = 0;
+ if (compress_format_version == 2) {
+ // new encoding, using varint32 to store size information
+ output_header_len = compression::PutDecompressedSizeInfo(
+ output, static_cast<uint32_t>(length));
+ } else {
+ // legacy encoding, which is not really portable (depends on big/little
+ // endianness)
+ output_header_len = 8;
+ output->resize(output_header_len);
+ char* p = const_cast<char*>(output->c_str());
+ memcpy(p, &length, sizeof(length));
+ }
+ int compress_bound = LZ4_compressBound(static_cast<int>(length));
+ output->resize(static_cast<size_t>(output_header_len + compress_bound));
+
+ int outlen;
+#if LZ4_VERSION_NUMBER >= 10400 // r124+
+ LZ4_stream_t* stream = LZ4_createStream();
+ Slice compression_dict = info.dict().GetRawDict();
+ if (compression_dict.size()) {
+ LZ4_loadDict(stream, compression_dict.data(),
+ static_cast<int>(compression_dict.size()));
+ }
+#if LZ4_VERSION_NUMBER >= 10700 // r129+
+ outlen =
+ LZ4_compress_fast_continue(stream, input, &(*output)[output_header_len],
+ static_cast<int>(length), compress_bound, 1);
+#else // up to r128
+ outlen = LZ4_compress_limitedOutput_continue(
+ stream, input, &(*output)[output_header_len], static_cast<int>(length),
+ compress_bound);
+#endif
+ LZ4_freeStream(stream);
+#else // up to r123
+ outlen = LZ4_compress_limitedOutput(input, &(*output)[output_header_len],
+ static_cast<int>(length), compress_bound);
+#endif // LZ4_VERSION_NUMBER >= 10400
+
+ if (outlen == 0) {
+ return false;
+ }
+ output->resize(static_cast<size_t>(output_header_len + outlen));
+ return true;
+#else // LZ4
+ (void)info;
+ (void)compress_format_version;
+ (void)input;
+ (void)length;
+ (void)output;
+ return false;
+#endif
+}
+
+// compress_format_version == 1 -- decompressed size is included in the
+// block header using memcpy, which makes database non-portable)
+// compress_format_version == 2 -- decompressed size is included in the block
+// header in varint32 format
+// @param compression_dict Data for presetting the compression library's
+// dictionary.
+inline CacheAllocationPtr LZ4_Uncompress(const UncompressionInfo& info,
+ const char* input_data,
+ size_t input_length,
+ int* decompress_size,
+ uint32_t compress_format_version,
+ MemoryAllocator* allocator = nullptr) {
+#ifdef LZ4
+ uint32_t output_len = 0;
+ if (compress_format_version == 2) {
+ // new encoding, using varint32 to store size information
+ if (!compression::GetDecompressedSizeInfo(&input_data, &input_length,
+ &output_len)) {
+ return nullptr;
+ }
+ } else {
+ // legacy encoding, which is not really portable (depends on big/little
+ // endianness)
+ if (input_length < 8) {
+ return nullptr;
+ }
+ memcpy(&output_len, input_data, sizeof(output_len));
+ input_length -= 8;
+ input_data += 8;
+ }
+
+ auto output = AllocateBlock(output_len, allocator);
+#if LZ4_VERSION_NUMBER >= 10400 // r124+
+ LZ4_streamDecode_t* stream = LZ4_createStreamDecode();
+ const Slice& compression_dict = info.dict().GetRawDict();
+ if (compression_dict.size()) {
+ LZ4_setStreamDecode(stream, compression_dict.data(),
+ static_cast<int>(compression_dict.size()));
+ }
+ *decompress_size = LZ4_decompress_safe_continue(
+ stream, input_data, output.get(), static_cast<int>(input_length),
+ static_cast<int>(output_len));
+ LZ4_freeStreamDecode(stream);
+#else // up to r123
+ *decompress_size = LZ4_decompress_safe(input_data, output.get(),
+ static_cast<int>(input_length),
+ static_cast<int>(output_len));
+#endif // LZ4_VERSION_NUMBER >= 10400
+
+ if (*decompress_size < 0) {
+ return nullptr;
+ }
+ assert(*decompress_size == static_cast<int>(output_len));
+ return output;
+#else // LZ4
+ (void)info;
+ (void)input_data;
+ (void)input_length;
+ (void)decompress_size;
+ (void)compress_format_version;
+ (void)allocator;
+ return nullptr;
+#endif
+}
+
+// compress_format_version == 1 -- decompressed size is included in the
+// block header using memcpy, which makes database non-portable)
+// compress_format_version == 2 -- decompressed size is included in the block
+// header in varint32 format
+// @param compression_dict Data for presetting the compression library's
+// dictionary.
+inline bool LZ4HC_Compress(const CompressionInfo& info,
+ uint32_t compress_format_version, const char* input,
+ size_t length, ::std::string* output) {
+#ifdef LZ4
+ if (length > std::numeric_limits<uint32_t>::max()) {
+ // Can't compress more than 4GB
+ return false;
+ }
+
+ size_t output_header_len = 0;
+ if (compress_format_version == 2) {
+ // new encoding, using varint32 to store size information
+ output_header_len = compression::PutDecompressedSizeInfo(
+ output, static_cast<uint32_t>(length));
+ } else {
+ // legacy encoding, which is not really portable (depends on big/little
+ // endianness)
+ output_header_len = 8;
+ output->resize(output_header_len);
+ char* p = const_cast<char*>(output->c_str());
+ memcpy(p, &length, sizeof(length));
+ }
+ int compress_bound = LZ4_compressBound(static_cast<int>(length));
+ output->resize(static_cast<size_t>(output_header_len + compress_bound));
+
+ int outlen;
+ int level;
+ if (info.options().level == CompressionOptions::kDefaultCompressionLevel) {
+ level = 0; // lz4hc.h says any value < 1 will be sanitized to default
+ } else {
+ level = info.options().level;
+ }
+#if LZ4_VERSION_NUMBER >= 10400 // r124+
+ LZ4_streamHC_t* stream = LZ4_createStreamHC();
+ LZ4_resetStreamHC(stream, level);
+ Slice compression_dict = info.dict().GetRawDict();
+ const char* compression_dict_data =
+ compression_dict.size() > 0 ? compression_dict.data() : nullptr;
+ size_t compression_dict_size = compression_dict.size();
+ LZ4_loadDictHC(stream, compression_dict_data,
+ static_cast<int>(compression_dict_size));
+
+#if LZ4_VERSION_NUMBER >= 10700 // r129+
+ outlen =
+ LZ4_compress_HC_continue(stream, input, &(*output)[output_header_len],
+ static_cast<int>(length), compress_bound);
+#else // r124-r128
+ outlen = LZ4_compressHC_limitedOutput_continue(
+ stream, input, &(*output)[output_header_len], static_cast<int>(length),
+ compress_bound);
+#endif // LZ4_VERSION_NUMBER >= 10700
+ LZ4_freeStreamHC(stream);
+
+#elif LZ4_VERSION_MAJOR // r113-r123
+ outlen = LZ4_compressHC2_limitedOutput(input, &(*output)[output_header_len],
+ static_cast<int>(length),
+ compress_bound, level);
+#else // up to r112
+ outlen =
+ LZ4_compressHC_limitedOutput(input, &(*output)[output_header_len],
+ static_cast<int>(length), compress_bound);
+#endif // LZ4_VERSION_NUMBER >= 10400
+
+ if (outlen == 0) {
+ return false;
+ }
+ output->resize(static_cast<size_t>(output_header_len + outlen));
+ return true;
+#else // LZ4
+ (void)info;
+ (void)compress_format_version;
+ (void)input;
+ (void)length;
+ (void)output;
+ return false;
+#endif
+}
+
+#ifdef XPRESS
+inline bool XPRESS_Compress(const char* input, size_t length,
+ std::string* output) {
+ return port::xpress::Compress(input, length, output);
+}
+#else
+inline bool XPRESS_Compress(const char* /*input*/, size_t /*length*/,
+ std::string* /*output*/) {
+ return false;
+}
+#endif
+
+#ifdef XPRESS
+inline char* XPRESS_Uncompress(const char* input_data, size_t input_length,
+ int* decompress_size) {
+ return port::xpress::Decompress(input_data, input_length, decompress_size);
+}
+#else
+inline char* XPRESS_Uncompress(const char* /*input_data*/,
+ size_t /*input_length*/,
+ int* /*decompress_size*/) {
+ return nullptr;
+}
+#endif
+
+inline bool ZSTD_Compress(const CompressionInfo& info, const char* input,
+ size_t length, ::std::string* output) {
+#ifdef ZSTD
+ if (length > std::numeric_limits<uint32_t>::max()) {
+ // Can't compress more than 4GB
+ return false;
+ }
+
+ size_t output_header_len = compression::PutDecompressedSizeInfo(
+ output, static_cast<uint32_t>(length));
+
+ size_t compressBound = ZSTD_compressBound(length);
+ output->resize(static_cast<size_t>(output_header_len + compressBound));
+ size_t outlen = 0;
+ int level;
+ if (info.options().level == CompressionOptions::kDefaultCompressionLevel) {
+ // 3 is the value of ZSTD_CLEVEL_DEFAULT (not exposed publicly), see
+ // https://github.com/facebook/zstd/issues/1148
+ level = 3;
+ } else {
+ level = info.options().level;
+ }
+#if ZSTD_VERSION_NUMBER >= 500 // v0.5.0+
+ ZSTD_CCtx* context = info.context().ZSTDPreallocCtx();
+ assert(context != nullptr);
+#if ZSTD_VERSION_NUMBER >= 700 // v0.7.0+
+ if (info.dict().GetDigestedZstdCDict() != nullptr) {
+ outlen = ZSTD_compress_usingCDict(context, &(*output)[output_header_len],
+ compressBound, input, length,
+ info.dict().GetDigestedZstdCDict());
+ }
+#endif // ZSTD_VERSION_NUMBER >= 700
+ if (outlen == 0) {
+ outlen = ZSTD_compress_usingDict(context, &(*output)[output_header_len],
+ compressBound, input, length,
+ info.dict().GetRawDict().data(),
+ info.dict().GetRawDict().size(), level);
+ }
+#else // up to v0.4.x
+ outlen = ZSTD_compress(&(*output)[output_header_len], compressBound, input,
+ length, level);
+#endif // ZSTD_VERSION_NUMBER >= 500
+ if (outlen == 0) {
+ return false;
+ }
+ output->resize(output_header_len + outlen);
+ return true;
+#else // ZSTD
+ (void)info;
+ (void)input;
+ (void)length;
+ (void)output;
+ return false;
+#endif
+}
+
+// @param compression_dict Data for presetting the compression library's
+// dictionary.
+inline CacheAllocationPtr ZSTD_Uncompress(
+ const UncompressionInfo& info, const char* input_data, size_t input_length,
+ int* decompress_size, MemoryAllocator* allocator = nullptr) {
+#ifdef ZSTD
+ uint32_t output_len = 0;
+ if (!compression::GetDecompressedSizeInfo(&input_data, &input_length,
+ &output_len)) {
+ return nullptr;
+ }
+
+ auto output = AllocateBlock(output_len, allocator);
+ size_t actual_output_length = 0;
+#if ZSTD_VERSION_NUMBER >= 500 // v0.5.0+
+ ZSTD_DCtx* context = info.context().GetZSTDContext();
+ assert(context != nullptr);
+#ifdef ROCKSDB_ZSTD_DDICT
+ if (info.dict().GetDigestedZstdDDict() != nullptr) {
+ actual_output_length = ZSTD_decompress_usingDDict(
+ context, output.get(), output_len, input_data, input_length,
+ info.dict().GetDigestedZstdDDict());
+ }
+#endif // ROCKSDB_ZSTD_DDICT
+ if (actual_output_length == 0) {
+ actual_output_length = ZSTD_decompress_usingDict(
+ context, output.get(), output_len, input_data, input_length,
+ info.dict().GetRawDict().data(), info.dict().GetRawDict().size());
+ }
+#else // up to v0.4.x
+ (void)info;
+ actual_output_length =
+ ZSTD_decompress(output.get(), output_len, input_data, input_length);
+#endif // ZSTD_VERSION_NUMBER >= 500
+ assert(actual_output_length == output_len);
+ *decompress_size = static_cast<int>(actual_output_length);
+ return output;
+#else // ZSTD
+ (void)info;
+ (void)input_data;
+ (void)input_length;
+ (void)decompress_size;
+ (void)allocator;
+ return nullptr;
+#endif
+}
+
+inline bool ZSTD_TrainDictionarySupported() {
+#ifdef ZSTD
+ // Dictionary trainer is available since v0.6.1 for static linking, but not
+ // available for dynamic linking until v1.1.3. For now we enable the feature
+ // in v1.1.3+ only.
+ return (ZSTD_versionNumber() >= 10103);
+#else
+ return false;
+#endif
+}
+
+inline std::string ZSTD_TrainDictionary(const std::string& samples,
+ const std::vector<size_t>& sample_lens,
+ size_t max_dict_bytes) {
+ // Dictionary trainer is available since v0.6.1 for static linking, but not
+ // available for dynamic linking until v1.1.3. For now we enable the feature
+ // in v1.1.3+ only.
+#if ZSTD_VERSION_NUMBER >= 10103 // v1.1.3+
+ assert(samples.empty() == sample_lens.empty());
+ if (samples.empty()) {
+ return "";
+ }
+ std::string dict_data(max_dict_bytes, '\0');
+ size_t dict_len = ZDICT_trainFromBuffer(
+ &dict_data[0], max_dict_bytes, &samples[0], &sample_lens[0],
+ static_cast<unsigned>(sample_lens.size()));
+ if (ZDICT_isError(dict_len)) {
+ return "";
+ }
+ assert(dict_len <= max_dict_bytes);
+ dict_data.resize(dict_len);
+ return dict_data;
+#else // up to v1.1.2
+ assert(false);
+ (void)samples;
+ (void)sample_lens;
+ (void)max_dict_bytes;
+ return "";
+#endif // ZSTD_VERSION_NUMBER >= 10103
+}
+
+inline std::string ZSTD_TrainDictionary(const std::string& samples,
+ size_t sample_len_shift,
+ size_t max_dict_bytes) {
+ // Dictionary trainer is available since v0.6.1, but ZSTD was marked stable
+ // only since v0.8.0. For now we enable the feature in stable versions only.
+#if ZSTD_VERSION_NUMBER >= 10103 // v1.1.3+
+ // skips potential partial sample at the end of "samples"
+ size_t num_samples = samples.size() >> sample_len_shift;
+ std::vector<size_t> sample_lens(num_samples, size_t(1) << sample_len_shift);
+ return ZSTD_TrainDictionary(samples, sample_lens, max_dict_bytes);
+#else // up to v1.1.2
+ assert(false);
+ (void)samples;
+ (void)sample_len_shift;
+ (void)max_dict_bytes;
+ return "";
+#endif // ZSTD_VERSION_NUMBER >= 10103
+}
+
+} // namespace ROCKSDB_NAMESPACE