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Diffstat (limited to 'src/third_party/wiredtiger/api/leveldb/leveldb/include/leveldb/slice.h')
-rw-r--r-- | src/third_party/wiredtiger/api/leveldb/leveldb/include/leveldb/slice.h | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/src/third_party/wiredtiger/api/leveldb/leveldb/include/leveldb/slice.h b/src/third_party/wiredtiger/api/leveldb/leveldb/include/leveldb/slice.h new file mode 100644 index 00000000000..1eb66dd825f --- /dev/null +++ b/src/third_party/wiredtiger/api/leveldb/leveldb/include/leveldb/slice.h @@ -0,0 +1,127 @@ +// 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. +// +// Slice is a simple structure containing a pointer into some external +// storage and a size. The user of a Slice must ensure that the slice +// is not used after the corresponding external storage has been +// deallocated. +// +// Multiple threads can invoke const methods on a Slice without +// external synchronization, but if any of the threads may call a +// non-const method, all threads accessing the same Slice must use +// external synchronization. + +#ifndef STORAGE_LEVELDB_INCLUDE_SLICE_H_ +#define STORAGE_LEVELDB_INCLUDE_SLICE_H_ + +#include "leveldb_wt_config.h" +#if defined(HAVE_ROCKSDB) && !defined(leveldb) +#define leveldb rocksdb +#endif + +#include <assert.h> +#include <stddef.h> +#include <string.h> +#include <string> + +namespace leveldb { + +class Slice { + public: + // Create an empty slice. + Slice() : data_(""), size_(0) { } + + // Create a slice that refers to d[0,n-1]. + Slice(const char* d, size_t n) : data_(d), size_(n) { } + + // Create a slice that refers to the contents of "s" + Slice(const std::string& s) : data_(s.data()), size_(s.size()) { } + + // Create a slice that refers to s[0,strlen(s)-1] + Slice(const char* s) : data_(s), size_(strlen(s)) { } + + // Return a pointer to the beginning of the referenced data + const char* data() const { return data_; } + + // Return the length (in bytes) of the referenced data + size_t size() const { return size_; } + + // Return true iff the length of the referenced data is zero + bool empty() const { return size_ == 0; } + + // Return the ith byte in the referenced data. + // REQUIRES: n < size() + char operator[](size_t n) const { + assert(n < size()); + return data_[n]; + } + + // Change this slice to refer to an empty array + void clear() { data_ = ""; size_ = 0; } + + // Drop the first "n" bytes from this slice. + void remove_prefix(size_t n) { + assert(n <= size()); + data_ += n; + size_ -= n; + } + + // Return a string that contains the copy of the referenced data. + std::string ToString() const { return std::string(data_, size_); } + + // Three-way comparison. Returns value: + // < 0 iff "*this" < "b", + // == 0 iff "*this" == "b", + // > 0 iff "*this" > "b" + int compare(const Slice& b) const; + + // Return true iff "x" is a prefix of "*this" + bool starts_with(const Slice& x) const { + return ((size_ >= x.size_) && + (memcmp(data_, x.data_, x.size_) == 0)); + } + +// The LevelDB JNI layer peeks in here +// private: + const char* data_; + size_t size_; + + // Intentionally copyable +}; + +#ifdef HAVE_ROCKSDB +// A set of Slices that are virtually concatenated together. 'parts' points +// to an array of Slices. The number of elements in the array is 'num_parts'. +struct SliceParts { + SliceParts(const Slice* _parts, int _num_parts) : + parts(_parts), num_parts(_num_parts) { } + + const Slice* parts; + int num_parts; +}; +#endif + +inline bool operator==(const Slice& x, const Slice& y) { + return ((x.size() == y.size()) && + (memcmp(x.data(), y.data(), x.size()) == 0)); +} + +inline bool operator!=(const Slice& x, const Slice& y) { + return !(x == y); +} + +inline int Slice::compare(const Slice& b) const { + const size_t min_len = (size_ < b.size_) ? size_ : b.size_; + int r = memcmp(data_, b.data_, min_len); + if (r == 0) { + if (size_ < b.size_) r = -1; + else if (size_ > b.size_) r = +1; + } + return r; +} + +} // namespace leveldb + + +#endif // STORAGE_LEVELDB_INCLUDE_SLICE_H_ |