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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:45:59 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:45:59 +0000 |
commit | 19fcec84d8d7d21e796c7624e521b60d28ee21ed (patch) | |
tree | 42d26aa27d1e3f7c0b8bd3fd14e7d7082f5008dc /src/zstd/contrib/pzstd/utils/Buffer.h | |
parent | Initial commit. (diff) | |
download | ceph-6d07fdb6bb33b1af39833b850bb6cf8af79fe293.tar.xz ceph-6d07fdb6bb33b1af39833b850bb6cf8af79fe293.zip |
Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/zstd/contrib/pzstd/utils/Buffer.h | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/src/zstd/contrib/pzstd/utils/Buffer.h b/src/zstd/contrib/pzstd/utils/Buffer.h new file mode 100644 index 000000000..f69c3b4d9 --- /dev/null +++ b/src/zstd/contrib/pzstd/utils/Buffer.h @@ -0,0 +1,99 @@ +/* + * Copyright (c) 2016-present, Facebook, Inc. + * All rights reserved. + * + * This source code is licensed under both the BSD-style license (found in the + * LICENSE file in the root directory of this source tree) and the GPLv2 (found + * in the COPYING file in the root directory of this source tree). + */ +#pragma once + +#include "utils/Range.h" + +#include <array> +#include <cstddef> +#include <memory> + +namespace pzstd { + +/** + * A `Buffer` has a pointer to a shared buffer, and a range of the buffer that + * it owns. + * The idea is that you can allocate one buffer, and write chunks into it + * and break off those chunks. + * The underlying buffer is reference counted, and will be destroyed when all + * `Buffer`s that reference it are destroyed. + */ +class Buffer { + std::shared_ptr<unsigned char> buffer_; + MutableByteRange range_; + + static void delete_buffer(unsigned char* buffer) { + delete[] buffer; + } + + public: + /// Construct an empty buffer that owns no data. + explicit Buffer() {} + + /// Construct a `Buffer` that owns a new underlying buffer of size `size`. + explicit Buffer(std::size_t size) + : buffer_(new unsigned char[size], delete_buffer), + range_(buffer_.get(), buffer_.get() + size) {} + + explicit Buffer(std::shared_ptr<unsigned char> buffer, MutableByteRange data) + : buffer_(buffer), range_(data) {} + + Buffer(Buffer&&) = default; + Buffer& operator=(Buffer&&) & = default; + + /** + * Splits the data into two pieces: [begin, begin + n), [begin + n, end). + * Their data both points into the same underlying buffer. + * Modifies the original `Buffer` to point to only [begin + n, end). + * + * @param n The offset to split at. + * @returns A buffer that owns the data [begin, begin + n). + */ + Buffer splitAt(std::size_t n) { + auto firstPiece = range_.subpiece(0, n); + range_.advance(n); + return Buffer(buffer_, firstPiece); + } + + /// Modifies the buffer to point to the range [begin + n, end). + void advance(std::size_t n) { + range_.advance(n); + } + + /// Modifies the buffer to point to the range [begin, end - n). + void subtract(std::size_t n) { + range_.subtract(n); + } + + /// Returns a read only `Range` pointing to the `Buffer`s data. + ByteRange range() const { + return range_; + } + /// Returns a mutable `Range` pointing to the `Buffer`s data. + MutableByteRange range() { + return range_; + } + + const unsigned char* data() const { + return range_.data(); + } + + unsigned char* data() { + return range_.data(); + } + + std::size_t size() const { + return range_.size(); + } + + bool empty() const { + return range_.empty(); + } +}; +} |