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include/xrpl/basics/CompressionAlgorithms.h

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+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2020 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#ifndef RIPPLED_COMPRESSIONALGORITHMS_H_INCLUDED
+#define RIPPLED_COMPRESSIONALGORITHMS_H_INCLUDED
+
+#include <ripple/basics/contract.h>
+#include <algorithm>
+#include <cstdint>
+#include <lz4.h>
+#include <stdexcept>
+#include <vector>
+
+namespace ripple {
+
+namespace compression_algorithms {
+
+/** LZ4 block compression.
+ * @tparam BufferFactory Callable object or lambda.
+ *     Takes the requested buffer size and returns allocated buffer pointer.
+ * @param in Data to compress
+ * @param inSize Size of the data
+ * @param bf Compressed buffer allocator
+ * @return Size of compressed data, or zero if failed to compress
+ */
+template <typename BufferFactory>
+std::size_t
+lz4Compress(void const* in, std::size_t inSize, BufferFactory&& bf)
+{
+    if (inSize > UINT32_MAX)
+        Throw<std::runtime_error>("lz4 compress: invalid size");
+
+    auto const outCapacity = LZ4_compressBound(inSize);
+
+    // Request the caller to allocate and return the buffer to hold compressed
+    // data
+    auto compressed = bf(outCapacity);
+
+    auto compressedSize = LZ4_compress_default(
+        reinterpret_cast<const char*>(in),
+        reinterpret_cast<char*>(compressed),
+        inSize,
+        outCapacity);
+    if (compressedSize == 0)
+        Throw<std::runtime_error>("lz4 compress: failed");
+
+    return compressedSize;
+}
+
+/**
+ * @param in Compressed data
+ * @param inSizeUnchecked Size of compressed data
+ * @param decompressed Buffer to hold decompressed data
+ * @param decompressedSizeUnchecked Size of the decompressed buffer
+ * @return size of the decompressed data
+ */
+inline std::size_t
+lz4Decompress(
+    std::uint8_t const* in,
+    std::size_t inSizeUnchecked,
+    std::uint8_t* decompressed,
+    std::size_t decompressedSizeUnchecked)
+{
+    int const inSize = static_cast<int>(inSizeUnchecked);
+    int const decompressedSize = static_cast<int>(decompressedSizeUnchecked);
+
+    if (inSize <= 0)
+        Throw<std::runtime_error>("lz4Decompress: integer overflow (input)");
+
+    if (decompressedSize <= 0)
+        Throw<std::runtime_error>("lz4Decompress: integer overflow (output)");
+
+    if (LZ4_decompress_safe(
+            reinterpret_cast<const char*>(in),
+            reinterpret_cast<char*>(decompressed),
+            inSize,
+            decompressedSize) != decompressedSize)
+        Throw<std::runtime_error>("lz4Decompress: failed");
+
+    return decompressedSize;
+}
+
+/** LZ4 block decompression.
+ * @tparam InputStream ZeroCopyInputStream
+ * @param in Input source stream
+ * @param inSize Size of compressed data
+ * @param decompressed Buffer to hold decompressed data
+ * @param decompressedSize Size of the decompressed buffer
+ * @return size of the decompressed data
+ */
+template <typename InputStream>
+std::size_t
+lz4Decompress(
+    InputStream& in,
+    std::size_t inSize,
+    std::uint8_t* decompressed,
+    std::size_t decompressedSize)
+{
+    std::vector<std::uint8_t> compressed;
+    std::uint8_t const* chunk = nullptr;
+    int chunkSize = 0;
+    int copiedInSize = 0;
+    auto const currentBytes = in.ByteCount();
+
+    // Use the first chunk if it is >= inSize bytes of the compressed message.
+    // Otherwise copy inSize bytes of chunks into compressed buffer and
+    // use the buffer to decompress.
+    while (in.Next(reinterpret_cast<void const**>(&chunk), &chunkSize))
+    {
+        if (copiedInSize == 0)
+        {
+            if (chunkSize >= inSize)
+            {
+                copiedInSize = inSize;
+                break;
+            }
+            compressed.resize(inSize);
+        }
+
+        chunkSize = chunkSize < (inSize - copiedInSize)
+            ? chunkSize
+            : (inSize - copiedInSize);
+
+        std::copy(chunk, chunk + chunkSize, compressed.data() + copiedInSize);
+
+        copiedInSize += chunkSize;
+
+        if (copiedInSize == inSize)
+        {
+            chunk = compressed.data();
+            break;
+        }
+    }
+
+    // Put back unused bytes
+    if (in.ByteCount() > (currentBytes + copiedInSize))
+        in.BackUp(in.ByteCount() - currentBytes - copiedInSize);
+
+    if ((copiedInSize == 0 && chunkSize < inSize) ||
+        (copiedInSize > 0 && copiedInSize != inSize))
+        Throw<std::runtime_error>("lz4 decompress: insufficient input size");
+
+    return lz4Decompress(chunk, inSize, decompressed, decompressedSize);
+}
+
+}  // namespace compression_algorithms
+
+}  // namespace ripple
+
+#endif  // RIPPLED_COMPRESSIONALGORITHMS_H_INCLUDED