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-rw-r--r--src/rocksdb/util/coding.cc89
1 files changed, 89 insertions, 0 deletions
diff --git a/src/rocksdb/util/coding.cc b/src/rocksdb/util/coding.cc
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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.
+
+#include "util/coding.h"
+
+#include <algorithm>
+#include "rocksdb/slice.h"
+#include "rocksdb/slice_transform.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+// conversion' conversion from 'type1' to 'type2', possible loss of data
+#if defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable : 4244)
+#endif
+char* EncodeVarint32(char* dst, uint32_t v) {
+ // Operate on characters as unsigneds
+ unsigned char* ptr = reinterpret_cast<unsigned char*>(dst);
+ static const int B = 128;
+ if (v < (1 << 7)) {
+ *(ptr++) = v;
+ } else if (v < (1 << 14)) {
+ *(ptr++) = v | B;
+ *(ptr++) = v >> 7;
+ } else if (v < (1 << 21)) {
+ *(ptr++) = v | B;
+ *(ptr++) = (v >> 7) | B;
+ *(ptr++) = v >> 14;
+ } else if (v < (1 << 28)) {
+ *(ptr++) = v | B;
+ *(ptr++) = (v >> 7) | B;
+ *(ptr++) = (v >> 14) | B;
+ *(ptr++) = v >> 21;
+ } else {
+ *(ptr++) = v | B;
+ *(ptr++) = (v >> 7) | B;
+ *(ptr++) = (v >> 14) | B;
+ *(ptr++) = (v >> 21) | B;
+ *(ptr++) = v >> 28;
+ }
+ return reinterpret_cast<char*>(ptr);
+}
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
+
+const char* GetVarint32PtrFallback(const char* p, const char* limit,
+ uint32_t* value) {
+ uint32_t result = 0;
+ for (uint32_t shift = 0; shift <= 28 && p < limit; shift += 7) {
+ uint32_t byte = *(reinterpret_cast<const unsigned char*>(p));
+ p++;
+ if (byte & 128) {
+ // More bytes are present
+ result |= ((byte & 127) << shift);
+ } else {
+ result |= (byte << shift);
+ *value = result;
+ return reinterpret_cast<const char*>(p);
+ }
+ }
+ return nullptr;
+}
+
+const char* GetVarint64Ptr(const char* p, const char* limit, uint64_t* value) {
+ uint64_t result = 0;
+ for (uint32_t shift = 0; shift <= 63 && p < limit; shift += 7) {
+ uint64_t byte = *(reinterpret_cast<const unsigned char*>(p));
+ p++;
+ if (byte & 128) {
+ // More bytes are present
+ result |= ((byte & 127) << shift);
+ } else {
+ result |= (byte << shift);
+ *value = result;
+ return reinterpret_cast<const char*>(p);
+ }
+ }
+ return nullptr;
+}
+
+} // namespace ROCKSDB_NAMESPACE