add leveldb

lib/leveldb/util/logging.cc

@@ -0,0 +1,82 @@
+// 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/logging.h"
+
+#include <cstdarg>
+#include <cstdio>
+#include <cstdlib>
+#include <limits>
+
+#include "leveldb/env.h"
+#include "leveldb/slice.h"
+
+namespace leveldb {
+
+void AppendNumberTo(std::string* str, uint64_t num) {
+  char buf[30];
+  std::snprintf(buf, sizeof(buf), "%llu", static_cast<unsigned long long>(num));
+  str->append(buf);
+}
+
+void AppendEscapedStringTo(std::string* str, const Slice& value) {
+  for (size_t i = 0; i < value.size(); i++) {
+    char c = value[i];
+    if (c >= ' ' && c <= '~') {
+      str->push_back(c);
+    } else {
+      char buf[10];
+      std::snprintf(buf, sizeof(buf), "\\x%02x",
+                    static_cast<unsigned int>(c) & 0xff);
+      str->append(buf);
+    }
+  }
+}
+
+std::string NumberToString(uint64_t num) {
+  std::string r;
+  AppendNumberTo(&r, num);
+  return r;
+}
+
+std::string EscapeString(const Slice& value) {
+  std::string r;
+  AppendEscapedStringTo(&r, value);
+  return r;
+}
+
+bool ConsumeDecimalNumber(Slice* in, uint64_t* val) {
+  // Constants that will be optimized away.
+  constexpr const uint64_t kMaxUint64 = std::numeric_limits<uint64_t>::max();
+  constexpr const char kLastDigitOfMaxUint64 =
+      '0' + static_cast<char>(kMaxUint64 % 10);
+
+  uint64_t value = 0;
+
+  // reinterpret_cast-ing from char* to uint8_t* to avoid signedness.
+  const uint8_t* start = reinterpret_cast<const uint8_t*>(in->data());
+
+  const uint8_t* end = start + in->size();
+  const uint8_t* current = start;
+  for (; current != end; ++current) {
+    const uint8_t ch = *current;
+    if (ch < '0' || ch > '9') break;
+
+    // Overflow check.
+    // kMaxUint64 / 10 is also constant and will be optimized away.
+    if (value > kMaxUint64 / 10 ||
+        (value == kMaxUint64 / 10 && ch > kLastDigitOfMaxUint64)) {
+      return false;
+    }
+
+    value = (value * 10) + (ch - '0');
+  }
+
+  *val = value;
+  const size_t digits_consumed = current - start;
+  in->remove_prefix(digits_consumed);
+  return digits_consumed != 0;
+}
+
+}  // namespace leveldb