作者: 韩晨旭 10225101440 李畅 10225102463
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// 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 <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include "leveldb/env.h"
#include "leveldb/slice.h"
namespace leveldb {
void AppendNumberTo(std::string* str, uint64_t num) {
char buf[30];
snprintf(buf, sizeof(buf), "%llu", (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];
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 ConsumeChar(Slice* in, char c) {
if (!in->empty() && (*in)[0] == c) {
in->remove_prefix(1);
return true;
} else {
return false;
}
}
bool ConsumeDecimalNumber(Slice* in, uint64_t* val) {
uint64_t v = 0;
int digits = 0;
while (!in->empty()) {
char c = (*in)[0];
if (c >= '0' && c <= '9') {
++digits;
const int delta = (c - '0');
static const uint64_t kMaxUint64 = ~static_cast<uint64_t>(0);
if (v > kMaxUint64/10 ||
(v == kMaxUint64/10 && delta > kMaxUint64%10)) {
// Overflow
return false;
}
v = (v * 10) + delta;
in->remove_prefix(1);
} else {
break;
}
}
*val = v;
return (digits > 0);
}
}