LogStream.h
// Use of this source code is governed by a BSD-style license
// that can be found in the License file.
//
// Author: Shuo Chen (chenshuo at chenshuo dot com)
#ifndef MUDUO_BASE_LOGSTREAM_H
#define MUDUO_BASE_LOGSTREAM_H
#include "muduo/base/noncopyable.h"
#include "muduo/base/StringPiece.h"
#include "muduo/base/Types.h"
#include <assert.h>
#include <string.h> // memcpy
namespace muduo
{
namespace detail
{
const int kSmallBuffer = 4000;
const int kLargeBuffer = 4000*1000;
//1k = 1024B
//1M = 1024k
//kLargeBuffer = 4M
template<int SIZE>
class FixedBuffer : noncopyable
{
public:
FixedBuffer()
: cur_(data_)
{
setCookie(cookieStart);
}
~FixedBuffer()
{
setCookie(cookieEnd);
}
void append(const char* /*restrict*/ buf, size_t len)
{
// FIXME: append partially
if (implicit_cast<size_t>(avail()) > len)
{
memcpy(cur_, buf, len);
cur_ += len;
}
}
const char* data() const { return data_; }
int length() const { return static_cast<int>(cur_ - data_); }
// write to data_ directly
char* current() { return cur_; }
int avail() const { return static_cast<int>(end() - cur_); }
void add(size_t len) { cur_ += len; }
void reset() { cur_ = data_; }
void bzero() { memZero(data_, sizeof data_); }
// for used by GDB
const char* debugString();
void setCookie(void (*cookie)()) { cookie_ = cookie; }
// for used by unit test
string toString() const { return string(data_, length()); }
StringPiece toStringPiece() const { return StringPiece(data_, length()); }
private:
const char* end() const { return data_ + sizeof data_; }
// Must be outline function for cookies.
static void cookieStart();
static void cookieEnd();
void (*cookie_)();
char data_[SIZE];
char* cur_;
};
} // namespace detail
class LogStream : noncopyable
{
typedef LogStream self;
public:
typedef detail::FixedBuffer<detail::kSmallBuffer> Buffer;
self& operator<<(bool v)
{
buffer_.append(v ? "1" : "0", 1);
return *this;
}
self& operator<<(short);
self& operator<<(unsigned short);
self& operator<<(int);
self& operator<<(unsigned int);
self& operator<<(long);
self& operator<<(unsigned long);
self& operator<<(long long);
self& operator<<(unsigned long long);
self& operator<<(const void*);
self& operator<<(float v)
{
*this << static_cast<double>(v);
return *this;
}
self& operator<<(double);
// self& operator<<(long double);
self& operator<<(char v)
{
buffer_.append(&v, 1);
return *this;
}
// self& operator<<(signed char);
// self& operator<<(unsigned char);
self& operator<<(const char* str)
{
if (str)
{
buffer_.append(str, strlen(str));
}
else
{
buffer_.append("(null)", 6);
}
return *this;
}
self& operator<<(const unsigned char* str)
{
return operator<<(reinterpret_cast<const char*>(str));
}
self& operator<<(const string& v)
{
buffer_.append(v.c_str(), v.size());
return *this;
}
self& operator<<(const StringPiece& v)
{
buffer_.append(v.data(), v.size());
return *this;
}
self& operator<<(const Buffer& v)
{
*this << v.toStringPiece();
return *this;
}
void append(const char* data, int len) { buffer_.append(data, len); }
const Buffer& buffer() const { return buffer_; }
void resetBuffer() { buffer_.reset(); }
private:
void staticCheck();
template<typename T>
void formatInteger(T);
Buffer buffer_;
static const int kMaxNumericSize = 32;
};
class Fmt // : noncopyable
{
public:
template<typename T>
Fmt(const char* fmt, T val); //模板構造函數
const char* data() const { return buf_; }
int length() const { return length_; }
private:
char buf_[32];
int length_;
};
inline LogStream& operator<<(LogStream& s, const Fmt& fmt)
{
s.append(fmt.data(), fmt.length());
return s;
}
// Format quantity n in SI units (k, M, G, T, P, E).
// The returned string is atmost 5 characters long.
// Requires n >= 0
string formatSI(int64_t n);
// Format quantity n in IEC (binary) units (Ki, Mi, Gi, Ti, Pi, Ei).
// The returned string is atmost 6 characters long.
// Requires n >= 0
string formatIEC(int64_t n);
} // namespace muduo
#endif // MUDUO_BASE_LOGSTREAM_H
LogStream.cc
// Use of this source code is governed by a BSD-style license
// that can be found in the License file.
//
// Author: Shuo Chen (chenshuo at chenshuo dot com)
#include "muduo/base/LogStream.h"
#include <algorithm>
#include <limits>
#include <type_traits>
#include <assert.h>
#include <string.h>
#include <stdint.h>
#include <stdio.h>
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include <inttypes.h>
using namespace muduo;
using namespace muduo::detail;
// TODO: better itoa.
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wtautological-compare"
#else
#pragma GCC diagnostic ignored "-Wtype-limits"
#endif
namespace muduo
{
namespace detail
{
const char digits[] = "9876543210123456789";
const char* zero = digits + 9;//zero兩邊對稱，因爲餘數可能爲負數
static_assert(sizeof(digits) == 20, "wrong number of digits");
const char digitsHex[] = "0123456789ABCDEF";//十六進制時使用
static_assert(sizeof digitsHex == 17, "wrong number of digitsHex");
// Efficient Integer to String Conversions, by Matthew Wilson.
template<typename T>
size_t convert(char buf[], T value)//把value轉爲字符串，並返回字符串放到buf中，並返回字符串長度
{
T i = value;
char* p = buf;
do
{
int lsd = static_cast<int>(i % 10);
i /= 10;
*p++ = zero[lsd];
} while (i != 0);
if (value < 0)
{
*p++ = '-';
}
*p = '\0';
std::reverse(buf, p);//逆轉[buf p)
return p - buf;
}
size_t convertHex(char buf[], uintptr_t value)//轉爲十六進制字符串
{
uintptr_t i = value;
char* p = buf;
do
{
int lsd = static_cast<int>(i % 16);
i /= 16;
*p++ = digitsHex[lsd];
} while (i != 0);
*p = '\0';
std::reverse(buf, p);
return p - buf;
}
template class FixedBuffer<kSmallBuffer>;//FixedBuffer實例化
template class FixedBuffer<kLargeBuffer>;//FixedBuffer實例化
} // namespace detail
/*
Format a number with 5 characters, including SI units.
[0, 999]
[1.00k, 999k]
[1.00M, 999M]
[1.00G, 999G]
[1.00T, 999T]
[1.00P, 999P]
[1.00E, inf)
*/
std::string formatSI(int64_t s)//格式數量單位爲(k, M, G, T, P, E)
{
double n = static_cast<double>(s);
char buf[64];
if (s < 1000)
snprintf(buf, sizeof(buf), "%" PRId64, s);
else if (s < 9995)
snprintf(buf, sizeof(buf), "%.2fk", n/1e3);
else if (s < 99950)
snprintf(buf, sizeof(buf), "%.1fk", n/1e3);
else if (s < 999500)
snprintf(buf, sizeof(buf), "%.0fk", n/1e3);
else if (s < 9995000)
snprintf(buf, sizeof(buf), "%.2fM", n/1e6);
else if (s < 99950000)
snprintf(buf, sizeof(buf), "%.1fM", n/1e6);
else if (s < 999500000)
snprintf(buf, sizeof(buf), "%.0fM", n/1e6);
else if (s < 9995000000)
snprintf(buf, sizeof(buf), "%.2fG", n/1e9);
else if (s < 99950000000)
snprintf(buf, sizeof(buf), "%.1fG", n/1e9);
else if (s < 999500000000)
snprintf(buf, sizeof(buf), "%.0fG", n/1e9);
else if (s < 9995000000000)
snprintf(buf, sizeof(buf), "%.2fT", n/1e12);
else if (s < 99950000000000)
snprintf(buf, sizeof(buf), "%.1fT", n/1e12);
else if (s < 999500000000000)
snprintf(buf, sizeof(buf), "%.0fT", n/1e12);
else if (s < 9995000000000000)
snprintf(buf, sizeof(buf), "%.2fP", n/1e15);
else if (s < 99950000000000000)
snprintf(buf, sizeof(buf), "%.1fP", n/1e15);
else if (s < 999500000000000000)
snprintf(buf, sizeof(buf), "%.0fP", n/1e15);
else
snprintf(buf, sizeof(buf), "%.2fE", n/1e18);
return buf;
}
/*
[0, 1023]
[1.00Ki, 9.99Ki]
[10.0Ki, 99.9Ki]
[ 100Ki, 1023Ki]
[1.00Mi, 9.99Mi]
*/
std::string formatIEC(int64_t s)
{
double n = static_cast<double>(s);
char buf[64];
const double Ki = 1024.0;
const double Mi = Ki * 1024.0;
const double Gi = Mi * 1024.0;
const double Ti = Gi * 1024.0;
const double Pi = Ti * 1024.0;
const double Ei = Pi * 1024.0;
if (n < Ki)
snprintf(buf, sizeof buf, "%" PRId64, s);
else if (n < Ki*9.995)
snprintf(buf, sizeof buf, "%.2fKi", n / Ki);
else if (n < Ki*99.95)
snprintf(buf, sizeof buf, "%.1fKi", n / Ki);
else if (n < Ki*1023.5)
snprintf(buf, sizeof buf, "%.0fKi", n / Ki);
else if (n < Mi*9.995)
snprintf(buf, sizeof buf, "%.2fMi", n / Mi);
else if (n < Mi*99.95)
snprintf(buf, sizeof buf, "%.1fMi", n / Mi);
else if (n < Mi*1023.5)
snprintf(buf, sizeof buf, "%.0fMi", n / Mi);
else if (n < Gi*9.995)
snprintf(buf, sizeof buf, "%.2fGi", n / Gi);
else if (n < Gi*99.95)
snprintf(buf, sizeof buf, "%.1fGi", n / Gi);
else if (n < Gi*1023.5)
snprintf(buf, sizeof buf, "%.0fGi", n / Gi);
else if (n < Ti*9.995)
snprintf(buf, sizeof buf, "%.2fTi", n / Ti);
else if (n < Ti*99.95)
snprintf(buf, sizeof buf, "%.1fTi", n / Ti);
else if (n < Ti*1023.5)
snprintf(buf, sizeof buf, "%.0fTi", n / Ti);
else if (n < Pi*9.995)
snprintf(buf, sizeof buf, "%.2fPi", n / Pi);
else if (n < Pi*99.95)
snprintf(buf, sizeof buf, "%.1fPi", n / Pi);
else if (n < Pi*1023.5)
snprintf(buf, sizeof buf, "%.0fPi", n / Pi);
else if (n < Ei*9.995)
snprintf(buf, sizeof buf, "%.2fEi", n / Ei );
else
snprintf(buf, sizeof buf, "%.1fEi", n / Ei );
return buf;
}
} // namespace muduo
template<int SIZE>
const char* FixedBuffer<SIZE>::debugString() //const成員函數
{
*cur_ = '\0';
return data_;
}
template<int SIZE>
void FixedBuffer<SIZE>::cookieStart() //靜態成員函數
{
}
template<int SIZE>
void FixedBuffer<SIZE>::cookieEnd() //靜態成員函數
{
}
void LogStream::staticCheck()// 靜態檢查，用於檢查一些類型的大小
{
static_assert(kMaxNumericSize - 10 > std::numeric_limits<double>::digits10,
"kMaxNumericSize is large enough");
static_assert(kMaxNumericSize - 10 > std::numeric_limits<long double>::digits10,
"kMaxNumericSize is large enough");
static_assert(kMaxNumericSize - 10 > std::numeric_limits<long>::digits10,
"kMaxNumericSize is large enough");
static_assert(kMaxNumericSize - 10 > std::numeric_limits<long long>::digits10,
"kMaxNumericSize is large enough");
}
template<typename T>
void LogStream::formatInteger(T v)//將T類型v轉爲10進制並綴到buffer_後
{
if (buffer_.avail() >= kMaxNumericSize)
{
size_t len = convert(buffer_.current(), v);
buffer_.add(len);
}
}
LogStream& LogStream::operator<<(short v)//重載<<的實現
{
*this << static_cast<int>(v);
return *this;
}
LogStream& LogStream::operator<<(unsigned short v)//重載
{
*this << static_cast<unsigned int>(v);
return *this;
}
LogStream& LogStream::operator<<(int v)//重載
{
formatInteger(v);
return *this;
}
LogStream& LogStream::operator<<(unsigned int v)//重載
{
formatInteger(v);
return *this;
}
LogStream& LogStream::operator<<(long v)//重載
{
formatInteger(v);
return *this;
}
LogStream& LogStream::operator<<(unsigned long v)//重載
{
formatInteger(v);
return *this;
}
LogStream& LogStream::operator<<(long long v)//重載
{
formatInteger(v);
return *this;
}
LogStream& LogStream::operator<<(unsigned long long v)//重載
{
formatInteger(v);
return *this;
}
LogStream& LogStream::operator<<(const void* p)//將p指向的內容轉換爲十六進制並綴到buffer_
{
uintptr_t v = reinterpret_cast<uintptr_t>(p);
if (buffer_.avail() >= kMaxNumericSize)
{
char* buf = buffer_.current();
buf[0] = '0';
buf[1] = 'x';
size_t len = convertHex(buf+2, v);
buffer_.add(len+2);
}
return *this;
}
// FIXME: replace this with Grisu3 by Florian Loitsch.
LogStream& LogStream::operator<<(double v)
{
if (buffer_.avail() >= kMaxNumericSize)
{
int len = snprintf(buffer_.current(), kMaxNumericSize, "%.12g", v);
buffer_.add(len);
}
return *this;
}
template<typename T>
Fmt::Fmt(const char* fmt, T val)
{
static_assert(std::is_arithmetic<T>::value == true, "Must be arithmetic type");
length_ = snprintf(buf_, sizeof buf_, fmt, val);
assert(static_cast<size_t>(length_) < sizeof buf_);
}
// Explicit instantiations
//構造函數
template Fmt::Fmt(const char* fmt, char);
template Fmt::Fmt(const char* fmt, short);
template Fmt::Fmt(const char* fmt, unsigned short);
template Fmt::Fmt(const char* fmt, int);
template Fmt::Fmt(const char* fmt, unsigned int);
template Fmt::Fmt(const char* fmt, long);
template Fmt::Fmt(const char* fmt, unsigned long);
template Fmt::Fmt(const char* fmt, long long);
template Fmt::Fmt(const char* fmt, unsigned long long);
template Fmt::Fmt(const char* fmt, float);
template Fmt::Fmt(const char* fmt, double);