WritePrivateProfileString和GetPrivateProfileString最大长度测试

• • 1. 前言
  • 2. 测试
  • 总结

1. 前言

• 读写Ini文件代码如下
  Ini.h

#ifndef __INI__
#define __INI__

#include <tchar.h>
#include <Windows.h>
#include <string>

class Ini
{
public:
    static BOOL WriteIni( 
        std::wstring lpNodeName,  // INI文件中的一个字段名[节名]可以有很多个节名
        std::wstring lpKeyName,   // lpNodeName 下的一个键名，也就是里面具体的变量名
        std::wstring lpValue,     // 键值,也就是数据
        std::wstring lpFileName   // INI文件的路径
    );

    static DWORD ReadStringFromIni(
        LPCTSTR lpAppName,           // 节名
        LPCTSTR lpKeyName,           // 键名，读取该键的值
        LPCTSTR lpDefault,       // 若指定的键不存在，该值作为读取的默认值
        LPTSTR lpReturnedString,     // 一个指向缓冲区的指针，接收读取的字符串
        DWORD nSize,                 // 指定lpReturnedString指向的缓冲区的大小
        LPCTSTR lpFileName
    );

    static UINT ReadIntFromIni(
        LPCTSTR lpAppName,     // 同上
        LPCTSTR lpKeyName,     // 同上
        INT nDefault,          // 若指定的键名不存在，该值作为读取的默认值
        LPCTSTR lpFileName
    );

private:
    Ini() {};
    Ini(const Ini &ini) {};
    ~Ini(){};

};

#endif

Ini.cpp

#include "Ini.h"

BOOL Ini::WriteIni( 
                   std::wstring lpNodeName, 
                   std::wstring lpKeyName, 
                   std::wstring lpValue,
                   std::wstring lpFileName 
)
{
    return WritePrivateProfileString(lpNodeName.c_str(), lpKeyName.c_str(), lpValue.c_str(), lpFileName.c_str());
}

DWORD Ini::ReadStringFromIni(
            LPCTSTR lpAppName, 
            LPCTSTR lpKeyName, 
            LPCTSTR lpDefault, 
            LPTSTR lpReturnedString, 
            DWORD nSize, 
            LPCTSTR lpFileName
)
{
    return GetPrivateProfileString(lpAppName, lpKeyName, lpDefault, lpReturnedString, nSize, lpFileName);
}

UINT Ini::ReadIntFromIni( 
            LPCTSTR lpAppName, 
            LPCTSTR lpKeyName, 
            INT nDefault, 
            LPCTSTR lpFileName 
)
{
    return GetPrivateProfileInt(lpAppName, lpKeyName, nDefault, lpFileName);
}

2. 测试

测试值的最大长度

• 测试单次写入键value的值长度为65000个字符
• 结果表明可以成功的写入65000个字符
  

测试的代码

#include <Windows.h>
#include <tchar.h>

#include "Ini.h"
#include <iostream>
#include <string>
using namespace std;

int _tmain(int argc, TCHAR const *argv[])
{
    TCHAR tmp[65000];
    wstring s(65000, L'.');
    wcout << s.length() << endl;
    Ini::WriteIni(L"test.txt", L"value", s, L".\\test.txt");
    Ini::ReadStringFromIni(L"test.txt", L"value", L"", tmp, 65000, L".\\test.txt");
    s = tmp;
    wcout << s.length() << endl;
    return 0;
}

• 但当单次写入的长度大于等于66000个字符时
• 第一次是成功写入了66000个字符，但读出只有464个字符的长度
  
• 且多次运行的话，value这个键的值的字符不是被覆盖，而是一直增加（65000个字符的情况下，重新写入值时，旧的值会被覆盖，不会增加）
• 运行三次的情况如下（结果显示写入并不是3*66000的长度）
  

测试的代码

#include <Windows.h>
#include <tchar.h>

#include "Ini.h"
#include <iostream>
#include <string>
using namespace std;

int _tmain(int argc, TCHAR const *argv[])
{
    TCHAR tmp[65000];
    wstring s(65000, L'.');
    wcout << s.length() << endl;
    Ini::WriteIni(L"test.txt", L"value", s, L".\\test.txt");
    Ini::ReadStringFromIni(L"test.txt", L"value", L"", tmp, 65000, L".\\test.txt");
    s = tmp;
    wcout << s.length() << endl;
    return 0;
}

• 写入多个键的值长度为65000个字符
• 结果如图，表明键的长度能够达到65000个字符
  

#include <Windows.h>
#include <tchar.h>

#include "Ini.h"
#include <iostream>
#include <string>
using namespace std;

int _tmain(int argc, TCHAR const *argv[])
{
    TCHAR tmp[65000];
    wstring s(65000, L'.');
    wcout << L"s length: "<< s.length() << endl;
    Ini::WriteIni(L"test.txt", L"value1", s, L".\\test.txt");
    Ini::ReadStringFromIni(L"test.txt", L"value1", L"", tmp, 65000, L".\\test.txt");
    s = tmp;
    wcout << L"value1 length: " << s.length() << endl;

    Ini::WriteIni(L"test.txt", L"value2", s, L".\\test.txt");
    Ini::ReadStringFromIni(L"test.txt", L"value2", L"", tmp, 65000, L".\\test.txt");
    s = tmp;
    wcout << L"value2 length: " << s.length() << endl;

    Ini::WriteIni(L"test.txt", L"value3", s, L".\\test.txt");
    Ini::ReadStringFromIni(L"test.txt", L"value3", L"", tmp, 65000, L".\\test.txt");
    s = tmp;
    wcout << L"value3 length: " << s.length() << endl;

    Ini::WriteIni(L"test.txt", L"value4", s, L".\\test.txt");
    Ini::ReadStringFromIni(L"test.txt", L"value4", L"", tmp, 65000, L".\\test.txt");
    s = tmp;
    wcout << L"value4 length: " << s.length() << endl;
    return 0;
}

测试键的最大长度

• 有了上述的经验
• 直接测试多个键的长度为65000个字符（结果表明也是正常的）
  

测试代码：

#include <Windows.h>
#include <tchar.h>

#include "Ini.h"
#include <iostream>
#include <string>
using namespace std;

int _tmain(int argc, TCHAR const *argv[])
{
    TCHAR tmp[65000];
    wstring s1(65000, L'1');
    wcout << L"s1 length: "<< s1.length() << endl;
    Ini::WriteIni(L"test.txt", s1, L"value1", L".\\test.txt");
    Ini::ReadStringFromIni(L"test.txt", s1.c_str(), L"", tmp, 65000, L".\\test.txt");
    wcout << L"value1: " << tmp << endl;

    wstring s2(65000, L'2');
    wcout << L"s2 length: "<< s2.length() << endl;
    Ini::WriteIni(L"test.txt", s2, L"value2", L".\\test.txt");
    Ini::ReadStringFromIni(L"test.txt", s2.c_str(), L"", tmp, 65000, L".\\test.txt");
    wcout << L"value2: " << tmp << endl;

    wstring s3(65000, L'3');
    wcout << L"s3 length: "<< s3.length() << endl;
    Ini::WriteIni(L"test.txt", s3, L"value3", L".\\test.txt");
    Ini::ReadStringFromIni(L"test.txt", s3.c_str(), L"", tmp, 65000, L".\\test.txt");
    wcout << L"value3: " << tmp << endl;
    return 0;
}

键与值长度均为65000个字符

• 结果显示也正常
  

#include <Windows.h>
#include <tchar.h>

#include "Ini.h"
#include <iostream>
#include <string>
using namespace std;

int _tmain(int argc, TCHAR const *argv[])
{
    TCHAR tmp[65000];
    wstring s(65000, L'.');
    wstring s1(65000, L'1');
    wcout << L"s1 length: "<< s1.length() << endl;
    Ini::WriteIni(L"test.txt", s1, s, L".\\test.txt");
    Ini::ReadStringFromIni(L"test.txt", s1.c_str(), L"", tmp, 65000, L".\\test.txt");
    s = tmp;
    wcout << L"value1 length: " << s.length() << endl;

    wstring s2(65000, L'2');
    wcout << L"s2 length: "<< s2.length() << endl;
    Ini::WriteIni(L"test.txt", s2, s, L".\\test.txt");
    Ini::ReadStringFromIni(L"test.txt", s2.c_str(), L"", tmp, 65000, L".\\test.txt");
    s = tmp;
    wcout << L"value2 length: " << s.length() << endl;

    wstring s3(65000, L'3');
    wcout << L"s3 length: "<< s3.length() << endl;
    Ini::WriteIni(L"test.txt", s3, s, L".\\test.txt");
    Ini::ReadStringFromIni(L"test.txt", s3.c_str(), L"", tmp, 65000, L".\\test.txt");
    s = tmp;
    wcout << L"value3 length: " << s.length() << endl;
    return 0;
}

总结

• WritePrivateProfileString和GetPrivateProfileString键与值的最大长度大概为 65000个字符， 精确值未测量
• 可能与编译器，操作系统有关； 上述结果使用的是vs2008， windows 7环境测试的