CStrFun

#ifndef _STR_FUN_H_030802
#define _STR_FUN_H_030802

#include <string>
#include <sstream>
#include <iostream>
#include <algorithm>

using namespace std;

class CStrFun
{
public:
    CStrFun();
    virtual ~CStrFun();
    //把类中的函数都定义成静态函数，这样相当于在编译时就分配了空间，这样不需要实体对象也可以调用泪中的函数了。
    static void Str2Lower(string &sSource, int nLen);
    static string itos(long long i)
    {
        stringstream s;
        s << i;
        return s.str();
    }

    /* Locate a substring ignoring case
     * The  function  returns a value equal or lager than zero,
         * or -1 if the substring is not found.
     */

    static string::size_type FindCase(string haystack, string needle);
    static string::size_type FindCaseFrom(string haystack, string needle, int From);

    static void ReplaceStr(string &str, string srstr, string dsstr);
    static void EraseStr(string &str, string substr);
};

#endif    // end _STR_FUN_H_030802

/*
ostringstream oss<<Dea<<'.'<<pre();

oss.str();
*/

#include "StrFun.h"

CStrFun::CStrFun() {

}

CStrFun::~CStrFun() {

}

void CStrFun::Str2Lower(string& str, int nLen) //将大写字母改写成小写字母
        {
    char distance = 'A' - 'a';

    for (int i = 0; i < nLen; i++)
        if (str[i] >= 'A' && str[i] <= 'Z')
            str[i] -= distance;
}

bool _nocase_compare(char c1, char c2) //不区分大小写的比较
        {
    return toupper(c1) == toupper(c2);
}

string::size_type CStrFun::FindCase(string haystack, string needle) //在haystack中找第一个匹配needle的位置
        {
    if (haystack.empty())
        return string::npos;
    if (needle.empty())
        return string::npos;

    string::iterator pos;
    pos = search(haystack.begin(), haystack.end(), needle.begin(), needle.end(),
            _nocase_compare);

    if (pos == haystack.end()) {
        return string::npos;
    } else {
        return (pos - haystack.begin());
    }
}

string::size_type CStrFun::FindCaseFrom(string haystack, string needle,
        int nFrom) //在haystack中的第n个位置找第一个匹配needle的位置
        {
    //assert( haystack.empty() == false );
    //assert( needle.empty() == false );
    if (haystack.empty())
        return string::npos;
    if (needle.empty())
        return string::npos;

    string::iterator pos;
    pos = search(haystack.begin() + nFrom, haystack.end(), needle.begin(),
            needle.end(), _nocase_compare);

    if (pos == haystack.end()) {
        return string::npos;
    } else {
        return (pos - haystack.begin());
    }
}

void CStrFun::EraseStr(string &str, string substr) //在str中删除所有出现的substr
        {
    if (str.size() == 0 || substr.size() == 0)
        return;

    string::size_type idx = 0;
    string::size_type sub_length = substr.length();
    idx = str.find(substr, idx);
    while (idx != string::npos) {
        str.erase(idx, sub_length);
        idx = str.find(substr, idx);
    }
}

void CStrFun::ReplaceStr(string&str, string srstr, string dsstr) //将str中的字串替换成dsstr
        {
    if (str.size() == 0 || srstr.size() == 0)
        return;

    string::size_type idx = 0;
    string::size_type sub_length = srstr.length();
    idx = str.find(srstr, idx);
    while (idx != string::npos) {
        str.replace(idx, sub_length, dsstr);

        if (idx + dsstr.size() > str.size())
            break;

        idx = str.find(srstr, idx + dsstr.size());
    }
}