/** 删除在source中两头的无效字符 */
// 无效的字符由target中的字符来指定
string Trim(const string& source, const string& target)
{
    if (source.size() <= 0)
        return "";

    size_t beginPos, endPos;
    size_t strLen = source.length();

    for (beginPos = 0 ; beginPos < strLen; beginPos++)
    {
        if (std::string::npos == target.find(source.at(beginPos)))
            break;
    }

    for (endPos = strLen - 1 ; endPos > 0 ; endPos--)
    {
        if (std::string::npos == target.find(source.at(endPos)))
            break;
    }

    if (beginPos > endPos)
        return "";

    return source.substr(beginPos, endPos - beginPos + 1);
}

//  删除字符两头的空格无效字符
std::string Trim(const std::string& source)
{
    if (source.empty())
        return source;

    size_t beginPos, endPos;
    size_t strLen = source.length();

    for (beginPos = 0 ; beginPos < strLen; beginPos++)
    {
        // 如果该字符不在要删除的字符串中
        if (!isspace((unsigned char)source[beginPos]))
            break;
    }

    for (endPos = strLen - 1 ; endPos > 0 ; endPos--)
    {
        // 如果该字符不在要删除的字符串中
        if (!isspace((unsigned char)source[endPos]))
            break;
    }

    if (beginPos > endPos)
        return "";

    return source.substr(beginPos, endPos - beginPos + 1);
}


/** 删除在中文字符串两头的中文空格 */
std::string TrimChineseSpace(const std::string& source)
{
    if (source.size() < 2)
        return source;

    int head = 0;
    int tail = (int)source.size() - 2;

    // 确定字符串前面的中文空格的个数
    while ((head <= (int)source.size() - 2) && 0xA1 == (unsigned char)source[head] && 0xA1 == (unsigned char)source[head+1])
        head += 2;

    // 确定字符串前面的中文空格的个数
    while (tail >= 0 && 0xA1 == (unsigned char)source[tail] && 0xA1 == (unsigned char)source[tail+1])
        tail -= 2;

    if (tail < head)
        return "";
    else
        return source.substr(head, tail - head + 2);
}


/** 删除在中文字符串两头的中文空格 */
std::string TrimChineseSpace(const std::string& source)
{
    if (source.size() < 2)
        return source;

    int head = 0;
    int tail = (int)source.size() - 2;

    // 确定字符串前面的中文空格的个数
    while ((head <= (int)source.size() - 2) && 0xA1 == (unsigned char)source[head] && 0xA1 == (unsigned char)source[head+1])
        head += 2;

    // 确定字符串前面的中文空格的个数
    while (tail >= 0 && 0xA1 == (unsigned char)source[tail] && 0xA1 == (unsigned char)source[tail+1])
        tail -= 2;

    if (tail < head)
        return "";
    else
        return source.substr(head, tail - head + 2);
}

/** 删除在中英文字符串两头的中英文空格 */
std::string TrimChEnSpace(const std::string& source)
{
    if (source.size() < 2)
        return source;

    size_t head = 0;
    size_t tail = source.size()-1;
    // 确定字符串前面的中文空格的个数
    while (head <= source.size()-2)
    {
        if (source[head] == ' ')
        {
            head ++;
        }
        else if (source[head] == (char)0xA1 && source[head+1] == (char)0xA1)
        {
            head += 2;
        }
        else
        {
            break;
        }
    }
    // 确定字符串后面的中英文空格的个数
    while (tail > 0)
    {
        if (source[tail] == ' ')
        {
            tail --;
        }
        else if (source[tail-1] == (char)0xA1 && source[tail] == (char)0xA1)
        {
            tail -= 2;
        }
        else
        {
            break;
        }
    }
    if (tail < head)
        return "";
    return source.substr(head, tail - head + 2);
}