darwin源码一些小问题

[白杨先生]

darwin streaming server 5.5.5 源码中，StrPtrLen.cpp文件下PrintStrEOL()函数定义：

void StrPtrLen::PrintStrEOL(char* stopStr, char *appendStr)
{
           
 
    char *thestr = GetAsCString();
    
    SInt32 i = 0;
    for (; i < (SInt32) Len; i ++) //for循环，保留thestr中没有被禁止打印的字符
    { 
       if (StrPtrLen::sNonPrintChars[Ptr[i]]) 
       {   thestr[i] = 0;
           break;
       }
       
    } 

    for (i = 0; thestr[i] != 0 ; i ++) 
    { 
       if (thestr[i] == '%' && thestr[i+1] != '%' ) 
       {   thestr[i] = '$';
       }       
    } //单"%"转"$"，这步处理这是为什么呢？

    SInt32 stopLen = 0;
    if (stopStr != NULL)
        stopLen = ::strlen(stopStr);

    if (stopLen > 0 && stopLen <= i)
    {
        char* stopPtr = ::strstr(thestr, stopStr);//搜索stopStr在theStr中的第一次出现。找到所搜索的字符串则返回字符串的地址。
        if (stopPtr != NULL)
        {   stopPtr +=  stopLen;
           *stopPtr = 0;
           i = stopPtr - thestr;
        }
    }

    char * theStrLine = thestr;
    char * nextLine = NULL;
    char * theChar = NULL;
    static char *cr="\\r";
    static char *lf="\\n\n";
    SInt32 tempLen = i;
    for (i = 0; i < tempLen; i ++) 
    {   
        if (theStrLine[i] == '\r')
        {   theChar = cr;
            theStrLine[i] = 0;
            nextLine = &theStrLine[i+1];
        }
        else if (theStrLine[i] == '\n')
        {   theChar = lf;
            theStrLine[i] = 0;
            nextLine = &theStrLine[i+1];
        }
        
        if (nextLine != NULL)
        { 
            qtss_printf(theStrLine);
            qtss_printf(theChar);
            
            theStrLine = nextLine;
            nextLine = NULL;  
            tempLen -= (i+1);
            i = -1;
        }
    }
    qtss_printf(theStrLine);
    delete thestr;

    if (appendStr != NULL)
        qtss_printf(appendStr);
   
}

一下代码段做这样一个单"%"转“$”有什么意义呢:

for (i = 0; thestr[i] != 0 ; i ++) 
    { 
       if (thestr[i] == '%' && thestr[i+1] != '%' ) 
       {   thestr[i] = '$';
       }       
    }