#
# https://scz.617.cn/python/200604120942.txt
#
# ByteArray( '\\0\\t\\r\\n\\x4\\x41\\xG\\' ).hexdump()
# ByteArray( '\\0\\t\\r\\n\\x4\\x41\\xG\\' ).dosomething().hexdump()
#
# byteArray [ 19 bytes ] -> 16 bytes per line
# 00000000  5C 30 5C 74 5C 72 5C 6E-5C 78 34 5C 78 34 31 5C    \0\t\r\n\x4\x41\
# 00000010  78 47 5C                                           xG\
# byteArray [ 10 bytes ] -> 16 bytes per line
# 00000000  00 09 0D 0A 04 41 5C 78-47 5C                      .....A\xG\
#

#
# 2006-04-12 09:42 scz
#
# 处理\\、\xH、\xHH、\r、\n、\t、\0这几种情形，形参、返回值均为字符串。
#
def dosomething ( str ) :
    xxx = ''
    i   = 0
    while i < len( str ) :
        #
        # Python里字符不再自动等于字节，是两种数据类型。
        #
        if '\\' != str[i] :
            xxx    += str[i]
        else :
            #
            # Python的字符串没有结尾的NUL字符，务必注意这点
            #
            if i + 1 >= len( str ) :
                #
                # 最后一个\
                #
                xxx    += str[i]
            elif '\\' == str[i+1] :
                #
                # 出现了两个\
                #
                xxx    += '\\'
                i      += 1
            elif 'r' == str[i+1] :
                #
                # 出现了\r
                #
                xxx    += '\r'
                i      += 1
            elif 'n' == str[i+1] :
                #
                # 出现了\n
                #
                xxx    += '\n'
                i      += 1
            elif 't' == str[i+1] :
                #
                # 出现了\t
                #
                xxx    += '\t'
                i      += 1
            elif '0' == str[i+1] :
                #
                # 出现了\0
                #
                xxx    += '\0'
                i      += 1
            elif 'x' == str[i+1] :
                #
                # 出现了\x
                #
                if ( str[i+2] >= '0' and str[i+2] <= '9' ) or ( str[i+2] >= 'a' and str[i+2] <= 'f' ) or ( str[i+2] >= 'A' and str[i+2] <= 'F' ) :
                    i      += 2
                    tmp     = str[i]
                    if ( str[i+1] >= '0' and str[i+1] <= '9' ) or ( str[i+1] >= 'a' and str[i+1] <= 'f' ) or ( str[i+1] >= 'A' and str[i+1] <= 'F' ) :
                        i      += 1
                        tmp    += str[i]
                    else :
                        tmp     = '0' + tmp
                    #
                    # 按16进制串处理
                    #
                    xxx    += tmp.decode( 'hex_codec' )
                else :
                    xxx    += str[i]
            else :
                #
                # 无需转义
                #
                xxx    += str[i]
            #
            # end of switch
            #
        #
        # end of else
        #
        i  += 1
    #
    # end of while
    #
    return( xxx )
#
# end of dosomething
#