DecUF is an acronym for DECode_Uuencoded_File. It is yet another program to 'uudecode' a file. It's features are:
o One input file might contain more than one encoded file. If the end statement of an encoded file is encountered, it will search for a begin statement of the next encoded file.
o Lines within an encoded file, which are obviously NOT uuencoded lines, can be skipped without causing a (fatal) error condition. This feature is usefull if a (big) uuencoded file is split up into multiple files by for instance an email system. After merging the (email) files, there are some email header lines within the encoded file which must be skipped while decoding the file.
o The I/O time is optimised by buffering the decoded file as much as possible in the heap. Once the heap is full, the whole heap is written to a disk file. This implementation minimises the number of head moves if the input and the output file(s) are located on the same disk.
o Three types of uuencoded files are supported. DecUF will recognise the type of encoding from the first encoded lines.
o Any CP/M, MS-DOS or UNIX pathname is removed from the filename specified in the begin statement.
Usage.
The calling sequence of DecUF can be described in a short way as:
Program DecUF expects at least the name of the file containing the encoded file(s) to be supplied. Moreover some options can be specified, which are all optional. An option is recognised by its first character, which must be a '/'.
The input file name must be a legal unambigious file name. However, one extension is allowed: between the drive letter and the colon, the user area number can be specified.
The '/o' option can be used to specify the path to the area to save the result file(s) in. The path consists of three fields: the drive letter, the user area number and a colon. If two or three of these fields are given, they must be specified in order stated above. If the drive and/or the user area are not specified, the current value is used.
The '/c' option controls the effect of illegally formatted lines within an encoded file. If the option is enabled (/c+), an illegally formatted line will cause the decoding to stop and the result file to be erased. If the option is disabled (/c-), illegally formatted lines are skipped. The default value for this option is disabled (/c-).
The '/s' option specifies the number of encoded files in the input file. If enabled (/s+), there is only one encoded file in the input file. If disabled (/s-), there can be more than one one encoded file in the input file. By enabling this option, the standard with regard to uuencoded files is followed: there it is specified that all lines following the 'end' line should be ignored. The default value for this option is disabled (/s-).
The '/v' option controls the amount of output on the screen. If enabled (/v+), the number of the line being decoded is displayed and a summary of the statistics is presented after completing the decoding of each file. If the option is disabled (/v-), neither the progres report nor the statistics are written to the screen. The default value for this option is enabled (/v+).
Remarks.
As already stated, DecUF recognises three types of encoding.
In the first encoding method an encoded line consists of a length indicator in the first poistion followed by that number of encoded octets. In order to avoid problems due to a possible removal of trailing spaces, the '`' character in stead of the blank space is used to encode a 6-bit zero.
In the second encoding method the blank space is used for a 6-bit zero and a terminator, the character 'M', is appended at the end of each encoded line, again to avoid problems due to a possible removal of trailing blank spaces.
In the third method, a checksum is appended at the end of each encoded line. In this method the '`' character is used to encode a 6-bit zero.
DecUF uses the EXTended_File_Name unit, which is also available seperately as EXTFN.ARK. In that archive you'll find some additional documentation about the EXTended_File_Name unit. The use of this unit has one drawback: if the program DecUF is terminated abnormally, that is with an error message from the TP run-time system, the pointer to the BDOS will be wrong. Any reference to BDOS (CP/M) will cause most probably a system hang. Thus if DecUF terminates abnormally, reboot your system.
Any remarks, comments and/or suggestions about DecUF are welcome. My address is:
Wim Nelis
Rozenhof 4
8316 CX Marknesse
The Netherlands
I am also reachable via e-mail at Internet address
(.txt)