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Text File | 1997-05-27 | 14.1 KB | 262 lines

HexEd, a Hexadecimal Editor for Binary Files, by Anthony F. Stuart, 1990. 1. Description HexEd is a fast and easy to use editor for binary files. It supports insert and overtype modes, character delete, and search and replace. Command line options let you customize it for your video hardware and processing preferences. HexEd uses memory and disk very efficiently. The executable file itself consumes less than 30 kb and it can edit files up to two megabytes in less than 100 kb of memory. HexEd uses the popular hexadecimal dump display, with address on the left, hexadecimal representation in the middle and character representation on the right. The current location in the file is marked by a pair of cursors, one for the hexadecimal representation and one for the character representation. The arrow keys, page up, page down, home and end select the current location in the file. There is also a goto command to select a specific address. Text can be inserted or overtyped as either hexadecimal or character codes. A single key combination switches between modes. In hexadecimal mode the hexadecimal cursor is active and lets you enter a one or two digit hex value. In character mode the character cursor is active and lets you enter a character. Characters can also be entered using decimal code by holding down the Alt key and entering the decimal code on the numeric keypad. HexEd makes an ideal binary file pager. The search and goto commands, and current address display field, let you quickly locate an address without having to count bytes. 2. Use To invoke HexEd with default display and processing options just type the command followed by an existing filename: hexed file HexEd will display its header and footer lines and the first page of the file. The current location is set to the first byte of the file. The header line contains the current address, file size, insert/ overtype indicator and hex/ascii indicator. The footer line contains the file name, time and date last modified and original file size. Press function key F1 for a help display that summarizes the interactive commands. This display is also produced if you enter an invalid function or Alt key sequence. The help display is cleared by pressing any key. The cursor positioning keys move the cursor around the file in the usual way. The home key selects the beginning of the file and the end key selects the end of the file. Page up and page down move one page backward or forward. The delete key deletes the current character, and all following characters shift up one. The insert key toggles insert/overtype mode. The default mode is overtype mode. In overtype mode each character that is entered replaces the character that was previously there. In insert mode each character that is entered is inserted at the current location and the following characters are shifted down one. The current mode is indicated on the header line. HexEd recognizes a variety of Alt key sequences: Alt-D (Dos Suspend) suspends the current editing session and enters the DOS command processor. Return to HexEd by typing exit at the DOS prompt. Caution: while suspended do not delete or modify the file you are editing or any "hexedtmp" files. Alt-G (Goto Address) prompts for an address and makes it the new current location. The address can be entered in octal, decimal or hexadecimal format. Octal addresses must be preceded by a 0 and hexadecimal addresses must be preceded by a 0x. For example, the octal address 010770 and the hexadecimal address 0x11f8 are equivalent to the decimal address 4600. Alt-H (Toggle Hex/Character Mode) controls which cursor is active for inserting or overtyping. In hexadecimal mode the hexadecimal cursor is active and you can enter any of the digits 0123456789abcdef. In character mode you can enter any character that can be typed from the keyboard. Remember that text lines in DOS are terminated by a carriage return, line feed combination. This can be entered using Ctrl-M, Ctrl-J. Also note that most PC BIOS's support decimal entry by holding down the Alt key and entering a decimal code on the numeric keypad. Alt-Q (Quit) exits the editor. First you are prompted for whether you really want to quit or not. Then, if you have made changes, you are prompted for whether you want to save them. Note that at this point it is only possible to write the changes back to the original file. If you want to write the changes to a different file use the Write command before quitting. Alt-R (Replace) prompts for a search pattern and a replace string and then interactively asks you whether you would like to replace each occurence of the pattern. A NO response skips to the next occurence. A YES response replaces the current occurence. An ALL response replaces all remaining occurences (to the end of the file). A STOP response terminates the search and replace operation. See the search command for a description of patterns. Alt-S (Search) prompts for a search pattern and locates the first occurence of it following the current location. A search pattern consists of a sequence of one or more characters, escape sequences and/or wildcards. Escape sequences are described below. Wildcards consist of the question mark character (?) which matches any one character and the asterisk character (*) which matches zero or more characters. The asterisk will match the shortest string that satisfies the remainder of the pattern. Alt-W (Write) writes the current editing session to a file. First you are prompted for whether or not you really want to write to a file. Then you are prompted for the name of a file. The editing session is then written to the file. If you have specified the original file as the output file then the time and date modified and original file size fields of the footer line will be updated. As mentioned above, text for the search and replace commands can be entered as a sequence of characters and/or escape sequences. The escape sequences use the common convention of a backslash followed by a mnemonic: Sequence Description ASCII Code or Comment -------- ----------- --------------------- \a audible alert BEL \b backspace BS \f formfeed FF \n newline (linefeed) LF \r carriage return CR \t horizontal tab HT \v vertical tab VT \? question mark negates wildcard function \* asterisk negates wildcard function \\ backslash negates escape function \0nnn octal code nnn e.g. \033 is an ASCII ESC \dnnn decimal code nnn e.g. \d27 is an ASCII ESC \xnn hexadecimal code nn e.g. \x1b is an ASCII ESC The escape sequences can be intermixed with text as long as the end of an octal, decimal or hexadecimal sequence is not ambiguous. When entering text for the search, replace or file commands, use the backspace key to delete the previous character and the escape key to delete the entire line. You can also cancel any of these commands by pressing escape followed by return. 3. Limits and Error Recovery HexEd creates a temporary file that is uses to keep track of changes you make. The file you are editing is not updated until you write the changes back to it or quit and save the changes. In fact, the write operation first writes the changes to another temporary file and then renames the temporary file to the name you specified. This way if anything goes wrong you will not lose your original file. Keep in mind that HexEd uses temporary files and that they require disk space. A good rule of thumb is to only use HexEd on disks that have at least 2-3 times as much free space as the size of the file you are editing. Also keep in mind that HexEd should not be used to edit files over two megabytes (hex 200000). If you run out of memory or disk space for temporary files the editor aborts and your changes are lost. 4. Defaults and Command Line Options HexEd lets you customize the way it operates by specifying command line options. If you want to use certain options every time you edit, create a batch file that invokes HexEd with the desired options. The following list summarizes the command line options. You can get a summary of this list by specifying the HexEd command without a filename. Note that command line options should be entered in lower case. Also, for options that require a parameter, there should be no space between the option and the parameter. -b creates a backup file before writing changes. The backup file uses the same base name and a .bak suffix. Caution: the new backup file will replace any existing file with the same name. -c<c> specifies the color to use for the cursor and help display. The method for specifying colors is described below. The default is -ckw for both monochrome and color. -d<d> specifies the display character to use for characters outside the printable ASCII character set. This character can be represented using the escape sequence notation described above. If no character is specified then the character from the PC character set is displayed. The default is -d\xfa for the centered dot. -e<f> specifies the fill character to use when characters are added beyond the end of the file. The default is -e\x0, i.e. fill from end of file to the current location with zeros. -f<c> specifies the color to use for the footer line. The default is -fkw for monochrome and -fyr for color. -h<c> specifies the color to use for the header line. The default is -hkw for monochrome and -fyr for color. -m<c> specifies the color to use for the message line. The default is -mwk for both monochrome and color. -s specifies silent mode. Invalid keys are ignored. The default is to produce a tone when an invalid key is entered. -t<c> specifies the color to use for the text area. The default is -twk for monochrome and -tck for color. -u<n> specifies the number of memory buffers to use. Specifying a large number makes editing faster but limits editing to smaller files. Specifying a small number slows down editing but lets you edit larger files. The default is -u8. The minimum is -u4. -v specifies use of the video BIOS instead of direct video access. Use this option if you have any problems with the display. The video BIOS is slower than direct access. Colors are specified as a two character sequence. The first character represents the foreground color. The second character represents the background color. Colors are abbreviated: b = blue, g = green, c = cyan, r = red, m = magenta, y = yellow, w = white, k = black For example, to specify a text area of white on black, use -twk. 5. Distribution HexEd is not copyrighted. It may be freely copied and distributed. All I ask is that you give me credit if you copy and distribute it and that you do not distribute copies that have been modified in any way or that are missing this documentation. My objective is to make HexEd the number one binary editor. Please distribute it to anyone who can benefit from it. HexEd is distributed as-is with no warranties, for use at your own risk. Every effort has been made to produce a robust and reliable program, but there are undoubtedly some bugs left in it. If you find a bug, try to reduce it to its simplest case and send me a description. I would also like to hear general comments or suggestions for new features. My name and address: Anthony F. Stuart 21042 Thoreau Court Sterling, VA 22170 The source to HexEd consists of about 3000 lines of 'C' language source code. It would make good reading for anyone who would like to learn more about editor data structures and file manipulation. If you would like a copy of the latest source code for HexEd, on 360 kb diskette, send a brief note and $10.00 to the above address. Note that the source code to HexEd is copyrighted and may not be redistributed in any format. Also note that this offer may withdrawn without notice.