Hex Dump In Many Programming Languages

Please use spaces rather than tabs in any code samples below (ConvertSpacesToTabsNotForCode).

A new ProgrammingChrestomathy challenge: hexdump a file, given a starting and ending offset in the file, and number of bytes to display per outline line. Newly recommended is to show the current offset at the start of each output line.

Read the file source and print a HexDump of the bytes in the file from start to end, formatted to show width bytes separated by space, followed by a separator, then followed by the ASCII values of the displayed bytes (or a period for non-ASCII bytes), in the order they exist in the file.

Has anyone tracked the most compact, yet viable, solutions? It seems to me that the Perl, Forth, and C examples solve the problem with the least fooling around.

SchemeLanguage: (alternative versions, or critiques of this one, would be welcome)
[Note: I've removed many of the comments from my original version; ironically, it is now much clearer and easier to read.]



 ;; (hex-dump) => #t OR identifier

 ;; To use:

 ;;	start the Scheme interpreter

 ;;	(load 'hexdump)

 ;;	(hexdump)

 ;;

 ;;  Special Instructions:

 ;;	The filename must be enclosed in double quotes.

 (define (hexdump)

	(let ((file	(begin (display "Filename: ") (read)))

	 (start  (begin (display "Start: ")(read)))

	 (finish (begin (display "End: ") (read)))

	 (width  (begin (display "Bytes per Line: ") (read))))

	(dump-file file width start finish)))
(define (dump-file filename line-length start finish)

	(cond ((not (string? filename))

	  'err-no-filename)

	 ((> 0 start)

	  'err-negative-start)

	 ((>= start finish)

	  'err-startpoint-after-endpoint)

	 (else (let ((src (open-input-file filename))

			(width (if (> line-length 0) ; default line width to 16

                                line-length

                                16))

			(size (- finish start)))	; total size of dump in bytes

		 (if (not (port? src))  ; check for valid port

			'err-no-file

			(if (seek src start)

			 (display-dump src width size)

			 'err-file-length-exceeded)))))) ; file ends before reaching start
(define (seek src entrypoint)

	(let find ((count entrypoint))

	(cond ((>= 0 count) #t)

		((eof-object? (read-char src))  ; if file ends before reaching entrypoint,

		(close-input-port src)	 ; close the file and return false

		#f)

		(else  (find (- count 1))))))
;; (display-dump port integer integer) => #t OR identifier

 ;; Print out a hexdump

 ;;

 ;; The function accumulate-lines is used to collect

 ;; a group of lines up to blocksize in length to be printed

 ;; together as a single string. The purpose for this is to minimize

 ;; the number of calls to (display), a very high-overhead function.

 (define (display-dump src width size)

	(let ((blocksize 64)

	 (height (/ size width)))

	(do ((blockcount height (- blockcount blocksize)) ; decrement by blocksize each pass

	  (dumpsize size (- dumpsize (* blocksize width))))

	((or (<= blockcount 0)

		(eof-object? (peek-char src)))

	(close-input-port src)

	#t)

	(display (accumulate-lines src width blocksize dumpsize)))))
(define (accumulate-lines src width blocksize dumpsize)

	(let accumulate ((count blocksize)

			(tailing dumpsize))

	(if (or (< count 0)	 ; if we've reached the end of the block,

		(< tailing 0))	; or the end of the dump region,

	 ""			; return an empty string

	 ; else, read a new line of data; if it is at the end of the region,

	 ; only get the remaining part of the line, otherwise get a full line

	 (let ((line (read-dump-line src (min tailing width))))

		(if (null? line) ; if we've reached the end of the file,

		""		; return an empty string

		; otherwise, continue accumulating lines

		(string-append (format-line line width)

				(accumulate (- count 1) (- tailing width))))))))
(define (read-dump-line src width)

	(let read-data ((count width))

	(if (>= 0 count)

	 '()

	 (let ((next (read-char src)))

		(if (eof-object? next)

		'()

		(cons next (read-data (- count 1))))))))
(define (format-line dump width)

	(string-append (format-dump-line dump)

		  (pad-string 3 (- width (length dump)))

		  ": "

		  (format-values-line dump)

		  line-marker))
(define line-marker (make-string 1 #\newline))
(define (pad-string pad-size padding)

	(if (< 0 padding)

	(make-string (* pad-size padding) #\space)

	""))
(define (format-values-line dump)

	(list->string (map char-value dump)))
(define (format-dump-line dump)

	(string-list-concat (map char->hex-string dump)	" "))
(define (string-list-concat string-list separator)

	(let cat ((stringlist string-list))

	(cond ((null? stringlist) "")

		((list? stringlist) (string-append (car stringlist)

						separator

						(cat (cdr stringlist))))

		(else stringlist))))
(define (char->hex-string c)

	(let* ((charval (char->integer c))

	  (hexval (number->string charval 16)))

	(if (> 16 charval)

	 (string-append "0" hexval)

	 hexval)))
(define (char-value c)

	(if (char-printable? c)

	c

	#\.))
(define (char-printable? c)

	(and (char<? #\space c)

	(char<? c #\~)))

A sample printout, using it's own source file:



 > (hexdump)

 Filename: "hexdump.scm"

 Start: 128

 End: 256

 Bytes per Line: 16

 20 53 70 65 63 69 61 6c 20 49 6e 73 74 72 75 63 : .Special.Instruc

 74 69 6f 6e 73 3a 0d 0a 3b 3b 20 20 20 20 54 68 : tions:..;;....Th

 65 20 66 69 6c 65 6e 61 6d 65 20 6d 75 73 74 20 : e.filename.must.

 62 65 20 65 6e 63 6c 6f 73 65 64 20 69 6e 20 64 : be.enclosed.in.d

 6f 75 62 6c 65 20 71 75 6f 74 65 73 2e 20 20 20 : ouble.quotes....

 20 0d 0a 0d 0a 28 64 65 66 69 6e 65 20 28 68 65 : .....(define.(he

 78 64 75 6d 70 29 0d 0a 20 20 28 6c 65 74 20 28 : xdump)....(let.(

 28 66 69 6c 65 20 20 20 28 62 65 67 69 6e 20 28 : (file...(begin.(

 #t

HaskellLanguage:



 import System

 import IO

 import Data.Char
hexdump start end width = unlines . map hexify . addLineNumber . splitGroups . takeRange

    where takeRange = take (end - start) . drop start

          splitGroups [] = []

          splitGroups xs = ys : splitGroups zs

              where (ys,zs) = splitAt width xs in

          addLineNumber = zip $ map (pad . show) $ iterate (+ width) start

              where pad str = replicate (6 - length str) '0' ++ str

          hexify (num, char) = num ++ ": " ++ (unwords $ map toHexDigit char)

                                   ++ ": " ++ map literal char

          toHexDigit = stringify . (`divMod` 16) . ord

              where stringify (x,y) = [intToDigit x, intToDigit y]

          literal c = if isPrint c then c else '.'
withFile file func = readFile file >>= putStrLn . func

 main = do args <- getArgs

           let intArg = read . (args !!) in

                        withFile (args !! 0) $ hexdump (intArg 1) (intArg 2) (intArg 3)

Output:



 debian:/home/jdtang/vm/spike# ./hexdump hexdump.hs 0 150 15

 000000: 69 6d 70 6f 72 74 20 53 79 73 74 65 6d 0a 69: import System.i

 000015: 6d 70 6f 72 74 20 49 4f 0a 69 6d 70 6f 72 74: mport IO.import

 000030: 20 44 61 74 61 2e 43 68 61 72 0a 0a 68 65 78:  Data.Char..hex

 000045: 64 75 6d 70 20 73 74 61 72 74 20 65 6e 64 20: dump start end

 000060: 77 69 64 74 68 20 3d 20 75 6e 6c 69 6e 65 73: width = unlines

 000075: 20 2e 20 6d 61 70 20 68 65 78 69 66 79 20 2e:  . map hexify .

 000090: 20 61 64 64 4c 69 6e 65 4e 75 6d 62 65 72 20:  addLineNumber

 000105: 2e 20 73 70 6c 69 74 47 72 6f 75 70 73 20 2e: . splitGroups .

 000120: 20 74 61 6b 65 52 61 6e 67 65 0a 20 20 20 20:  takeRange.

 000135: 77 68 65 72 65 20 74 61 6b 65 52 61 6e 67 65: where takeRange

-- JonathanTang

VisualBasicNine

The following direct/imperative-style program does the trick



 Imports System

 Imports System.IO
Module InManyLanguages

   Public Sub HexDump(ByVal filename As String, _

                       ByVal startOffset As Integer, _

                       ByVal endOffset As Integer, _

                       ByVal width As Integer)

     Using fs = New FileStream(filename, FileMode.Open, FileAccess.Read)

       Console.WriteLine("Filename: {0}", filename)

       Console.WriteLine("Start: {0}", startOffset)

       Console.WriteLine("End: {0}", endOffset)

       Console.WriteLine("Bytes per line: {0}", width)

       If (fs.Length > startOffset) Then

         fs.Position = startOffset

         Dim buffer(width - 1) As Byte

         Dim bytesRead = 0

         Dim maxBytes = endOffset - startOffset

         Dim done = False

         While Not done

           Dim bytesToRead = IIf(maxBytes - bytesRead < width, maxBytes - bytesRead, width)

           Dim cb = fs.Read(buffer, 0, bytesToRead)

           bytesRead += cb

           done = cb < width Or bytesRead = maxBytes
For index As Integer = 0 To cb - 1

             Console.Write("{0:X2} ", buffer(index))

           Next

           For index As Integer = cb To width - 1

             Console.Write("   ")

           Next

           Console.Write(": ")

           For index As Integer = 0 To cb - 1

             Dim b = buffer(index)

             Console.Write(IIf(b > 32 And b < 126, ChrW(b), "."))

           Next

           Console.WriteLine()

         End While

       End If

     End Using

   End Sub

 End Module

Which prints out the following:

Filename: InManyLanguages.vb
Start: 128
End: 256
Bytes per line: 16
41 73 20 49 6E 74 65 67 65 72 2C 20 42 79 56 61 : As.Integer,.ByVa
6C 20 65 6E 64 4F 66 66 73 65 74 20 41 73 20 49 : l.endOffset.As.I
6E 74 65 67 65 72 2C 20 42 79 56 61 6C 20 77 69 : nteger,.ByVal.wi
64 74 68 20 41 73 20 49 6E 74 65 67 65 72 29 0D : dth.As.Integer).
0A 20 20 20 20 20 20 20 20 55 73 69 6E 67 20 66 : .........Using.f
73 20 3D 20 4E 65 77 20 46 69 6C 65 53 74 72 65 : s.=.New.FileStre
61 6D 28 66 69 6C 65 6E 61 6D 65 2C 20 46 69 6C : am(filename,.Fil
65 4D 6F 64 65 2E 4F 70 65 6E 2C 20 46 69 6C 65 : eMode.Open,.File

The imperative printing code within the loop could be replaced by this functional LINQ expression:



 Dim s = String.Join(" ", (From index In Enumerable.Range(0, cb) _

         Select buffer(index).ToString?("X2")).Concat( _

         Enumerable.Repeat("  ", width - cb)).ToArray()) _

         & " : " & _

         New String((From index In Enumerable.Range(0, cb) _

         Let b = buffer(index) _

         Select CType(IIf(b > 32 And b < 126, ChrW(b), "."c), Char)).ToArray())

 Console.WriteLine?(s)

This isn't necessarily more maintainable or readable, but it proves the point.

PythonLanguage:



 import sys
def hexdump( chars, sep, width ):

	while chars:

		line = chars[:width]

		chars = chars[width:]

		line = line.ljust( width, '\000' )

		print "%s%s%s" % ( sep.join( "%02x" % ord(c) for c in line ),

 			 sep, quotechars( line ))
def quotechars( chars ):

	return ''.join( ['.', c][c.isalnum()] for c in chars )
def file_section( name, start, end ):

	contents = open( name, "rb" ).read()

	return contents[start:end]
if __name__ == '__main__':

	hexdump( file_section( sys.argv[1], int( sys.argv[2] ), int( sys.argv[3] )),

			' ', int( sys.argv[4] ))

Run output:

$ python hexdump.py hexdump.py 0 60 16
0a 69 6d 70 6f 72 74 20 73 79 73 0a 0a 64 65 66 .import.sys..def
20 68 65 78 64 75 6d 70 28 20 63 68 61 72 73 2c .hexdump..chars.
20 73 65 70 2c 20 77 69 64 74 68 20 29 3a 0a 20 .sep..width.....
20 20 77 68 69 6c 65 20 63 68 61 72 00 00 00 00 ..while.char....

Should this one lose points for reading the whole file into memory?

I don't think so. After all, memory-mapped files are a very powerful paradigm. There have been operating systems that only offered that option, and their proponents were very disdainful of the other approach.

Long ago on systems with tiny RAM, this might have been crippling, since one couldn't view large files, but these days with big RAM and huge swap areas, it seems unlikely to be a pragmatic issue.

There is something to be said for stream-based solutions as part of a DataFlowProgramming system, but that doesn't seem a big deal on this particular page.

The above version is buggy - it doesn't print brackets, etc, properly. Here's an idiomatic version that handles large files. It's less terse than it could be (but that's because it's more readable than it could be ;-)



 import sys
def hexdump(fname, start, end, width):

    for line in get_lines(fname, int(start), int(end), int(width)):

        nums = ["%02x" % ord(c) for c in line]

        txt = [fixchar(c) for c in line]

        print " ".join(nums), "".join(txt)
def fixchar(char):

    from string import printable

    if char not in printable[:-5]:

        return "."

    return char
def get_lines(fname, start, end, width):

    f = open(fname, "rb")

    f.seek(start)

    chunk = f.read(end-start)

    gap = width - (len(chunk) % width)

    chunk += gap * '\000'

    while chunk:

        yield chunk[:width]

        chunk = chunk[width:]
if __name__ == '__main__':

    try:

        hexdump(*sys.argv[1:5])

    except TypeError?:

        hexdump("hexdump.py", 0, 100, 16)

RubyLanguage:



 def hexdump(filename, start = 0, finish = nil, width = 16)

   ascii = ''

   counter = 0

   print '%06x  ' % start

   File.open(filename).each_byte do |c|

     if counter >= start

       print '%02x ' % c

       ascii << (c.between?(32, 126) ? c : ?.)

       if ascii.length >= width

         puts ascii

         ascii = ''

         print '%06x  ' % (counter + 1)

       end

     end

     throw :done if finish && finish <= counter

     counter += 1

   end rescue :done

   puts '   ' * (width - ascii.length) + ascii

 end
if $0 == __FILE__

   if ARGV.empty?

     hexdump $0

   else

     filename = ARGV.shift

     hexdump filename, *(ARGV.map {|arg| arg.to_i })

   end

 end
% hexdump.rb hexdump.rb 0 58 16

 000000  64 65 66 20 68 65 78 64 75 6d 70 28 66 69 6c 65 def hexdump(file

 000010  6e 61 6d 65 2c 20 73 74 61 72 74 20 3d 20 30 2c name, start = 0,

 000020  20 66 69 6e 69 73 68 20 3d 20 6e 69 6c 2c 20 77  finish = nil, w

 000030  69 64 74 68 20 3d 20 31 36 29 0a                idth = 16).

CeeLanguage or maybe CeePlusPlus - Not actually CeeLanguage - There are CeePlusPlus specifics used(like declaring variables in the middle of a function for readability). Why do people think CeePlusPlus means one must use class. Sigh. I guess the CeeLanguage/CeePlusPlus are popular enough that people must post follow ups with their own visions. An OO solution is probably overkill, but it wouldn't be unreasonable to ask that something purporting to be a CeePlusPlus example use things like the CeePlusPlus standard library, rather than the CeeLanguage standard library... (or if you're going to use the CeeLanguage library, at least use the standard CeePlusPlus headers for it [that's #include <cstdio> and #include <cstdlib>, rather than <stdio.h> and <stdlib.h>])... - Fair enough, we'll call it a draw - if just to avoid a LanguageHolyWar?.

I posted one of the straight C language solutions below, which should tell you that I'm not a rabid foaming-at-the-mouth OO bigot, however I was the one that said it was C, not C++, and I stand by that. Aside from utterly trivial issues, it could compile with a C compiler. And yes, I would in fact want to see use of classes or templates, although as someone said above, at least using native C++ facilities for IO would put you in a more defensible position.

Re: "follow up with their own visions" - there's room for multiple solutions in each language. I like to go for very terse solutions because I think that's a virtue in itself. Others obviously have somewhat different philosophies that they like to illustrate. -- dm

Not that I'm disagreeing with you - I do have strong CeeLanguage influences, but just to explain where I was coming from - Can you imagine the ThreadMess if someone really did post a "true" CeePlusPlus example?

You could guarantee a HolyWar over:

Whether writing to a generic stream is better than writing to cout.
Whether it was encapsulated enough or had had too many "Get/Put" methods.
What design patterns it followed incorrectly or *gasp*didn't use at all.
The missing or excessive use of interfaces/templates/overloading.

I don't think this little exercises risk major HolyWars?. Anyway,

generic streams make it more reusable, so that is more desirable. I'd agree, but I would also consider the decision subjective
- On this page, yes, but in a real project, inevitably you want to direct something to cerr, not just cout, so I wouldn't call it subjective in general.
Get/Put has of course been discussed, and I don't think there's any question: it's a Smell, but not necessarily wrong.
Failing to use a known DesignPattern - now you're being silly. If you can cite any instances of that on the entire web by an apparently sane person, I'd be interested in seeing it. True. . . and I do love being silly
Operator overloading ideally should be used only on numeric operators to implement new numeric types, except that Stroustrup brain damage means that it also should be used to extend standard operators like << and >>.
Redefining other operators like ()[] etc usually should be done if and only if one is redefining essentially all operators transparently in order to play tricks like reference-counted garbage collection, and otherwise it's a major smell.
Templates should be used any time there is a need to parameterize an algorithm by type. They should not be used to play other kinds of tricks -- except that by now there are a lot of C++ specific patterns on using them in bizarre ways in order to work around limitations of the language, so there are some peculiar cases where you've got a point.
What do you mean by missing/overuse of interfaces?
- ''I meant whether the objects should have abstract interfaces, be wrapped in COM layers, etc - but I guess that goes back to the design patterns.
- Ah.

Even in straight C, getting to the elegant minimum is fiercely debated. Perhaps the posts of "true" CeePlusPlus examples are so large that they could be the cause of the denied access problems we've been having. ;)

Perhaps. I've been thinking about doing one, and have refrained so far because of the mental image. ;-)



 /*

  This entry contains certain functionality the others may not.

The stop-start span does not need to be equal to width
The command-line is checked for missing arguments



 */

 #include <stdio.h>

 #include <stdlib.h>
void hexdump(unsigned char *buffer, unsigned long index, unsigned long width)

 {

  unsigned long i;

  for (i=0;i<index;i++)

	{

	printf("%02x ",buffer[i]);

	}

  for (unsigned long spacer=index;spacer<width;spacer++)

	printf("	");

  printf(": ");

  for (i=0;i<index;i++)

	{

	if (buffer[i] < 32) printf(".");

	else printf("%c",buffer[i]);

	}

  printf("\n");

 }
int hexdump_file(FILE *infile,unsigned long start, unsigned long stop, unsigned long width)

  {

  char ch;

  unsigned long f_index=0;

  unsigned long bb_index=0;

  unsigned char *byte_buffer = malloc(width);

  if (byte_buffer == NULL)

	{

	printf("Could not allocate memory for byte_buffer\n");

	return -1;

	}

  while (!feof(infile))

	{

	ch = getc(infile);

	if ((f_index >= start)&&(f_index <= stop))

	{

	 byte_buffer[bb_index] = ch;

	 bb_index++;

	}

	if (bb_index >= width)

	{

	  hexdump(byte_buffer,bb_index,width);

	  bb_index=0;

	}

	f_index++;

	}

  if (bb_index)

	hexdump(byte_buffer,bb_index,width);

  fclose(infile);

  free(byte_buffer);

  return 0;

 }
int main(int argc, char *argv[])

 {

  if (argc != 5)

	{

	printf("Usage: hexdump <infile> <start> <end> <width>\n");

	return 0;

	}

  FILE *infile=fopen(argv[1],"rb");

  if (infile==(FILE *)NULL)

	{

	printf("Error opening input file %s\n",argv[1]);

	return 0;

	}

  printf("Filename: \"%s\"\n",	argv[1]);

  printf("Start : %lu\n",	atoi(argv[2]));

  printf("End	: %lu\n",	atoi(argv[3]));

  printf("Bytes per Line: %lu\n",atoi(argv[4]));

  int result = hexdump_file(infile,atoi(argv[2]),atoi(argv[3]),atoi(argv[4]));

  return 0;

 }

Run output:

$ hexdump hexdump.c 0 100 16
Filename: "hexdump.c"
Start : 0
End : 100
Bytes per Line: 16
2f 2a 0d 0a 20 20 54 68 69 73 20 65 6e 74 72 79 : /*.. This entry
20 63 6f 6e 74 61 69 6e 73 20 63 65 72 74 61 69 : contains certai
6e 20 66 75 6e 63 74 69 6f 6e 61 6c 69 74 79 20 : n functionality
74 68 65 20 6f 74 68 65 72 73 20 6d 61 79 20 6e : the others may n
6f 74 2e 0d 0a 20 20 20 20 2a 20 54 68 65 20 73 : ot... * The s
74 6f 70 2d 73 74 61 72 74 20 73 70 61 6e 20 64 : top-start span d
6f 65 73 20 6e : oes n

-- LayneThomas

ForthLanguage

DUMP is in the ANS Tools word set, e.g. GNU Forth:

HERE 32 DUMP
27790: 80 C0 0C CC C3 33 0C 30 - CC 33 0C C3 30 C3 0C CC .....3.0.3..0...
277A0: CC CC CC CC CC CC CC CC - C3 0C CC CC CC CC CC CC ................

Here's an implementation that meets the new spec. (Usage: "start end width HEXDUMP filename")



 0 value fileid

 : .pos ( ud -- )

   <# # # # #S #> type ." : " ;

 : .hex ( addr len -- )

   over + swap do I c@ S>D <# # # #> type space loop ;

 : .spacer ( width read -- )

   - 3 * spaces ." : " ;

 : .chars ( addr len -- )

   over + swap do I c@ dup 127 bl within if drop [char] . then emit loop ;

 : (hd) ( start end width "filename" -- )

   R/O OPEN-FILE throw  to fileid

   >R over - R> rot ( count width start )

   S>D fileid REPOSITION-FILE throw ( count width )

   begin  cr fileid FILE-POSITION throw .pos

          2dup min pad swap fileid READ-FILE throw ?dup

   while  pad over .hex	2dup .spacer  pad over .chars

          over =          \ end of file?

   while  tuck - tuck 0>  \ end of range?

   while repeat then then 2drop

   fileid CLOSE-FILE throw cr ;

 : hexdump ( start end width "filename" -- )

   bl parse  base @ >R hex  ['] (hd) catch  R> base !  throw ;

Sample output, testing EOF handling and partial last line :

930 950 8 hexdump hexdump.f
03A2: 61 73 65 20 21 20 20 74 : ase ! t
03AA: 68 72 6F 77 20 3B 0A : hrow ;.

I believe that <# #> is underrated even in the Forth world, and certainly outside it. People seem to think it's pretty much equivalent to formatting in C or Lisp, but I think it is instead an example of an entire paradigm of programming that is mostly unexplored, although alluded to by ChuckMoore.

Could you expand on this? Forth pictured numerics are simple, but not exactly the friendliest of constructs (you are specifying digits in reverse order, for example). Here is GNU Forth's simple implementation (though I added digit>char for clarity).



 variable holdptr

 variable holdend

 create holdbuf 64 allot

 here constant holdbuf-end

 : <# ( ud -- ud ) holdbuf-end dup holdptr ! holdend ! ;

 : hold ( c -- ) -1 holdptr +! holdptr @  dup holdbuf u< -17 and throw  c! ;

 : digit>char ( 0-35 -- [0-9A-Z] ) 9 over < IF 7 + THEN [char] 0 + ;

 : # ( ud -- ud/base ) base @ ud/mod rot digit>char hold ;

 : #s ( ud -- 0d ) BEGIN # 2dup or 0= UNTIL ;

 : #> ( ud -- addr len ) 2drop holdptr @ holdend @ over - ;

Yeah, and many in the Forth community actually regard them as obsolete. But I'm not talking about their literal use for formatting, I'm talking about them as an example of a different way of approaching doing programming. Recall anything that ChuckMoore has said about how he approaches problem solving in Forth?

Here's one example of what Moore said:

"The whole point of Forth was that you didn't write programs in Forth you wrote vocabularies in Forth. When you devised an application you wrote a hundred words or so that discussed the application and you used those hundred words to write a one line definition to solve the application. It is not easy to find those hundred words, but they exist, they always exist."

"I wish I knew what to tell you that would lead you to write good Forth. I can demonstrate. I have demonstrated in the past, ad nauseam, applications where I can reduce the amount of code by 90% percent and in some cases 99%. It can be done, but in a case by case basis. The general principle still eludes me."
http://www.ultratechnology.com/1xforth.htm

He doesn't know how to explain how he goes about finding just the right set of words. I think <# #> serves as an illustration, not of the ultimate way to format, but of the paradigm he exercises unconsciously. -- dm

ColorForth

The wiki doesn't do color, so these are the mappings:

red words are definitions
green words and numbers are normal
white words are (commentary)
yellow words are executed [immediately]
purple words are in-source variables (var x). The numbers shown after them are their actual contents.
dark green hex constants are normal here
color implementation and semantics are described on http://www.colorforth.com/parsed.html
- I see your new links on ColorForth, but I still don't see a pointer to a list of ColorForth words. Previously I would have assumed that I could have guessed some of them, like "dup", since it seems vaguely similar to constructs in other versions of Forth. :-) But since you assure me ColorForth is so very different (and since Moore has such disdain for ANS Forth), I'd better not take that on faith. Maybe "dup" stands for "DuPont?".
  - Many are the same (dup, drop, swap, @, !, +, etc.), but many others are different from their Forth counterparts (or, if, -, ;), some words are renamed (push, pop, minus), and many more are unique to the system (show, screen, keyboard). It is dangerous to assume too much when reading ColorForth source.
    - Huh? I don't want to assume anything; I keep asking if you know where there is a list of ColorForth word definitions. If the answer is "no, you have to infer it from reading their implementation in x86 assembly or in terms of the 27 forth chip primitives", ok, then that's the way it is, and if I ever truly need to figure it out, I'll do that. But it seems more likely to me that there is in fact a word list in English somewhere, and it's merely in an obscure location. Also, if the answer is "I don't know offhand, and I don't have time to search it out for you", of course that's fine too. :-) I just thought it was potentially interesting, and oddly hard to find. Then again, the Forth world is strangely allergic to anything resembling standards, it seems, ANS Forth notwithstanding, since so many seem to despise it, not just Moore.

Other Strange Things:

(I didn't find the definition for h., so it's probably in the assembly kernel.)
- At first I thought perhaps h. was doing a 4 bit to hex conversion per call, but every two calls are followed by cr, so I must be misunderstanding the context.
or drop if: unlike Forth, if uses the processor zero flag, not the top stack item. or sets the flag for if, drop clears the unneeded numeric result. Since or is an exclusive-or (don't ask), the clause is equivalent to <> if in standard Forth.
dump falls through into r and u falls through into +xy to avoid a function call (a common AssemblyLanguage idiom)
dump, r, and cmp set the background task (straight dump or diff of two regions). The displayed dump is active and displays changes to memory in real time.
dump, byte, u, d, and +xy update the address to show.
The dumps don't show ASCII because ColorForth uses a Huffman encoding for text. The format per line for dump is "<hex word> <hex address>" and for cmp it is "<hex x> <hex y> <[red] offset>" with the x and y base addresses listed at the top. The offset is printed red if the contents differ.

{block 32}



 (dump) var x (200000) var y (201200)

 one dup @ h. space dup h. cr ;

 lines for one -1 + next drop ;

 dump x !

 r show black screen x @ 15 + 16 text lines keyboard ;

 it @ + @ dup h. space ;

 lines for white i [x] it i [y] it or drop if red then i . cr -next ;

 cmp show blue screen text 19 lines red [x] @ h. space [y] @ h. keyboard ;

 u 16

 +xy dup [x] +! [y] +! ;

 d -16 +xy ;

 ati F4100000 (ff7fc000) or

 byte 4 / dump ;

 fix for 0 over ! 1 + next ; [dump]

{block 33} this is the shadow block, commentary on the previous block. An editor command flips between a block and its shadow.



 (does not say empty, compiles on top of application)

 x -a (current address)

 one a-a (line of display)

 lines an

 dump a (background task continually displays memory)

 u (increment address)

 d (decrement)

 ati (address of AGP graphic registers)

 byte (a byte address dump)

 fix an-a (test word)

I just looked (for way too long) and couldn't find a list of the standard (well - common) colorforth words anywhere at all (Moore has an annoying page purporting to help programmers that basically says "try it! I'll add documentation some year. Maybe"). Where can I find one?

ColorForth is primarily ChuckMoore's personal programming system. As a working engineer, he hasn't had much time or inclination to document his evolving experiment. He admits communication is one of his weaknesses. Others have written better documented variants that keep the flavor of ColorForth; I'll try to add more references to the ColorForth page. This particular snippet came from some webified source on http://www.merlintec.com/download/color.html

You've already largely translated it out of colorforth; may as well continue until it's 100% one of the regular forths. After all, there seem to be, what, 20 regular colorforth users, and 1 colorforth expert, in the world? :-)

Actually, I haven't changed it a whit; it's a direct mapping from color to markup. ColorForth has very different semantics from standard Forth. They're even further apart than SchemeLanguage is from CommonLisp.

Magenta variables are interesting, since they're basically a bizarre way of doing persistence.

JavaLanguage:



 import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileNotFoundException;

 import java.io.IOException;

 import java.io.UnsupportedEncodingException;
public class HexDump {
public static void main(String[] args) throws IOException {

		String inputFileName = args[0];

		int start = Integer.parseInt(args[1]);

		int end = Integer.parseInt(args[2]);

		int width = Integer.parseInt(args[3]);

		byte[] bytes = read(inputFileName, start, end);

		for (int index = 0; index < bytes.length; index += width) {

			printHex(bytes, index, width);

			printAscii(bytes, index, width);

		}

	}
private static byte[] read(String inputFileName, int start, int end)

		throws FileNotFoundException, IOException {

		File theFile = new File(inputFileName);

		FileInputStream input = new FileInputStream(theFile);

		int skipped = 0;

		while (skipped < start) {

			skipped += input.skip(start - skipped);

		}

		int length = (int) (Math.min(end, theFile.length()) - start);

		byte[] bytes = new byte[length];

		int bytesRead = 0;

		while (bytesRead < bytes.length) {

			bytesRead = input.read(bytes, bytesRead, bytes.length - bytesRead);

			if (bytesRead == -1) {

				break;

			}

		}

		return bytes;

	}
private static void printHex(byte[] bytes, int offset, int width) {

		for (int index = 0; index < width; index++) {

			if (index + offset < bytes.length) {

				System.out.printf("%02x ", bytes[index + offset]);

			} else {

				System.out.print("	");

			}

		}

	}
private static void printAscii(byte[] bytes, int index, int width)

		throws UnsupportedEncodingException? {

		if (index < bytes.length) {

			width = Math.min(width, bytes.length - index);

			System.out.println(

				":"

					+ new String(bytes, index, width, "UTF-8").replaceAll("\r\n", " ").replaceAll(

						"\n",

						" "));

		} else {

			System.out.println();

		}

	}

}



 Arguments: HexDump.java 0 100 16
69 6d 70 6f 72 74 20 6a 61 76 61 2e 69 6f 2e 46 :import java.io.F

 69 6c 65 3b 0d 0a 69 6d 70 6f 72 74 20 6a 61 76 :ile; import jav

 61 2e 69 6f 2e 46 69 6c 65 49 6e 70 75 74 53 74 :a.io.FileInputSt

 72 65 61 6d 3b 0d 0a 69 6d 70 6f 72 74 20 6a 61 :ream; import ja

 76 61 2e 69 6f 2e 46 69 6c 65 4e 6f 74 46 6f 75 :va.io.FileNotFou

 6e 64 45 78 63 65 70 74 69 6f 6e 3b 0d 0a 69 6d :ndException; im

 70 6f 72 74					:port

And another JavaLanguage example factored differently:



 package main;

 import java.io.*;

 import java.util.*;
public class Dump {
public static void main(String[] args) {

        byte[] bytes = new ContentFile?(args[0]).content().getBytes();

        int start = integer(args[1]);

        bytes = slice(bytes, start, integer(args[2]));

        int perLine = integer(args[3]);

        List<Line> chunks = chunks(start, bytes ,perLine);

        for(Line x : chunks)

            x.writeLn(perLine);

    }
private static String leftPadded(String s, int num) {while (s.length() < num) s = " " + s; return s; }

    private static int integer(String s) {  return Integer.parseInt(s);  }
private static List<Line> chunks(int start, byte[] bytes, int perLine) {

        List<Line> result = new ArrayList<Line>();

        while (bytes.length > 0) {

            result.add(new Line(start, slice(bytes, 0, perLine)));

            bytes = slice(bytes, perLine, bytes.length);

            start += perLine;

        }

        return result;

    }
private static byte[] slice(byte[] bytes, int start, int end) {

        if (end > bytes.length) end = bytes.length;

        if (end - start <= 0) return new byte[0];

        byte[] result = new byte[end - start];

        System.arraycopy(bytes, start, result, 0, end - start);

        return result;

    }
static class ContentFile? {

        File file_;

        public ContentFile?(String name) {

            file_ = new File(name);

        }

        public String content() {

            try {

                StringBuffer buf = new StringBuffer();

                BufferedReader? in = new BufferedReader?(new FileReader?(file_));

                for(String s = in.readLine(); s != null; s = in.readLine())

                    buf.append(s);

                return buf.toString();

            } catch (Exception e) {

                throw new RuntimeException("couldn't get content", e);

            }

        }

    }
static class Line {

        final int start;

        final byte[] bytes;

        public Line(int start, byte[] bytes) {

            this.bytes = bytes;

            this.start = start;

        }

        public void writeLn(int perLine) {

            System.out.println("O: " + leftPadded("" + start, 4) + " " + bytesText(perLine) + ":" + text());

        }

        private String text() {

            String result = "";

            for(int i = 0; i < bytes.length; i++) {

                char c = (char) bytes[i];

                result += Character.isLetterOrDigit(c) || Character.isSpace(c) ? c : '.';

            }

            return result;

        }

        private String bytesText(int perLine) {

            String result = "";

            for(int i = 0; i < bytes.length; i++) {

                result += String.format("%02x ", bytes[i]);

            }

            while (perLine-- > bytes.length) result += "   ";

            return result;

        }

    }

 }
C:\eclipserc3\eclipse\workspace\hex\bin>java -cp . main.Dump ..\src\main\Dump.java 0 100 16

 O:   00 70 61 63 6b 61 67 65 20 6d 61 69 6e 3b 69 6d 70 :package main.imp

 O:   16 6f 72 74 20 6a 61 76 61 2e 69 6f 2e 2a 3b 69 6d :ort java.io...im

 O:   32 70 6f 72 74 20 6a 61 76 61 2e 75 74 69 6c 2e 2a :port java.util..

 O:   48 3b 70 75 62 6c 69 63 20 63 6c 61 73 73 20 44 75 :.public class Du

 O:   64 6d 70 20 7b 20 20 20 20 70 75 62 6c 69 63 20 73 :mp .    public s

 O:   80 74 61 74 69 63 20 76 6f 69 64 20 6d 61 69 6e 28 :tatic void main.

 O:   96 53 74 72 69                                     :Stri

C:\eclipserc3\eclipse\workspace\hex\bin>

I wanted to factor the chunks method into the Line class by creating a line with the entire source byte array, and then calling a method subdivide, which would call a method line() and a method rest(). Think that would pretty up a bit more, but hey - real work calls.

-- JeffBay

BourneShell:



 #!/bin/sh
if [ $# -ne 4 ]

 then

	echo "Usage: $0 <source> <start> <end> <width>" 1>&2

	exit 2

 fi
SOURCE="$1"

 START="$2"

 END="$3"

 WIDTH="$4"

 LENGTH=`expr $END - $START`
hexdump -s $START -n $LENGTH -e $WIDTH'/1 "%02X "' -e '" : "' -e '"%_p"' -e '"\n"' $SOURCE

...HaHaOnlySerious!

PerlLanguage:



 #!/usr/bin/perl -w

 use Fcntl qw(:seek);

 use List::Util qw(min);

 use strict;

 if(@ARGV != 4) {

	print STDERR "Usage: $0 <source> <start> <end> <width>\n";

	exit(2);

 }

 my ($source, $start, $end, $width) = @ARGV;

 open(SOURCE, "<", $source) or die("Can't open $source");

 seek(SOURCE, $start, SEEK_SET) or die("Can't seek to $start");

 my $block;

 for(my $left = $end - $start; $left > 0 && read(SOURCE, $block, min($width, $left)); $left -= length($block)) {

	my $hex = join(" ", (map { sprintf("%02X", ord($_)) } split(//, $block)));

	$hex .= '	' x ($width - length($block));

	my $plain = join("", (map { printable($_) ? $_ : "." } split(//, $block)));

	print "$hex: $plain\n";

 }

 sub printable { my $o = ord($_[0]); return $o >= 33 && $o <= 126; }

CeeLanguage:



 #include <stdio.h>

 #include <stdlib.h>

 #include <ctype.h>

 int min(int a, int b) { return a < b ? a : b; }

 int main(int argc, char *argv[]) {

	FILE *fp;

	int i, start, end, width, left, count;

	unsigned char *buf;

	if(argc != 5) {

	fprintf(stderr, "Usage: %s <source> <start> <end> <width>\n", argv[0]);

	exit(2);

	}

	if((fp = fopen(argv[1], "r")) == NULL) { perror("fopen"); exit(2); }

	start = atoi(argv[2]);

	end	= atoi(argv[3]);

	width = atoi(argv[4]);

	left = end - start;

	if((buf = malloc(width)) == NULL) {

	fprintf(stderr, "No memory?!?\n");

	exit(2);

	}

	if(fseek(fp, start, SEEK_SET)) { perror("fseek"); exit(2); }

	while(left > 0 && (count = fread(buf, 1, min(left, width), fp))) {

	for(i = 0; i < count; i++)	 printf("%02X ", buf[i]);

	for(i = 0; i < width - count; i++) printf("	");

	printf(": ");

	for(i = 0; i < count; i++) printf("%c", isgraph(buf[i]) ? buf[i] : '.');

	printf("\n");

	left -= count;

	}

      free(buf);

	return 0;

 }

Hmm, this doesn't appear to be totally debugged:

./a.out a.out 0 50 16

7F 45 4C 46 01 01 01 00 00 00 00 00 00 00 00 00 : .ELF............
02 00 03 00 01 00 00 00 FFFFFFB0 FFFFFF84 04 08 34 00 00 00 : ............4...
FFFFFFC0 23 00 00 00 00 00 00 34 00 20 00 06 00 28 00 : .#......4.....(.
23 00 : #.

You need to add a mask: printf("%02X ", buf[i] & 0xff);

Minor detail.

Ah. Signed chars are sign extended into signed ints... Fixed by making the chars unsigned.

You beat me to the edit, and with a shorter solution, it looks like.

CeeLanguage:

After great struggle, I transformed the natural but verbose approach of C closures, reflection, and metaclasses into something a little more terse:



 #include	<assert.h>

 #include	<stdio.h>

 #include	<ctype.h>

 void displayHexRecord(char *data, int count, int record_length) {

	int	i;

	for (i=0; i < count; i++) printf("%02x ", data[i] & 0xff);

	for (; i < record_length; i++) printf("	");

	printf(": ");

	for (i=0; i < count; i++) {

		if (isgraph(data[i])) putchar(data[i]);

		else		  putchar('.');

	}

	putchar('\n');

 }

 void hexDump(FILE *f, long cur_addr, long end, int bytes_per_line) {

	int	record_length, read_count;

	char	*data;

	assert(data = (char*) calloc(sizeof(data[0]), bytes_per_line));

	if (-1 == fseek(f, cur_addr, SEEK_SET)) perror("fseek");

	while (1) {

		printf("%05x  ", cur_addr);

		read_count = end - cur_addr;

		if (read_count > bytes_per_line) read_count = bytes_per_line;

		record_length = fread(data, sizeof(char), read_count, f);

		displayHexRecord(data, record_length, bytes_per_line);

		if (record_length < bytes_per_line) break;

		if (end <= (cur_addr += record_length)) break;

	}

	free(data);

 }

Output for hexDump(f, 0, 55, 16) of its own executable:

00000 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00 : .ELF............
00010 02 00 03 00 01 00 00 00 f0 83 04 08 34 00 00 00 : ............4...
00020 44 35 00 00 00 00 00 00 34 00 20 00 06 00 28 00 : D5......4.....(.
00030 23 00 20 00 06 00 00 : #......

There's something strange about powerful languages having longer examples than powerless languages...

where's the main() and why no checking of command line arguments - it wouldn't produce a full executable without some other harness, so. . . where is it?

It's a library function. Requiring a full program violates the spirit of these ProgrammingChrestomathy pages; someone has already commented on searching and hex editing, and why exactly are we leaving out the GUI? :-P That's all foolishness, so I created a library routine. I also left out e.g. printing the filename, because that violates principles outlined in TheArtOfUnixProgramming; that, too, is an inappropriate requirement, although obviously it only adds one line of code to a program in any language.

Printing the filename wasn't a requirement. The Scheme program prompts the user for the filename, etc., from the console because command-line arguments aren't part of the standard language. Apparently, the person who wrote the C++ example (which, as someone else pointed it, is actually plain C) mistook the Scheme program prompting the user for input as printing the arguments out.

Ah, I think I see. Incidentally, I was the one who pointed out the C++ was actually C, so it wasn't "someone else", it was just "someone". :-)

Anyone who fails to grok these points should immediately go download and examine the (huge) GNU hello world distribution, and ponder how it is that hello world got to be so big.

(It got to be that big because it's an example of how to release packages The GNU Way and they wanted to give an example of every bell, whistle, and gong you can accomplish with standard GNU packaging tools. In other words, it got that big because it's demonstrating a nontrivial solution set to a highly nontrivial problem.)

But if you just want to try it, a trivial main will do it:



      #include <stdio.h>
int main(void) {

	FILE *f = fopen("a.out", "r");

	if (f == NULL) {

		perror("a.out");

		exit(1);

	}

	hexDump(f, 0, 55, 16);

      return 0;

   }

Parse command line args? What's that got to do with hex dump Chrestomathy? How about a test harness? I never saw a Marketing Requirements doc, either. Where's our sysadmin plan? Budget? HR-required ergonomic classes? Shall I go on? :-)

It's not really terse if it's missing a main, and puts printfs on the same line as the for loop. How many corners can you cut and claim "but it's terse!"? :->

(Bug fixed, thanks.)

How many corners can you cut and claim "but it's terse"? That's a good question. But you know, textbooks and magazine columns that illustrate algorithms almost always leave out error checks, because they get in the way of seeing the algorithm that is the true point.

The question of whether to sometimes put trivial bodies on the same line as the control construct, or whether to always put them on separate lines, is purely stylistic, and obviously HolyWars have been fought about that. Some people claim that it makes a huge difference in readability, but I personally don't think it matters too much either way in most cases.

The other CeeLanguage author did similar things - while finding an even more terse algorithm kernel as well.

Well, every programmer thinks their coding style is the "pragmatic optimum", so I won't argue that. The whole Chrestomathy idea should apply to samples
within the same language too. I guess the "real-world" origins of this page have changed, but now it's kind of a loose problem. How does the file get read? What does it link with? Does it require a host environment? Unfortunately "hex dumping" isn't really an algorithmic problem. . . so . . I guess I have no point than to say I'm not sure what the criteria for a good example is anymore.

It's not a huge algorithmic problem; none of these chrestomathy pages are. But it's an interesting small algorithmic problem. I still need to finish examining why it is that the other author got a smaller kernel than I did, so as to keep in mind any points I observe for future use. Look for general principles whenever possible, I say.

P.S. I thought I already addressed the issue of the missing main(), but to be somewhat more explicit: it would be all but trivially the same for all of these chrestomathy pages. It's not interesting, it's not illustrative, it doesn't vary, but it certainly adds clutter. And also, come now, I added one after someone implied they didn't want to be bothered writing one to test my code...but I still don't see that it is part of the chrestomathy proper. A proper Hello World illustrates half of how to do it in C, and an example of any use of getopts illustrates the other half.

JavaScript: (JScript running under WSH - Windows Script Host - uses ActiveXscripting for its file API)

note about ActiveXscripting:
one way or another you don't have direct access to file I/O (Input Output) inside an ECMAscript implementation (meaning the core language definition), the file I/O depends on the environment where the language is implemented.
Here in WSH, Microsoft has provided external COM objects for file I/O access, in another environment like FESI ( http://www.lugrin.ch/fesi/fioext.html ) you could use another way to access file I/O with the File constructor, anyway the code provided can be easyly ported to different ECMAscript environment just edit the readFile method in HexDump.

usage:
cscript hexdump.js <filename> <start> <end> <width>

limitation: this work only for ASCII files

'''if you want to edit the code edit it correctly, or make a fork with your own version,
if I have formated or given a particular structure to this script there are good reasons for that:'''

code readability
code reuse

if you're not happy with it make your own entry and dont't garbage my own.

/* Function: trace */



 function trace( /*String*/ txt )

    {

    WScript.Echo( txt.toString() );

    }

/* Singleton: Application */
Application = {};
Application.arguments = [];

Application.getArguments = function()



    {

    var args, i;

    args = WScript.Arguments;
for( i=0; i<args.length; i++ )

        {

        this.arguments.push( args(i) );

        }
return this.arguments;

    }

/* Class: HexDump */



 HexDump = function( /*String*/ source, /*Int*/ start, /*Int*/ end, /*Int*/ width )

    {

    this.source = source;

    this.start  = start;

    this.end    = end;

    this.width  = width;
this.file   = "";

    this.hex    = [];

    this.dump   = [];
this.parse();

    }
HexDump.prototype.toString = function()

    {

    var data, CRLF;

    data = "";

    CRLF = "\r\n";
data += "HexDump: \""+this.source+"\" ["+this.start+"-"+this.end+"] ("+this.width+")" + CRLF;

    data += this.dump.join( CRLF );

    return data;

    }
HexDump.prototype.readFile = function( /*String*/ filepath )

    {

    var FSO, file, data;

    FSO   = new ActiveXObject( "Scripting.FileSystemObject?" );

    file  = FSO.OpenTextFile?( filepath, /*FileIOmode.reading*/ 1, false, /*FileFormat?.ascii*/ false );

    data  = file.ReadAll?();

    file.Close();
return data;

    }
HexDump.prototype.formatText = function( /*String*/ txt )

    {

    txt = txt.split( " " ).join( "." );

    txt = txt.split( "\n" ).join( " " );

    txt = txt.split( "\r" ).join( " " );

    return txt;

    }
HexDump.prototype.charToHex = function( /*Char*/ c )

    {

    var hex;

    hex = c.charCodeAt( 0 ).toString( 16 );

    return( (hex.length==2)? hex: "0"+hex );

    }
HexDump.prototype.parse = function()

    {

    var i, j, char, hexLine, fileLine;
this.file = this.readFile( this.source );

    this.file = this.file.substring( this.start, this.end );
for( i=0; i<this.file.length; i++ )

        {

        char = this.file.charAt( i );

        this.hex.push( this.charToHex( char ) );

        }
j        = 0;

    hexLine  = "";

    fileLine = "";

    while( j < this.file.length )

        {

        hexLine  = this.hex.slice( j, j+this.width+1 );

        while( hexLine.length <= this.width )

            {

            hexLine.push( "  " );

            }

        hexLine  = hexLine.join( " " );
fileLine = this.file.slice( j, j+this.width+1 );

        fileLine = this.formatText( fileLine );
this.dump.push( hexLine + " : " + fileLine );
j += this.width;

        }
}

/* MAIN ENTRY POINT */



 Application.main = function()

   {

    var args, dump;
args = this.getArguments();
if( args[3] == null )

        {

        args[3] = 16; //default value

        }
if( args[2] == null )

        {

        args[2] = 100; //default value

        }
if( args[1] == null )

        {

        args[1] = 0; //default value

        }
if( args[0] == null )

        {

        trace( "usage:\r\ncscript hexdump.js <filename> <start> <end> <width>" );

        return;

        }
dump = new HexDump( args[0], parseInt(args[1]), parseInt(args[2]), parseInt(args[3]) );
trace( dump );

    }
Application.main();

output for cscript hexdump.js hexdump.js 0 100 16



 HexDump: "hexdump.js" [0-100] (16)

 2f 2a 20 46 75 6e 63 74 69 6f 6e 3a 20 74 72 61 63 : /*.Function:.trac

 63 65 0d 0a 2a 2f 0d 0a 74 72 61 63 65 20 3d 20 66 : ce  */  trace.=.f

 66 75 6e 63 74 69 6f 6e 28 20 2f 2a 53 74 72 69 6e : function(./*Strin

 6e 67 2a 2f 20 74 78 74 20 20 29 0d 0a 20 20 20 20 : ng*/.txt..)  ....

 20 7b 0d 0a 20 20 20 20 57 53 63 72 69 70 74 2e 45 : .{  ....WScript.E

 45 63 68 6f 28 20 74 78 74 2e 74 6f 53 74 72 69 6e : Echo(.txt.toStrin

 6e 67 28 29					: ng()

(My 1st participation in this great wiki ;) -- ZwetanKjukov
[sideNote: I can provide also a oneliner totally obscured and unreadable but I don't really see any usefulness to that.]

Neither does anyone else. Layne did that to be sarcastic because I wrote something like:



   if (x) y();

where he thought style required always writing



   if (x) {

      y();

   }

That's the only reason that he posted his unreadable oneliners; they were an editorial comment.

Here's a CommonLisp version without pretense of efficiency or command-line parsing:



 (defun dump-line (in start width count)

   (let ((bytes (loop for i below count

                      for byte = (read-byte in nil nil)

                      while byte collect byte)))

 	(format t "~&~8,'0X ~{~2,'0X ~}~A | ~{~C~}"

             start

             bytes

             (make-string (* 3 (- width (length bytes)))

                          :initial-element #\Space)

             (loop for byte in bytes

                   for char = (code-char byte)

                   when (graphic-char-p char) collect char

                   else collect #\.))))
(defun dump (file start end width)

   (with-open-file (in file

                       :direction :input

                       :element-type '(unsigned-byte 8))

     (when (file-position in start)

       (loop with true-end = (min end (file-length in))

             for i from start below true-end by width

             do (dump-line in i width (min width (- true-end i))))))

   (format t "~%"))

Sample output, generated by evaluating (dump "dump.lisp" 3 37 16):

00000003 66 75 6E 20 64 75 6D 70 2D 6C 69 6E 65 20 28 69 | fun dump-line (i
00000013 6E 20 73 74 61 72 74 20 63 6F 75 6E 74 20 77 69 | n start count wi
00000023 64 74 | dt

-- DanMuller

Standard CommonLisp doesn't provide a way to get command-line arguments. Guess I'll have to add interactive argument acquisition.

[Historical note: The original version of this page stated that other chrestomathy pages "do not demonstrate the use of the languages in a way that is applicable to real-world programming", with implication that this one would. It also placed several requirements on the program which were out of place in this sort of demonstration (that it had to be a stand-alone program, that read user input from the either the command line or the console, etc.). This naturally enough garnered several scornful remarks. When the problem definition was refactored, the origianl version and the subsequent discussion were moved here for reference sake.]

While there are several ProgrammingChrestomathy pages already, most of them deal with a task that is either trivial (printimg "Hello, World!" or the lyrics to "99 Bottles of Beer", encrypting a cleartext in RotThirteen), or of primarily theoretical or abstract importance (the 8-Queens Problem, calculating dot-products). While these are all valuable in their own way, one could argue that they do not demonstrate the use of the languages in a way that is applicable to real-world programming.

To this end, I am hereby proposing a new chrestomathy challenge: a program in the format

hexdump source start end width

which reads the file source and prints a HexDump of the bytes in the file from start to end, formatted to show width bytes separated by space, followed by a separator, then followed by the ASCII values of the displayed bytes, in the order they exist in the file. The program include the code to read these arguments, either from the command line, or from user input. Either console or GUI programs are acceptable, though portable code is preferred where possible. The code should be testable by independent third parties. Any instructions needed for testing the code (target environment, special requirements) should be listed in the program comments.

I wouldn't say that this problem is any more or less trivial than the other chrestomathy (great word!) pages. Depends what your real world is, I guess.

There are a host of "real world" factors ignored here too:

Reusability - There is no incentive here to make the code reusable.
Error handling - Missing arguments, bad read on file, etc are very vague
Hex searching - Nothing is more annoying than a hex editor you can't search in
Agility - How agile is the code? Would it respond well to requests for new features?
Installability - A standalone EXE would be easier than having to install interpreters, etc.
Cross-platform issues - Does it need recompilation? Does an interpreter exist for system <X>?
Code readability - Which was a hazy problem to begin with.
Graphics - Color highlighting of the "selected hex" surrounded by "unselected hex"

I just don't think it's possible to take all the complexities of "real software" and reduce it to a single problem - because the solutions will be optomized to fit the rules of the game, and not the realities of customer satisfaction.

Late note: although it wasn't originally mentioned, in real life it is fairly essential to show the current address at the start of each line, so I recommend adding that to the existing examples below.

Very well, the point is conceded. It was a mistake for me to use the phrase 'real-world' for something as artificial and isolated as this. I might replace it with 'practical', but that has nearly as many problems, now doesn't it? My intention was simply that it would show some of the aspects of languages which normally are ignored in such demonstration programs, not to make a commercial-quality project of it. Perhaps even that was poorly considered - after all, it is still a very small task, and such details only serve to confuse. While I still think it is a good example project, my presentation was regrettable (though perhaps not as regrettable as the Scheme example I wrote). -- JayOsako

The 8 queens chrestomathy page had people talking about "extra points" for things like N-queens rather than just 8; not everyone bothered. I would think that approach would be appropriate for all such things: the challenge itself should be quite minimal, but with recognition of extras that make sense. I sure would give someone brownie points if they added a gui, searching, editing, color high lighting, etc etc, all in a small enough amount of code to not be absurd to put on this page (not sure how feasible that would be).

Perhaps I should refactor the page to that model, then. I don't want to step on too many toes, however; I'm fairly new to Wiki (modulo a few things I wrote years ago, and have largely regretted), and I'm still not comfortable with the editing ettiquette. -- JayOsako

The cautious approach would be to just rewrite what you yourself wrote, noting in broad outline any changes you made that might surprise someone who already contributed code to the page. We're only hoping to improve things, not to make people feel like we're unfairly changing the rules on them or something, thus the note about what changed.

I presume there is no current motivation to rewrite everyone's code, so it's not really about refactoring the whole page.

You are correct, of course; there's no need to refactor anything except the requirements (and my awful Scheme code). I'm not sure what will be done with the comments that were made about it; for now, I'll leave them as the are, though I'll put a separator and a note as to what they refer to).

FoxPro

Someone already posted a Perl solution and a C/C++ solution, and portability seems to be important, so I won't post an AssemblyLanguage solution, but I do have another portable language (this will also run as-is in XBase++ and probably in both FlagShip and Clipper).



  *	fhdump.prg
parameters	filename, start, stop, dwidth

  private	talking, hex_ascii, d_len, di, str16, d_str, hex_str
if set("talk") = "ON"

	  set talk OFF

	  talking = .T.

  else

	  talking = .F.

  endif

  crlf = chr(13) + chr(10)			&& for convenience

  hex_ascii = ""				&& buffer for output line

  dwidth = min(dwidth, 200)			&& largest reasonable display width

  dwidth = max(dwidth, 1)			&& smallest reasonable display width

  fh = fopen(filename)				&& open file at low level

  if fh > 0					&& proceed only if valid handle

	  ?					&& begin new line

	  xi = fseek(fh, start)			&& skip to desired offset in file

	  do while !feof(fh) AND xi <= stop	&& stop at end of file

		  raw = fread(fh, dwidth)	&& read a block of desired size

		  hex_str = padr(hex(raw, " "), dwidth * 3)	&& pad short line

		  hex_ascii = str(xi, 5) +": "+ hex_str +"| "+ strip(raw) + crlf

		  ?? hex_ascii			&& offset: hex digits | stripped ASCII

		  xi = xi + dwidth		&& bump the offset

	  enddo

  endif

  fh = fclose(fh)				&& housekeeping
if talking

	  set talk ON

  endif
return
*	-----------------
* most output devices don't deal well with control characters, so  ...

  function strip				&& replace control chars in string with '.'

	  parameters	rawstring

	  private	outstring, sx, byte

	  outstring = ""

	  for sx = 1 to len(rawstring)		&& examine each byte in string

		  byte = substr(rawstring, sx, 1)	&& get single byte

		  outstring = outstring + iif(asc(byte) > 31, byte, ".")

	  endfor				&& keep printables, convert controls

  return outstring
* convert a string of bytes to hex, padded with 'padchar'

  function hex

	  parameters	string, padchr		&& bytes and separator

	  private	nbytes, hex_str, ix, bc

	  padchr = iif(type("padchr") = "C", padchr, "")	&& optional separator

	  hex_str = ""				&& result buffer

	  nbytes = len(string)			&& count the bytes

	  for ix = 1 to nbytes			&& and one by one ...

		  bc = substr(string, ix, 1)	&& extract a byte

		  hex_str = hex_str + hdigits(bc) + iif(ix = nbytes, "", padchr)

	  endfor				&& and build result hex digit string

  return hex_str
* render a byte as a pair of hex digits

  function hdigits

	  parameters	char

	  private	ch_hi, ch_lo, av, nib

	  av = asc(char)			&& ASCII value of byte

	  nib = int(av / 16)			&& high order nibble

	  ch_hi = chr(nib + iif(nib > 9, 55, 48))	&& hex nibble

	  nib = mod(av, 16)			&& low order nibble

	  ch_lo = chr(nib + iif(nib > 9, 55, 48))	&& hex nibble

  return ch_hi + ch_lo				&& two nibbles to a byte
*	eof

  - - - - - - - - - -

  output of do fhdump with fhdump.prg", 0, 128, 16

  	  0: 2A 09 66 68 64 75 6D 70 2E 70 72 67 0D 0A 0D 0A | *.fhdump.prg....

  	 16: 70 61 72 61 6D 65 74 65 72 09 66 69 6C 65 6E 61 | parameter.filena

  	 32: 6D 65 2C 20 73 74 61 72 74 2C 20 73 74 6F 70 2C | me, start, stop,

  	 48: 20 64 77 69 64 74 68 0D 0A 70 72 69 76 61 74 65 |  dwidth..private

  	 64: 09 09 74 61 6C 6B 69 6E 67 2C 20 68 65 78 5F 61 | ..talking, hex_a

  	 80: 73 63 69 69 2C 20 64 5F 6C 65 6E 2C 20 64 69 2C | scii, d_len, di,

  	 96: 20 73 74 72 31 36 2C 20 64 5F 73 74 72 2C 20 68 |  str16, d_str, h

  	112: 65 78 5F 73 74 72 0D 0A 0D 0A 69 66 20 73 65 74 | ex_str....if set

  	128: 28 22 74 61 6C 6B 22 29 20 3D 20 22 4F 4E 22 0D | ("talk") = "ON".

  - - - - - - - - - -

  output of do fhdump with "fhdump.prg", 0, 64, 8

  	  0: 2A 09 66 68 64 75 6D 70 | *.fhdump

  	  8: 2E 70 72 67 0D 0A 0D 0A | .prg....

  	 16: 70 61 72 61 6D 65 74 65 | paramete

  	 24: 72 09 66 69 6C 65 6E 61 | r.filena

  	 32: 6D 65 2C 20 73 74 61 72 | me, star

  	 40: 74 2C 20 73 74 6F 70 2C | t, stop,

  	 48: 20 64 77 69 64 74 68 0D |  dwidth.

  	 56: 0A 70 72 69 76 61 74 65 | .private

  	 64: 09 09 74 61 6C 6B 69 6E | ..talkin

Minimally Excessive CeeLanguage example:

There was debate about my other C example, so here's what happens when C gets a little too terse. . . -- LayneThomas



  #include <stdio.h>

  hexer(FILE *f,int b,int e,int w){

	unsigned char cb[2048];int z[3]={0,0,0};

	while(!feof(f)){

	fscanf(f,"%c",&cb[z[2]]);

	if ((z[1]>=b)&&(z[1]<e)){

	if (z[2]==0) printf("%4u : ",z[1]);printf("%02X ",cb[z[2]],z[2]++);

	if ((((z[1]-b)%w)==(w-1)||((z[1]==e-1)?z[0]=1:z[0]=0))){

	if (z[0]) for (z[0]=0;z[0]<(w-z[2]);z[0]++){printf("__ ");}printf(" : ");

	for (z[0]=0;z[0]<w;z[0]++)(cb[z[0]]<32)?printf("."):printf("%c",cb[z[0]],z[2]=0);	  printf("\n");

	}}z[1]++;}

	return 0;

  }

  int main(void){FILE *inf=fopen("main.cpp","rt"); hexer(inf,10,243,16);fclose(inf);return 0;}
output of "hasaproblem", 10 100, 16
10 : 73 74 64 69 6F 2E 68 3E 0A 68 65 78 65 72 28 46  : stdio.h>.hexer(F

  26 : 49 4C 45 20 2A 66 2C 69 6E 74 20 62 2C 69 6E 74  : ILE *f,int b,int

  42 : 20 65 2C 69 6E 74 20 77 29 7B 0A 20 20 75 6E 73  :  e,int w){.  uns

  58 : 69 67 6E 65 64 20 63 68 61 72 20 63 62 5B 32 30  : igned char cb[20

  74 : 34 38 5D 3B 69 6E 74 20 7A 5B 33 5D 3D 7B 30 2C  : 48];int z[3]={0,

  90 : 30 2C 30 7D 3B 0A 20 20 77 68 69 6C 65 28 21 66  : 0,0};.  while(!f

 106 : 65 6F 66 28 66 29 29 7B 0A 20 20 66 73 63 61 6E  : eof(f)){.  fscan

 122 : 66 28 66 2C 22 25 63 22 2C 26 63 62 5B 7A 5B 32  : f(f,"%c",&cb[z[2

 138 : 5D 5D 29 3B 0A 20 20 69 66 20 28 28 7A 5B 31 5D  : ]]);.  if ((z[1]

 154 : 3E 3D 62 29 26 26 28 7A 5B 31 5D 3C 65 29 29 7B  : >=b)&&(z[1]<e)){

 170 : 0A 20 20 69 66 20 28 7A 5B 32 5D 3D 3D 30 29 20  : .  if (z[2]==0)

 186 : 70 72 69 6E 74 66 28 22 25 34 75 20 3A 20 22 2C  : printf("%4u : ",

 202 : 7A 5B 31 5D 29 3B 70 72 69 6E 74 66 28 22 25 30  : z[1]);printf("%0

 218 : 32 58 20 22 2C 63 62 5B 7A 5B 32 5D 5D 2C 7A 5B  : 2X ",cb[z[2]],z[

 234 : 32 5D 2B 2B 29 3B 0A 20 20 __ __ __ __ __ __ __  : 2]++);.  [2]],z[

Allow me to don the CeeLanguage evil advocate's hat for a moment:

It is readable, I didn't PGP it. Heck, I didn't even Rot13 it.
Some people say it won't compile for ANSI C. I submit that a real CeeLanguage programmer would make it.
Some would say that the final line of output has a bug at the end. I would say that any good programmer would see the blank lines and know to ignore the equivalent text, therefore there is no problem.
It is very memory efficient for its hard-coded 2048 limit. . . but that's twice as good as other examples! Including ones that don't handle the line
It has all three parts - address, hex and character display.
It is a fully compiling executable
It only uses stdio.h
It even closes the file at the end. . . uhm. . . cause. . . it's awesome. . .
The variables are reasonably named - except for "z" - which is terser to save space
Is this better?

Super Two-Line Excessively Minimal CeeLanguage example:



  #include <stdio.h>

  hexer(FILE *f,int b,int e,int w){unsigned char cb[2048];int z[3]={0,0,0};while(!feof(f)){fscanf(f,"%c",&cb[z[2]]);if ((z[1]>=b)&&(z[1]<e)){if (z[2]==0)	printf("%4u : ",z[1]);printf("%02X ",cb[z[2]],z[2]++);if ((((z[1]-b)%w)==(w-1)||((z[1]==e-1)?z[0]=1:z[0]=0))){if (z[0]) for (z[0]=0;z[0]<(w-z[2]);z[0]++){printf("__ ");}printf(" : ");for (z[0]=0;z[0]<w;z[0]++)(cb[z[0]]<32)?printf("."):printf("%c",cb[z[0]],z[2]=0);printf("\n");}}z[1]++;}return 0;}int main(void){ FILE	*inf=fopen("main.cpp","rt"); hexer(inf,10,243,16); fclose(inf);return 0;}

I am of course joking about all this.

Sarcastic, you mean. Since you have all this boundless energy, where's that C++ version?

I'm currently uploading it. . . Even at 700k/s, it will still take until tomorrow morning.

Smaller than I expected; congratulations.

Here is an attempt at a reasonable-length CeePlusPlus version:



  #include <iostream>

  #include <algorithm>

  #include <sstream>

  #include <iomanip>

  using namespace std;
struct hexwriter

  {

  	stringstream _numbers,_letters;

  	int _start,_width,_position;
hexwriter(int start,int width) :

  		_start(start), _width(width), _position(0)

  	{

  	}
void operator()(char value)

  	{

  		_numbers << setw(2) << setfill('0') << hex;

  		_numbers << static_cast<int>(static_cast<unsigned char>(value)) << ' ';

  		_letters << (iscntrl(value)?'.':value);

  		if(++_position%_width==0)

  			flush();

  	}
void flush()

  	{

  		if(0!=_position)

  		{

  			cout << right << setw(8) << hex << _start << " : ";

  			cout << left << setw(3*_width) << _numbers.str() << ": " << _letters.str() << endl;

  			_position=0;

  			_start+=_width;

  		}

  		_numbers.str("");

  		_letters.str("");

  	}

  };
int main(int argc,char** argv)

  {

  	int first=(argc>1)?atoi(argv[1]):0;

  	int last=(argc>2)?atoi(argv[2]):string::npos;

  	int width=(argc>3)?atoi(argv[3]):16;
typedef istreambuf_iterator<char> cinit;

  	string buffer(cinit(cin.rdbuf()),cinit());

  	buffer=buffer.substr(first,last);
hexwriter writer(first,width);

  	for_each<string::iterator,hexwriter&>(buffer.begin(),buffer.end(),writer);

  	writer.flush();

  }
$ hexdump 10 110 24 < hexdump.cpp

         a : 69 6f 73 74 72 65 61 6d 3e 0a 23 69 6e 63 6c 75 64 65 20 3c 61 6c 67 6f : iostream>.#include <algo

        22 : 72 69 74 68 6d 3e 0a 23 69 6e 63 6c 75 64 65 20 3c 73 73 74 72 65 61 6d : rithm>.#include <sstream

        3a : 3e 0a 23 69 6e 63 6c 75 64 65 20 3c 69 6f 6d 61 6e 69 70 3e 0a 75 73 69 : >.#include <iomanip>.usi

        52 : 6e 67 20 6e 61 6d 65 73 70 61 63 65 20 73 74 64 3b 0a 0a 73 74 72 75 63 : ng namespace std;..struc

        6a : 74 20 68 65 78 77 72 69 74 65 72 0a 7b 0a                               : t hexwriter.{.

-- MichaelSparks

OcamlLanguage:



    open Printf
let hexadecimal str =

      let buffer = Buffer.create ((String.length str) * 3) in begin

        String.iter (fun char ->

          Buffer.add_string buffer (sprintf " %02x" (int_of_char char))) str;

        Buffer.contents buffer

      end

    and ascii str =

      let buffer = Buffer.create (String.length str) in begin

        String.iter (fun char ->

          Buffer.add_char buffer

            (match char with

              ' ' .. '~' -> char

            | _ -> '.')) str;

        Buffer.contents buffer

      end
let front width pos str =

      printf "%08x:%*s | %*s\n"

        pos (3*width) (hexadecimal str) width (ascii str)

    and back width pos str =

      printf "%08x:%-*s | %-*s\n"

        pos (3*width) (hexadecimal str) width (ascii str)
let dump filename ?s:(s = 0) ?e:e ?width:(width = 16) () =

      let chan = open_in_bin filename in

      let display f length =

        let buf = (String.make length '\000') in

        let real_length = input chan buf 0 length in

        let _ = if real_length > 0 then

          (f (String.sub buf 0 real_length)) else () in

        if real_length < length then raise End_of_file else ()

      in

      let front_off = (width - (s mod width)) in

      let (final, remaining) =

        match e with

          Some e -> ((fun pos -> (e - pos) <= width),

                     (fun pos -> (e - pos)))

        | None -> ((fun pos -> false),

                   (fun pos -> 0))

      in

      try begin

        seek_in chan s;

        display (front width s) front_off;

        let rec continue pos =

          if (final pos) then begin

            display (back width pos) (remaining pos);

            raise End_of_file

          end else begin

            display (back width pos) width;

            continue (pos+width)

          end

        in continue (s + front_off)

      end with End_of_file -> begin

        close_in chan;

        ()

      end

    ;;
let usage () =

      eprintf "Usage: %s file [start [end [width]]]\n" Sys.argv.(0) in

    let main () =

      match Sys.argv with

        [|_|] -> usage ()

      | [|_; file|] -> dump file ()

      | [|_; file; s|] -> dump file ~s:(int_of_string s) ()

      | [|_; file; s; e|] ->

          dump file ~s:(int_of_string s) ~e:(int_of_string e) ()

      | [|_; file; s; e; width|] ->

          dump file ~s:(int_of_string s) ~e:(int_of_string e)

            ~width:(int_of_string width) ()

      | _ -> usage ()

    in main ()

JayLanguage:



 nhex =: 3 : 0  NB. res;val

	' ',~"1(((>0{y.)$16) #: >1{y.){ '0123456789ABCDEF'

 )
hex =: 3 : ',.nhex 2;a.i.y.'
prt =: 3 : 0

	pa =. (32+i.96){a.

	mk =. '.'

	(pa i.y.){pa,mk

 )

 hexdump =: 3 : 0	NB. 'file';start;end;width

	fn =. >0{y.

	st=. >1{y.

	sz=. >:((1!:4 <fn)<.>2{y.)-st

	w=. >3{y.

	r=. >.sz%w

	adrs=. nhex 4;st+w*i.r

	text=. (r,w)$(1!:11 fn;st,sz),(-sz-r*w)${.a.

	adrs,. (hex text),. ':',.' ',. prt text

 )

Put to use:



   hexdump 'c:\prj\j\hexdump.ijs';20;73;10

 0014 65 78 20 3D 3A 20 33 20 3A 20 : ex =: 3 :

 001E 30 20 20 4E 42 2E 20 72 65 73 : 0  NB. res

 0028 3B 76 61 6C 0D 0A 09 27 20 27 : ;val...' '

 0032 2C 7E 22 31 28 28 28 3E 30 7B : ,~"1(((>0{

 003C 79 2E 29 24 31 36 29 20 23 3A : y.)$16) #:

 0046 20 3E 31 7B 00 00 00 00 00 00 :  >1{......

-- MarcThibault

Here is an attempt at a reasonable-length Java version:

import java.io.FileInputStream;

public class HexDump {



	public static void main(final String[] args) throws Exception {

		final int width = 3 * Integer.parseInt(args[3]);

		final FileInputStream inS = new FileInputStream(args[0]);

		inS.skip(Integer.parseInt(args[1]));

		final StringBuilder hex = new StringBuilder();

		final StringBuilder chr = new StringBuilder();
for (int pos = Integer.parseInt(args[2]); pos > 0 && inS.available() > 0; pos--) {

			chr.append((char) inS.read());

			hex.append(String.format("%1$02x ", (byte) chr.charAt(chr.length() - 1)));

			if (hex.length() >= width || pos <= 1) {

				System.out.println(String.format("%1$-" + (width) + "s", hex) + ":"

						+ chr.toString().replaceAll("[^!-~]", " "));

				hex.setLength(0);

				chr.setLength(0);

			}

		}

	}

}

Arguments: HexDump.java 0 100 16



 69 6d 70 6f 72 74 20 6a 61 76 61 2e 69 6f 2e 46 :import java.io.F

 69 6c 65 49 6e 70 75 74 53 74 72 65 61 6d 3b 0d :ileInputStream;

 0a 0d 0a 70 75 62 6c 69 63 20 63 6c 61 73 73 20 :   public class

 48 65 78 44 75 6d 70 20 7b 0d 0a 09 70 75 62 6c :HexDump {   publ

 69 63 20 73 74 61 74 69 63 20 76 6f 69 64 20 6d :ic static void m

 61 69 6e 28 66 69 6e 61 6c 20 53 74 72 69 6e 67 :ain(final String

 5b 5d 20 61                                     :[] a

A shorter CeePlusPlus version, with error checking:



    #include <algorithm>

    #include <cctype>

    #include <fstream>

    #include <iomanip>

    #include <iostream>

    #include <stdexcept>

    #include <string>

    #include <vector>
using namespace std;
void show_char(char c) { cout << (isprint(c) ? c : '.'); }

    void show_hex(char c) { cout << setw(2) << (c & 0xff) << ' '; }
int main(int argc, char** argv) {

      try {

        if (argc != 5)

          throw invalid_argument("Usage: hexdump <file> <start> <end> <width>");

        ifstream in(argv[1], ios::binary);

        if (! in)

          throw invalid_argument("File not found");

        size_t pos(strtoul(argv[2], 0, 0)), end(strtoul(argv[3], 0, 0)), width(strtoul(argv[4], 0, 0));

        if (end < pos || width < 1)

          throw invalid_argument("Invalid arguments");

        in.seekg(pos);

        if (! in)

          throw invalid_argument("Start position is past end of file");

        vector<char> buf(width);

        cout << hex << setfill('0');

        for (; in && pos < end; pos += width) {

          in.read(&buf[0], min(end - pos, width));

          size_t bytes(in.gcount());

          if (bytes) {

            cout << setw(8) << pos << " : ";

            for_each(&buf[0], &buf[bytes], show_hex);

            cout << string(3 * (width - bytes), ' ') << ": ";

            for_each(&buf[0], &buf[bytes], show_char);

            cout << '\n';

          }

        }

        return 0;

      }

      catch (const exception& ex) {

        cerr << "*** " << ex.what() << '\n';

        return 1;

      }

    }
./hexdump hexdump.cpp 100 200 16

    00000064 : 63 6c 75 64 65 20 3c 73 74 64 65 78 63 65 70 74 : clude <stdexcept

    00000074 : 3e 0a 23 69 6e 63 6c 75 64 65 20 3c 73 74 72 69 : >.#include <stri

    00000084 : 6e 67 3e 0a 23 69 6e 63 6c 75 64 65 20 3c 76 65 : ng>.#include <ve

    00000094 : 63 74 6f 72 3e 0a 0a 75 73 69 6e 67 20 6e 61 6d : ctor>..using nam

    000000a4 : 65 73 70 61 63 65 20 73 74 64 3b 0a 0a 76 6f 69 : espace std;..voi

    000000b4 : 64 20 73 68 6f 77 5f 63 68 61 72 28 63 68 61 72 : d show_char(char

    000000c4 : 20 63 29 20                                     :  c)

-- RossSmith?

A EuphoriaLanguage version. I'd forgotten how verbose Euphoria is, although this could be shortened...



  include get.e

  include file.e
constant STDOUT = 1, STDERR = 2
sequence Filename

  integer Start, End, Width, FileHandle?, Lines
procedure Error(sequence msg)

    puts(STDERR, msg)

    abort(2)

  end procedure
procedure Usage()

    Error("Usage: ex hexdump.ex <filename> <start> <end> <width>\n")

  end procedure
-- Convert string to integer, erroring with invalid parameter if not valid

  function IntParam?(sequence string)

    sequence tmp

    tmp = value(string)

    if tmp[1] = GET_SUCCESS and integer(tmp[2]) then

      return tmp[2]

    end if

    Usage()

  end function
-- Check command line parameters

  procedure GetParams?()

    sequence cmd

    cmd = command_line()

    cmd = cmd[3..length(cmd)]

    if length(cmd) != 4 then

      Usage()

    end if

    Filename = cmd[1]

    Start = IntParam?(cmd[2])

    End = IntParam?(cmd[3])

    Width = IntParam?(cmd[4])

    Lines = floor((End - Start + 1) / Width)

    if remainder((End - Start + 1), Width) != 0 then

      Lines = Lines + 1

    end if

  end procedure
-- Main Program start!

  GetParams?()

  FileHandle? = open(Filename, "rb")

  if FileHandle? = -1 then

    Error("Unable to read file '" & Filename & "'\n")

  end if
sequence Bytes

  sequence Output

  integer Void, RemainingBytes?, BytesToRead?, Offset, Padding
Void = seek(FileHandle?, Start)

  RemainingBytes? = End - Start + 1

  Offset = Start
for lindex = 1 to Lines do

    Output = sprintf("%04x : ", Offset)
if Width < RemainingBytes? then

      BytesToRead? = Width

    else

      BytesToRead? = RemainingBytes?

    end if

    RemainingBytes? -= BytesToRead?

    Offset += BytesToRead?
Bytes = get_bytes(FileHandle?, BytesToRead?)

    for bindex = 1 to length(Bytes) do

      Output &= sprintf("%02x ", Bytes[bindex])

    end for
Padding = 3 * Width + 7

    if length(Output) < Padding then

      Output &= repeat(' ', Padding - length(Output))

    end if
Output &= ": "

    for bindex = 1 to length(Bytes) do

      if Bytes[bindex] >= 32 and Bytes[bindex] <= 127 then

        Output &= Bytes[bindex] -- printable

      else

        Output &= ' ' -- not printable, show space instead

      end if

    end for
Output &= "\n"

    puts(STDOUT, Output)

  end for

Outputs:

0000 : 69 6E 63 6C 75 64 65 20 67 65 74 2E 65 0D 0A 69 : include get.e i
0010 : 6E 63 6C 75 64 65 20 66 69 6C 65 2E 65 0D 0A 0D : nclude file.e
0020 : 0A 63 6F 6E 73 74 61 6E 74 20 53 54 44 4F 55 54 : constant STDOUT
0030 : 20 3D 20 31 2C 20 53 54 44 45 52 52 20 3D 20 32 : = 1, STDERR = 2
0040 : 0D 0A 0D 0A 73 65 71 75 65 6E 63 65 20 46 69 6C : sequence Fil
0050 : 65 6E 61 6D 65 0D 0A 69 6E 74 65 67 65 72 20 53 : ename integer S
0060 : 74 61 72 74 : tart

In PhpLanguage:



  <?php

  array_shift($argv);

  if (count($argv) !== 4) {

    die("Usage: php hexdump.php <filename> <start> <end> <width>\n");

  }

  list($filename, $start, $end, $width) = $argv;

  $fn = @fopen($filename, 'rb');

  if ($fn === FALSE) {

    die("Unable to open file '$filename'\n");

  }

  fseek($fn, $start);

  $offset = $start;

  while ($offset < $end && !feof($fn)) {

    $readto = min(array($offset + $width - 1, $end));

    $bytes = fread($fn, $readto - $offset + 1);

    $bytes = str_split($bytes);

    $line = sprintf('%04x : ', $offset);

    foreach ($bytes as $byte) {

      $line .= sprintf('%02x ', ord($byte));

    }

    if (strlen($line) < ($width * 3 + 7)) {

      $line .= str_repeat(' ', $width * 3 + 7 - strlen($line));

    }

    $line .= ': ';

    foreach ($bytes as $byte) {

      $line .= (ord($byte) >= 32 && ord($byte) <= 127) ? $byte : ' ';

    }

    print $line ."\n";

    $offset += $width;

  }

  fclose($fn);

Outputs:



  C:\programming-exercises\hexdump>php hexdump.php hexdump.php 0 99 16

  0000 : 3c 3f 70 68 70 0a 61 72 72 61 79 5f 73 68 69 66 : <?php array_shif

  0010 : 74 28 24 61 72 67 76 29 3b 0a 69 66 20 28 63 6f : t($argv); if (co

  0020 : 75 6e 74 28 24 61 72 67 76 29 20 21 3d 3d 20 34 : unt($argv) !== 4

  0030 : 29 20 7b 0a 20 20 64 69 65 28 22 55 73 61 67 65 : ) {   die("Usage

  0040 : 3a 20 70 68 70 20 68 65 78 64 75 6d 70 2e 70 68 : : php hexdump.ph

  0050 : 70 20 3c 66 69 6c 65 6e 61 6d 65 3e 20 3c 73 74 : p <filename> <st

  0060 : 61 72 74 3e                                     : art>

TCL



 package require binary
proc hexdump {str} {

        set s ""

        set addr 0
append s "[format "%07x" $addr]: "

        set t ""

        for {set i 0} {$i < [string length $str]} {incr i} {

                if {$i > 0 && [expr $i % 16] == 0} {

                        append s "  $t\n"

                        append s "[format "%07x" $addr]: "

                        incr addr 16

                        set t ""

                } elseif {$i > 0 && [expr $i % 2] == 0} {

                        append s " "

                }
set char [string index $str $i]

                binary scan $char H2 cc

                append s $cc

                if {[string is print $char]} {

                        append t $char

                } else {

                        append t "."

                }

        }

        puts $s

 }

CategoryInManyProgrammingLanguages

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Hex Dump In Many Programming Languages

Hex Dump In Many Programming Languages

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