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GETOPT_.PAS
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Pascal/Delphi Source File
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1993-04-08
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7KB
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230 lines
{
Original module in C is
Copyright (c) 1986,1992 by Borland International Inc.
All Rights Reserved.
%% port to BPASCAL and enhancements by Juancarlo Anez
%% CIS id [73000,1064]
%% date 92.04.08
}
UNIT GETOPT_;
INTERFACE
CONST
MaxArgs = 50; { Maximun number of comandline arguments }
MaxCmdLin = 255; { Maximun comandline lenth }
EOFch = #24; { returned by getOpt when no more options }
NONOPTch = '√'; { returned by getOpt when arg is non-option}
ERRORch = #1;
UNKNOWNch = '?';
optind :Integer = 1; { index of which argument is next }
optarg :pChar = nil; { pointer to argument of current option }
opterr :Boolean = FALSE; { allow error message }
argc :Integer = 0; { count of non-opt arguments when
getOpt has returned EOFch }
VAR
argv :array[0..MaxArgs] of pChar; { non-opt arguments }
function getopt(optionS:pChar):Char;
{
Parse the command line options, System V style.
The original standard option syntax is:
option ::= SW [optLetter]* [argLetter space* argument]
%%% 92.04.08 -- Juancarlo Anez, CIS 73000,1064
It has been augmented to:
option ::= SW ([optLetter]* [argLetter space* argument])*
In ohter words, options and non-options may be interplaced.
Additionaly, after getOpt returns EOFch, argv[] will point only to
non-options and argc will be the exact count of them
%%%
where
- SW is either '/' or '-', according to the current setting
of the MSDOS switchar (int 21h function 37h).
- there is no space before any optLetter or argLetter.
- opt/arg letters are alphabetic, not punctuation characters.
- optLetters, if present, must be matched in optionS.
- argLetters, if present, are found in optionS followed by ':'.
- argument is any white-space delimited string. Note that it
can include the SW character.
- upper and lower case letters are distinct.
There may be multiple option clusters on a command line, each
beginning with a SW, but all must appear before any non-option
arguments (arguments not introduced by SW). Opt/arg letters may
be repeated: it is up to the caller to decide if that is an error.
The character SW appearing alone as the last argument is an error.
The lead-in sequence SWSW ("--" or "//") causes itself and all the
rest of the line to be ignored (allowing non-options which begin
with the switch char).
The string *optionS allows valid opt/arg letters to be recognized.
argLetters are followed with ':'. Getopt () returns the value of
the option character found, or EOF if no more options are in the
command line. If option is an argLetter then the global optarg is
set to point to the argument string (having skipped any white-space).
The global optind is initially 1 and is always left as the index
of the next argument of argv[] which getopt has not taken. Note
that if "--" or "//" are used then optind is stepped to the next
argument before getopt() returns EOF.
If an error occurs, that is an SW char precedes an unknown letter,
then getopt() will return a '?' character and normally prints an
error message via perror(). If the global variable opterr is set
to false (zero) before calling getopt() then the error message is
not printed.
For example, if the MSDOS switch char is '/' (the MSDOS norm) and
*optionS == "A:F:PuU:wXZ:"
then 'P', 'u', 'w', and 'X' are option letters and 'F', 'U', 'Z'
are followed by arguments. A valid command line may be:
aCommand /uPFPi /X /A L someFile
where:
- 'u' and 'P' will be returned as isolated option letters.
- 'F' will return with "Pi" as its argument string.
- 'X' is an isolated option.
- 'A' will return with "L" as its argument.
- "someFile" is not an option, and terminates getOpt. The
caller may collect remaining arguments using argv pointers.
}
IMPLEMENTATION
USES
WINDOS,
STRINGS;
CONST
letP :pChar = nil; { remember next option char's location }
SW :Char = #0; { DOS switch character, either '-' or '/' }
VAR
cmdlin :array[0..MaxCmdLin] of Char;
{ delete an already processed option from argv }
procedure compressArgs(i :Integer);
begin
while i < argc
do begin
argv[i] := argv[i+1];
inc(i)
end;
argv[argc] := nil;
dec(argc)
end;
{ initialization, determine argc and argv
using the parsing already done by WINDOS unit
}
procedure init;
var
i :Integer;
pos :pChar;
regs :TRegisters;
begin
{ get SW using dos call 0x37 }
regs.AX := $3700;
msDOS(regs);
SW := Char(regs.DL);
argc := getArgCount;
pos := cmdlin;
for i := 0 to argc
do begin
argv[i] := pos;
getArgStr(pos, i, 512-(pos-cmdlin));
pos := strEnd(pos);
inc(pos);
end;
pos^ := #0;
for i := argc+1 to MaxArgs
do
argv[i] := nil;
end;
function getopt(optionS:pChar):Char;
label
gopERROR;
var
ch :array[0..1] of Char;
optP :pChar;
begin
if (SW = #0)
then
init;
ch[0] := EOFch;
ch[1] := #0;
optarg := nil;
while (optind <= argc)
do begin
if (letP = nil) then begin
letP := argv[optind];
if (letP = nil) then break;
if not (letP^ in [SW,'-','/'])then begin
optArg := letP;
letP := nil;
ch[0] := NONOPTch;
inc(optind);
break
end;
compressArgs(optind);
inc(letP);
if letP^ in [SW,'-','/'] then begin
letP := nil;
optind := argc+1;
break;
end
end;
ch[0] := letP^;
if ch[0] = #0 then goto gopERROR;
optP := strPos(optionS, ch);
if (ch[0] = ':') or (optP = nil) then goto gopError;
inc(letP);
inc(optP);
if (optP^ = ':')
then begin
if (letP^ = #0)
then begin
if (optind >= argc) then goto gopError;
letP := argv[optind];
compressArgs(optind)
end;
optarg := letP;
letP := nil;
end
else begin
if (letP^ = #0)
then begin
letP := nil
end;
optarg := nil;
end;
break
end;
getopt := ch[0];
exit;
gopError:
if (opterr)
then begin
writeln(output,'Error, unknown switch',SW,ch[0]);
halt(1)
end;
getopt := ERRORch;
optArg := letP;
letP := nil;
exit;
end;
END.