mapstr.txt

Dos6.0

SUMMARY Translate abbreviated strings to integers.

KEYWORDS mapAbbrStr

USAGE

#include <mapstr.h>


// basic lookup structure
typedef char *MapTxt;
typedef int MapVal;
typedef char* (*MapTst) ( char*, char* );

typedef struct {
    MapTxt label;
    MapVal value;	// use your favorite enum here
    } MapItemRec, *MapItemPtr;

MapItemPtr mapAbbrStr (
    MapTxt szArg,
    MapItemPtr pTable,
    MapTst pTest
    );

DESCRIPTION

The mapAbbrStr routine maps a string to an integer, especially in
the face of multiple string matches.  It uses an array of
label and value pairs to define the mapping function, and calls
a user supplied test routine to actually preform comparisons.

The table argument defines the mapping from labels to values.
It is terminated with an element having a NULL label.  A pointer
to this element is returned if no match is found.

If the arg parameter is a perfect match for any of the labels,
a pointer to the corresponding MapItemRec is returned.	If arg
is a partial match of any of the labels, a pointer to the first
MapItemRec is returned unless there are ambiguous matches.  If
there are ambiguous matches, NULL is returned.

The test routine will be called with the arg parameter as the
first parameter and one of the labels as the second parameter.
The test routine must determine if the two strings don't match,
partially match, or perfectly match.

If the two strings do not match, test must return NULL.  If
the two string match "perfectly", test must return a the address
of the terminating null character of its second argument.  This
indicates a "full" match.  If the two strings partially match,
any non-NULL pointer can be returned.

SEE ALSO

strprefix

striprefix


EXAMPLE

#include <stdlib.h>
#include <stdio.h>

#include "strpfx.h"
#include "mapstr.h"

typedef enum {
    ARG_UNK,
    ARG_SRC, ARG_DST, ARG_BINARY, ARG_ASCII,
    ARG_AMBIGUOUS, ARG_DEMO,
    ARG_BAD }
    ArgSet;

MapItemRec allow[] = {
    // "standard" strings
    { "SRC",	ARG_SRC },
    { "DST",	ARG_DST	},
    { "BINARY", ARG_BINARY },
    { "ASCII",	ARG_ASCII },

    { "AMBIGUOUS", ARG_AMBIGUOUS },
    { "DEMO",	   ARG_DEMO },

    // "alias" strings
    { "SOURCE",      ARG_SRC },
    { "DESTINATION", ARG_DST },
    { "D",	     ARG_DST },     // exact match on "d" is not ambiguous

    // must be last
    { NULL,	     ARG_UNK }
    };

void
main (
    int argc,
    char **argv
    )
{
    MapItemPtr arg;

    for ( ; *argv; argv++ ) {

	arg = mapAbbrStr ( *argv, allow, striprefix );

	if ( arg == NULL )
	    printf ( "argument %s had multiple ambiguous matches.\n", *argv );
	else if ( arg->label == NULL )
	    printf ( "argument %s not in table.\n", *argv );
	else
	    printf ( "argument %s matched %s (%d).\n",
		     *argv, arg->label, arg->value );
	}
    }