/* 

  * tclIndexObj.c --

  *

  *	This file implements objects of type "index".  This object type

  *	is used to lookup a keyword in a table of valid values and cache

  *	the index of the matching entry.

  *

  * Copyright (c) 1997 Sun Microsystems, Inc.

  * Portions Copyright (c) 2007-2008 Nokia Corporation and/or its subsidiaries. All rights reserved.  

  *

  * See the file "license.terms" for information on usage and redistribution

  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.

  *

  * RCS: @(#) $Id: tclIndexObj.c,v 1.16.2.5 2006/04/06 18:57:24 dgp Exp $

  */

 #include "tclInt.h"

 #include "tclPort.h"

 /*

  * Prototypes for procedures defined later in this file:

  */

 static int		SetIndexFromAny _ANSI_ARGS_((Tcl_Interp *interp,

 			    Tcl_Obj *objPtr));

 static void		UpdateStringOfIndex _ANSI_ARGS_((Tcl_Obj *objPtr));

 static void		DupIndex _ANSI_ARGS_((Tcl_Obj *srcPtr,

 			    Tcl_Obj *dupPtr));

 static void		FreeIndex _ANSI_ARGS_((Tcl_Obj *objPtr));

 /*

  * The structure below defines the index Tcl object type by means of

  * procedures that can be invoked by generic object code.

  */

 Tcl_ObjType tclIndexType = {

     "index",				/* name */

     FreeIndex,				/* freeIntRepProc */

     DupIndex,				/* dupIntRepProc */

     UpdateStringOfIndex,		/* updateStringProc */

     SetIndexFromAny			/* setFromAnyProc */

 };

 /*

  * The definition of the internal representation of the "index"

  * object; The internalRep.otherValuePtr field of an object of "index"

  * type will be a pointer to one of these structures.

  *

  * Keep this structure declaration in sync with tclTestObj.c

  */

 typedef struct {

     VOID *tablePtr;			/* Pointer to the table of strings */

     int offset;				/* Offset between table entries */

     int index;				/* Selected index into table. */

 } IndexRep;

 /*

  * The following macros greatly simplify moving through a table...

  */

 #define STRING_AT(table, offset, index) \

 	(*((CONST char * CONST *)(((char *)(table)) + ((offset) * (index)))))

 #define NEXT_ENTRY(table, offset) \

 	(&(STRING_AT(table, offset, 1)))

 #define EXPAND_OF(indexRep) \

 	STRING_AT((indexRep)->tablePtr, (indexRep)->offset, (indexRep)->index)

 /*

  *----------------------------------------------------------------------

  *

  * Tcl_GetIndexFromObj --

  *

  *	This procedure looks up an object's value in a table of strings

  *	and returns the index of the matching string, if any.

  *

  * Results:

  *

  *	If the value of objPtr is identical to or a unique abbreviation

  *	for one of the entries in objPtr, then the return value is

  *	TCL_OK and the index of the matching entry is stored at

  *	*indexPtr.  If there isn't a proper match, then TCL_ERROR is

  *	returned and an error message is left in interp's result (unless

  *	interp is NULL).  The msg argument is used in the error

  *	message; for example, if msg has the value "option" then the

  *	error message will say something flag 'bad option "foo": must be

  *	...'

  *

  * Side effects:

  *	The result of the lookup is cached as the internal rep of

  *	objPtr, so that repeated lookups can be done quickly.

  *

  *----------------------------------------------------------------------

  */

 EXPORT_C int

 Tcl_GetIndexFromObj(interp, objPtr, tablePtr, msg, flags, indexPtr)

     Tcl_Interp *interp; 	/* Used for error reporting if not NULL. */

     Tcl_Obj *objPtr;		/* Object containing the string to lookup. */

     CONST char **tablePtr;	/* Array of strings to compare against the

 				 * value of objPtr; last entry must be NULL

 				 * and there must not be duplicate entries. */

     CONST char *msg;		/* Identifying word to use in error messages. */

     int flags;			/* 0 or TCL_EXACT */

     int *indexPtr;		/* Place to store resulting integer index. */

 {

     /*

      * See if there is a valid cached result from a previous lookup

      * (doing the check here saves the overhead of calling

      * Tcl_GetIndexFromObjStruct in the common case where the result

      * is cached).

      */

     if (objPtr->typePtr == &tclIndexType) {

 	IndexRep *indexRep = (IndexRep *) objPtr->internalRep.otherValuePtr;

 	/*

 	 * Here's hoping we don't get hit by unfortunate packing

 	 * constraints on odd platforms like a Cray PVP...

 	 */

 	if (indexRep->tablePtr == (VOID *)tablePtr &&

 		indexRep->offset == sizeof(char *)) {

 	    *indexPtr = indexRep->index;

 	    return TCL_OK;

 	}

     }

     return Tcl_GetIndexFromObjStruct(interp, objPtr, tablePtr, sizeof(char *),

 	    msg, flags, indexPtr);

 }

 /*

  *----------------------------------------------------------------------

  *

  * Tcl_GetIndexFromObjStruct --

  *

  *	This procedure looks up an object's value given a starting

  *	string and an offset for the amount of space between strings.

  *	This is useful when the strings are embedded in some other

  *	kind of array.

  *

  * Results:

  *

  *	If the value of objPtr is identical to or a unique abbreviation

  *	for one of the entries in objPtr, then the return value is

  *	TCL_OK and the index of the matching entry is stored at

  *	*indexPtr.  If there isn't a proper match, then TCL_ERROR is

  *	returned and an error message is left in interp's result (unless

  *	interp is NULL).  The msg argument is used in the error

  *	message; for example, if msg has the value "option" then the

  *	error message will say something flag 'bad option "foo": must be

  *	...'

  *

  * Side effects:

  *	The result of the lookup is cached as the internal rep of

  *	objPtr, so that repeated lookups can be done quickly.

  *

  *----------------------------------------------------------------------

  */

 EXPORT_C int

 Tcl_GetIndexFromObjStruct(interp, objPtr, tablePtr, offset, msg, flags, 

 	indexPtr)

     Tcl_Interp *interp; 	/* Used for error reporting if not NULL. */

     Tcl_Obj *objPtr;		/* Object containing the string to lookup. */

     CONST VOID *tablePtr;	/* The first string in the table. The second

 				 * string will be at this address plus the

 				 * offset, the third plus the offset again,

 				 * etc. The last entry must be NULL

 				 * and there must not be duplicate entries. */

     int offset;			/* The number of bytes between entries */

     CONST char *msg;		/* Identifying word to use in error messages. */

     int flags;			/* 0 or TCL_EXACT */

     int *indexPtr;		/* Place to store resulting integer index. */

 {

     int index, i, numAbbrev;

     char *key, *p1;

     CONST char *p2;

     CONST char * CONST *entryPtr;

     Tcl_Obj *resultPtr;

     IndexRep *indexRep;

     /*

      * See if there is a valid cached result from a previous lookup.

      */

     if (objPtr->typePtr == &tclIndexType) {

 	indexRep = (IndexRep *) objPtr->internalRep.otherValuePtr;

 	if (indexRep->tablePtr==tablePtr && indexRep->offset==offset) {

 	    *indexPtr = indexRep->index;

 	    return TCL_OK;

 	}

     }

     /*

      * Lookup the value of the object in the table.  Accept unique

      * abbreviations unless TCL_EXACT is set in flags.

      */

     key = TclGetString(objPtr);

     index = -1;

     numAbbrev = 0;

     /*

      * Scan the table looking for one of:

      *  - An exact match (always preferred)

      *  - A single abbreviation (allowed depending on flags)

      *  - Several abbreviations (never allowed, but overridden by exact match)

      */

     for (entryPtr = tablePtr, i = 0; *entryPtr != NULL; 

 	    entryPtr = NEXT_ENTRY(entryPtr, offset), i++) {

 	for (p1 = key, p2 = *entryPtr; *p1 == *p2; p1++, p2++) {

 	    if (*p1 == '\0') {

 		index = i;

 		goto done;

 	    }

 	}

 	if (*p1 == '\0') {

 	    /*

 	     * The value is an abbreviation for this entry.  Continue

 	     * checking other entries to make sure it's unique.  If we

 	     * get more than one unique abbreviation, keep searching to

 	     * see if there is an exact match, but remember the number

 	     * of unique abbreviations and don't allow either.

 	     */

 	    numAbbrev++;

 	    index = i;

 	}

     }

     /*

      * Check if we were instructed to disallow abbreviations. 

      */

     if ((flags & TCL_EXACT) || (key[0] == '\0') || (numAbbrev != 1)) {

 	goto error;

     }

     done:

     /*

      * Cache the found representation.  Note that we want to avoid

      * allocating a new internal-rep if at all possible since that is

      * potentially a slow operation.

      */

     if (objPtr->typePtr == &tclIndexType) {

  	indexRep = (IndexRep *) objPtr->internalRep.otherValuePtr;

     } else {

  	if ((objPtr->typePtr != NULL)

 		&& (objPtr->typePtr->freeIntRepProc != NULL)) {

  	    objPtr->typePtr->freeIntRepProc(objPtr);

  	}

  	indexRep = (IndexRep *) ckalloc(sizeof(IndexRep));

  	objPtr->internalRep.otherValuePtr = (VOID *) indexRep;

  	objPtr->typePtr = &tclIndexType;

     }

     indexRep->tablePtr = (VOID*) tablePtr;

     indexRep->offset = offset;

     indexRep->index = index;

     *indexPtr = index;

     return TCL_OK;

     error:

     if (interp != NULL) {

 	/*

 	 * Produce a fancy error message.

 	 */

 	int count;

 	TclNewObj(resultPtr);

 	Tcl_SetObjResult(interp, resultPtr);

 	Tcl_AppendStringsToObj(resultPtr, (numAbbrev > 1) &&

 		!(flags & TCL_EXACT) ? "ambiguous " : "bad ", msg, " \"",

 		key, "\": must be ", STRING_AT(tablePtr,offset,0), (char*)NULL);

 	for (entryPtr = NEXT_ENTRY(tablePtr, offset), count = 0;

 		*entryPtr != NULL;

 		entryPtr = NEXT_ENTRY(entryPtr, offset), count++) {

 	    if (*NEXT_ENTRY(entryPtr, offset) == NULL) {

 		Tcl_AppendStringsToObj(resultPtr,

 			(count > 0) ? ", or " : " or ", *entryPtr,

 			(char *) NULL);

 	    } else {

 		Tcl_AppendStringsToObj(resultPtr, ", ", *entryPtr,

 			(char *) NULL);

 	    }

 	}

     }

     return TCL_ERROR;

 }

 /*

  *----------------------------------------------------------------------

  *

  * SetIndexFromAny --

  *

  *	This procedure is called to convert a Tcl object to index

  *	internal form. However, this doesn't make sense (need to have a

  *	table of keywords in order to do the conversion) so the

  *	procedure always generates an error.

  *

  * Results:

  *	The return value is always TCL_ERROR, and an error message is

  *	left in interp's result if interp isn't NULL. 

  *

  * Side effects:

  *	None.

  *

  *----------------------------------------------------------------------

  */

 static int

 SetIndexFromAny(interp, objPtr)

     Tcl_Interp *interp;		/* Used for error reporting if not NULL. */

     register Tcl_Obj *objPtr;	/* The object to convert. */

 {

     Tcl_AppendToObj(Tcl_GetObjResult(interp),

 	    "can't convert value to index except via Tcl_GetIndexFromObj API",

 	    -1);

     return TCL_ERROR;

 }

 /*

  *----------------------------------------------------------------------

  *

  * UpdateStringOfIndex --

  *

  *	This procedure is called to convert a Tcl object from index

  *	internal form to its string form.  No abbreviation is ever

  *	generated.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	The string representation of the object is updated.

  *

  *----------------------------------------------------------------------

  */

 static void

 UpdateStringOfIndex(objPtr)

     Tcl_Obj *objPtr;

 {

     IndexRep *indexRep = (IndexRep *) objPtr->internalRep.otherValuePtr;

     register char *buf;

     register unsigned len;

     register CONST char *indexStr = EXPAND_OF(indexRep);

     len = strlen(indexStr);

     buf = (char *) ckalloc(len + 1);

     memcpy(buf, indexStr, len+1);

     objPtr->bytes = buf;

     objPtr->length = len;

 }

 /*

  *----------------------------------------------------------------------

  *

  * DupIndex --

  *

  *	This procedure is called to copy the internal rep of an index

  *	Tcl object from to another object.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	The internal representation of the target object is updated

  *	and the type is set.

  *

  *----------------------------------------------------------------------

  */

 static void

 DupIndex(srcPtr, dupPtr)

     Tcl_Obj *srcPtr, *dupPtr;

 {

     IndexRep *srcIndexRep = (IndexRep *) srcPtr->internalRep.otherValuePtr;

     IndexRep *dupIndexRep = (IndexRep *) ckalloc(sizeof(IndexRep));

     memcpy(dupIndexRep, srcIndexRep, sizeof(IndexRep));

     dupPtr->internalRep.otherValuePtr = (VOID *) dupIndexRep;

     dupPtr->typePtr = &tclIndexType;

 }

 /*

  *----------------------------------------------------------------------

  *

  * FreeIndex --

  *

  *	This procedure is called to delete the internal rep of an index

  *	Tcl object.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	The internal representation of the target object is deleted.

  *

  *----------------------------------------------------------------------

  */

 static void

 FreeIndex(objPtr)

     Tcl_Obj *objPtr;

 {

     ckfree((char *) objPtr->internalRep.otherValuePtr);

 }

 /*

  *----------------------------------------------------------------------

  *

  * Tcl_WrongNumArgs --

  *

  *	This procedure generates a "wrong # args" error message in an

  *	interpreter.  It is used as a utility function by many command

  *	procedures.

  *

  * Results:

  *	None.

  *

  * Side effects:

  *	An error message is generated in interp's result object to

  *	indicate that a command was invoked with the wrong number of

  *	arguments.  The message has the form

  *		wrong # args: should be "foo bar additional stuff"

  *	where "foo" and "bar" are the initial objects in objv (objc

  *	determines how many of these are printed) and "additional stuff"

  *	is the contents of the message argument.

  *

  *----------------------------------------------------------------------

  */

 EXPORT_C void

 Tcl_WrongNumArgs(interp, objc, objv, message)

     Tcl_Interp *interp;			/* Current interpreter. */

     int objc;				/* Number of arguments to print

 					 * from objv. */

     Tcl_Obj *CONST objv[];		/* Initial argument objects, which

 					 * should be included in the error

 					 * message. */

     CONST char *message;		/* Error message to print after the

 					 * leading objects in objv. The

 					 * message may be NULL. */

 {

     Tcl_Obj *objPtr;

     int i;

     register IndexRep *indexRep;

     TclNewObj(objPtr);

     Tcl_SetObjResult(interp, objPtr);

     Tcl_AppendToObj(objPtr, "wrong # args: should be \"", -1);

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

 	/*

 	 * If the object is an index type use the index table which allows

 	 * for the correct error message even if the subcommand was

 	 * abbreviated.  Otherwise, just use the string rep.

 	 */

 	if (objv[i]->typePtr == &tclIndexType) {

 	    indexRep = (IndexRep *) objv[i]->internalRep.otherValuePtr;

 	    Tcl_AppendStringsToObj(objPtr, EXPAND_OF(indexRep), (char *) NULL);

 	} else {

 	    Tcl_AppendStringsToObj(objPtr, Tcl_GetString(objv[i]),

 		    (char *) NULL);

 	}

 	/*

 	 * Append a space character (" ") if there is more text to follow

 	 * (either another element from objv, or the message string).

 	 */

 	if ((i < (objc - 1)) || message) {

 	    Tcl_AppendStringsToObj(objPtr, " ", (char *) NULL);

 	}

     }

     if (message) {

 	Tcl_AppendStringsToObj(objPtr, message, (char *) NULL);

     }

     Tcl_AppendStringsToObj(objPtr, "\"", (char *) NULL);

 }