/****************************************************************************** MODUL varstack.c DESCRIPTION Variable Stack for DME/XDME NOTES -/- BUGS TODO -/- EXAMPLES -/- SEE ALSO vars.c INDEX HISTORY ******************************************************************************/ /* ** (C)Copyright 1992 by Bernd Noll for null/zero-soft ** All Rights Reserved ** ** RCS Header: $Id: varstack.c,v 1.65 92/12/05 12:47:24 b_noll Exp $ ** ** *!********************************************************** *! *! Variable Stacking: *! *! Stacking for all structures, which may be read and *! written via GetTypedVar() *! (Please notice that stackable are only variables, *! not macros, menues or mappings (they are stackable, but *! popping or picking might fail)) *! *! Users should be aware to pop their entries from the stack *! when they are needed not any more *! (We have NOT planned to create a garbage-collector :-)) *! ************************************************************ ** ** Implementator's note: ** ** variable stacking is done in a quiet simple way: ** all variables are searched with gettypedvar and their types ** are used as Node.ln_Type - entry ** ** currently (12-92) we use the same structure for storing variables ** on varstack which is used for storage in the main variable ** lists, but I preferred redefining that structure, as this method ** gives us the possibility of changing our definitions locally. ** (This is as we are just implementing AVL-Trees for Varstorage) */ /************************************** Includes **************************************/ #include "defs.h" /************************************** Globale Exports **************************************/ Prototype void do_pushVAR (void); Prototype void do_pickVAR (void); Prototype void do_popVAR (void); Prototype void do_swapVAR (void); Prototype void do_purgeVAR (void); #ifdef PATCH_NULL #ifdef PATCH_VARS /************************************** Interne Defines & Strukturen **************************************/ #define MLIST struct MinList #define MNODE struct MinNode static MLIST varstack = { (MNODE*)&varstack.mlh_Tail, NULL, (MNODE*)&varstack.mlh_Head }; typedef struct _VARS { NODE Node; CHAR* Str; } VARS; /************************************** Interne Prototypes **************************************/ /************************************** Impementation **************************************/ /* *! >PUSHVAR varname *! *! push the contents of the variable varname onto variable-stack *! */ void do_pushVAR (void) { VARS* v; int type; if (v = malloc (sizeof (VARS))) { /* allocate a node */ setmem(v, sizeof (VARS), 0); v->Node.ln_Name = strdup (av[1]); /* and space for name and value */ v->Str = GetTypedVar (av[1], &type); if (v->Node.ln_Name && v->Str) { /* if its done, fill in all values and push the node onto the varstack */ v->Node.ln_Type = type; AddHead((LIST*)&varstack, (NODE*)v); } else { if (v->Node.ln_Name) { /* else free all what yu have already allocated */ free(v->Node.ln_Name); } /* if */ if (v->Str) { free(v->Str); } /* if */ free(v); error ("%s: failure!\nno memory or unknown variable", av[0]); } /* if (not) malloced|found */ } else { error ("%s: no memory for stack-entry", av[0]); } /* if (not) malloced */ } /* do_pushVAR */ /* *! >POPVAR varname *! *! get the latest to variable-stack pushed contents of the variable *! varname back and free the stack-entry *! */ void do_popVAR (void) { VARS* v; if (v = (VARS*)FindName((LIST*)&varstack, av[1])) { /* if there is a stack-entry of the right name */ SetTypedVar(av[1], v->Str, v->Node.ln_Type); /* do a setvar to the right variable and the right contents */ Remove((NODE*)v); /* then remove the node from varstack and */ free(v->Str); /* free all its data */ free(v->Node.ln_Name); free(v); } else { error ("%s: stackentry %s not found", av[0], av[1]); } /* if (not) found */ } /* do_popVAR */ /* *! >PICKVAR varname *! *! get the latest to variable-stack pushed contents of the variable *! varname back without freeing the stack-entry *! */ void do_pickVAR (void) { VARS* v; if (v = (VARS*)FindName((LIST*)&varstack, av[1])) { /* if there is a stack-entry of the right name */ SetTypedVar(av[1], v->Str, v->Node.ln_Type); /* do a setvar to the right variable and the right contents */ } else { error ("%s: stackentry %s not found", av[0], av[1]); } /* if (not) found */ } /* do_pickVAR */ /* *! >SWAPVAR varname *! *! swap the contents of the variable varname and of its first occurancy in variable-stack *! ** this is not a very effective way of change, I would say, ** but it is one of the shortest */ void do_swapVAR (void) { VARS* v; if (v = (VARS*)FindName((LIST*)&varstack, av[1])) { /* if there is a stack-entry of the right name */ Remove((NODE*)v); /* remove it */ do_pushVAR(); /* push the variables current contents onto stack */ AddHead((LIST*)&varstack, (NODE*)v); /* set the elder stack-entry before that new node */ do_popVAR(); /* and then pop it into the variable */ } else { error ("%s: stackentry %s not found", av[0], av[1]); } /* if (not) found */ } /* do_swapVAR */ /* *! >PURGEVAR varname *! *! remove all entries with the name varname from varstack *! */ void do_purgeVAR (void) { VARS* v; for (v = (VARS*)varstack.mlh_Head; v; v = (VARS*)v->Node.ln_Succ) { /* with all entries of varstack do */ if (strcmp(v->Node.ln_Name, av[1]) == 0) { /* if they match the requested name */ Remove((NODE*)v); /* remove them and free their parts */ free(v->Str); free(v->Node.ln_Name); free(v); } /* if */ } /* for */ } /* do_purgeVAR */ #endif /* PATCH_VARS */ #endif /* PATCH_NULL */ /****************************************************************************** ***** ENDE varstack.c ******************************************************************************/