cde/programs/dtksh/ksh93/src/lib/libast/misc/stack.c

   1 /*
   2  * CDE - Common Desktop Environment
   3  *
   4  * Copyright (c) 1993-2012, The Open Group. All rights reserved.
   5  *
   6  * These libraries and programs are free software; you can
   7  * redistribute them and/or modify them under the terms of the GNU
   8  * Lesser General Public License as published by the Free Software
   9  * Foundation; either version 2 of the License, or (at your option)
  10  * any later version.
  11  *
  12  * These libraries and programs are distributed in the hope that
  13  * they will be useful, but WITHOUT ANY WARRANTY; without even the
  14  * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  15  * PURPOSE. See the GNU Lesser General Public License for more
  16  * details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with these librararies and programs; if not, write
  20  * to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
  21  * Floor, Boston, MA 02110-1301 USA
  22  */
  23 /* $XConsortium: stack.c /main/3 1995/11/01 18:04:55 rswiston $ */
  24 /***************************************************************
  25 *                                                              *
  26 *                      AT&T - PROPRIETARY                      *
  27 *                                                              *
  28 *         THIS IS PROPRIETARY SOURCE CODE LICENSED BY          *
  29 *                          AT&T CORP.                          *
  30 *                                                              *
  31 *                Copyright (c) 1995 AT&T Corp.                 *
  32 *                     All Rights Reserved                      *
  33 *                                                              *
  34 *           This software is licensed by AT&T Corp.            *
  35 *       under the terms and conditions of the license in       *
  36 *       http://www.research.att.com/orgs/ssr/book/reuse        *
  37 *                                                              *
  38 *               This software was created by the               *
  39 *           Software Engineering Research Department           *
  40 *                    AT&T Bell Laboratories                    *
  41 *                                                              *
  42 *               For further information contact                *
  43 *                     gsf@research.att.com                     *
  44 *                                                              *
  45 ***************************************************************/
  46
  47 /* : : generated by proto : : */
  48
  49 #if !defined(__PROTO__)
  50 #if defined(__STDC__) || defined(__cplusplus) || defined(_proto) || defined(c_plusplus)
  51 #if defined(__cplusplus)
  52 #define __MANGLE__      "C"
  53 #else
  54 #define __MANGLE__
  55 #endif
  56 #define __STDARG__
  57 #define __PROTO__(x)    x
  58 #define __OTORP__(x)
  59 #define __PARAM__(n,o)  n
  60 #if !defined(__STDC__) && !defined(__cplusplus)
  61 #if !defined(c_plusplus)
  62 #define const
  63 #endif
  64 #define signed
  65 #define void            int
  66 #define volatile
  67 #define __V_            char
  68 #else
  69 #define __V_            void
  70 #endif
  71 #else
  72 #define __PROTO__(x)    ()
  73 #define __OTORP__(x)    x
  74 #define __PARAM__(n,o)  o
  75 #define __MANGLE__
  76 #define __V_            char
  77 #define const
  78 #define signed
  79 #define void            int
  80 #define volatile
  81 #endif
  82 #if defined(__cplusplus) || defined(c_plusplus)
  83 #define __VARARG__      ...
  84 #else
  85 #define __VARARG__
  86 #endif
  87 #if defined(__STDARG__)
  88 #define __VA_START__(p,a)       va_start(p,a)
  89 #else
  90 #define __VA_START__(p,a)       va_start(p)
  91 #endif
  92 #endif
  93 static const char id_stack[] = "\n@(#)stack (AT&T Bell Laboratories) 05/01/84\0\n";
  94
  95 #include <ast.h>
  96 #include <stack.h>
  97
  98 /*
  99  * create a new stack
 100  */
 101
 102 STACK
 103 stackalloc __PARAM__((register int size, __V_* error), (size, error)) __OTORP__(register int size; __V_* error;){
 104         register STACK                  stack;
 105         register struct stackblock      *b;
 106
 107         if (size <= 0) size = 100;
 108         if (!(stack = newof(0, struct stacktable, 1, 0))) return(0);
 109         if (!(b = newof(0, struct stackblock, 1, 0)))
 110         {
 111                 free(stack);
 112                 return(0);
 113         }
 114         if (!(b->stack = newof(0, __V_*, size, 0)))
 115         {
 116                 free(b);
 117                 free(stack);
 118                 return(0);
 119         }
 120         stack->blocks = b;
 121         stack->size = size;
 122         stack->error = error;
 123         stack->position.block = b;
 124         stack->position.index = -1;
 125         b->next = 0;
 126         b->prev = 0;
 127         return(stack);
 128 }
 129
 130 /*
 131  * remove a stack
 132  */
 133
 134 void
 135 stackfree __PARAM__((register STACK stack), (stack)) __OTORP__(register STACK stack;){
 136         register struct stackblock*     b;
 137         register struct stackblock*     p;
 138
 139         b = stack->blocks;
 140         while (p = b)
 141         {
 142                 b = p->next;
 143                 free(p->stack);
 144                 free(p);
 145         }
 146         free(stack);
 147 }
 148
 149 /*
 150  * clear stack
 151  */
 152
 153 void
 154 stackclear __PARAM__((register STACK stack), (stack)) __OTORP__(register STACK stack;){
 155         stack->position.block = stack->blocks;
 156         stack->position.index = -1;
 157 }
 158
 159 /*
 160  * get value on top of stack
 161  */
 162
 163 __V_*
 164 stackget __PARAM__((register STACK stack), (stack)) __OTORP__(register STACK stack;){
 165         if (stack->position.index < 0) return(stack->error);
 166         else return(stack->position.block->stack[stack->position.index]);
 167 }
 168
 169 /*
 170  * push value on to stack
 171  */
 172
 173 int
 174 stackpush __PARAM__((register STACK stack, __V_* value), (stack, value)) __OTORP__(register STACK stack; __V_* value;){
 175         register struct stackblock      *b;
 176
 177         if (++stack->position.index >= stack->size)
 178         {
 179                 b = stack->position.block;
 180                 if (b->next) b = b->next;
 181                 else
 182                 {
 183                         if (!(b->next = newof(0, struct stackblock, 1, 0)))
 184                                 return(-1);
 185                         b = b->next;
 186                         if (!(b->stack = newof(0, __V_*, stack->size, 0)))
 187                                 return(-1);
 188                         b->prev = stack->position.block;
 189                         b->next = 0;
 190                 }
 191                 stack->position.block = b;
 192                 stack->position.index = 0;
 193         }
 194         stack->position.block->stack[stack->position.index] = value;
 195         return(0);
 196 }
 197
 198 /*
 199  * pop value off stack
 200  */
 201
 202 int
 203 stackpop __PARAM__((register STACK stack), (stack)) __OTORP__(register STACK stack;){
 204         /*
 205          * return:
 206          *
 207          *      -1      if stack empty before pop
 208          *       0      if stack empty after pop
 209          *       1      if stack not empty before & after pop
 210          */
 211
 212         if (stack->position.index < 0) return(-1);
 213         else if (--stack->position.index < 0)
 214         {
 215                 if (!stack->position.block->prev) return(0);
 216                 stack->position.block = stack->position.block->prev;
 217                 stack->position.index = stack->size - 1;
 218                 return(1);
 219         }
 220         else return(1);
 221 }
 222
 223 /*
 224  * set|get stack position
 225  */
 226
 227 void
 228 stacktell __PARAM__((register STACK stack, int set, STACKPOS* position), (stack, set, position)) __OTORP__(register STACK stack; int set; STACKPOS* position;){
 229         if (set) stack->position = *position;
 230         else *position = stack->position;
 231 }