source/blender/blenlib/BLI_utildefines_stack.h

   1 /* SPDX-FileCopyrightText: 2023 Blender Authors
   2  *
   3  * SPDX-License-Identifier: GPL-2.0-or-later */
   4
   5 #pragma once
   6
   7 /** \file
   8  * \ingroup bli
   9  *
  10  * Macro's for a simple array based stack
  11  * \note Caller handles alloc & free.
  12  */
  13
  14 /* only validate array-bounds in debug mode */
  15 #ifndef NDEBUG
  16 #  define STACK_DECLARE(stack) unsigned int _##stack##_index, _##stack##_num_alloc
  17 #  define STACK_INIT(stack, stack_num) \
  18     ((void)stack, \
  19      (void)((_##stack##_index) = 0), \
  20      (void)((_##stack##_num_alloc) = (unsigned int)(stack_num)))
  21 #  define _STACK_SIZETEST(stack, off) \
  22     (BLI_assert((_##stack##_index) + (off) <= _##stack##_num_alloc))
  23 #  define _STACK_SWAP_TOTALLOC(stack_a, stack_b) \
  24     SWAP(unsigned int, _##stack_a##_num_alloc, _##stack_b##_num_alloc)
  25 #else
  26 #  define STACK_DECLARE(stack) unsigned int _##stack##_index
  27 #  define STACK_INIT(stack, stack_num) \
  28     ((void)stack, (void)((_##stack##_index) = 0), (void)(0 ? (stack_num) : 0))
  29 #  define _STACK_SIZETEST(stack, off) (void)(stack), (void)(off)
  30 #  define _STACK_SWAP_TOTALLOC(stack_a, stack_b) (void)(stack_a), (void)(stack_b)
  31 #endif
  32 #define _STACK_BOUNDSTEST(stack, index) \
  33   ((void)stack, BLI_assert((unsigned int)(index) < _##stack##_index))
  34
  35 #define STACK_SIZE(stack) ((void)stack, (_##stack##_index))
  36 #define STACK_CLEAR(stack) \
  37   { \
  38     (void)stack; \
  39     _##stack##_index = 0; \
  40   } \
  41   ((void)0)
  42 /** add item to stack */
  43 #define STACK_PUSH(stack, val) \
  44   ((void)stack, _STACK_SIZETEST(stack, 1), ((stack)[(_##stack##_index)++] = (val)))
  45 #define STACK_PUSH_RET(stack) \
  46   ((void)stack, _STACK_SIZETEST(stack, 1), ((stack)[(_##stack##_index)++]))
  47 #define STACK_PUSH_RET_PTR(stack) \
  48   ((void)stack, _STACK_SIZETEST(stack, 1), &((stack)[(_##stack##_index)++]))
  49 /** take last item from stack */
  50 #define STACK_POP(stack) ((_##stack##_index) ? ((stack)[--(_##stack##_index)]) : NULL)
  51 #define STACK_POP_PTR(stack) ((_##stack##_index) ? &((stack)[--(_##stack##_index)]) : NULL)
  52 #define STACK_POP_DEFAULT(stack, r) ((_##stack##_index) ? ((stack)[--(_##stack##_index)]) : (r))
  53 /** look at last item (assumes non-empty stack) */
  54 #define STACK_PEEK(stack) (BLI_assert(_##stack##_index), ((stack)[_##stack##_index - 1]))
  55 #define STACK_PEEK_PTR(stack) (BLI_assert(_##stack##_index), &((stack)[_##stack##_index - 1]))
  56 /** remove any item from the stack, take care, re-orders */
  57 #define STACK_REMOVE(stack, i) \
  58   { \
  59     const unsigned int _i = i; \
  60     _STACK_BOUNDSTEST(stack, _i); \
  61     if (--_##stack##_index != _i) { \
  62       stack[_i] = stack[_##stack##_index]; \
  63     } \
  64   } \
  65   ((void)0)
  66 #define STACK_DISCARD(stack, n) \
  67   { \
  68     const unsigned int _n = n; \
  69     BLI_assert(_##stack##_index >= _n); \
  70     (void)stack; \
  71     _##stack##_index -= _n; \
  72   } \
  73   ((void)0)
  74 #ifdef __GNUC__
  75 #  define STACK_SWAP(stack_a, stack_b) \
  76     { \
  77       SWAP(typeof(stack_a), stack_a, stack_b); \
  78       SWAP(unsigned int, _##stack_a##_index, _##stack_b##_index); \
  79       _STACK_SWAP_TOTALLOC(stack_a, stack_b); \
  80     } \
  81     ((void)0)
  82 #else
  83 #  define STACK_SWAP(stack_a, stack_b) \
  84     { \
  85       SWAP(void *, *(void **)&stack_a, *(void **)&stack_b); \
  86       SWAP(unsigned int, _##stack_a##_index, _##stack_b##_index); \
  87       _STACK_SWAP_TOTALLOC(stack_a, stack_b); \
  88     } \
  89     ((void)0)
  90 #endif