Home | History | Annotate | Download | only in src 
      1 /*
      2  * Copyright 2011 Tresys Technology, LLC. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are met:
      6  *
      7  *    1. Redistributions of source code must retain the above copyright notice,
      8  *       this list of conditions and the following disclaimer.
      9  *
     10  *    2. Redistributions in binary form must reproduce the above copyright notice,
     11  *       this list of conditions and the following disclaimer in the documentation
     12  *       and/or other materials provided with the distribution.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY TRESYS TECHNOLOGY, LLC ``AS IS'' AND ANY EXPRESS
     15  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     16  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     17  * EVENT SHALL TRESYS TECHNOLOGY, LLC OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
     18  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     19  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     21  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
     22  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     23  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  *
     25  * The views and conclusions contained in the software and documentation are those
     26  * of the authors and should not be interpreted as representing official policies,
     27  * either expressed or implied, of Tresys Technology, LLC.
     28  */
     29 
     30 #include <stdlib.h>
     31 
     32 #include "cil_internal.h"
     33 #include "cil_log.h"
     34 #include "cil_mem.h"
     35 #include "cil_stack.h"
     36 
     37 
     38 #define CIL_STACK_INIT_SIZE 16
     39 
     40 void cil_stack_init(struct cil_stack **stack)
     41 {
     42 	struct cil_stack *new_stack = cil_malloc(sizeof(*new_stack));
     43 	new_stack->stack = cil_malloc(sizeof(*(new_stack->stack)) * CIL_STACK_INIT_SIZE);
     44 	new_stack->size = CIL_STACK_INIT_SIZE;
     45 	new_stack->pos = -1;
     46 	*stack = new_stack;
     47 }
     48 
     49 void cil_stack_destroy(struct cil_stack **stack)
     50 {
     51 	if (stack == NULL || *stack == NULL) {
     52 		return;
     53 	}
     54 
     55 	free((*stack)->stack);
     56 	free(*stack);
     57 	*stack = NULL;
     58 }
     59 
     60 void cil_stack_empty(struct cil_stack *stack)
     61 {
     62 	stack->pos = -1;
     63 }
     64 
     65 int cil_stack_is_empty(struct cil_stack *stack)
     66 {
     67 	return (stack->pos == -1);
     68 }
     69 
     70 void cil_stack_push(struct cil_stack *stack, enum cil_flavor flavor, void *data)
     71 {
     72 	stack->pos++;
     73 
     74 	if (stack->pos == stack->size) {
     75 		stack->size *= 2;
     76 		stack->stack = cil_realloc(stack->stack, sizeof(*stack->stack) * stack->size);
     77 	}
     78 
     79 	stack->stack[stack->pos].flavor = flavor;
     80 	stack->stack[stack->pos].data = data;
     81 }
     82 
     83 struct cil_stack_item *cil_stack_pop(struct cil_stack *stack)
     84 {
     85 	if (stack->pos == -1) {
     86 		return NULL;
     87 	}
     88 
     89 	stack->pos--;
     90 	return &stack->stack[stack->pos + 1];
     91 }
     92 
     93 struct cil_stack_item *cil_stack_peek(struct cil_stack *stack)
     94 {
     95 	if (stack->pos < 0) {
     96 		return NULL;
     97 	}
     98 
     99 	return &stack->stack[stack->pos];
    100 }
    101 
    102 struct cil_stack_item *cil_stack_peek_at(struct cil_stack *stack, int pos)
    103 {
    104 	int peekpos = stack->pos - pos;
    105 
    106 	if (peekpos < 0 || peekpos > stack->pos) {
    107 		return NULL;
    108 	}
    109 
    110 	return &stack->stack[peekpos];
    111 }
    112