82 lines
1.1 KiB
C
82 lines
1.1 KiB
C
#include "stack.h"
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#include <string.h>
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int
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stack_grow(struct stack *st, size_t new_size)
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{
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void **new_st;
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if (st->asize >= new_size)
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return 0;
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new_st = realloc(st->item, new_size * sizeof(void *));
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if (new_st == NULL)
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return -1;
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memset(new_st + st->asize, 0x0,
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(new_size - st->asize) * sizeof(void *));
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st->item = new_st;
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st->asize = new_size;
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if (st->size > new_size)
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st->size = new_size;
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return 0;
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}
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void
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stack_free(struct stack *st)
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{
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if (!st)
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return;
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free(st->item);
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st->item = NULL;
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st->size = 0;
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st->asize = 0;
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}
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int
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stack_init(struct stack *st, size_t initial_size)
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{
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st->item = NULL;
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st->size = 0;
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st->asize = 0;
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if (!initial_size)
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initial_size = 8;
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return stack_grow(st, initial_size);
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}
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void *
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stack_pop(struct stack *st)
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{
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if (!st->size)
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return NULL;
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return st->item[--st->size];
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}
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int
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stack_push(struct stack *st, void *item)
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{
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if (stack_grow(st, st->size * 2) < 0)
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return -1;
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st->item[st->size++] = item;
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return 0;
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}
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void *
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stack_top(struct stack *st)
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{
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if (!st->size)
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return NULL;
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return st->item[st->size - 1];
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}
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