81 lines
1.3 KiB
C
81 lines
1.3 KiB
C
#include "stack.h"
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#include <string.h>
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int 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 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 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* 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 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* 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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