generic-stack/stack.c at master · igniting/generic-stack · GitHub

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#include<stdio.h>
#include<stdlib.h>
#include"stack.h"

voidinit(Stack*s, intelemSize, intmaxElements) {
byte*storage;

/* Try to allocate memory */
storage= (byte*)malloc(elemSize*maxElements);
if(storage==NULL) {
fprintf(stderr, "Insufficient memory to initialize stack.\n");
exit(1);
 }

/* Initialize an empty stack */
s->top=0;
s->maxElements=maxElements;
s->elemSize=elemSize;
s->storage=storage;
}

intisEmpty(Stack*s) {
/* top is 0 for an empty stack */
return (s->top==0);
}

intsize(Stack*s) {
returns->top;
}

voidpush(Stack*s, void*elem) {
if(s->top==s->maxElements) {
fprintf(stderr, "Element can not be pushed: Stack is full.\n");
exit(1);
 }
intstart=s->top*s->elemSize, i;
for(i=0; i<s->elemSize; i++) {
*(s->storage+start+i) =*((byte*)(elem+i));
 }
s->top=s->top+1;
}

void*pop(Stack*s) {
if(isEmpty(s)) {
fprintf(stderr, "Can not pop from an empty stack.\n");
exit(1);
 }
void*elem=top(s);
s->top=s->top-1;
returnelem;
}

void*top(Stack*s) {
if(isEmpty(s)) {
fprintf(stderr, "Can not pop from an empty stack.\n");
exit(1);
 }
intstart= (s->top-1) *s->elemSize, i;
byte*elem;
elem= (byte*)malloc(s->elemSize);
for(i=0; i<s->elemSize; i++) {
*(elem+i) =*(s->storage+start+i);
 }
return (void*)elem;
}

voiddestroy(Stack*s) {
free(s->storage);
s->top=0;
}