CStash

#include "stdafx.h"
#include <vector>
#include <iostream>
#include <cassert>
using namespace std;

const int increment=100;

typedef struct {
    int size;    //每个元素所需空间
    int quantity;    //存储空间总数量
    int next;    //下一个空的空间
    unsigned char * storage;
}CStash;

void initialize(CStash *s, int sz){
    s->size=sz;
    s->quantity=0;
    s->next=0;
    s->storage=0;    
}

int add(CStash *s, const void * element){
    if(s->next >= s->quantity)
        inflate(s,increment);
    int startByte =s->next * s->size;
    unsigned char * e=(unsigned char *)element;    //这相当于数组了！！
    for(int i=0;i< s->size;i++){
        s->storage[startByte+i]=e[i];
    }
    s->next++;
    return(s->next -1);
}

void * fetch(CStash * s,int index){
    assert(0 <= index);
    if(index >= s->next)return 0;
    return &(s->storage[index * s->size]);
}

int count(CStash *s){
    return s->next;
}

void inflate(CStash *s,int increase){
    assert(increase > 0);
    int newQuantity = s->quantity+ increase;
    int newBytes = newQuantity* s->size;
    int oldBytes = s->quantity *s->size;
    unsigned char *b= new unsigned char[newBytes];
    for(int i=0;i<oldBytes;i++)
        b[i]=s->storage[i];
    delete [](s->storage);
    s->storage=b;
    s->quantity=newQuantity;
}

void cleanup(CStash *s){
    if(s->storage != 0){
        cout<<"freeing storage"<<endl;
        delete [](s->storage);
    }
}