libcpp.cpp

Think in C++文中代码实现

// File from page 106 in "Thinking in C++" by Bruce Eckel
//////////////////////////////////////////////////
// From the compressed package ECKELT02.ZIP 4/11/95
// (Original ECKELT01.ZIP dated 2/21/95)
// Copyright (c) Bruce Eckel, 1995 
// Source code file from the book "Thinking in C++", 
// Prentice Hall, 1995, ISBN: 0-13-917709-4
// All rights reserved EXCEPT as allowed by the following 
// statements: You may freely use this file for your own 
// work, including modifications and distribution in 
// executable form only. You may copy and distribute this 
// file, as long as it is only distributed in the complete 
// (compressed) package with the other files from this 
// book and you do not remove this copyright and notice. 
// You may not distribute modified versions of the source 
// code in this package. This package may be freely placed 
// on bulletin boards, internet nodes, shareware disks and 
// product vendor disks. You may not use this file in 
// printed media without the express permission of the 
// author. Bruce Eckel makes no 
// representation about the suitability of this software 
// for any purpose. It is provided "as is" without express 
// or implied warranty of any kind. The entire risk as to 
// the quality and performance of the software is with 
// you. Should the software prove defective, you assume 
// the cost of all necessary servicing, repair, or 
// correction. 
// If you think you've found an error, please 
// email all modified files with loudly commented changes 
// to: [e-mail] (please use the same 
// address for non-code errors found in the book).
//////////////////////////////////////////////////

//: LIBCPP.CPP -- C library converted to C++
// Declare structure and functions:
#include "..\1\libcpp.h"
#include <assert.h> // Error testing macros
#include <stdlib.h> // Dynamic memory
#include <string.h> // memcpy()
#include <stdio.h>

void stash::initialize(int Size) {
  size = Size;
  quantity = 0;
  storage = 0;
  next = 0;
}

void stash::cleanup() {
  if(storage) {
    puts("freeing storage");
    free(storage);
  }
}

int stash::add(void* element) {
  if(next >= quantity) // Enough space left?
    inflate(100);
  // Copy element into storage,
  // starting at next empty space:
  memcpy(&(storage[next * size]),
         element, size);
  next++;
  return(next - 1); // Index number
}

void* stash::fetch(int index) {
  if(index >= next || index < 0)
    return 0;  // Not out of bounds?
  // Produce pointer to desired element:
  return &(storage[index * size]);
}

int stash::count() {
  return next; // Number of elements in stash
}

void stash::inflate(int increase) {
  void* v = 
    realloc(storage, (quantity+increase)*size);
  assert(v);  // Was it successful?
  storage = (unsigned char*)v;
  quantity += increase;
}