string.c

Object-Oriented Programming With ANSI-C这本书中的源代码!找了很久

#include <assert.h>
#include <stdlib.h>
#include <string.h>

#include "String.h"
#include "new.h"
#include "new.r"

struct String {
	const void * class;	/* must be first */
	char * text;
};

static void * String_ctor (void * _self, va_list * app)
{	struct String * self = _self;
	const char * text = va_arg(* app, const char *);

	self -> text = malloc(strlen(text) + 1);
	assert(self -> text);
	strcpy(self -> text, text);
	return self;
}

static void * String_dtor (void * _self)
{	struct String * self = _self;

	free(self -> text), self -> text = 0;
	return self;
}

static void * String_clone (const void * _self)
{	const struct String * self = _self;

	return new(String, self -> text);
}

static int String_differ (const void * _self, const void * _b)
{	const struct String * self = _self;
	const struct String * b = _b;

	if (self == b)
		return 0;
	if (! b || b -> class != String)
		return 1;
	return strcmp(self -> text, b -> text);
}

static const struct Class _String = {
	sizeof(struct String),
	String_ctor, String_dtor,
	String_clone, String_differ
};

const void * String = & _String;