/**
 * Forms the symbols available to all D programs. Includes
 * Object, which is the root of the class object heirarchy.
 *
 * This module is implicitly imported.
 * Macros:
 *	WIKI = Phobos/Object
 */

/*
 *  Copyright (C) 2004-2005 by Digital Mars, www.digitalmars.com
 *  Written by Walter Bright
 *
 *  This software is provided 'as-is', without any express or implied
 *  warranty. In no event will the authors be held liable for any damages
 *  arising from the use of this software.
 *
 *  Permission is granted to anyone to use this software for any purpose,
 *  including commercial applications, and to alter it and redistribute it
 *  freely, in both source and binary form, subject to the following
 *  restrictions:
 *
 *  o  The origin of this software must not be misrepresented; you must not
 *     claim that you wrote the original software. If you use this software
 *     in a product, an acknowledgment in the product documentation would be
 *     appreciated but is not required.
 *  o  Altered source versions must be plainly marked as such, and must not
 *     be misrepresented as being the original software.
 *  o  This notice may not be removed or altered from any source
 *     distribution.
 */


module object;

extern (C)
{   /// C's printf function.
    int printf(char *, ...);

    int memcmp(void *, void *, size_t);
    void* memcpy(void *, void *, size_t);
}

/// Standard boolean type. Implemented as a $(B bit) type.
alias bool bit;

version (X86_64)
{
    /**
     * An unsigned integral type large enough to span the memory space. Use for
     * array indices and pointer offsets for maximal portability to
     * architectures that have different memory address ranges. This is
     * analogous to C's size_t.
     */
    alias ulong size_t;

    /**
     * A signed integral type large enough to span the memory space. Use for
     * pointer differences and for size_t differences for maximal portability to
     * architectures that have different memory address ranges. This is
     * analogous to C's ptrdiff_t.
     */
    alias long ptrdiff_t;
}
else
{
    alias uint size_t;
    alias int ptrdiff_t;
}

/******************
 * All D class objects inherit from Object.
 */
class Object
{
    void print()
    {
	printf("%.*s\n", toString());
    }

    /**
     * Convert Object to a human readable string.
     */
    char[] toString()
    {
	return this.classinfo.name;
    }

    /**
     * Compute hash function for Object.
     */
    uint toHash()
    {
	// BUG: this prevents a compacting GC from working, needs to be fixed
	return cast(uint)cast(void *)this;
    }

    /**
     * Compare with another Object obj.
     * Returns:
     *	$(TABLE
     *  $(TR $(TD this < obj) $(TD < 0))
     *  $(TR $(TD this == obj) $(TD 0))
     *  $(TR $(TD this > obj) $(TD > 0))
     *  )
     */
    int opCmp(Object o)
    {
	// BUG: this prevents a compacting GC from working, needs to be fixed
	return cast(int)cast(void *)this - cast(int)cast(void *)o;
    }

    /**
     * Returns !=0 if this object does have the same contents as obj.
     */
    int opEquals(Object o)
    {
	return this is o;
    }
}

/**
 * Information about an interface.
 */
struct Interface
{
    ClassInfo classinfo;	/// .classinfo for this interface
    void *[] vtbl;
    int offset;			// offset to Interface 'this' from Object 'this'
}

/**
 * Runtime type information about a class. Can be retrieved for any class type
 * or instance by using the .classinfo property.
 */
class ClassInfo : Object
{
    byte[] init;		/** class static initializer
				 * (init.length gives size in bytes of class)
				 */
    char[] name;		/// class name
    void *[] vtbl;		/// virtual function pointer table
    Interface[] interfaces;	/// interfaces this class implements
    ClassInfo base;		/// base class
    void *destructor;
    void (*classInvariant)(Object);
    uint flags;
    //	1:			// IUnknown
    void *deallocator;
}

private import std.string;

/**
 * Runtime type information about a type.
 * Can be retrieved for any type using a
 * <a href="../expression.html#typeidexpression">TypeidExpression</a>.
 */
class TypeInfo
{
    uint toHash()
    {	uint hash;

	foreach (char c; this.classinfo.name)
	    hash = hash * 9 + c;
	return hash;
    }

    int opCmp(Object o)
    {
	return std.string.cmp(this.classinfo.name, o.classinfo.name);
    }

    int opEquals(Object o)
    {
	/* TypeInfo instances are singletons, but duplicates can exist
	 * across DLL's. Therefore, comparing for a name match is
	 * sufficient.
	 */
	return this is o || this.classinfo.name == o.classinfo.name;
    }

    /// Returns a hash of the instance of a type.
    uint getHash(void *p) { return cast(uint)p; }

    /// Compares two instances for equality.
    int equals(void *p1, void *p2) { return p1 == p2; }

    /// Compares two instances for &lt;, ==, or &gt;.
    int compare(void *p1, void *p2) { return 0; }

    /// Returns size of the type.
    size_t tsize() { return 0; }

    /// Swaps two instances of the type.
    void swap(void *p1, void *p2)
    {
	size_t n = tsize();
	for (size_t i = 0; i < n; i++)
	{   byte t;

	    t = (cast(byte *)p1)[i];
	    (cast(byte *)p1)[i] = (cast(byte *)p2)[i];
	    (cast(byte *)p2)[i] = t;
	}
    }
}

class TypeInfo_Typedef : TypeInfo
{
    char[] toString() { return name; }
    uint getHash(void *p) { return base.getHash(p); }
    int equals(void *p1, void *p2) { return base.equals(p1, p2); }
    int compare(void *p1, void *p2) { return base.compare(p1, p2); }
    size_t tsize() { return base.tsize(); }
    void swap(void *p1, void *p2) { return base.swap(p1, p2); }

    TypeInfo base;
    char[] name;
}

class TypeInfo_Enum : TypeInfo_Typedef
{
}

class TypeInfo_Pointer : TypeInfo
{
    char[] toString() { return next.toString() ~ "*"; }

    uint getHash(void *p)
    {
        return cast(uint)*cast(void* *)p;
    }

    int equals(void *p1, void *p2)
    {
        return *cast(void* *)p1 == *cast(void* *)p2;
    }

    int compare(void *p1, void *p2)
    {
        return *cast(void* *)p1 - *cast(void* *)p2;
    }

    size_t tsize()
    {
	return (void*).sizeof;
    }

    void swap(void *p1, void *p2)
    {	void* tmp;
	tmp = *cast(void**)p1;
	*cast(void**)p1 = *cast(void**)p2;
	*cast(void**)p2 = tmp;
    }

    TypeInfo next;
}

class TypeInfo_Array : TypeInfo
{
    char[] toString() { return next.toString() ~ "[]"; }

    uint getHash(void *p)
    {	size_t sz = next.tsize();
	uint hash = 0;
	void[] a = *cast(void[]*)p;
	for (size_t i = 0; i < a.length; i++)
	    hash += next.getHash(a.ptr + i * sz);
        return hash;
    }

    int equals(void *p1, void *p2)
    {
	void[] a1 = *cast(void[]*)p1;
	void[] a2 = *cast(void[]*)p2;
	if (a1.length != a2.length)
	    return 0;
	size_t sz = next.tsize();
	for (size_t i = 0; i < a1.length; i++)
	{
	    if (!next.equals(a1.ptr + i * sz, a2.ptr + i * sz))
		return 0;
	}
        return 1;
    }

    int compare(void *p1, void *p2)
    {
	void[] a1 = *cast(void[]*)p1;
	void[] a2 = *cast(void[]*)p2;
	size_t sz = next.tsize();
	size_t len = a1.length;

        if (a2.length < len)
            len = a2.length;
        for (size_t u = 0; u < len; u++)
        {
            int result = next.compare(a1.ptr + u * sz, a2.ptr + u * sz);
            if (result)
                return result;
        }
        return cast(int)a1.length - cast(int)a2.length;
    }

    size_t tsize()
    {
	return (void[]).sizeof;
    }

    void swap(void *p1, void *p2)
    {	void[] tmp;
	tmp = *cast(void[]*)p1;
	*cast(void[]*)p1 = *cast(void[]*)p2;
	*cast(void[]*)p2 = tmp;
    }

    TypeInfo next;
}

class TypeInfo_StaticArray : TypeInfo
{
    char[] toString()
    {
	return next.toString() ~ "[" ~ std.string.toString(len) ~ "]";
    }

    uint getHash(void *p)
    {	size_t sz = next.tsize();
	uint hash = 0;
	for (size_t i = 0; i < len; i++)
	    hash += next.getHash(p + i * sz);
        return hash;
    }

    int equals(void *p1, void *p2)
    {
	size_t sz = next.tsize();

        for (size_t u = 0; u < len; u++)
        {
	    if (!next.equals(p1 + u * sz, p2 + u * sz))
		return 0;
        }
        return 1;
    }

    int compare(void *p1, void *p2)
    {
	size_t sz = next.tsize();

        for (size_t u = 0; u < len; u++)
        {
            int result = next.compare(p1 + u * sz, p2 + u * sz);
            if (result)
                return result;
        }
        return 0;
    }

    size_t tsize()
    {
	return len * next.tsize();
    }

    void swap(void *p1, void *p2)
    {	ubyte* tmp;
	size_t sz = next.tsize();
	ubyte[16] buffer;
	ubyte* pbuffer;

	if (sz < buffer.sizeof)
	    tmp = buffer;
	else
	    tmp = pbuffer = new ubyte[sz];

	for (size_t u = 0; u < len; u += sz)
	{   size_t o = u * sz;
	    memcpy(tmp, p1 + o, sz);
	    memcpy(p1 + o, p2 + o, sz);
	    memcpy(p2 + o, tmp, sz);
	}
	if (pbuffer)
	    delete pbuffer;
    }

    TypeInfo next;
    size_t len;
}

class TypeInfo_AssociativeArray : TypeInfo
{
    char[] toString()
    {
	return next.toString() ~ "[" ~ key.toString() ~ "]";
    }

    // BUG: need to add the rest of the functions

    size_t tsize()
    {
	return (void[]).sizeof;
    }

    TypeInfo next;
    TypeInfo key;
}

class TypeInfo_Function : TypeInfo
{
    char[] toString()
    {
	return next.toString() ~ "()";
    }

    // BUG: need to add the rest of the functions

    size_t tsize()
    {
	return 0;	// no size for functions
    }

    TypeInfo next;
}

class TypeInfo_Delegate : TypeInfo
{
    char[] toString()
    {
	return next.toString() ~ " delegate()";
    }

    // BUG: need to add the rest of the functions

    size_t tsize()
    {	alias int delegate() dg;
	return dg.sizeof;
    }

    TypeInfo next;
}

class TypeInfo_Class : TypeInfo
{
    char[] toString() { return info.name; }

    uint getHash(void *p)
    {
	Object o = *cast(Object*)p;
	assert(o);
	return o.toHash();
    }

    int equals(void *p1, void *p2)
    {
	Object o1 = *cast(Object*)p1;
	Object o2 = *cast(Object*)p2;

	return o1 == o2 || (o1 && o1.opCmp(o2) == 0);
    }

    int compare(void *p1, void *p2)
    {
	Object o1 = *cast(Object*)p1;
	Object o2 = *cast(Object*)p2;
	int c = 0;

	// Regard null references as always being "less than"
	if (o1 != o2)
	{
	    if (o1)
	    {	if (!o2)
		    c = 1;
		else
		    c = o1.opCmp(o2);
	    }
	    else
		c = -1;
	}
	return c;
    }

    size_t tsize()
    {
	return Object.sizeof;
    }

    ClassInfo info;
}

class TypeInfo_Struct : TypeInfo
{
    char[] toString() { return name; }

    uint getHash(void *p)
    {	uint h;

	assert(p);
	if (xtoHash)
	{   //printf("getHash() using xtoHash\n");
	    h = (*xtoHash)(p);
	}
	else
	{
	    //printf("getHash() using default hash\n");
	    // A sorry hash algorithm.
	    // Should use the one for strings.
	    // BUG: relies on the GC not moving objects
	    for (size_t i = 0; i < xsize; i++)
	    {	h = h * 9 + *cast(ubyte*)p;
		p++;
	    }
	}
	return h;
    }

    int equals(void *p2, void *p1)
    {	int c;

	if (p1 == p2)
	    c = 1;
	else if (!p1 || !p2)
	    c = 0;
	else if (xopEquals)
	    c = (*xopEquals)(p1, p2);
	else
	    // BUG: relies on the GC not moving objects
	    c = (memcmp(p1, p2, xsize) == 0);
	return c;
    }

    int compare(void *p2, void *p1)
    {
	int c = 0;

	// Regard null references as always being "less than"
	if (p1 != p2)
	{
	    if (p1)
	    {	if (!p2)
		    c = 1;
		else if (xopCmp)
		    c = (*xopCmp)(p1, p2);
		else
		    // BUG: relies on the GC not moving objects
		    c = memcmp(p1, p2, xsize);
	    }
	    else
		c = -1;
	}
	return c;
    }

    size_t tsize()
    {
	return xsize;
    }

    char[] name;
    size_t xsize;

    uint function(void*) xtoHash;
    int function(void*,void*) xopEquals;
    int function(void*,void*) xopCmp;
}

/**
 * All recoverable exceptions should be derived from class Exception.
 */
class Exception : Object
{
    char[] msg;

    /**
     * Constructor; msg is a descriptive message for the exception.
     */
    this(char[] msg)
    {
	this.msg = msg;
    }

    void print()
    {
	printf("%.*s\n", toString());
    }

    char[] toString() { return msg; }
}

/**
 * All irrecoverable exceptions should be derived from class Error.
 */
class Error : Exception
{
    Error next;

    /**
     * Constructor; msg is a descriptive message for the exception.
     */
    this(char[] msg)
    {
	super(msg);
    }

    this(char[] msg, Error next)
    {
	super(msg);
	this.next = next;
    }
}

//extern (C) int nullext = 0;