/*	Copyright  (c)	Günter Woigk 2018 - 2019
					mailto:kio@little-bat.de

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

	Permission to use, copy, modify, distribute, and sell this software and
	its documentation for any purpose is hereby granted without fee, provided
	that the above copyright notice appear in all copies and that both that
	copyright notice and this permission notice appear in supporting
	documentation, and that the name of the copyright holder not be used
	in advertising or publicity pertaining to distribution of the software
	without specific, written prior permission.  The copyright holder makes no
	representations about the suitability of this software for any purpose.
	It is provided "as is" without express or implied warranty.

	THE COPYRIGHT HOLDER DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
	INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
	EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY SPECIAL, INDIRECT OR
	CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
	DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
	TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
	PERFORMANCE OF THIS SOFTWARE.
*/

#include "Names.h"


/*
	class Names provides uint identifier IDs for strings.
	get(cstr) returns the ID and
	get(uint) returns the string.

	Intended use: for compilers.
	If compiler instances can run in parallel (to compile a bunch of files),
	then each instance must have it's own Names. (else each lookup must be wrapped with a mutex.)
	When linking 2 files, their Names must be merged, which will assign new IDs to the added names.
*/


Names::Names(const cstr* stdnames, uint num_stdnames)
:
	pool(nullptr),
	pool_ptr(nullptr),
	pool_end(nullptr),
	stdnames(stdnames),
	num_stdnames(num_stdnames)
{
	// setup hashmap with standard names
	// => standard names have fixed IDs as enumerated in "idf_id.h"
	// standard names (the keys) are not copied into the mempool
	// names are never removed from hashmap
	// => position in hashmap.items[] / hashmap.keys[] won't change
	// => names for IDs can be looked up with hashmap.keys[ID]
	// IDs for names are looked up with hashmap.get() / hashmap.add()

	for (uint id=0; id<num_stdnames; id++)
	{
		hashmap.add(stdnames[id],IdfID(id));
	}

	assert(hashmap.count() == num_stdnames);	// assert: no idf added twice
}

Names::~Names()
{
	delete pool;
}

void Names::purge()
{
	if (hashmap.count() == num_stdnames) return;
	this->~Names();
	new(this) Names(stdnames,num_stdnames);
}

IdfID Names::add (cstr name)
{
	// add name if not in list
	// return ID

	const uint mapsize = hashmap.count();
	IdfID id = hashmap.get(name,IdfID(mapsize));
	if (id != mapsize) return id;	// name found

	// not found => add to map:

	size_t slen = strlen(name) + 1;
	if (pool_ptr+slen > pool_end)
	{
		assert(slen <= sizeof(pool->data));

		pool = new Chunk(pool);
		pool_ptr = pool->data;
		pool_end = pool->data + sizeof(pool->data);
	}

	memcpy(pool_ptr, name, slen);
	hashmap.add(pool_ptr, id);
	pool_ptr += slen;

	return id;
}

Array<IdfID> Names::merge(const Names& q)
{
	// append names from another Names map.
	// returns array with old-to-new ID mappings.

	Array<IdfID> map(q.hashmap.count());

	for (uint id=0; id<map.count(); id++)
	{
		map[id] = add(q.get(IdfID(id)));
	}

	return map;
}

#define MAGIC 0x2355

void Names::serialize(FD& fd) const
{
	uint a = num_stdnames;
	uint e = hashmap.count();

	fd.write_uint16(MAGIC);
	fd.write_uint32(a);
	fd.write_uint32(e);

	for (uint id=a; id<e; id++)
	{
		fd.write_nstr(get(IdfID(id)));
	}
}

void Names::deserialize(FD& fd)
{
	uint m = fd.read_uint16();
	uint a = fd.read_uint32();
	uint e = fd.read_uint32();

	if (m != MAGIC) throw DataError("Names: wrong MAGIC");
	if (a != num_stdnames) throw DataError("Names: wrong num_stdnames");

	purge();

	for (uint id=a; id<e; id++)
	{
		add(fd.read_nstr());
	}
}