gzdoom/libraries/timidityplus/mblock.cpp

/*
    TiMidity++ -- MIDI to WAVE converter and player
    Copyright (C) 1999-2002 Masanao Izumo <mo@goice.co.jp>
    Copyright (C) 1995 Tuukka Toivonen <tt@cgs.fi>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    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.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*/

#include <stdio.h>
#include <stdlib.h>

#include <string.h>

#include "timidity.h"
#include "common.h"

namespace TimidityPlus
{

struct MBlock
{
	MBlockNode* free_mblock_list = NULL;

	~MBlock()
	{
		int cnt;

		cnt = 0;
		while (free_mblock_list)
		{
			MBlockNode* tmp;

			tmp = free_mblock_list;
			free_mblock_list = free_mblock_list->next;
			free(tmp);
			cnt++;
		}
	}
};

static MBlock free_list;

#define ADDRALIGN 8
/* #define DEBUG */

void init_mblock(MBlockList *mblock)
{
    mblock->first = NULL;
    mblock->allocated = 0;
}

static MBlockNode *new_mblock_node(size_t n)
{
	MBlockNode *p;

	if (n > MIN_MBLOCK_SIZE)
	{
		if ((p = (MBlockNode *)safe_malloc(n + sizeof(MBlockNode))) == NULL)
			return NULL;
		p->block_size = n;
	}
	else if (free_list.free_mblock_list == NULL)
	{
		if ((p = (MBlockNode *)safe_malloc(sizeof(MBlockNode) + MIN_MBLOCK_SIZE)) == NULL)
			return NULL;
		p->block_size = MIN_MBLOCK_SIZE;
	}
	else
	{
		p = free_list.free_mblock_list;
		free_list.free_mblock_list = free_list.free_mblock_list->next;
	}

	p->offset = 0;
	p->next = NULL;

	return p;
}

static int enough_block_memory(MBlockList *mblock, size_t n)
{
    size_t newoffset;

    if(mblock->first == NULL)
	return 0;

    newoffset = mblock->first->offset + n;

    if(newoffset < mblock->first->offset) /* exceed representable in size_t */
	return 0;

    if(newoffset > mblock->first->block_size)
	return 0;

    return 1;
}

void *new_segment(MBlockList *mblock, size_t nbytes)
{
	MBlockNode *p;
	void *addr;

	/* round up to ADDRALIGN */
	nbytes = ((nbytes + ADDRALIGN - 1) & ~(ADDRALIGN - 1));
	if (!enough_block_memory(mblock, nbytes))
	{
		p = new_mblock_node(nbytes);
		p->next = mblock->first;
		mblock->first = p;
		mblock->allocated += p->block_size;
	}
	else
		p = mblock->first;

	addr = (void *)(p->buffer + p->offset);
	p->offset += nbytes;

	return addr;
}

static void reuse_mblock1(MBlockNode *p)
{
	if (p->block_size > MIN_MBLOCK_SIZE)
		free(p);
	else /* p->block_size <= MIN_MBLOCK_SIZE */
	{
		p->next = free_list.free_mblock_list;
		free_list.free_mblock_list = p;
	}
}

void reuse_mblock(MBlockList *mblock)
{
	MBlockNode *p;

	if ((p = mblock->first) == NULL)
		return;			/* There is nothing to collect memory */

	while (p)
	{
		MBlockNode *tmp;

		tmp = p;
		p = p->next;
		reuse_mblock1(tmp);
	}
	init_mblock(mblock);
}

char *strdup_mblock(MBlockList *mblock, const char *str)
{
    int len;
    char *p;

    len = (int)strlen(str);
    p = (char *)new_segment(mblock, len + 1); /* for '\0' */
    memcpy(p, str, len + 1);
    return p;
}

}