/* Copyright (C) 1995, 1997, 1998, 1999 artofcode LLC.  All rights reserved.
  
  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.

*/

/*$Id: szlibc.c,v 1.3.2.1.2.1 2003/01/17 00:49:05 giles Exp $ */
/* Code common to zlib encoding and decoding streams */
#include "std.h"
#include "gserror.h"
#include "gserrors.h"
#include "gstypes.h"
#include "gsmemory.h"
#include "gsmalloc.h"
#include "gsstruct.h"
#include "strimpl.h"
#include "szlibxx.h"
#include "zconf.h"

private_st_zlib_block();
private_st_zlib_dynamic_state();
public_st_zlib_state();

/* Set defaults for stream parameters. */
void
s_zlib_set_defaults(stream_state * st)
{
    stream_zlib_state *const ss = (stream_zlib_state *)st;

    ss->windowBits = MAX_WBITS;
    ss->no_wrapper = false;
    ss->level = Z_DEFAULT_COMPRESSION;
    ss->method = Z_DEFLATED;
    /* DEF_MEM_LEVEL should be in zlib.h or zconf.h, but it isn't. */
    ss->memLevel = min(MAX_MEM_LEVEL, 8);
    ss->strategy = Z_DEFAULT_STRATEGY;
    /* Clear pointers */
    ss->dynamic = 0;
}

/* Allocate the dynamic state. */
int
s_zlib_alloc_dynamic_state(stream_zlib_state *ss)
{
    gs_memory_t *mem = (ss->memory ? ss->memory : &gs_memory_default);
    zlib_dynamic_state_t *zds =
	gs_alloc_struct_immovable(mem, zlib_dynamic_state_t,
				  &st_zlib_dynamic_state,
				  "s_zlib_alloc_dynamic_state");

    ss->dynamic = zds;
    if (zds == 0)
	return_error(gs_error_VMerror);
    zds->blocks = 0;
    zds->memory = mem;
    zds->zstate.zalloc = (alloc_func)s_zlib_alloc;
    zds->zstate.zfree = (free_func)s_zlib_free;
    zds->zstate.opaque = (voidpf)zds;
    return 0;
}

/* Free the dynamic state. */
void
s_zlib_free_dynamic_state(stream_zlib_state *ss)
{
    if (ss->dynamic)
	gs_free_object(ss->dynamic->memory, ss->dynamic,
		       "s_zlib_free_dynamic_state");
}

/* Provide zlib-compatible allocation and freeing functions. */
void *
s_zlib_alloc(void *zmem, uint items, uint size)
{
    zlib_dynamic_state_t *const zds = zmem;
    gs_memory_t *mem = zds->memory->stable_memory;
    zlib_block_t *block =
	gs_alloc_struct(mem, zlib_block_t, &st_zlib_block,
			"s_zlib_alloc(block)");
    void *data =
	gs_alloc_byte_array_immovable(mem, items, size, "s_zlib_alloc(data)");

    if (block == 0 || data == 0) {
	gs_free_object(mem, data, "s_zlib_alloc(data)");
	gs_free_object(mem, block, "s_zlib_alloc(block)");
	return Z_NULL;
    }
    block->data = data;
    block->next = zds->blocks;
    block->prev = 0;
    if (zds->blocks)
	zds->blocks->prev = block;
    zds->blocks = block;
    return data;
}
void
s_zlib_free(void *zmem, void *data)
{
    zlib_dynamic_state_t *const zds = zmem;
    gs_memory_t *mem = zds->memory->stable_memory;
    zlib_block_t *block = zds->blocks;

    gs_free_object(mem, data, "s_zlib_free(data)");
    for (; ; block = block->next) {
	if (block == 0) {
	    lprintf1("Freeing unrecorded data 0x%lx!\n", (ulong)data);
	    return;
	}
	if (block->data == data)
	    break;
    }
    if (block->next)
	block->next->prev = block->prev;
    if (block->prev)
	block->prev->next = block->next;
    else
	zds->blocks = block->next;
    gs_free_object(mem, block, "s_zlib_free(block)");
}