/* Copyright (C) 1993, 1995, 1996, 1998 Aladdin Enterprises.  All rights reserved.

   This file is part of Aladdin Ghostscript.

   Aladdin Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author
   or distributor accepts any responsibility for the consequences of using it,
   or for whether it serves any particular purpose or works at all, unless he
   or she says so in writing.  Refer to the Aladdin Ghostscript Free Public
   License (the "License") for full details.

   Every copy of Aladdin Ghostscript must include a copy of the License,
   normally in a plain ASCII text file named PUBLIC.  The License grants you
   the right to copy, modify and redistribute Aladdin Ghostscript, but only
   under certain conditions described in the License.  Among other things, the
   License requires that the copyright notice and this notice be preserved on
   all copies.
 */

/*$Id: ialloc.c $ */
/* Memory allocator for Ghostscript interpreter */
#include "gx.h"
#include "memory_.h"
#include "errors.h"
#include "gsstruct.h"
#include "gxarith.h"		/* for small_exact_log2 */
#include "iref.h"		/* must precede iastate.h */
#include "iastate.h"
#include "ipacked.h"
#include "iutil.h"
#include "ivmspace.h"
#include "store.h"

/*
 * Define global and local instances.
 */
gs_dual_memory_t gs_imemory;

/* Initialize the allocator */
void
ialloc_init(gs_raw_memory_t * rmem, uint chunk_size, bool level2)
{
    gs_ref_memory_t *ilmem = ialloc_alloc_state(rmem, chunk_size);
    gs_ref_memory_t *igmem =
    (level2 ?
     ialloc_alloc_state(rmem, chunk_size) :
     ilmem);
    gs_ref_memory_t *ismem = ialloc_alloc_state(rmem, chunk_size);
    int i;

    for (i = 0; i < countof(gs_imemory.spaces.indexed); i++)
	gs_imemory.spaces.indexed[i] = 0;
    gs_imemory.space_local = ilmem;
    gs_imemory.space_global = igmem;
    gs_imemory.space_system = ismem;
    gs_imemory.reclaim = 0;
    /* Level 1 systems have only local VM. */
    igmem->space = avm_global;
    ilmem->space = avm_local;	/* overrides if ilmem == igmem */
    igmem->global = ilmem->global = igmem;

    ismem->space = avm_system;
    ialloc_set_space(&gs_imemory, avm_global);
}

/* ================ Local/global VM ================ */

/* Get the space attribute of an allocator */
uint
imemory_space(gs_ref_memory_t * iimem)
{
    return iimem->space;
}

/* Select the allocation space. */
void
ialloc_set_space(gs_dual_memory_t * dmem, uint space)
{
    gs_ref_memory_t *mem = dmem->spaces.indexed[space >> r_space_shift];

    dmem->current = mem;
    dmem->current_space = mem->space;
}

/* Reset the requests. */
void
ialloc_reset_requested(gs_dual_memory_t * dmem)
{
    dmem->space_system->gc_status.requested = 0;
    dmem->space_global->gc_status.requested = 0;
    dmem->space_local->gc_status.requested = 0;
}

/* ================ Refs ================ */

/* Register a ref root. */
int
gs_register_ref_root(gs_memory_t *mem, gs_gc_root_t *root,
		     void **pp, client_name_t cname)
{
    return gs_register_root(mem, root, ptr_ref_type, pp, cname);
}

/*
 * As noted in iastate.h, every run of refs has an extra ref at the end
 * to hold relocation information for the garbage collector;
 * since sizeof(ref) % obj_align_mod == 0, we never need to
 * allocate any additional padding space at the end of the block.
 */

/* Allocate an array of refs. */
int
gs_alloc_ref_array(gs_ref_memory_t * mem, ref * parr, uint attrs,
		   uint num_refs, client_name_t cname)
{
    ref *obj;

    /* If we're allocating a run of refs already, */
    /* and we aren't about to overflow the maximum run length, use it. */
    if (mem->cc.rtop == mem->cc.cbot &&
	num_refs < (mem->cc.ctop - mem->cc.cbot) / sizeof(ref) &&
	mem->cc.rtop - (byte *) mem->cc.rcur + num_refs * sizeof(ref) <
	max_size_st_refs
	) {
	ref *end;

	obj = (ref *) mem->cc.rtop - 1;		/* back up over last ref */
	if_debug4('A', "[a%d:+$ ]%s(%u) = 0x%lx\n", mem->space,
		  client_name_string(cname), num_refs, (ulong) obj);
	mem->cc.rcur[-1].o_size += num_refs * sizeof(ref);
	end = (ref *) (mem->cc.rtop = mem->cc.cbot +=
		       num_refs * sizeof(ref));
	make_mark(end - 1);
    } else {
	/*
	 * Allocate a new run.  We have to distinguish 3 cases:
	 *      - Same chunk: pcc unchanged, end == cc.cbot.
	 *      - Large chunk: pcc unchanged, end != cc.cbot.
	 *      - New chunk: pcc changed.
	 */
	chunk_t *pcc = mem->pcc;
	ref *end;

	obj = gs_alloc_struct_array((gs_memory_t *) mem, num_refs + 1,
				    ref, &st_refs, cname);
	if (obj == 0)
	    return_error(e_VMerror);
	/* Set the terminating ref now. */
	end = (ref *) obj + num_refs;
	make_mark(end);
	/* Set has_refs in the chunk. */
	if (mem->pcc != pcc || mem->cc.cbot == (byte *) (end + 1)) {
	    /* Ordinary chunk. */
	    mem->cc.rcur = (obj_header_t *) obj;
	    mem->cc.rtop = (byte *) (end + 1);
	    mem->cc.has_refs = true;
	} else {
	    /* Large chunk. */
	    /* This happens only for very large arrays, */
	    /* so it doesn't need to be cheap. */
	    chunk_locator_t cl;

	    cl.memory = mem;
	    cl.cp = mem->clast;
	    chunk_locate_ptr(obj, &cl);
	    cl.cp->has_refs = true;
	}
    }
    make_array(parr, attrs | mem->space, num_refs, obj);
    return 0;
}

/* Resize an array of refs.  Currently this is only implemented */
/* for shrinking, not for growing. */
int
gs_resize_ref_array(gs_ref_memory_t * mem, ref * parr,
		    uint new_num_refs, client_name_t cname)
{
    uint old_num_refs = r_size(parr);
    uint diff;
    ref *obj = parr->value.refs;

    if (new_num_refs > old_num_refs || !r_has_type(parr, t_array))
	return_error(e_Fatal);
    diff = old_num_refs - new_num_refs;
    /* Check for LIFO.  See gs_free_ref_array for more details. */
    if (mem->cc.rtop == mem->cc.cbot &&
	(byte *) (obj + (old_num_refs + 1)) == mem->cc.rtop
	) {
	/* Shorten the refs object. */
	ref *end = (ref *) (mem->cc.cbot = mem->cc.rtop -=
			    diff * sizeof(ref));

	if_debug4('A', "[a%d:<$ ]%s(%u) 0x%lx\n", mem->space,
		  client_name_string(cname), diff, (ulong) obj);
	mem->cc.rcur[-1].o_size -= diff * sizeof(ref);
	make_mark(end - 1);
    } else {
	/* Punt. */
	if_debug4('A', "[a%d:<$#]%s(%u) 0x%lx\n", mem->space,
		  client_name_string(cname), diff, (ulong) obj);
	mem->lost.refs += diff * sizeof(ref);
    }
    r_set_size(parr, new_num_refs);
    return 0;
}

/* Deallocate an array of refs.  Only do this if LIFO, or if */
/* the array occupies an entire chunk by itself. */
void
gs_free_ref_array(gs_ref_memory_t * mem, ref * parr, client_name_t cname)
{
    uint num_refs = r_size(parr);
    ref *obj = parr->value.refs;

    /*
     * Compute the storage size of the array, and check for LIFO
     * freeing or a separate chunk.  Note that the array might be packed;
     * for the moment, if it's anything but a t_array, punt.
     * The +1s are for the extra ref for the GC.
     */
    if (!r_has_type(parr, t_array))
	DO_NOTHING;		/* don't look for special cases */
    else if (mem->cc.rtop == mem->cc.cbot &&
	     (byte *) (obj + (num_refs + 1)) == mem->cc.rtop
	) {
	if ((obj_header_t *) obj == mem->cc.rcur) {
	    /* Deallocate the entire refs object. */
	    gs_free_object((gs_memory_t *) mem, obj, cname);
	    mem->cc.rcur = 0;
	    mem->cc.rtop = 0;
	} else {
	    /* Deallocate it at the end of the refs object. */
	    if_debug4('A', "[a%d:-$ ]%s(%u) 0x%lx\n",
		      mem->space, client_name_string(cname),
		      num_refs, (ulong) obj);
	    mem->cc.rcur[-1].o_size -= num_refs * sizeof(ref);
	    mem->cc.rtop = mem->cc.cbot = (byte *) (obj + 1);
	    make_mark(obj);
	}
	return;
    } else if (num_refs >= (mem->large_size / arch_sizeof_ref - 1)) {
	/* See if this array has a chunk all to itself. */
	/* We only make this check when freeing very large objects, */
	/* so it doesn't need to be cheap. */
	chunk_locator_t cl;

	cl.memory = mem;
	cl.cp = mem->clast;
	if (chunk_locate_ptr(obj, &cl) &&
	    obj == (ref *) ((obj_header_t *) (cl.cp->cbase) + 1) &&
	    (byte *) (obj + (num_refs + 1)) == cl.cp->cend
	    ) {
	    /* Free the chunk. */
	    if_debug4('a', "[a%d:-$L]%s(%u) 0x%lx\n",
		      mem->space, client_name_string(cname),
		      num_refs, (ulong) obj);
	    alloc_free_chunk(cl.cp, mem);
	    return;
	}
    }
    /* Punt, but fill the array with nulls so that there won't be */
    /* dangling references to confuse the garbage collector. */
    if_debug4('A', "[a%d:-$#]%s(%u) 0x%lx\n", mem->space,
	      client_name_string(cname), num_refs, (ulong) obj);
    {
	uint size;

	switch (r_type(parr)) {
	    case t_shortarray:
		size = num_refs * sizeof(ref_packed);
		break;
	    case t_mixedarray:{
		    /* We have to parse the array to compute the storage size. */
		    uint i = 0;
		    const ref_packed *p = parr->value.packed;

		    for (; i < num_refs; ++i)
			p = packed_next(p);
		    size = (const byte *)p - (const byte *)parr->value.packed;
		    break;
		}
	    case t_array:
		size = num_refs * sizeof(ref);
		break;
	    default:
		lprintf3("Unknown type 0x%x in free_ref_array(%u,0x%lx)!",
			 r_type(parr), num_refs, (ulong) obj);
		return;
	}
	/* If there are any leftover packed elements, we don't */
	/* worry about them, since they can't be dangling references. */
	refset_null(obj, size / sizeof(ref));
	mem->lost.refs += size;
    }
}

/* Allocate a string ref. */
int
gs_alloc_string_ref(gs_ref_memory_t * mem, ref * psref,
		    uint attrs, uint nbytes, client_name_t cname)
{
    byte *str = gs_alloc_string((gs_memory_t *) mem, nbytes, cname);

    if (str == 0)
	return_error(e_VMerror);
    make_string(psref, attrs | mem->space, nbytes, str);
    return 0;
}
