/* Copyright (C) 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: gsmalloc.c $ */
/* C heap allocator */
#include "malloc_.h"
#include "gdebug.h"
#include "gstypes.h"
#include "gsmemory.h"
#include "gsmdebug.h"
#include "gsstruct.h"		/* for st_bytes */
#include "gsmalloc.h"

/* ------ Heap allocator ------ */

/*
 * An implementation of Ghostscript's memory manager interface
 * that works directly with the C heap.  We keep track of all allocated
 * blocks so we can free them at cleanup time.
 */
/* Raw memory procedures */
private gs_memory_proc_alloc_bytes(gs_heap_alloc_bytes);
private gs_memory_proc_resize_object(gs_heap_resize_object);
private gs_memory_proc_free_object(gs_heap_free_object);
private gs_memory_proc_status(gs_heap_status);
private gs_memory_proc_free_all(gs_heap_free_all);

/* Object memory procedures */
private gs_memory_proc_alloc_struct(gs_heap_alloc_struct);
private gs_memory_proc_alloc_byte_array(gs_heap_alloc_byte_array);
private gs_memory_proc_alloc_struct_array(gs_heap_alloc_struct_array);
private gs_memory_proc_object_size(gs_heap_object_size);
private gs_memory_proc_object_type(gs_heap_object_type);
private gs_memory_proc_alloc_string(gs_heap_alloc_string);
private gs_memory_proc_resize_string(gs_heap_resize_string);
private gs_memory_proc_free_string(gs_heap_free_string);
private gs_memory_proc_register_root(gs_heap_register_root);
private gs_memory_proc_unregister_root(gs_heap_unregister_root);
private gs_memory_proc_enable_free(gs_heap_enable_free);
private const gs_memory_procs_t gs_malloc_memory_procs =
{
    /* Raw memory procedures */
    gs_heap_alloc_bytes,
    gs_heap_resize_object,
    gs_heap_free_object,
    gs_heap_status,
    gs_heap_free_all,
    gs_ignore_consolidate_free,
    /* Object memory procedures */
    gs_heap_alloc_bytes,
    gs_heap_alloc_struct,
    gs_heap_alloc_struct,
    gs_heap_alloc_byte_array,
    gs_heap_alloc_byte_array,
    gs_heap_alloc_struct_array,
    gs_heap_alloc_struct_array,
    gs_heap_object_size,
    gs_heap_object_type,
    gs_heap_alloc_string,
    gs_heap_alloc_string,
    gs_heap_resize_string,
    gs_heap_free_string,
    gs_heap_register_root,
    gs_heap_unregister_root,
    gs_heap_enable_free
};

/* We must make sure that malloc_blocks leave the block aligned. */
/*typedef struct gs_malloc_block_s gs_malloc_block_t; */
#define malloc_block_data\
	gs_malloc_block_t *next;\
	gs_malloc_block_t *prev;\
	uint size;\
	gs_memory_type_ptr_t type;\
	client_name_t cname
struct malloc_block_data_s {
    malloc_block_data;
};
struct gs_malloc_block_s {
    malloc_block_data;
/* ANSI C does not allow zero-size arrays, so we need the following */
/* unnecessary and wasteful workaround: */
#define _npad (-size_of(struct malloc_block_data_s) & 7)
    byte _pad[(_npad == 0 ? 8 : _npad)];	/* pad to double */
#undef _npad
};

/* Define the default allocator. */
gs_malloc_memory_t *gs_malloc_memory_default;

/* Initialize a malloc allocator. */
private long heap_available(P0());
gs_malloc_memory_t *
gs_malloc_memory_init(void)
{
    gs_malloc_memory_t *mem = malloc(sizeof(gs_malloc_memory_t));

    mem->procs = gs_malloc_memory_procs;
    mem->allocated = 0;
    mem->limit = max_long;
    mem->used = 0;
    mem->max_used = 0;
    return mem;
}
/*
 * Estimate the amount of available memory by probing with mallocs.
 * We may under-estimate by a lot, but that's better than winding up with
 * a seriously inflated address space.  This is quite a hack!
 */
#define max_malloc_probes 20
#define malloc_probe_size 64000
private long
heap_available(void)
{
    long avail = 0;
    void *probes[max_malloc_probes];
    uint n;

    for (n = 0; n < max_malloc_probes; n++) {
	if ((probes[n] = malloc(malloc_probe_size)) == 0)
	    break;
	if_debug2('a', "[a]heap_available probe[%d]=0x%lx\n",
		  n, (ulong) probes[n]);
	avail += malloc_probe_size;
    }
    while (n)
	free(probes[--n]);
    return avail;
}

/* Allocate various kinds of blocks. */
private byte *
gs_heap_alloc_bytes(gs_memory_t * mem, uint size, client_name_t cname)
{
    gs_malloc_memory_t *mmem = (gs_malloc_memory_t *) mem;
    byte *ptr = 0;

#ifdef DEBUG
    const char *msg;
    static const char *const ok_msg = "OK";

#  define set_msg(str) (msg = (str))
#else
#  define set_msg(str) DO_NOTHING
#endif

    if (size > mmem->limit - sizeof(gs_malloc_block_t)) {
	/* Definitely too large to allocate; also avoids overflow. */
	set_msg("exceeded limit");
    } else {
	uint added = size + sizeof(gs_malloc_block_t);

	if (mmem->limit - added < mmem->used)
	    set_msg("exceeded limit");
	else if ((ptr = (byte *) malloc(added)) == 0)
	    set_msg("failed");
	else {
	    gs_malloc_block_t *bp = (gs_malloc_block_t *) ptr;

	    if (mmem->allocated)
		mmem->allocated->prev = bp;
	    bp->next = mmem->allocated;
	    bp->prev = 0;
	    bp->size = size;
	    bp->type = &st_bytes;
	    bp->cname = cname;
	    mmem->allocated = bp;
	    set_msg(ok_msg);
	    ptr = (byte *) (bp + 1);
	    gs_alloc_fill(ptr, gs_alloc_fill_alloc, size);
	    mmem->used += size + sizeof(gs_malloc_block_t);
	    if (mmem->used > mmem->max_used)
		mmem->max_used = mmem->used;
	}
    }
#ifdef DEBUG
    if (gs_debug_c('a') || msg != ok_msg)
	dlprintf4("[a+]gs_malloc(%s)(%u) = 0x%lx: %s\n",
		  client_name_string(cname), size, (ulong) ptr, msg);
#endif
    return ptr;
#undef set_msg
}
private void *
gs_heap_alloc_struct(gs_memory_t * mem, gs_memory_type_ptr_t pstype,
		     client_name_t cname)
{
    void *ptr =
    gs_heap_alloc_bytes(mem, gs_struct_type_size(pstype), cname);

    if (ptr == 0)
	return 0;
    ((gs_malloc_block_t *) ptr)[-1].type = pstype;
    return ptr;
}
private byte *
gs_heap_alloc_byte_array(gs_memory_t * mem, uint num_elements, uint elt_size,
			 client_name_t cname)
{
    ulong lsize = (ulong) num_elements * elt_size;

    if (lsize != (uint) lsize)
	return 0;
    return gs_heap_alloc_bytes(mem, (uint) lsize, cname);
}
private void *
gs_heap_alloc_struct_array(gs_memory_t * mem, uint num_elements,
			   gs_memory_type_ptr_t pstype, client_name_t cname)
{
    void *ptr =
    gs_heap_alloc_byte_array(mem, num_elements,
			     gs_struct_type_size(pstype), cname);

    if (ptr == 0)
	return 0;
    ((gs_malloc_block_t *) ptr)[-1].type = pstype;
    return ptr;
}
private void *
gs_heap_resize_object(gs_memory_t * mem, void *obj, uint new_num_elements,
		      client_name_t cname)
{
    gs_malloc_memory_t *mmem = (gs_malloc_memory_t *) mem;
    gs_malloc_block_t *ptr = (gs_malloc_block_t *) obj - 1;
    gs_memory_type_ptr_t pstype = ptr->type;
    uint old_size = gs_object_size(mem, obj) + sizeof(gs_malloc_block_t);
    uint new_size =
    gs_struct_type_size(pstype) * new_num_elements +
    sizeof(gs_malloc_block_t);
    gs_malloc_block_t *new_ptr =
    (gs_malloc_block_t *) gs_realloc(ptr, old_size, new_size);

    if (new_ptr == 0)
	return 0;
    if (new_ptr->prev)
	new_ptr->prev->next = new_ptr;
    else
	mmem->allocated = new_ptr;
    if (new_ptr->next)
	new_ptr->next->prev = new_ptr;
    new_ptr->size = new_size - sizeof(gs_malloc_block_t);
    mmem->used -= old_size;
    mmem->used += new_size;
    if (new_size > old_size)
	gs_alloc_fill((byte *) new_ptr + old_size,
		      gs_alloc_fill_alloc, new_size - old_size);
    return new_ptr + 1;
}
private uint
gs_heap_object_size(gs_memory_t * mem, const void *ptr)
{
    return ((const gs_malloc_block_t *)ptr)[-1].size;
}
private gs_memory_type_ptr_t
gs_heap_object_type(gs_memory_t * mem, const void *ptr)
{
    return ((const gs_malloc_block_t *)ptr)[-1].type;
}
private void
gs_heap_free_object(gs_memory_t * mem, void *ptr, client_name_t cname)
{
    gs_malloc_memory_t *mmem = (gs_malloc_memory_t *) mem;
    gs_malloc_block_t *bp = mmem->allocated;

    if_debug3('a', "[a-]gs_free(%s) 0x%lx(%u)\n",
	      client_name_string(cname), (ulong) ptr,
	      (ptr == 0 ? 0 : ((gs_malloc_block_t *) ptr)[-1].size));
    if (ptr == 0)
	return;
    if (ptr == bp + 1) {
	mmem->allocated = bp->next;
	mmem->used -= bp->size + sizeof(gs_malloc_block_t);

	if (mmem->allocated)
	    mmem->allocated->prev = 0;
	gs_alloc_fill(bp, gs_alloc_fill_free,
		      bp->size + sizeof(gs_malloc_block_t));
	free(bp);
    } else {
	gs_malloc_block_t *np;

	/*
	 * bp == 0 at this point is an error, but we'd rather have an
	 * error message than an invalid access.
	 */
	if (bp) {
	    for (; (np = bp->next) != 0; bp = np) {
		if (ptr == np + 1) {
		    bp->next = np->next;
		    if (np->next)
			np->next->prev = bp;
		    mmem->used -= np->size + sizeof(gs_malloc_block_t);
		    gs_alloc_fill(np, gs_alloc_fill_free,
				  np->size + sizeof(gs_malloc_block_t));
		    free(np);
		    return;
		}
	    }
	}
	lprintf2("%s: free 0x%lx not found!\n",
		 client_name_string(cname), (ulong) ptr);
	free((char *)((gs_malloc_block_t *) ptr - 1));
    }
}
private byte *
gs_heap_alloc_string(gs_memory_t * mem, uint nbytes, client_name_t cname)
{
    return gs_heap_alloc_bytes(mem, nbytes, cname);
}
private byte *
gs_heap_resize_string(gs_memory_t * mem, byte * data, uint old_num, uint new_num,
		      client_name_t cname)
{
    if (gs_heap_object_type(mem, data) != &st_bytes)
	lprintf2("%s: resizing non-string 0x%lx!\n",
		 client_name_string(cname), (ulong) data);
    return gs_heap_resize_object(mem, data, new_num, cname);
}
private void
gs_heap_free_string(gs_memory_t * mem, byte * data, uint nbytes,
		    client_name_t cname)
{
    /****** SHOULD CHECK SIZE IF DEBUGGING ******/
    gs_heap_free_object(mem, data, cname);
}
private int
gs_heap_register_root(gs_memory_t * mem, gs_gc_root_t * rp,
		      gs_ptr_type_t ptype, void **up, client_name_t cname)
{
    return 0;
}
private void
gs_heap_unregister_root(gs_memory_t * mem, gs_gc_root_t * rp,
			client_name_t cname)
{
}
private void
gs_heap_status(gs_memory_t * mem, gs_memory_status_t * pstat)
{
    gs_malloc_memory_t *mmem = (gs_malloc_memory_t *) mem;

    pstat->allocated = mmem->used + heap_available();
    pstat->used = mmem->used;
}
private void
gs_heap_enable_free(gs_memory_t * mem, bool enable)
{
    if (enable)
	mem->procs.free_object = gs_heap_free_object,
	    mem->procs.free_string = gs_heap_free_string;
    else
	mem->procs.free_object = gs_ignore_free_object,
	    mem->procs.free_string = gs_ignore_free_string;
}

/* Release all memory acquired by this allocator. */
private void
gs_heap_free_all(gs_memory_t * mem, uint free_mask, client_name_t cname)
{
    gs_malloc_memory_t *const mmem = (gs_malloc_memory_t *) mem;

    if (free_mask & FREE_ALL_DATA) {
	gs_malloc_block_t *bp = mmem->allocated;
	gs_malloc_block_t *np;

	for (; bp != 0; bp = np) {
	    np = bp->next;
	    if_debug3('a', "[a]gs_heap_free_all(%s) 0x%lx(%u)\n",
		      client_name_string(bp->cname), (ulong) (bp + 1),
		      bp->size);
	    gs_alloc_fill(bp + 1, gs_alloc_fill_free, bp->size);
	    free(bp);
	}
    }
    if (free_mask & FREE_ALL_ALLOCATOR)
	free(mem);
}
