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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#include "sci/engine/state.h"
#include "sci/scicore/sciconsole.h"
#include "sci/engine/heap.h"
namespace Sci {
#define assert_in_range(pos) assert(pos >= 1000 && pos <= 0xffff)
static void set_size(heap_t *h, int block_pos, int size) {
assert_in_range(block_pos);
assert(size <= 0xffff - 1000);
putInt16(h->start + block_pos, size);
}
static void set_next(heap_t *h, int block_pos, int next) {
assert_in_range(block_pos);
assert_in_range(next);
putInt16(h->start + block_pos + 2, next);
}
static unsigned int get_size(heap_t *h, int block_pos) {
assert_in_range(block_pos);
return (uint16)getInt16(h->start + block_pos);
}
static unsigned int get_next(heap_t *h, int block_pos) {
assert_in_range(block_pos);
return (uint16)getInt16(h->start + block_pos + 2);
}
// Allocates a new heap
heap_t *heap_new() {
heap_t *h;
if ((h = (heap_t*)sci_malloc(sizeof(heap_t))) == 0)
return 0;
if ((h->start = (byte *)sci_calloc(SCI_HEAP_SIZE, 1)) == 0) {
free(h);
return 0;
}
h->base = h->start + 1000;
h->first_free = 1000;
h->old_ff = -1;
set_size(h, 1000, 0xffff - 1000);
set_next(h, 1000, 0xffff);
return h;
}
// Deletes a heap
void heap_del(heap_t *h) {
free(h->start);
free(h);
}
int heap_meminfo(heap_t *h) {
heap_ptr current = h->first_free;
int total = 0;
while (current != 0xffff) {
total += get_size(h, current);
current = get_next(h, current);
}
return total;
}
int heap_largest(heap_t *h) {
int current = h->first_free;
int best_pos = -1, best_size = 0;
while (current != 0xffff) {
int size = get_size(h, current);
int next = get_next(h, current);
if (size > best_size) {
best_pos = current;
best_size = size;
}
current = next;
}
return best_size;
}
heap_ptr heap_allocate(heap_t *h, int size) {
unsigned int previous = h->first_free;
unsigned int current = previous;
if (!size) {
fprintf(stderr, "Warning: heap_alloc'd zero bytes!\n");
size += 2;
}
size += 2 + (size & 1);
while (current < 0xffff) {
int block_size = get_size(h, current);
int next = get_next(h, current);
// Is this block large enough?
if (block_size >= size) {
// Swallow the block whole
if (block_size <= size + 4) {
size = block_size;
set_next(h, previous, next);
} else {
// Split the block
int rest = current + size;
set_next(h, previous, rest);
set_size(h, rest, block_size - size);
set_next(h, rest, next);
next = rest;
}
set_size(h, current, size);
if (current == h->first_free) h->first_free = next;
return current;
}
previous = current;
current = next;
}
// No large enough block was found.
return 0;
}
void heap_free(heap_t *h, unsigned int m) {
unsigned int previous, next;
assert_in_range(m);
previous = next = h->first_free;
// Find the previous and next blocks
while (next < m) {
previous = next;
assert(previous < 0xffff);
next = get_next(h, previous);
if (next <= previous) {
sciprintf("Heap corrupt. Aborting heap_free()...\n");
return;
}
}
if (h->first_free > m)
h->first_free = m; // Guarantee that first_free is correct
if (previous == next) {
if (m < previous) {
h->first_free = m;
if (m + get_size(h, m) == previous) {
set_size(h, m, get_size(h, m) + get_size(h, previous));
set_next(h, m, get_next(h, previous));
} else
set_next(h, m, previous);
} else {
if (previous + get_size(h, previous) == m) {
set_size(h, previous, get_size(h, previous) + get_size(h, m));
set_next(h, previous, 0xffff);
} else {
set_next(h, previous, m);
set_next(h, m, next);
}
}
} else {
set_next(h, previous, m);
set_next(h, m, next);
// Try to merge with previous
if (previous + get_size(h, previous) == m) {
set_size(h, previous, get_size(h, previous) + get_size(h, m));
set_next(h, previous, next);
m = previous;
}
// Try to merge with next
if (m + get_size(h, m) == next) {
set_size(h, m, get_size(h, m) + get_size(h, next));
set_next(h, m, get_next(h, next));
}
}
}
void save_ff(heap_t *h) {
h->old_ff = h->first_free;
}
void restore_ff(heap_t *h) {
h->first_free = h->old_ff;
set_size(h, h->first_free, 0xffff - h->first_free);
set_next(h, h->first_free, 0xffff);
}
void heap_dump_free(heap_t *h) {
int freedomseeker;
printf("\tfirst_free= %#x (oldff= %#x)\n\tFree Blocks:\n", h->first_free, h->old_ff);
freedomseeker = h->first_free;
while (freedomseeker != 0xffff) {
printf("\t %#04x: size: %#04x\n", freedomseeker, get_size(h, freedomseeker));
freedomseeker = get_next(h, freedomseeker);
}
}
void heap_dump_all(heap_t *h) {
int seeker = 1000;
int free_seeker = h->first_free;
while (seeker < 0xffff) {
int is_free = (seeker == free_seeker);
int size = get_size(h, seeker);
if (is_free)
free_seeker = get_next(h, free_seeker);
printf("%04x\t%d\t%s\n", seeker, size, is_free ? "FREE" : "");
seeker += size;
}
}
#if 0
int main(int argc, char **argv) {
heap_t *h = heap_new();
int a, b, c, d, e;
printf("Running heap tests:\nHeap initialization:\n");
heap_dump_free(h);
printf("[a] Allocating 0x1: position is %#x\n", a = heap_allocate(h, 1));
heap_dump_free(h);
printf("[b] Allocating 0x10: position is %#x\n", b = heap_allocate(h, 0x10));
printf("[c] Allocating 0x10: position is %#x\n", c = heap_allocate(h, 0x10));
printf("[d] Allocating 0x10: position is %#x\n", d = heap_allocate(h, 0x10));
printf("[e] Allocating 0x1000: position is %#x\n", e = heap_allocate(h, 0x1000));
heap_dump_free(h);
printf("Freeing [b]:\n");
heap_free(h, b);
heap_dump_free(h);
printf("Freeing [d]:\n");
heap_free(h, d);
heap_dump_free(h);
printf("Freeing [c]:\n");
heap_free(h, c);
heap_dump_free(h);
heap_del(h);
return 0;
}
#endif
} // End of namespace Sci
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