2019-05-11 16:15:07 +10:00

311 lines
6.9 KiB
C++

/* 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.
*
*/
#include "glk/frotz/mem.h"
#include "glk/frotz/frotz.h"
#include "common/memstream.h"
#include "common/textconsole.h"
namespace Glk {
namespace Frotz {
Mem::Mem() : story_fp(nullptr), story_size(0), first_undo(nullptr), last_undo(nullptr),
curr_undo(nullptr), undo_mem(nullptr), zmp(nullptr), pcp(nullptr), prev_zmp(nullptr),
undo_diff(nullptr), undo_count(0), reserve_mem(0) {
}
void Mem::initialize() {
initializeStoryFile();
loadGameHeader();
loadMemory();
initializeUndo();
// Read header extension table
hx_table_size = get_header_extension(HX_TABLE_SIZE);
hx_unicode_table = get_header_extension(HX_UNICODE_TABLE);
hx_flags = get_header_extension(HX_FLAGS);
}
void Mem::initializeStoryFile() {
if (story_fp->size() < 64)
error("This file is too small to be a Z-code file.");
}
void Mem::loadGameHeader() {
// Load header
zmp = (byte *)malloc(64);
story_fp->seek(0);
story_fp->read(zmp, 64);
Common::MemoryReadStream h(zmp, 64);
loadHeader(h);
// Calculate story file size in bytes
if (h_file_size != 0) {
story_size = (long)2 * h_file_size;
if (h_version >= V4)
story_size *= 2;
if (h_version >= V6)
story_size *= 2;
} else {
// Some old games lack the file size entry
story_size = story_fp->size();
}
}
void Mem::loadMemory() {
// Allocate memory for story data
if ((zmp = (zbyte *)realloc(zmp, story_size)) == nullptr)
error("Out of memory");
// Load story file in chunks of 32KB
uint n = 0x8000;
for (uint size = 64; size < story_size; size += n) {
if (story_size - size < 0x8000)
n = story_size - size;
if (story_fp->read(zmp + size, n) != n)
error("Story file read error");
}
}
void Mem::initializeUndo() {
byte *reserved = nullptr;
if (reserve_mem != 0) {
if ((reserved = new byte[reserve_mem]) == nullptr)
return;
}
// Allocate h_dynamic_size bytes for previous dynamic zmp state
// + 1.5 h_dynamic_size for Quetzal diff + 2.
undo_mem = new zbyte[(h_dynamic_size * 5) / 2 + 2];
if (undo_mem != nullptr) {
prev_zmp = undo_mem;
undo_diff = undo_mem + h_dynamic_size;
memcpy(prev_zmp, zmp, h_dynamic_size);
} else {
_undo_slots = 0;
}
if (reserve_mem)
delete[] reserved;
}
zword Mem::get_header_extension(int entry) {
zword addr;
zword val;
if (h_extension_table == 0 || entry > hx_table_size)
return 0;
addr = h_extension_table + 2 * entry;
LOW_WORD(addr, val);
return val;
}
void Mem::set_header_extension(int entry, zword val) {
zword addr;
if (h_extension_table == 0 || entry > hx_table_size)
return;
addr = h_extension_table + 2 * entry;
SET_WORD(addr, val);
}
void Mem::restart_header(void) {
zword screen_x_size;
zword screen_y_size;
zbyte font_x_size;
zbyte font_y_size;
int i;
SET_BYTE(H_CONFIG, h_config);
SET_WORD(H_FLAGS, h_flags);
if (h_version >= V4) {
SET_BYTE(H_INTERPRETER_NUMBER, h_interpreter_number);
SET_BYTE(H_INTERPRETER_VERSION, h_interpreter_version);
SET_BYTE(H_SCREEN_ROWS, h_screen_rows);
SET_BYTE(H_SCREEN_COLS, h_screen_cols);
}
// It's less trouble to use font size 1x1 for V5 games, especially because of
// a bug in the unreleased German version of "Zork 1"
if (h_version != V6) {
screen_x_size = (zword)h_screen_cols;
screen_y_size = (zword)h_screen_rows;
font_x_size = 1;
font_y_size = 1;
} else {
screen_x_size = h_screen_width;
screen_y_size = h_screen_height;
font_x_size = h_font_width;
font_y_size = h_font_height;
}
if (h_version >= V5) {
SET_WORD(H_SCREEN_WIDTH, screen_x_size);
SET_WORD(H_SCREEN_HEIGHT, screen_y_size);
SET_BYTE(H_FONT_HEIGHT, font_y_size);
SET_BYTE(H_FONT_WIDTH, font_x_size);
SET_BYTE(H_DEFAULT_BACKGROUND, h_default_background);
SET_BYTE(H_DEFAULT_FOREGROUND, h_default_foreground);
}
if (h_version == V6)
for (i = 0; i < 8; i++)
storeb((zword)(H_USER_NAME + i), h_user_name[i]);
SET_BYTE(H_STANDARD_HIGH, h_standard_high);
SET_BYTE(H_STANDARD_LOW, h_standard_low);
set_header_extension(HX_FLAGS, hx_flags);
set_header_extension(HX_FORE_COLOUR, hx_fore_colour);
set_header_extension(HX_BACK_COLOUR, hx_back_colour);
}
void Mem::storeb(zword addr, zbyte value) {
if (addr >= h_dynamic_size)
runtimeError(ERR_STORE_RANGE);
if (addr == H_FLAGS + 1) {
// flags register is modified
h_flags &= ~(SCRIPTING_FLAG | FIXED_FONT_FLAG);
h_flags |= value & (SCRIPTING_FLAG | FIXED_FONT_FLAG);
flagsChanged(value);
}
SET_BYTE(addr, value);
}
void Mem::storew(zword addr, zword value) {
storeb((zword)(addr + 0), hi(value));
storeb((zword)(addr + 1), lo(value));
}
void Mem::free_undo(int count) {
undo_t *p;
if (count > undo_count)
count = undo_count;
while (count--) {
p = first_undo;
if (curr_undo == first_undo)
curr_undo = curr_undo->next;
first_undo = first_undo->next;
free(p);
undo_count--;
}
if (first_undo)
first_undo->prev = nullptr;
else
last_undo = nullptr;
}
void Mem::reset_memory() {
story_fp = nullptr;
if (undo_mem) {
free_undo(undo_count);
delete[] undo_mem;
}
undo_mem = nullptr;
undo_count = 0;
free(zmp);
zmp = nullptr;
}
long Mem::mem_diff(zbyte *a, zbyte *b, zword mem_size, zbyte *diff) {
unsigned size = mem_size;
zbyte *p = diff;
unsigned j;
zbyte c = 0;
for (;;) {
for (j = 0; size > 0 && (c = *a++ ^ *b++) == 0; j++)
size--;
if (size == 0) break;
size--;
if (j > 0x8000) {
*p++ = 0;
*p++ = 0xff;
*p++ = 0xff;
j -= 0x8000;
}
if (j > 0) {
*p++ = 0;
j--;
if (j <= 0x7f) {
*p++ = j;
} else {
*p++ = (j & 0x7f) | 0x80;
*p++ = (j & 0x7f80) >> 7;
}
}
*p++ = c;
*(b - 1) ^= c;
}
return p - diff;
}
void Mem::mem_undiff(zbyte *diff, long diff_length, zbyte *dest) {
zbyte c;
while (diff_length) {
c = *diff++;
diff_length--;
if (c == 0) {
unsigned runlen;
if (!diff_length)
return; // Incomplete run
runlen = *diff++;
diff_length--;
if (runlen & 0x80) {
if (!diff_length)
return; // Incomplete extended run
c = *diff++;
diff_length--;
runlen = (runlen & 0x7f) | (((unsigned)c) << 7);
}
dest += runlen + 1;
} else {
*dest++ ^= c;
}
}
}
} // End of namespace Frotz
} // End of namespace Glk