ShuriZma
/
bsnes
mirror of https://github.com/bsnes-emu/bsnes.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
bsnes/Core/save_state.c

414 lines
13 KiB
C
Raw Blame History

#include "gb.h"
#include <stdio.h>
#include <errno.h>
static bool dump_section(FILE *f, const void *src, uint32_t size)
{
if (fwrite(&size, 1, sizeof(size), f) != sizeof(size)) {
return false;
}
if (fwrite(src, 1, size, f) != size) {
return false;
}
return true;
}
#define DUMP_SECTION(gb, f, section) dump_section(f, GB_GET_SECTION(gb, section), GB_SECTION_SIZE(section))
/* Todo: we need a sane and protable save state format. */
int GB_save_state(GB_gameboy_t *gb, const char *path)
{
FILE *f = fopen(path, "wb");
if (!f) {
GB_log(gb, "Could not open save state: %s.\n", strerror(errno));
return errno;
}
if (fwrite(GB_GET_SECTION(gb, header), 1, GB_SECTION_SIZE(header), f) != GB_SECTION_SIZE(header)) goto error;
if (!DUMP_SECTION(gb, f, core_state)) goto error;
if (!DUMP_SECTION(gb, f, dma )) goto error;
if (!DUMP_SECTION(gb, f, mbc )) goto error;
if (!DUMP_SECTION(gb, f, hram )) goto error;
if (!DUMP_SECTION(gb, f, timing )) goto error;
if (!DUMP_SECTION(gb, f, apu )) goto error;
if (!DUMP_SECTION(gb, f, rtc )) goto error;
if (!DUMP_SECTION(gb, f, video )) goto error;
if (GB_is_hle_sgb(gb)) {
if (!dump_section(f, gb->sgb, sizeof(*gb->sgb))) goto error;
}
if (fwrite(gb->mbc_ram, 1, gb->mbc_ram_size, f) != gb->mbc_ram_size) {
goto error;
}
if (fwrite(gb->ram, 1, gb->ram_size, f) != gb->ram_size) {
goto error;
}
if (fwrite(gb->vram, 1, gb->vram_size, f) != gb->vram_size) {
goto error;
}
errno = 0;
error:
fclose(f);
return errno;
}
#undef DUMP_SECTION
size_t GB_get_save_state_size(GB_gameboy_t *gb)
{
return GB_SECTION_SIZE(header)
+ GB_SECTION_SIZE(core_state) + sizeof(uint32_t)
+ GB_SECTION_SIZE(dma ) + sizeof(uint32_t)
+ GB_SECTION_SIZE(mbc ) + sizeof(uint32_t)
+ GB_SECTION_SIZE(hram ) + sizeof(uint32_t)
+ GB_SECTION_SIZE(timing ) + sizeof(uint32_t)
+ GB_SECTION_SIZE(apu ) + sizeof(uint32_t)
+ GB_SECTION_SIZE(rtc ) + sizeof(uint32_t)
+ GB_SECTION_SIZE(video ) + sizeof(uint32_t)
+ (GB_is_hle_sgb(gb)? sizeof(*gb->sgb) + sizeof(uint32_t) : 0)
+ gb->mbc_ram_size
+ gb->ram_size
+ gb->vram_size;
}
/* A write-line function for memory copying */
static void buffer_write(const void *src, size_t size, uint8_t **dest)
{
memcpy(*dest, src, size);
*dest += size;
}
static void buffer_dump_section(uint8_t **buffer, const void *src, uint32_t size)
{
buffer_write(&size, sizeof(size), buffer);
buffer_write(src, size, buffer);
}
#define DUMP_SECTION(gb, buffer, section) buffer_dump_section(&buffer, GB_GET_SECTION(gb, section), GB_SECTION_SIZE(section))
void GB_save_state_to_buffer(GB_gameboy_t *gb, uint8_t *buffer)
{
buffer_write(GB_GET_SECTION(gb, header), GB_SECTION_SIZE(header), &buffer);
DUMP_SECTION(gb, buffer, core_state);
DUMP_SECTION(gb, buffer, dma );
DUMP_SECTION(gb, buffer, mbc );
DUMP_SECTION(gb, buffer, hram );
DUMP_SECTION(gb, buffer, timing );
DUMP_SECTION(gb, buffer, apu );
DUMP_SECTION(gb, buffer, rtc );
DUMP_SECTION(gb, buffer, video );
if (GB_is_hle_sgb(gb)) {
buffer_dump_section(&buffer, gb->sgb, sizeof(*gb->sgb));
}
buffer_write(gb->mbc_ram, gb->mbc_ram_size, &buffer);
buffer_write(gb->ram, gb->ram_size, &buffer);
buffer_write(gb->vram, gb->vram_size, &buffer);
}
/* Best-effort read function for maximum future compatibility. */
static bool read_section(FILE *f, void *dest, uint32_t size, bool fix_broken_windows_saves)
{
uint32_t saved_size = 0;
if (fread(&saved_size, 1, sizeof(size), f) != sizeof(size)) {
return false;
}
if (fix_broken_windows_saves) {
if (saved_size < 4) {
return false;
}
saved_size -= 4;
fseek(f, 4, SEEK_CUR);
}
if (saved_size <= size) {
if (fread(dest, 1, saved_size, f) != saved_size) {
return false;
}
}
else {
if (fread(dest, 1, size, f) != size) {
return false;
}
fseek(f, saved_size - size, SEEK_CUR);
}
return true;
}
#undef DUMP_SECTION
static bool verify_and_update_state_compatibility(GB_gameboy_t *gb, GB_gameboy_t *save)
{
if (save->ram_size == 0 && (&save->ram_size)[-1] == gb->ram_size) {
/* This is a save state with a bad printer struct from a 32-bit OS */
memmove(save->extra_oam + 4, save->extra_oam, (uintptr_t)&save->ram_size - (uintptr_t)&save->extra_oam);
}
if (save->ram_size == 0) {
/* Save doesn't have ram size specified, it's a pre 0.12 save state with potentially
incorrect RAM amount if it's a CGB instance */
if (GB_is_cgb(save)) {
save->ram_size = 0x2000 * 8; // Incorrect RAM size
}
else {
save->ram_size = gb->ram_size;
}
}
if (gb->version != save->version) {
GB_log(gb, "The save state is for a different version of SameBoy.\n");
return false;
}
if (gb->mbc_ram_size < save->mbc_ram_size) {
GB_log(gb, "The save state has non-matching MBC RAM size.\n");
return false;
}
if (gb->vram_size != save->vram_size) {
GB_log(gb, "The save state has non-matching VRAM size. Try changing the emulated model.\n");
return false;
}
if (GB_is_hle_sgb(gb) != GB_is_hle_sgb(save)) {
GB_log(gb, "The save state is %sfor a Super Game Boy. Try changing the emulated model.\n", GB_is_hle_sgb(save)? "" : "not ");
return false;
}
if (gb->ram_size != save->ram_size) {
if (gb->ram_size == 0x1000 * 8 && save->ram_size == 0x2000 * 8) {
/* A bug in versions prior to 0.12 made CGB instances allocate twice the ammount of RAM.
Ignore this issue to retain compatibility with older, 0.11, save states. */
}
else {
GB_log(gb, "The save state has non-matching RAM size. Try changing the emulated model.\n");
return false;
}
}
return true;
}
static void sanitize_state(GB_gameboy_t *gb)
{
for (unsigned i = 0; i < 32; i++) {
GB_palette_changed(gb, false, i * 2);
GB_palette_changed(gb, true, i * 2);
}
gb->bg_fifo.read_end &= 0xF;
gb->bg_fifo.write_end &= 0xF;
gb->oam_fifo.read_end &= 0xF;
gb->oam_fifo.write_end &= 0xF;
gb->object_low_line_address &= gb->vram_size & ~1;
gb->fetcher_x &= 0x1f;
if (gb->lcd_x > gb->position_in_line) {
gb->lcd_x = gb->position_in_line;
}
if (gb->object_priority == GB_OBJECT_PRIORITY_UNDEFINED) {
gb->object_priority = gb->cgb_mode? GB_OBJECT_PRIORITY_INDEX : GB_OBJECT_PRIORITY_X;
}
}
#define READ_SECTION(gb, f, section) read_section(f, GB_GET_SECTION(gb, section), GB_SECTION_SIZE(section), fix_broken_windows_saves)
int GB_load_state(GB_gameboy_t *gb, const char *path)
{
GB_gameboy_t save;
/* Every unread value should be kept the same. */
memcpy(&save, gb, sizeof(save));
/* ...Except ram size, we use it to detect old saves with incorrect ram sizes */
save.ram_size = 0;
FILE *f = fopen(path, "rb");
if (!f) {
GB_log(gb, "Could not open save state: %s.\n", strerror(errno));
return errno;
}
bool fix_broken_windows_saves = false;
if (fread(GB_GET_SECTION(&save, header), 1, GB_SECTION_SIZE(header), f) != GB_SECTION_SIZE(header)) goto error;
if (save.magic == 0) {
/* Potentially legacy, broken Windows save state */
fseek(f, 4, SEEK_SET);
if (fread(GB_GET_SECTION(&save, header), 1, GB_SECTION_SIZE(header), f) != GB_SECTION_SIZE(header)) goto error;
fix_broken_windows_saves = true;
}
if (gb->magic != save.magic) {
GB_log(gb, "The file is not a save state, or is from an incompatible operating system.\n");
return false;
}
if (!READ_SECTION(&save, f, core_state)) goto error;
if (!READ_SECTION(&save, f, dma )) goto error;
if (!READ_SECTION(&save, f, mbc )) goto error;
if (!READ_SECTION(&save, f, hram )) goto error;
if (!READ_SECTION(&save, f, timing )) goto error;
if (!READ_SECTION(&save, f, apu )) goto error;
if (!READ_SECTION(&save, f, rtc )) goto error;
if (!READ_SECTION(&save, f, video )) goto error;
if (!verify_and_update_state_compatibility(gb, &save)) {
errno = -1;
goto error;
}
if (GB_is_hle_sgb(gb)) {
if (!read_section(f, gb->sgb, sizeof(*gb->sgb), false)) goto error;
}
memset(gb->mbc_ram + save.mbc_ram_size, 0xFF, gb->mbc_ram_size - save.mbc_ram_size);
if (fread(gb->mbc_ram, 1, save.mbc_ram_size, f) != save.mbc_ram_size) {
fclose(f);
return EIO;
}
if (fread(gb->ram, 1, gb->ram_size, f) != gb->ram_size) {
fclose(f);
return EIO;
}
/* Fix for 0.11 save states that allocate twice the amount of RAM in CGB instances */
fseek(f, save.ram_size - gb->ram_size, SEEK_CUR);
if (fread(gb->vram, 1, gb->vram_size, f) != gb->vram_size) {
fclose(f);
return EIO;
}
size_t orig_ram_size = gb->ram_size;
memcpy(gb, &save, sizeof(save));
gb->ram_size = orig_ram_size;
errno = 0;
sanitize_state(gb);
error:
fclose(f);
return errno;
}
#undef READ_SECTION
/* An read-like function for buffer-copying */
static size_t buffer_read(void *dest, size_t length, const uint8_t **buffer, size_t *buffer_length)
{
if (length > *buffer_length) {
length = *buffer_length;
}
memcpy(dest, *buffer, length);
*buffer += length;
*buffer_length -= length;
return length;
}
static bool buffer_read_section(const uint8_t **buffer, size_t *buffer_length, void *dest, uint32_t size, bool fix_broken_windows_saves)
{
uint32_t saved_size = 0;
if (buffer_read(&saved_size, sizeof(size), buffer, buffer_length) != sizeof(size)) {
return false;
}
if (saved_size > *buffer_length) return false;
if (fix_broken_windows_saves) {
if (saved_size < 4) {
return false;
}
saved_size -= 4;
*buffer += 4;
}
if (saved_size <= size) {
if (buffer_read(dest, saved_size, buffer, buffer_length) != saved_size) {
return false;
}
}
else {
if (buffer_read(dest, size, buffer, buffer_length) != size) {
return false;
}
*buffer += saved_size - size;
*buffer_length -= saved_size - size;
}
return true;
}
#define READ_SECTION(gb, buffer, length, section) buffer_read_section(&buffer, &length, GB_GET_SECTION(gb, section), GB_SECTION_SIZE(section), fix_broken_windows_saves)
int GB_load_state_from_buffer(GB_gameboy_t *gb, const uint8_t *buffer, size_t length)
{
GB_gameboy_t save;
/* Every unread value should be kept the same. */
memcpy(&save, gb, sizeof(save));
bool fix_broken_windows_saves = false;
if (buffer_read(GB_GET_SECTION(&save, header), GB_SECTION_SIZE(header), &buffer, &length) != GB_SECTION_SIZE(header)) return -1;
if (save.magic == 0) {
/* Potentially legacy, broken Windows save state*/
buffer -= GB_SECTION_SIZE(header) - 4;
length += GB_SECTION_SIZE(header) - 4;
if (buffer_read(GB_GET_SECTION(&save, header), GB_SECTION_SIZE(header), &buffer, &length) != GB_SECTION_SIZE(header)) return -1;
fix_broken_windows_saves = true;
}
if (gb->magic != save.magic) {
GB_log(gb, "The file is not a save state, or is from an incompatible operating system.\n");
return false;
}
if (!READ_SECTION(&save, buffer, length, core_state)) return -1;
if (!READ_SECTION(&save, buffer, length, dma )) return -1;
if (!READ_SECTION(&save, buffer, length, mbc )) return -1;
if (!READ_SECTION(&save, buffer, length, hram )) return -1;
if (!READ_SECTION(&save, buffer, length, timing )) return -1;
if (!READ_SECTION(&save, buffer, length, apu )) return -1;
if (!READ_SECTION(&save, buffer, length, rtc )) return -1;
if (!READ_SECTION(&save, buffer, length, video )) return -1;
if (!verify_and_update_state_compatibility(gb, &save)) {
return -1;
}
if (GB_is_hle_sgb(gb)) {
if (!buffer_read_section(&buffer, &length, gb->sgb, sizeof(*gb->sgb), false)) return -1;
}
memset(gb->mbc_ram + save.mbc_ram_size, 0xFF, gb->mbc_ram_size - save.mbc_ram_size);
if (buffer_read(gb->mbc_ram, save.mbc_ram_size, &buffer, &length) != save.mbc_ram_size) {
return -1;
}
if (buffer_read(gb->ram, gb->ram_size, &buffer, &length) != gb->ram_size) {
return -1;
}
if (buffer_read(gb->vram, gb->vram_size, &buffer, &length) != gb->vram_size) {
return -1;
}
/* Fix for 0.11 save states that allocate twice the amount of RAM in CGB instances */
buffer += save.ram_size - gb->ram_size;
length -= save.ram_size - gb->ram_size;
memcpy(gb, &save, sizeof(save));
sanitize_state(gb);
return 0;
}
#undef READ_SECTION
Reference in New Issue View Git Blame Copy Permalink