SameBoy/Core/cheats.c

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C
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#include "gb.h"
#include "cheats.h"
#include <stdio.h>
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#include <assert.h>
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#include <errno.h>
static inline uint8_t hash_addr(uint16_t addr)
{
return addr;
}
static uint16_t bank_for_addr(GB_gameboy_t *gb, uint16_t addr)
{
if (addr < 0x4000) {
return gb->mbc_rom0_bank;
}
if (addr < 0x8000) {
return gb->mbc_rom_bank;
}
if (addr < 0xD000) {
return 0;
}
if (addr < 0xE000) {
return gb->cgb_ram_bank;
}
return 0;
}
void GB_apply_cheat(GB_gameboy_t *gb, uint16_t address, uint8_t *value)
{
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if (!gb->cheat_enabled) return;
if (!gb->boot_rom_finished) return;
const GB_cheat_hash_t *hash = gb->cheat_hash[hash_addr(address)];
if (hash) {
for (unsigned i = 0; i < hash->size; i++) {
GB_cheat_t *cheat = hash->cheats[i];
if (cheat->address == address && cheat->enabled && (!cheat->use_old_value || cheat->old_value == *value)) {
if (cheat->bank == GB_CHEAT_ANY_BANK || cheat->bank == bank_for_addr(gb, address)) {
*value = cheat->value;
break;
}
}
}
}
}
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bool GB_cheats_enabled(GB_gameboy_t *gb)
{
return gb->cheat_enabled;
}
void GB_set_cheats_enabled(GB_gameboy_t *gb, bool enabled)
{
gb->cheat_enabled = enabled;
}
void GB_add_cheat(GB_gameboy_t *gb, const char *description, uint16_t address, uint16_t bank, uint8_t value, uint8_t old_value, bool use_old_value, bool enabled)
{
GB_cheat_t *cheat = malloc(sizeof(*cheat));
cheat->address = address;
cheat->bank = bank;
cheat->value = value;
cheat->old_value = old_value;
cheat->use_old_value = use_old_value;
cheat->enabled = enabled;
strncpy(cheat->description, description, sizeof(cheat->description));
cheat->description[sizeof(cheat->description) - 1] = 0;
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gb->cheats = realloc(gb->cheats, (++gb->cheat_count) * sizeof(gb->cheats[0]));
gb->cheats[gb->cheat_count - 1] = cheat;
GB_cheat_hash_t **hash = &gb->cheat_hash[hash_addr(address)];
if (!*hash) {
*hash = malloc(sizeof(GB_cheat_hash_t) + sizeof(cheat));
(*hash)->size = 1;
(*hash)->cheats[0] = cheat;
}
else {
(*hash)->size++;
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*hash = realloc(*hash, sizeof(GB_cheat_hash_t) + sizeof(cheat) * (*hash)->size);
(*hash)->cheats[(*hash)->size - 1] = cheat;
}
}
const GB_cheat_t *const *GB_get_cheats(GB_gameboy_t *gb, size_t *size)
{
*size = gb->cheat_count;
return (void *)gb->cheats;
}
void GB_remove_cheat(GB_gameboy_t *gb, const GB_cheat_t *cheat)
{
for (unsigned i = 0; i < gb->cheat_count; i++) {
if (gb->cheats[i] == cheat) {
gb->cheats[i] = gb->cheats[--gb->cheat_count];
if (gb->cheat_count == 0) {
free(gb->cheats);
gb->cheats = NULL;
}
else {
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gb->cheats = realloc(gb->cheats, gb->cheat_count * sizeof(gb->cheats[0]));
}
break;
}
}
GB_cheat_hash_t **hash = &gb->cheat_hash[hash_addr(cheat->address)];
for (unsigned i = 0; i < (*hash)->size; i++) {
if ((*hash)->cheats[i] == cheat) {
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(*hash)->cheats[i] = (*hash)->cheats[--(*hash)->size];
if ((*hash)->size == 0) {
free(*hash);
*hash = NULL;
}
else {
*hash = malloc(sizeof(GB_cheat_hash_t) + sizeof(cheat) * (*hash)->size);
}
break;
}
}
free((void *)cheat);
}
bool GB_import_cheat(GB_gameboy_t *gb, const char *cheat, const char *description, bool enabled)
{
uint8_t dummy;
/* GameShark */
{
uint8_t bank;
uint8_t value;
uint16_t address;
if (sscanf(cheat, "%02hhx%02hhx%04hx%c", &bank, &value, &address, &dummy) == 3) {
if (bank >= 0x80) {
bank &= 0xF;
}
GB_add_cheat(gb, description, address, bank, value, 0, false, enabled);
return true;
}
}
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/* GameGenie */
{
char stripped_cheat[10] = {0,};
for (unsigned i = 0; i < 9 && *cheat; i++) {
stripped_cheat[i] = *(cheat++);
while (*cheat == '-') {
cheat++;
}
}
// Delete the 7th character;
stripped_cheat[7] = stripped_cheat[8];
stripped_cheat[8] = 0;
uint8_t old_value;
uint8_t value;
uint16_t address;
if (sscanf(stripped_cheat, "%02hhx%04hx%02hhx%c", &value, &address, &old_value, &dummy) == 3) {
address = (uint16_t)(address >> 4) | (uint16_t)(address << 12);
address ^= 0xF000;
if (address > 0x7FFF) {
return false;
}
old_value = (uint8_t)(old_value >> 2) | (uint8_t)(old_value << 6);
old_value ^= 0xBA;
GB_add_cheat(gb, description, address, GB_CHEAT_ANY_BANK, value, old_value, true, enabled);
return true;
}
if (sscanf(stripped_cheat, "%02hhx%04hx%c", &value, &address, &dummy) == 2) {
address = (uint16_t)(address >> 4) | (uint16_t)(address << 12);
address ^= 0xF000;
if (address > 0x7FFF) {
return false;
}
GB_add_cheat(gb, description, address, GB_CHEAT_ANY_BANK, value, false, true, enabled);
return true;
}
}
return false;
}
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void GB_update_cheat(GB_gameboy_t *gb, const GB_cheat_t *_cheat, const char *description, uint16_t address, uint16_t bank, uint8_t value, uint8_t old_value, bool use_old_value, bool enabled)
{
GB_cheat_t *cheat = NULL;
for (unsigned i = 0; i < gb->cheat_count; i++) {
if (gb->cheats[i] == _cheat) {
cheat = gb->cheats[i];
break;
}
}
assert(cheat);
if (cheat->address != address) {
/* Remove from old bucket */
GB_cheat_hash_t **hash = &gb->cheat_hash[hash_addr(cheat->address)];
for (unsigned i = 0; i < (*hash)->size; i++) {
if ((*hash)->cheats[i] == cheat) {
(*hash)->cheats[i] = (*hash)->cheats[--(*hash)->size];
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if ((*hash)->size == 0) {
free(*hash);
*hash = NULL;
}
else {
*hash = malloc(sizeof(GB_cheat_hash_t) + sizeof(cheat) * (*hash)->size);
}
break;
}
}
cheat->address = address;
/* Add to new bucket */
hash = &gb->cheat_hash[hash_addr(address)];
if (!*hash) {
*hash = malloc(sizeof(GB_cheat_hash_t) + sizeof(cheat));
(*hash)->size = 1;
(*hash)->cheats[0] = cheat;
}
else {
(*hash)->size++;
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*hash = realloc(*hash, sizeof(GB_cheat_hash_t) + sizeof(cheat) * (*hash)->size);
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(*hash)->cheats[(*hash)->size - 1] = cheat;
}
}
cheat->bank = bank;
cheat->value = value;
cheat->old_value = old_value;
cheat->use_old_value = use_old_value;
cheat->enabled = enabled;
if (description != cheat->description) {
strncpy(cheat->description, description, sizeof(cheat->description));
cheat->description[sizeof(cheat->description) - 1] = 0;
}
}
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#define CHEAT_MAGIC 'SBCh'
void GB_load_cheats(GB_gameboy_t *gb, const char *path)
{
FILE *f = fopen(path, "rb");
if (!f) {
return;
}
uint32_t magic = 0;
uint32_t struct_size = 0;
fread(&magic, sizeof(magic), 1, f);
fread(&struct_size, sizeof(struct_size), 1, f);
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if (magic != LE32(CHEAT_MAGIC) && magic != BE32(CHEAT_MAGIC)) {
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GB_log(gb, "The file is not a SameBoy cheat database");
return;
}
if (struct_size != sizeof(GB_cheat_t)) {
GB_log(gb, "This cheat database is not compatible with this version of SameBoy");
return;
}
// Remove all cheats first
while (gb->cheats) {
GB_remove_cheat(gb, gb->cheats[0]);
}
GB_cheat_t cheat;
while (fread(&cheat, sizeof(cheat), 1, f)) {
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if (magic != CHEAT_MAGIC) {
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cheat.address = __builtin_bswap16(cheat.address);
cheat.bank = __builtin_bswap16(cheat.bank);
}
cheat.description[sizeof(cheat.description) - 1] = 0;
GB_add_cheat(gb, cheat.description, cheat.address, cheat.bank, cheat.value, cheat.old_value, cheat.use_old_value, cheat.enabled);
}
return;
}
int GB_save_cheats(GB_gameboy_t *gb, const char *path)
{
if (!gb->cheat_count) return 0; // Nothing to save.
FILE *f = fopen(path, "wb");
if (!f) {
GB_log(gb, "Could not dump cheat database: %s.\n", strerror(errno));
return errno;
}
uint32_t magic = CHEAT_MAGIC;
uint32_t struct_size = sizeof(GB_cheat_t);
if (fwrite(&magic, sizeof(magic), 1, f) != 1) {
fclose(f);
return EIO;
}
if (fwrite(&struct_size, sizeof(struct_size), 1, f) != 1) {
fclose(f);
return EIO;
}
for (size_t i = 0; i <gb->cheat_count; i++) {
if (fwrite(gb->cheats[i], sizeof(*gb->cheats[i]), 1, f) != 1) {
fclose(f);
return EIO;
}
}
errno = 0;
fclose(f);
return errno;
}