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Create cheevos_is_nes_game

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This commit is contained in:
twinaphex 2017-05-06 18:43:45 +02:00
parent 24ac625179
commit 637e8d76ab
1 changed files with 57 additions and 47 deletions
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104
tasks/task_cheevos.c
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@ -2828,36 +2828,67 @@ static unsigned cheevos_find_game_id_genesis(
return cheevos_get_game_id(hash, &timeout);
}
/* Note about the references to the FCEU emulator below. There is no
* core-specific code in this function, it's rather Retro Achievements
* specific code that must be followed to the letter so we compute
* the correct ROM hash. Retro Achievements does indeed use some
* FCEU related method to compute the hash, since its NES emulator
* is based on it. */
struct nes_header
{
uint8_t id[4]; /* NES^Z */
uint8_t rom_size;
uint8_t vrom_size;
uint8_t rom_type;
uint8_t rom_type2;
uint8_t reserve[8];
};
static unsigned cheevos_is_nes_game(
struct nes_header *header,
size_t *bytes, size_t *offset)
{
size_t rom_size = 256;
int mapper_no = 0;
bool round = false;
if ( header->id[0] != 'N'
|| header->id[1] != 'E'
|| header->id[2] != 'S'
|| header->id[3] != 0x1a)
return false;
if (header->rom_size)
rom_size = next_pow2(header->rom_size);
/* from FCEU core - compute size using the cart mapper */
mapper_no = (header->rom_type >> 4) | (header->rom_type2 & 0xF0);
/* for games not to the power of 2, so we just read enough
* PRG rom from it, but we have to keep ROM_size to the power of 2
* since PRGCartMapping wants ROM_size to be to the power of 2
* so instead if not to power of 2, we just use head.ROM_size when
* we use FCEU_read. */
round = mapper_no != 53 && mapper_no != 198 && mapper_no != 228;
*bytes = (round) ? rom_size : header->rom_size;
/* from FCEU core - check if Trainer included in ROM data */
*offset = sizeof(struct nes_header) +
(header->rom_type & 4 ? sizeof(struct nes_header) : 0);
return true;
}
static unsigned cheevos_find_game_id_nes(
const struct retro_game_info *info,
retro_time_t timeout)
{
/* Note about the references to the FCEU emulator below. There is no
* core-specific code in this function, it's rather Retro Achievements
* specific code that must be followed to the letter so we compute
* the correct ROM hash. Retro Achievements does indeed use some
* FCEU related method to compute the hash, since its NES emulator
* is based on it. */
struct
{
uint8_t id[4]; /* NES^Z */
uint8_t rom_size;
uint8_t vrom_size;
uint8_t rom_type;
uint8_t rom_type2;
uint8_t reserve[8];
} header;
size_t rom_size, offset, count;
struct nes_header header;
size_t bytes;
size_t offset, count;
MD5_CTX ctx;
uint8_t hash[16];
size_t bytes;
RFILE *file;
ssize_t num_read;
int mapper_no;
bool round;
if (info->data)
{
if (info->size < sizeof(header))
@ -2867,7 +2898,8 @@ static unsigned cheevos_find_game_id_nes(
}
else
{
file = filestream_open(info->path, RFILE_MODE_READ, 0);
ssize_t num_read = 0;
RFILE *file = filestream_open(info->path, RFILE_MODE_READ, 0);
if (!file)
return 0;
@ -2879,31 +2911,9 @@ static unsigned cheevos_find_game_id_nes(
return 0;
}
if ( header.id[0] != 'N'
|| header.id[1] != 'E'
|| header.id[2] != 'S'
|| header.id[3] != 0x1a)
if (!cheevos_is_nes_game(&header, &bytes, &offset))
return 0;
if (header.rom_size)
rom_size = next_pow2(header.rom_size);
else
rom_size = 256;
/* from FCEU core - compute size using the cart mapper */
mapper_no = (header.rom_type >> 4) | (header.rom_type2 & 0xF0);
/* for games not to the power of 2, so we just read enough
* PRG rom from it, but we have to keep ROM_size to the power of 2
* since PRGCartMapping wants ROM_size to be to the power of 2
* so instead if not to power of 2, we just use head.ROM_size when
* we use FCEU_read. */
round = mapper_no != 53 && mapper_no != 198 && mapper_no != 228;
bytes = (round) ? rom_size : header.rom_size;
/* from FCEU core - check if Trainer included in ROM data */
offset = sizeof(header) + (header.rom_type & 4 ? sizeof(header) : 0);
MD5_Init(&ctx);
count = cheevos_eval_md5(info, offset, 0x4000 * bytes, &ctx);
count = 0x4000 * bytes - count;