For those who can't play a video game without dissecting it
Mostly for fun, I started implementing a parser for the save game data in Disgaea:AoD in Hammer. (Also to shill Hammer.) Currently it’s lacking the various enums for skill, weapon and specialist job IDs, as well as the encoding for text characters. When I get around to it, they’ll probably be good showcases for custom token types and semantic actions. Writing this was about as easy as working in, e.g. ImHex’s pattern language. However, it’s slightly more flexible working in C instead of a domain-specific language. Getting transform and format working for the text character encoding was slightly frustrating, because they didn’t behave like my intuition said they should.
Here’s the entire code for a parser that, in its current state, parses a single character’s data, then dumps it as numbers to stdout in the default pretty printing format:
#include <hammer/hammer.h>
#include <hammer/glue.h>
#include <err.h>
#include <fcntl.h> /* open() */
#include <unistd.h> /* lseek() */
#include <sys/mman.h> /* mmap() */
HParser *d1achar; // character data, not the specially encoded text
HParser *d1aitem;
HParser *d1aspecialist;
HParser *d1atxtstring;
void init_text_string_parser()
{
H_RULE(text_string, h_repeat_n(h_uint16(), 16));
d1atxtstring = text_string;
}
void init_specialist_parser()
{
H_RULE(spec_level, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(spec_job, h_uint8());
H_RULE(spec_uniquer, h_uint8());
d1aspecialist = h_sequence(spec_level, spec_job, spec_uniquer, NULL);
}
void init_item_parser()
{
H_RULE(item_specialists, h_repeat_n(d1aspecialist, 16));
H_RULE(item_basesalep, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(item_unk_1, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(item_hp, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(item_sp, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(item_atk, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(item_def, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(item_int, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(item_spd, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(item_hit, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(item_res, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(item_hp_base, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(item_sp_base, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(item_atk_base, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(item_def_base, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(item_int_base, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(item_spd_base, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(item_hit_base, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(item_res_base, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(item_type, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(item_level, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(item_unk2, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(item_rarity, h_uint8());
H_RULE(item_unk3, h_uint8());
H_RULE(item_unk4, h_uint8()); // Possbily the item's range
H_RULE(item_spec_slots, h_uint8());
H_RULE(item_unk5, h_repeat_n(h_uint8(), 14));
d1aitem = h_sequence(item_specialists, item_basesalep, item_unk_1, item_hp,
item_sp, item_atk, item_def, item_int, item_spd, item_hit,
item_res, item_hp_base, item_sp_base, item_atk_base,
item_def_base, item_int_base, item_spd_base, item_hit_base,
item_res_base, item_type, item_level, item_unk2, item_rarity,
item_unk3, item_unk4, item_spec_slots, item_unk5, NULL);
}
void init_char_parser()
{
H_RULE(char_exp, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint64()));
H_RULE(char_weapon, d1aitem);
H_RULE(char_etc_items, h_repeat_n(d1aitem, 3));
H_RULE(char_name, d1atxtstring);
H_RULE(char_unk1, h_uint8());
H_RULE(char_class, d1atxtstring);
H_RULE(char_unk98, h_repeat_n(h_uint8(), 35));
H_RULE(char_psn_resist, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(char_slp_resist, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(char_par_resist, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(char_fgt_resist, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(char_dpr_resist, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()));
H_RULE(char_unk2, h_repeat_n(h_uint8(), 110));
H_RULE(char_skillexps, h_repeat_n(h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()), 96));
H_RULE(char_skillids, h_repeat_n(h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint16()), 96));
H_RULE(char_skillevels, h_repeat_n(h_uint8(), 96));
H_RULE(char_hp_current, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_sp_current, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_hp, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_sp, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_atk, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_def, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_int, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_spd, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_hit, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_res, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_hp_actual, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_sp_actual, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_atk_actual, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_def_actual, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_int_actual, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_spd_actual, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_hit_actual, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_res_actual, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_unk4, h_repeat_n(h_uint8(), 32));
H_RULE(char_mana, h_with_endianness(BYTE_LITTLE_ENDIAN|BIT_BIG_ENDIAN, h_uint32()));
H_RULE(char_unk99, h_repeat_n(h_uint8(), 40));
H_RULE(char_hp_base, h_uint8());
H_RULE(char_sp_base, h_uint8());
H_RULE(char_atk_base, h_uint8());
H_RULE(char_def_base, h_uint8());
H_RULE(char_int_base, h_uint8());
H_RULE(char_spd_base, h_uint8());
H_RULE(char_hit_base, h_uint8());
H_RULE(char_res_base, h_uint8());
H_RULE(char_unk96, h_repeat_n(h_uint8(), 20));
H_RULE(char_fire_res_base, h_int8()); // order of actual vs. base could be different here, needs more testing
H_RULE(char_wind_res_base, h_int8());
H_RULE(char_ice_res_base, h_int8());
H_RULE(char_fire_res_actual, h_int8());
H_RULE(char_wind_res_actual, h_int8());
H_RULE(char_ice_res_actual, h_int8());
H_RULE(char_jump_base, h_uint8());
H_RULE(char_jump_actual, h_uint8());
H_RULE(char_mv_base, h_uint8());
H_RULE(char_mv_actual, h_uint8());
H_RULE(char_counter_base, h_uint8());
H_RULE(char_counter_actual, h_uint8());
H_RULE(char_unk97, h_repeat_n(h_uint8(), 13));
H_RULE(char_assemblyrank, h_uint8());
H_RULE(char_unk95, h_repeat_n(h_uint8(), 26));
d1achar = h_sequence(char_exp, char_weapon, char_etc_items, char_name, char_unk1,
char_class, char_unk98, char_psn_resist, char_slp_resist,
char_par_resist, char_fgt_resist, char_dpr_resist,
char_unk2, char_skillexps, char_skillids,
char_skillevels, char_hp_current, char_sp_current,
char_hp, char_sp, char_atk, char_def, char_int, char_spd,
char_hit, char_res, char_hp_actual, char_sp_actual,
char_atk_actual, char_def_actual, char_int_actual,
char_spd_actual, char_hit_actual, char_res_actual,
char_unk4, char_mana, char_unk99, char_hp_base,
char_sp_base, char_atk_base, char_def_base,
char_int_base, char_spd_base, char_hit_base,
char_res_base, char_unk96, char_fire_res_base,
char_wind_res_base, char_ice_res_base,
char_fire_res_actual, char_wind_res_actual,
char_ice_res_actual, char_jump_base, char_jump_actual,
char_mv_base, char_mv_actual, char_counter_base,
char_counter_actual, char_unk97, char_assemblyrank,
char_unk95, NULL);
}
int main(int argc, char *argv[])
{
int fd;
off_t sz;
const uint8_t *input_bytes;
HParseResult *res_d1char;
if (argc < 2 || argc > 2)
{
fprintf(stderr, "Usage: %s <file>\n", argv[0]);
return 1;
}
fd = open(argv[1], O_RDONLY);
if (fd == -1)
err(1, "%s", argv[1]);
sz = lseek(fd, 0, SEEK_END);
if (sz == -1)
err(1, "lseek error");
if (sz < 0)
err(1, "lseek: returned size less than 0");
input_bytes = mmap(NULL, sz ? sz : 1, PROT_READ, MAP_PRIVATE, fd, 0);
if (input_bytes == MAP_FAILED)
err(1, "mmap error");
init_text_string_parser();
init_specialist_parser();
init_item_parser();
init_char_parser();
res_d1char = h_parse(d1achar, input_bytes, sz);
if(!res_d1char)
{
fprintf(stderr, "%s: parse failed lol\n", argv[1]);
close(fd);
return 2;
}
h_pprintln(stdout, res_d1char->ast);
close(fd);
return 0;
}
It’s also available on GitHub.