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AnonBaiter, posted Fri Jun 29, 2018 5:23 pm (36294)

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okay, so i've already written a .bms script out of the DVD.[BIN/DAT] format as seen in WRC: World Rally Championship
the thing is, i want to apart the hashing algorithm as seen in the EVO_OPT4.IRX file into the .bms script - back when i did this i never knew i was pushing myself this hard just for this

Code:

set test01 string "game_intro.str"
strlen name_size test01

log memory_file10 0 0
putct test01 string -1 memory_file10
goto 0 memory_file10

math hash_a_value == 0x7ab7
math hash_b_value == 0x6a2f
math hash == 0

for sb = 0 < name_size
   get string_byte byte memory_file10
   putarray 1 sb string_byte
next sb

for x = 0 < name_size
   getarray string_byte 1 x
   xmath hash1 "(((hash_a_value << 24) | (hash_b_value >> 24))   string_byte) & 0x7fffffff"
   putarray 0 0 hash1
next x

here's said IRX file for anyone interested
also included is a part of said IRX file i'm trying to adapt into the .bms language

aluigi, posted Sun Jul 01, 2018 4:56 am (36325)

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Not sure if yours is a request about bms or reverse engineering, from the bms side you don't need to use memory files and array, just getvarchr.
You can even make a C function and calling it with the "tcc" prototype of calldll.

If you need help with reverse engineering I suggest you searching those constants on a search engine:
"31415" "27183"

AnonBaiter, posted Sun Jul 01, 2018 6:35 pm (36344)

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holy shit this is *SPAM* startling
they used the most basic shit you can ever find regarding hashing algorithms, i don't even think it's worth posting some random links for

anyway see if i'm getting close enough with this

Code:

math alpha == 0x7ab7
math beta == 0x6a2f
math hash == 0
math table_size == 0x7fffffff

set test01 string "game_intro.str"
strlen name_size test01

for sb = 0 < name_size
   getvarchr string_byte test01 sb byte
   xmath hash "hash * alpha"
   xmath hash "((hash   string_byte) % table_size)"
   xmath alpha "(alpha * beta) % (table_size - 1)"
   putarray 0 0 hash
   putarray 1 0 alpha
next sb

AnonBaiter, posted Sun Jul 01, 2018 8:33 pm (36346)

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second try

Code:

math alpha == 0x7ab7
math beta == 0x6a2f
math hash == 0
math table_size == 0x7fffffff

set test01 string "game_intro.str"
strlen name_size test01

for sb = 0 < name_size
   getvarchr string_byte test01 sb byte
   xmath alpha "(alpha * beta) % (table_size - 1)"
   xmath hash "((alpha * hash)   string_byte) % table_size"
   putarray 0 0 alpha
   putarray 1 0 hash
next sb

at this point i might be trying to pick off the MIPS code(hash_function.txt) to flesh this out

mtik333, posted Sat Mar 14, 2020 7:32 am (54624)

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Hi, sorry for "digging out" this thread after such time, but have you managed to achieve something here? I wanted to fetch game soundtrack from the archive file, but it seems that this is the only thread trying to solve mystery behind game files.