SARC - Revision history

Leoetlino: /* Hash algorithm */

2021-01-13T23:45:16Z

Hash algorithm

← Older revision		Revision as of 23:45, 13 January 2021
Line 27:		Line 27:
	Note that in older versions of sead, characters were not explicitly casted to <code>s8</code> so the end result would depend on the signedness of <code>char</code> (which is implementation-defined). For GHS compiled code on the Wii U, <code>char</code> is unsigned whereas it's signed with Clang (AArch64 target). PC tools most likely use a signed <code>char</code> as that is the default signedness for x86 targets.		Note that in older versions of sead, characters were not explicitly casted to <code>s8</code> so the end result would depend on the signedness of <code>char</code> (which is implementation-defined). For GHS compiled code on the Wii U, <code>char</code> is unsigned whereas it's signed with Clang (AArch64 target). PC tools most likely use a signed <code>char</code> as that is the default signedness for x86 targets.

	In newer versions of sead, an explicit cast to <code>signed char</code>, aka <code>std::int8_t</code>, aka <code>s8</code>, to ensure hashes are the same regardless of the target platform. Without the cast, non-ASCII characters (e.g. Japanese UTF-8 bytes) would result in hashes being different across platforms.		In newer versions of sead, an explicit cast to <code>signed char</code>, aka <code>std::int8_t</code>, aka <code>s8</code>, was added to ensure hashes are the same regardless of the target platform. Without the cast, non-ASCII characters (e.g. Japanese UTF-8 bytes) would result in hashes being different across platforms.

	== Usage in ''Breath of the Wild'' ==		== Usage in ''Breath of the Wild'' ==

Leoetlino: /* Hash algorithm */

2021-01-13T23:43:09Z

Hash algorithm

← Older revision		Revision as of 23:43, 13 January 2021
Line 5:		Line 5:

	=== Hash algorithm ===		=== Hash algorithm ===
	Nintendo's algorithm uses an unsigned 32-bit integer for the hash variable~~, and a '''''signed'' char variable'''~~. Also note that Nintendo iterates over each byte, not each string character.		Nintendo's algorithm uses an unsigned 32-bit integer for the hash variable. Also note that Nintendo iterates over each byte, not each string character.

	Here is an accurate implementation of the algorithm, written in C++:		Here is an accurate implementation of the algorithm, written in C++:

Leoetlino: /* Hash algorithm */ replace the code snippet with the sead implementation and add more information about the s8 cast

2021-01-13T23:42:39Z

Hash algorithm: replace the code snippet with the sead implementation and add more information about the s8 cast

← Older revision		Revision as of 23:42, 13 January 2021
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	<source lang="c++">		<source lang="c++">
	const ~~uint32_t multiplier = 0x65;~~		// key is equal to 0x65
	const char* ~~string~~ = ~~"月クッパ戦Lv3~~(~~クリア後~~)~~.baglshpp"~~;		u32 calcHash32(const sead::SafeString& str, u32 key)
	~~uint32_t hash~~ = 0;		{
	~~int~~ i = 0;		const char* str_ = str.cstr();
	~~while (true~~) {
	~~char c~~ = ~~string~~[i++]; ~~// signed char~~		u32 result = 0;
	~~if (!c)~~		// Each character must be treated as a signed value.
	~~break;~~		// The cast to s8 (not s32) is necessary to avoid unsigned conversions.
	~~hash = hash * multiplier + c~~;		for (s32 i = 0; str_[i] != '\0'; i++)
			result = result * key + s8(str_[i]);

			return result;
	}		}
	</source>		</source>

			Note that in older versions of sead, characters were not explicitly casted to <code>s8</code> so the end result would depend on the signedness of <code>char</code> (which is implementation-defined). For GHS compiled code on the Wii U, <code>char</code> is unsigned whereas it's signed with Clang (AArch64 target). PC tools most likely use a signed <code>char</code> as that is the default signedness for x86 targets.

			In newer versions of sead, an explicit cast to <code>signed char</code>, aka <code>std::int8_t</code>, aka <code>s8</code>, to ensure hashes are the same regardless of the target platform. Without the cast, non-ASCII characters (e.g. Japanese UTF-8 bytes) would result in hashes being different across platforms.

	== Usage in ''Breath of the Wild'' ==		== Usage in ''Breath of the Wild'' ==

imported>Leoetlino: Undo revision 8169 by Leoetlino (talk)

2020-03-11T22:34:06Z

Undo revision 8169 by Leoetlino (talk)

← Older revision		Revision as of 22:34, 11 March 2020
Line 30:		Line 30:
	The following extensions are specific to the game:		The following extensions are specific to the game:
	* [[pack]]		* [[pack]]
	* [[~~actor pack~~]]		* [[bactorpack]]
	* bmodelsh		* bmodelsh
	* [[~~event pack~~]]		* [[beventpack]]
	* stera		* stera
	* stats		* stats

imported>Leoetlino: bactorpack, beventpack -> actor pack, event pack

2020-03-11T22:31:47Z

bactorpack, beventpack -> actor pack, event pack

← Older revision		Revision as of 22:31, 11 March 2020
Line 30:		Line 30:
	The following extensions are specific to the game:		The following extensions are specific to the game:
	* [[pack]]		* [[pack]]
	* [[~~bactorpack~~]]		* [[actor pack]]
	* bmodelsh		* bmodelsh
	* [[~~beventpack~~]]		* [[event pack]]
	* stera		* stera
	* stats		* stats

imported>Leoetlino: /* Hash algorithm */

2018-12-04T17:12:01Z

Hash algorithm

← Older revision		Revision as of 17:12, 4 December 2018
Line 5:		Line 5:

	=== Hash algorithm ===		=== Hash algorithm ===
	~~The algorithm given on the MK8 wiki is not fully correct: it fails to account for the fact that~~ Nintendo's algorithm uses an unsigned 32-bit integer for the hash variable, and a '''''signed'' char variable'''. ~~It is also misleading in~~ that Nintendo iterates over each byte, not each string character.		Nintendo's algorithm uses an unsigned 32-bit integer for the hash variable, and a '''''signed'' char variable'''. Also note that Nintendo iterates over each byte, not each string character.

	Here is an accurate implementation of the algorithm, written in C++:		Here is an accurate implementation of the algorithm, written in C++:
Line 21:		Line 21:
	}		}
	</source>		</source>

	~~It appears that Nintendo's compiler treats a char as a signed type.~~

	== Usage in ''Breath of the Wild'' ==		== Usage in ''Breath of the Wild'' ==

imported>Leoetlino: /* Hash algorithm */

2018-11-20T21:27:15Z

Hash algorithm

← Older revision		Revision as of 21:27, 20 November 2018
Line 5:		Line 5:

	=== Hash algorithm ===		=== Hash algorithm ===
	The algorithm given on the MK8 wiki is not fully correct: it fails to account for the fact that Nintendo's algorithm uses an unsigned 32-bit integer for the hash variable, and a '''''signed'' char variable'''.		The algorithm given on the MK8 wiki is not fully correct: it fails to account for the fact that Nintendo's algorithm uses an unsigned 32-bit integer for the hash variable, and a '''''signed'' char variable'''. It is also misleading in that Nintendo iterates over each byte, not each string character.

	Here is an accurate implementation of the algorithm, written in C++:		Here is an accurate implementation of the algorithm, written in C++:

imported>Leoetlino: /* Hash algorithm */

2018-11-20T21:26:16Z

Hash algorithm

← Older revision		Revision as of 21:26, 20 November 2018
Line 7:		Line 7:
	The algorithm given on the MK8 wiki is not fully correct: it fails to account for the fact that Nintendo's algorithm uses an unsigned 32-bit integer for the hash variable, and a '''''signed'' char variable'''.		The algorithm given on the MK8 wiki is not fully correct: it fails to account for the fact that Nintendo's algorithm uses an unsigned 32-bit integer for the hash variable, and a '''''signed'' char variable'''.

	Here is ~~more~~ accurate implementation of the algorithm, written in C++:		Here is an accurate implementation of the algorithm, written in C++:

	<source lang="c++">		<source lang="c++">

imported>Leoetlino: /* Hash algorithm */

2018-11-20T21:26:05Z

Hash algorithm

← Older revision		Revision as of 21:26, 20 November 2018
Line 10:		Line 10:

	<source lang="c++">		<source lang="c++">
	const uint32_t multiplier = 0x65;		const uint32_t multiplier = 0x65;
	const char* string = "月クッパ戦Lv3(クリア後).baglshpp";		const char* string = "月クッパ戦Lv3(クリア後).baglshpp";
	uint32_t hash = 0;		uint32_t hash = 0;
	int i = 0;		int i = 0;
	while (true) {		while (true) {
	char c = string[i++]; // signed char		char c = string[i++]; // signed char
	if (!c)		if (!c)
	break;		break;
	hash = hash * multiplier + c;		hash = hash * multiplier + c;
	}		}
	</source>		</source>

imported>Leoetlino: /* Structure */

2018-11-20T21:25:38Z

Structure

@@ Line 3: / Line 3: @@
 == Structure ==
 The basic structure of SARC files is documented on the [[mk8:SARC (File Format)|MK8 wiki]].
 == Usage in ''Breath of the Wild'' ==