Byaml

Byaml is Nintendo EPD's binary take on Yet Another Markup Language. It is handled by a dedicated library under the namespace "byaml" in later titles. Every version up to version 10 is supported by Nintendo's library as of Super Mario Wonder. Library supports both little and big endian.

Header

Version 4-7

Offset	Size	Type	Description
0x0	0x2	u16	Magic ("YB" in little-endian, "BY" in big-endian)
0x2	0x2	u16	Version (Up to 10 since Super Mario Wonder)
0x4	0x4	u32	Key table offset (to ByamlContainer)
0x8	0x4	u32	String table offset (to ByamlContainer)
0xc	0x4	u32	Root data offset (to ByamlContainer)

Byaml Container

Version 4-7

Offset	Size	Type	Description
0x0	0x1	u8 (NodeDataType Enum)	Container data type
0x1	0x3	u24	Count of container elements
			NodeDataType specific data

As of version 10 the root data of a header can point to a non-container type, in which case the ByamlContainer header will contain only the data type, with the single value stored directly after the ByamlContainer header.

Node Data Types

u8 enum of node data types that can appear. "Value" describes what the Value in a NodeDataType + Value pair means. These pairs are found in every container type.

Version 7

Name(unofficial)	Enum Value	Container "Value" Description
HashArray	0x20-0x2f	Value is an absolute offset to a ByamlContainer of the Hash Array type
HashArrayWithRemap	0x30-0x3f	Same as above but when accessing elements by index that index is remapped
StringIndex	0xa0	Value is an index into the string table
BinaryData	0xa1	Value is an absolute offset from the header to size of binary data followed by the binary data
BinaryDataWithAlignment	0xa2	Same as above but pointing to the size of the binary data, followed by alignment, followed by binary data
Array	0xc0	Value is an absolute offset to a ByamlContainer of the Array type
Dictionary	0xc1	Value is an absolute offset to a ByamlContainer of the Dictionary type
Key/StringTable	0xc2	(Only found in ByamlContainer pointed to by header)
DictionaryWithRemap	0xc4	Value is an absolute offset to a ByamlContainer of the Dictionary with remap type
RelocatedKey/StringTable	0xc5	(Only found in ByamlContainer pointed to by header)
MonoTypedArray	0xc8	Value is an absolute offset to a ByamlContainer of the Array with remap type
Bool	0xd0	Value is a bool
S32	0xd1	Value is a signed 32-bit integer
F32	0xd2	Value is a 32-bit floating point number
U32	0xd3	Value is a unsigned 32-bit integer
S64	0xd4	Value is an absolute offset to a signed 64-bit integer
U64	0xd5	Value is an absolute offset to a unsigned 64-bit integer
F64	0xd6	Value is an absolute offset to a 64-bit floating point number
Null	0xff	Value is 0 (null)

Key/String Tables (0xc2, 0xc5)

Only pointed to by the header, these tables are responsible for storing strings. The key table is used for dictionary containers and is sorted, the string table is for string data.

Key/String Table (0xc2)

Version 4-7

Offset	Size	Type	Description
0x0	0x4	ByamlContainer
0x4	0x4 * ByamlContainer count	u32	String offset array, offsets relative to string table header
		string data	Array of strings

Relocated Key/String Table (0xc5)

Version 7

Offset	Size	Type	Description
0x0	0x4	ByamlContainer
0x4	0x4 * ByamlContainer count	u32	String offset array, except the first element, which is an offset to a u64 value to be added to the other string offsets

Hash Array (0x20-0x2f)

Recent container types first noticed (to writer's knowledge) in the byaml library of the 3d All Stars menu. NodeDataType + Value pairs can be accessed through hash values and indices.

Hash Pair

Version 7

Offset	Size	Type	Description
0x0	(container NodeDataType & 0xf) * 0x4	u32[N]	Hash
	0x4	u32	Value

Hash Array (0x20-0x2f)

Version 7

Offset	Size	Type	Description
0x0	0x4	ByamlContainer
0x4	0xN * ByamlContainer count	HashPair	Hash + value array sorted by hash
	0x1 * ByamlContainer count	u8	NodeDataType for HashPair value

Hash Array With Remap (0x30-0x3f)

Version 7

Offset	Size	Type	Description
0x0	0x4	ByamlContainer
0x4	0xN * ByamlContainer count	HashPair	Hash + value array sorted by hash
	0x1 * ByamlContainer count	u8	NodeDataType for HashPair value
	(if count < 0x100) 0x1 * ByamlContainer count (if count < 0x10000) 0x2 * ByamlContainer count (else) 0x4 * ByamlContainer count	u8, u16, u32	Index remap table

Array (0xc0, 0xc8)

Container types where NodeDataType + Value pairs can be accessed through indices.

Array (0xc0)

Version 4-7

Offset	Size	Type	Description
0x0	0x4	ByamlContainer
0x4	0x1 * ByamlContainer count	u8	NodeDataType array matching index of value
	0x4 * ByamlContainer count	u32	Value array

Mono-Typed Array (0xc8)

Version 7

Offset	Size	Type	Description
0x0	0x4	ByamlContainer
0x4	0x1 (aligned up by 0x4)	u8	NodeDataType for every array value
0x8	0x4 * ByamlContainer count	u32	Value array

Dictionary (0xc1, 0xc4)

Container types where NodeDataType + Value pairs can be accessed through a string key or indices.

Byaml Dictionary Pair

Version 4-7

Offset	Size	Type	Description
0x0	0x3	u24	Key table index
0x1	0x1	u8	Node Data Type
0x4	0x4	u32	Value

Dictionary (0xc1)

Version 4-7

Offset	Size	Type	Description
0x0	0x4	ByamlContainer
0x4	0x8 * ByamlContainer count	ByamlDictionaryPair	Dictionary pair array sorted by key index

Dictionary With Remap (0xc4)

Version 7

Offset	Size	Type	Description
0x0	0x4	ByamlContainer
0x4	0x8 * ByamlContainer count	ByamlDictionaryPair	Dictionary pair array sorted by key index
	(if count < 0x100) 0x1 * ByamlContainer count (if count < 0x10000) 0x2 * ByamlContainer count (else) 0x4 * ByamlContainer count	u8, u16, u32	Index remap table