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ltdsave.app docs

Data types

Every entry in a save file is associated with a DataType that determines how its payload is laid out and interpreted. There are 33 types in total, numbered 0 through 32.

The entry table is a flat sequence of 8-byte (hash, slot) pairs. The hash field doubles as a discriminator:

  • hash != 0 - a data entry. slot is either the inline value (for inline scalars) or a byte offset into the heap region (for everything else), interpreted under the current DataType.
  • hash == 0 - a type sentinel. slot is itself a DataType value, and it sets the current type for every data entry that follows, until the next sentinel.

Inline scalars

Section titled “Inline scalars”

These types fit in the 4-byte inline slot of an entry. No separate payload is allocated.

Bool

Section titled “Bool”

tag = 0 - single byte interpreted as false when zero and true otherwise. Stored in the low byte of the inline slot.

Int

Section titled “Int”

tag = 2 - signed 32-bit integer, little-endian.

UInt

Section titled “UInt”

tag = 20 - unsigned 32-bit integer, little-endian.

Float

Section titled “Float”

tag = 4 - IEEE-754 binary32, little-endian. The inline slot holds the raw bits.

Enum

Section titled “Enum”

tag = 6 - unsigned 32-bit murmur3 hash of an enum value name. The set of accepted hashes for each field is listed on the Enums pages.

64-bit scalars

Section titled “64-bit scalars”

These types are too large for the inline slot and live in the payload region.

Int64

Section titled “Int64”

tag = 22 - signed 64-bit integer, little-endian, 8-byte payload.

UInt64

Section titled “UInt64”

tag = 24 - unsigned 64-bit integer, little-endian, 8-byte payload.

Vectors

Section titled “Vectors”

Packed sequences of 32-bit floats, little-endian, in payload.

Vector2

Section titled “Vector2”

tag = 8 - (x, y) as two float32 values. 8-byte payload.

Vector3

Section titled “Vector3”

tag = 10 - (x, y, z) as three float32 values. 12-byte payload.

Narrow strings

Section titled “Narrow strings”

Fixed-capacity UTF-8 byte buffers, NUL-terminated when shorter than the capacity. The number suffix is the buffer length in bytes.

String16

Section titled “String16”

tag = 12 - up to 16 bytes of UTF-8.

String32

Section titled “String32”

tag = 14 - up to 32 bytes of UTF-8.

String64

Section titled “String64”

tag = 16 - up to 64 bytes of UTF-8.

Wide strings

Section titled “Wide strings”

Fixed-capacity UTF-16LE buffers, NUL-terminated when shorter than the capacity. The number suffix is the buffer length in UTF-16 code units, so each holds twice as many bytes as the suffix suggests.

WString16

Section titled “WString16”

tag = 26 - up to 16 UTF-16 code units (32 bytes).

WString32

Section titled “WString32”

tag = 28 - up to 32 UTF-16 code units (64 bytes).

WString64

Section titled “WString64”

tag = 30 - up to 64 UTF-16 code units (128 bytes).

Binary

Section titled “Binary”

Binary

Section titled “Binary”

tag = 18 - arbitrary byte buffer of variable length. The container records the byte count; the interpretation is per-field.

Arrays

Section titled “Arrays”

Array types share tag = scalar_tag + 1. Each is encoded as a 4-byte little-endian count followed by tightly-packed elements in the same layout as the scalar form, with the exception of BoolArray (see below). Strings inside an array still use their full fixed capacity.

BoolArray

Section titled “BoolArray”

tag = 1 - bit-packed array of Bool. Stored as ⌈count / 8⌉ bytes (minimum 4) after the count, rounded up to a multiple of 4.

IntArray

Section titled “IntArray”

tag = 3 - array of Int.

UIntArray

Section titled “UIntArray”

tag = 21 - array of UInt.

FloatArray

Section titled “FloatArray”

tag = 5 - array of Float.

EnumArray

Section titled “EnumArray”

tag = 7 - array of Enum hashes.

Int64Array

Section titled “Int64Array”

tag = 23 - array of Int64.

UInt64Array

Section titled “UInt64Array”

tag = 25 - array of UInt64.

Vector2Array

Section titled “Vector2Array”

tag = 9 - array of Vector2.

Vector3Array

Section titled “Vector3Array”

tag = 11 - array of Vector3.

String16Array

Section titled “String16Array”

tag = 13 - array of String16. Each element occupies 16 bytes.

String32Array

Section titled “String32Array”

tag = 15 - array of String32. Each element occupies 32 bytes.

String64Array

Section titled “String64Array”

tag = 17 - array of String64. Each element occupies 64 bytes.

WString16Array

Section titled “WString16Array”

tag = 27 - array of WString16. Each element occupies 32 bytes.

WString32Array

Section titled “WString32Array”

tag = 29 - array of WString32. Each element occupies 64 bytes.

WString64Array

Section titled “WString64Array”

tag = 31 - array of WString64. Each element occupies 128 bytes.

BinaryArray

Section titled “BinaryArray”

tag = 19 - array of Binary buffers. Each element is preceded by its own 4-byte length.

Special

Section titled “Special”

Bool64bitKey

Section titled “Bool64bitKey”

tag = 32 - a type carried over from the underlying save framework, not used as a schema field type by Tomodachi Life. GameDataList.Product.100.byml declares zero Bool64bitKey fields. The only entries the game writes in this section are one per save file, whose hash is murmur3(file_name) (Player -> 0x08b37691, Mii -> 0x5917a80c, Map -> 0x441c30df), with slot = 0 and no heap payload.