Constants

The following constants are exposed by lz4 for format introspection, buffer sizing, and protocol integration.

Magic Numbers

Constant	Value	Description
lz4.FRAME_MAGIC	0x184D2204	Standard LZ4 Frame Format magic identifier (Little Endian).
lz4.LEGACY_MAGIC	0x184C2102	Legacy LZ4 frame magic number from older tooling.
lz4.SKIPPABLE_MAGIC_MIN	0x184D2A50	Lower bound of the 16 skippable user frame magic numbers.
lz4.SKIPPABLE_MAGIC_MAX	0x184D2A5F	Upper bound of the 16 skippable user frame magic numbers.
lz4.END_MARK	0x00000000	4-byte block size marker designating the end of blocks in a frame.

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Algorithm & Size Limits

Constant	Value	Description
lz4.MINMATCH	4	Minimum byte length for an LZ4 back-reference match sequence.
lz4.MAX_DISTANCE	65535	Maximum backwards offset distance (64 KiB - 1 byte).
lz4.MAX_INPUT_SIZE	0x7E000000	Maximum single-block uncompressed size (~2,113,929,216 bytes).

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Block Capacity Limits

Constant	Value	Description
BLOCK_SIZE_64KB	65,536 bytes	64 KiB uncompressed block buffer capacity.
BLOCK_SIZE_256KB	262,144 bytes	256 KiB uncompressed block buffer capacity.
BLOCK_SIZE_1MB	1,048,576 bytes	1 MiB uncompressed block buffer capacity.
BLOCK_SIZE_4MB	4,194,304 bytes	4 MiB uncompressed block buffer capacity.