nx_zstd_lit.nx

nx_zstd_lit.nx -- Zstandard literals section, header and payload. The wiring layer that composes everything below it: nx_zstd_frame (blocks), nx_zstd_bits (the backward reader), nx_zstd_huf (the flat decode table). Raw and RLE literals decode fully here; Huffman-coded literals decode through a table the caller supplies. THE HEADER IS 1 TO 5 BYTES AND THE SIZE FIELDS ARE NOT BYTE-ALIGNED. Two bits of block type and two of size format share byte 0 with the TOP of the regenerated size, so every size read starts at bit 4 of byte 0 and runs into the following bytes little-endian. Reading the size as whole bytes gives a value that is plausible and wrong -- and wrong by a factor of 16, so it usually fails loudly on the first block and silently on a block whose true size happens to be small. SIZE_FORMAT 0 AND 2 MEAN THE SAME THING FOR RAW AND RLE. Both select the one-byte header with a 5-bit size; only the low bit of the format field is consulted. For Compressed and Treeless the same two values mean DIFFERENT things -- 0 is a single stream, 1 is four streams, both with 10-bit sizes. One field, two interpretations, decided by the block type. FOUR STREAMS, NOT ONE. Above the smallest size format, compressed literals are split into four independently-decodable streams so a decoder can run them in parallel. A reader that assumes one stream consumes the first stream's jump table as literal data. genealogy_id: zstandard_rfc8878_literals lineage_id: nx_zstd_lit_v1 license_tier: ORIGINAL