asmjson 0.1.0

This module parses JSON strings 64 bytes at a time using AVX-512BW instructions to quickly identify structural characters, enabling entire whitespace runs and string bodies to be skipped in a single operation.

Each byte of the input is labelled below with the state that handles it. States that skip whitespace via trailing_zeros handle both the whitespace bytes and the following dispatch byte in the same loop iteration.

{ "key1" : "value1" , "key2": [123, 456 , 768], "key3" : { "nested_key" : true} }
VOOKKKKKDDCCSSSSSSSFFOOKKKKKDCCRAAARRAAAFRRAAAFOOKKKKKDDCCOOKKKKKKKKKKKDDCCAAAAFF

State key:

• V = ValueWhitespace — waiting for the first byte of any value
• O = ObjectStart — after { or , in an object; skips whitespace, expects " or }
• K = KeyChars — inside a quoted key; bulk-skipped via the backslash/quote masks
• D = KeyEnd — after closing " of a key; skips whitespace, expects :
• C = AfterColon — after :; skips whitespace, dispatches to the value type
• S = StringChars — inside a quoted string value; bulk-skipped via the backslash/quote masks
• F = AfterValue — after any complete value; skips whitespace, expects ,/}/]
• R = ArrayStart — after [ or , in an array; skips whitespace, dispatches value
• A = AtomChars — inside a number, true, false, or null

A few things to notice in the annotation:

• OO: ObjectStart eats the space and the opening " of a key in one shot via the trailing_zeros whitespace skip.
• DD / CC: KeyEnd eats the space and : together; AfterColon eats the space and the value-start byte — structural punctuation costs no extra iterations.
• SSSSSSS: StringChars covers the entire value1" run including the closing quote (bulk AVX-512 skip + dispatch in one pass through the chunk).
• RAAARRAAAFRRAAAF: inside the array [123, 456 , 768] each R covers the skip-to-digit hop; AAA covers the digit characters plus their terminating , / space / ].
• KKKKKKKKKKK (11 bytes): the 10-character nested_key body and its closing " are all handled by KeyChars in one bulk-skip pass.