protocol.header

Read and write header data.

Reader functions take [buf start ctx] and return [end value] where end is the offset in buf after the read value(s).

Writer functions take [buf msg-map start ctx] and return end where end is the offset in buf after the written value(s).

(read-header buf start {:keys [readers spec path length], :as ctx})

Reads/decodes buf starting at start based on (:spec ctx) using reader functions in (:readers ctx).

Parameters:

(read-header-full buf start ctx)

Like read-header but returns only the read value.

Header readers

(write-header buf msg-map start {:keys [writers spec path], :as ctx})

Writes/encodes data in msg-map into buf starting at start based on (:spec ctx) using writer functions in (:writers ctx).

buf: is the buffer to write into (if nil then allocates a buffer of DEFAULT-BUF-SIZE bytes)
msg-map: map of field names -> field values to encode.
start: start writing at offset
ctx: a map of additional parsing context:
- writers is a map of types to writer functions
- writer functions that take buf val start ctx
- spec: sequence of name, type, lenth, default
  - name: field key to lookup in msg-map.
  - type: type to lookup in writers map
  - extra-ctx: extra context merged into ctx before writing
    - default: if msg-map does not contain name then this is used instead
    - length:
      - number: the number of bytes from the start of field (offset)
      - field: the name of a field in msg-map that contains number of bytes from start of the field (offset)
- msg-map: parent msg-map for compound writers

(write-header-full buf msg-map start ctx)

Like write-header but allocates a default sized buffer if not provided and returns the encoded buffer sliced to size of the actual written data.

Header writers