binarygen/

binarygen, a Golang code generator for Opentype files

This tool extends [go/packages] to understand the syntax describing the binary layout used is Opentype font files, and generates Go parsing functions.

Custom syntax

The binary layout is specified in Go source files using struct tags :

• 'arrayCount' : FirstUint16 | FirstUint32 | ToEnd | To- | ComputedField-
• 'offsetSize' : Offset16 | Offset32
• 'offsetsArray' : Offset16 | Offset32 , for an array of offsets. Zero offsets are resolved to zero values.
• 'offsetRelativeTo' : Parent | GrandParent
• 'unionField' : the name of a previous field
• 'unionTag' : the value of the tag identifying an union member
• 'isOpaque' : anything (even the empty string), to use custom parsing/writing functions
• 'subsliceStart' : AtStart | AtCurrent , used for opaque fields and raw data ([]byte)
• 'arguments' : a comma separated list of values to pass to the field parsing function

The special comment // binarygen: argument=<name> <type> indicates that the parsing function requires additionnal argument.