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Re: [ft-devel] Optional fields and stream reading in WOFF2
From: |
Werner LEMBERG |
Subject: |
Re: [ft-devel] Optional fields and stream reading in WOFF2 |
Date: |
Thu, 13 Jun 2019 11:10:59 +0200 (CEST) |
> [...] what is the point of using `FT_GET_XXX' if I can't use
> `FT_STREAM_SEEK' or `FT_STREAM_POS'? How do I decide whether to use
> `FT_READ_XXX' or `FT_GET_XXX'?
FT_GET_XXX' calls are to be used within a frame (which sets up
`stream->cursor' and `stream->limit').
However, if you have to jump around in a file to get data here and
there, `FT_READ_XXX' is preferable since it does check the boundaries
while accessing the data (from `stream->pos').
To summarize:
function acts on increases does range for emits
pointer checking frames error
-------------------------------------------------------------------
FT_PEEK_XXX buffer pointer no no no no
FT_NEXT_XXX buffer pointer yes no no no
FT_GET_XXX stream->cursor yes yes yes no
FT_READ_XXX stream->pos yes yes no yes
Werner