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Re: [PATCH] Faster glyph lookup by BMP index

From: address@hidden
Subject: Re: [PATCH] Faster glyph lookup by BMP index
Date: Sun, 29 Nov 2009 10:24:57 -0600

Is this table stored in the file or built during font load?  128KiB in
memory is no issue at all on modern systems, 128KiB in a file is
somewhat more troublesome since it won't fit in a boot sector, is a
big chunk of a rescue diskette, and the I/O cost is noticeable.  These
glyphs are stored in sorted order in the file, correct?  May I suggest
that only every Nth index be stored in the file header (where N = 16
for example) and the intermediate ones discovered at runtime, in those
subranges containing a character actually used (and the indexes and
character data for those glyphs are then cached in memory)?  This also
means block reads from the file (block length is easily calculated as
the difference of two adjacent indices) instead of extraction of
individual characters, most languages tend to have good locality so
this should also be a win.  Or is the entire font file cached in
memory anyway?

2009/11/29 Vladimir 'φ-coder/phcoder' Serbinenko <address@hidden>:
> Hello. Basic Multilingual Plane is range of Unicode characters in
> 0-65535 and it contains most of the characters needed by most of the
> languages of the world. By keeping an array with pointers to such
> characters at the cost of 128KiB per font we can almost instantenously
> lookup characters which are likely to be used in grub. Available in
> experimental
> --
> Regards
> Vladimir 'φ-coder/phcoder' Serbinenko
> _______________________________________________
> Grub-devel mailing list
> address@hidden

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