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When trying to use U-Boot's regex facility, it is a rather large
gotcha that [a-z] range syntax is not supported. It doesn't require a
lot of extra code to implement that; we just let the regular parsing
emit the start and end literal symbols as usual, and add a new
"escape" code RANGE.
At match time, this means the code will first just see an 'a' and try
to match that, and only then recognize that it's actually part of a
range and then do the 'a' <= ch <= 'z' test.
Of course, this means that a - in the middle of a [] pair no longer
matches a literal dash, but I highly doubt anybody relies on
that. Putting it first or last, or escaping it with \, as in most
other RE engines, continues to work.
Reviewed-by: Simon Glass <[email protected]>
Signed-off-by: Rasmus Villemoes <[email protected]>
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At the compile stage, the anyof() function clearly intends to handle escape
sequences like \d (for digits) inside square brackets, since the logic
emits a 0 byte followed by the code representing the character
class (NONSPACE, SPACE or DIGIT).
However, this is not handled in the corresponding match helper
is_any_of(); it just naively loops over all the bytes in the ->data
array emitted by anyof() and compares those directly to the current
character. For example, this means that the string "\x11" (containing
the single character with value 17) is matched by the regex "[#%\d]",
because DIGIT happens to be 17.
Fix that by recognizing a zero byte as indicating something special
and act accordingly. In order not to repeat the "increment *ofs and
return 1" in all places, put those two lines after a new match: label.
Reviewed-by: Simon Glass <[email protected]>
Signed-off-by: Rasmus Villemoes <[email protected]>
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As preparation for fixing the handling of backslash-escapes used
inside a character class, refactor is_any_but() to be defined in terms
of is_any_of() so we don't have to repeat the same logic in two places.
Reviewed-by: Simon Glass <[email protected]>
Signed-off-by: Rasmus Villemoes <[email protected]>
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The regex '^a|b' means "does the string start with a, or does it have
a b anywhere", not "does the string start with a or b" (the latter
should be spelled '^[ab]' or '^(a|b)'). It should match exactly the
same strings as 'b|^a'. But the current implementation hard-codes an
assumption that when the regex starts with a ^, the whole regex must
match from the beginning, i.e. it only attempts at offset 0.
It really should be completely symmetrical to 'b|c$' ("does it have a
b anywhere or end with c?"), which is treated correctly.
Another quirk is that currently the regex 'x*$', which should match
all strings (because it just means "does the string end
with 0 or more x'es"), does not, because in the unanchored case we
never attempt to match at ofs==len. In the anchored case, '^x*$', this
works correctly and matches exactly strings (including the empty
string) consisting entirely of x'es.
Fix both of these issues by dropping all use of the slre->anchored
member and always test at all possible offsets. If the regex does have
a ^ somewhere (including after a | branch character), that is
correctly handled by the match engine by only matching when *ofs is 0.
Reviewed-by: Simon Glass <[email protected]>
Signed-off-by: Rasmus Villemoes <[email protected]>
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After some header file cleanups to add missing include files, remove
common.h from all files in the lib directory. This primarily means just
dropping the line but in a few cases we need to add in other header
files now.
Reviewed-by: Simon Glass <[email protected]>
Signed-off-by: Tom Rini <[email protected]>
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Signed-off-by: Francois Berder <[email protected]>
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Move this header out of the common header.
Signed-off-by: Simon Glass <[email protected]>
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It makes no sense to assign a value to 'res' if the next use of the
variable is an assignment.
Signed-off-by: Heinrich Schuchardt <[email protected]>
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The value assigned to saved_offset is never used.
The problem was indicated by clang scan-build.
Signed-off-by: Heinrich Schuchardt <[email protected]>
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Signed-off-by: Wolfgang Denk <[email protected]>
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Downloaded from http://slre.sourceforge.net/
and adapted for U-Boot environment.
Used to implement regex operations on environment variables.
Code size is ~ 3.5 KiB on PPC.
To enable this code, define the CONFIG_REGEX option in your board
config file.
Note: There are more recent versions of the SLRE library available at
http://slre.googlecode.com ; unfortunately, the new code has a heavily
reorked API which makes it less usable for our purposes:
- the return code is strings, which are more difficult to process
- we don't get any information any more which sub-string of the data
was matched by the given regex
- it is much more cumbersome to work with arbitrary expressions, where
for example the number of substrings for capturing are not known at
compile time
Also, there does not seem to be any real changes or improvements of
the functionality.
Because of this, we deliberately stick with the older code.
Note 2: the test code (built when SLRE_TEST is defined) was modified
to allow for more extensive testing; now we can test the regexp
matching on all lines on a text file (instead of the whole data in the
file as a single block).
Signed-off-by: Wolfgang Denk <[email protected]>
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