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diff --git a/libraries/liblunicode/ure/README b/libraries/liblunicode/ure/README new file mode 100644 index 0000000..c9918f5 --- /dev/null +++ b/libraries/liblunicode/ure/README @@ -0,0 +1,212 @@ +# +# $Id: README,v 1.3 1999/09/21 15:47:43 mleisher Exp $ +# +# Copyright 1997, 1998, 1999 Computing Research Labs, +# New Mexico State University +# +# Permission is hereby granted, free of charge, to any person obtaining a +# copy of this software and associated documentation files (the "Software"), +# to deal in the Software without restriction, including without limitation +# the rights to use, copy, modify, merge, publish, distribute, sublicense, +# and/or sell copies of the Software, and to permit persons to whom the +# Software is furnished to do so, subject to the following conditions: +# +# The above copyright notice and this permission notice shall be included in +# all copies or substantial portions of the Software. +# +# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL +# THE COMPUTING RESEARCH LAB OR NEW MEXICO STATE UNIVERSITY BE LIABLE FOR ANY +# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT +# OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR +# THE USE OR OTHER DEALINGS IN THE SOFTWARE. +# + + + Unicode and Regular Expressions + Version 0.5 + +This is a simple regular expression package for matching against Unicode text +in UCS2 form. The implementation of this URE package is a variation on the +RE->DFA algorithm done by Mark Hopkins (markh@csd4.csd.uwm.edu). Mark +Hopkins' algorithm had the virtue of being very simple, so it was used as a +model. + +--------------------------------------------------------------------------- + +Assumptions: + + o Regular expression and text already normalized. + + o Conversion to lower case assumes a 1-1 mapping. + +Definitions: + + Separator - any one of U+2028, U+2029, '\n', '\r'. + +Operators: + . - match any character. + * - match zero or more of the last subexpression. + + - match one or more of the last subexpression. + ? - match zero or one of the last subexpression. + () - subexpression grouping. + + Notes: + + o The "." operator normally does not match separators, but a flag is + available for the ure_exec() function that will allow this operator to + match a separator. + +Literals and Constants: + + c - literal UCS2 character. + \x.... - hexadecimal number of up to 4 digits. + \X.... - hexadecimal number of up to 4 digits. + \u.... - hexadecimal number of up to 4 digits. + \U.... - hexadecimal number of up to 4 digits. + +Character classes: + + [...] - Character class. + [^...] - Negated character class. + \pN1,N2,...,Nn - Character properties class. + \PN1,N2,...,Nn - Negated character properties class. + + POSIX character classes recognized: + + :alnum: + :alpha: + :cntrl: + :digit: + :graph: + :lower: + :print: + :punct: + :space: + :upper: + :xdigit: + + Notes: + + o Character property classes are \p or \P followed by a comma separated + list of integers between 1 and 32. These integers are references to + the following character properties: + + N Character Property + -------------------------- + 1 _URE_NONSPACING + 2 _URE_COMBINING + 3 _URE_NUMDIGIT + 4 _URE_NUMOTHER + 5 _URE_SPACESEP + 6 _URE_LINESEP + 7 _URE_PARASEP + 8 _URE_CNTRL + 9 _URE_PUA + 10 _URE_UPPER + 11 _URE_LOWER + 12 _URE_TITLE + 13 _URE_MODIFIER + 14 _URE_OTHERLETTER + 15 _URE_DASHPUNCT + 16 _URE_OPENPUNCT + 17 _URE_CLOSEPUNCT + 18 _URE_OTHERPUNCT + 19 _URE_MATHSYM + 20 _URE_CURRENCYSYM + 21 _URE_OTHERSYM + 22 _URE_LTR + 23 _URE_RTL + 24 _URE_EURONUM + 25 _URE_EURONUMSEP + 26 _URE_EURONUMTERM + 27 _URE_ARABNUM + 28 _URE_COMMONSEP + 29 _URE_BLOCKSEP + 30 _URE_SEGMENTSEP + 31 _URE_WHITESPACE + 32 _URE_OTHERNEUT + + o Character classes can contain literals, constants, and character + property classes. Example: + + [abc\U10A\p1,3,4] + +--------------------------------------------------------------------------- + +Before using URE +---------------- +Before URE is used, two functions need to be created. One to check if a +character matches a set of URE character properties, and one to convert a +character to lower case. + +Stubs for these function are located in the urestubs.c file. + +Using URE +--------- + +Sample pseudo-code fragment. + + ure_buffer_t rebuf; + ure_dfa_t dfa; + ucs2_t *re, *text; + unsigned long relen, textlen; + unsigned long match_start, match_end; + + /* + * Allocate the dynamic storage needed to compile regular expressions. + */ + rebuf = ure_buffer_create(); + + for each regular expression in a list { + re = next regular expression; + relen = length(re); + + /* + * Compile the regular expression with the case insensitive flag + * turned on. + */ + dfa = ure_compile(re, relen, 1, rebuf); + + /* + * Look for the first match in some text. The matching will be done + * in a case insensitive manner because the expression was compiled + * with the case insensitive flag on. + */ + if (ure_exec(dfa, 0, text, textlen, &match_start, &match_end)) + printf("MATCH: %ld %ld\n", match_start, match_end); + + /* + * Look for the first match in some text, ignoring non-spacing + * characters. + */ + if (ure_exec(dfa, URE_IGNORE_NONSPACING, text, textlen, + &match_start, &match_end)) + printf("MATCH: %ld %ld\n", match_start, match_end); + + /* + * Free the DFA. + */ + ure_free_dfa(dfa); + } + + /* + * Free the dynamic storage used for compiling the expressions. + */ + ure_free_buffer(rebuf); + +--------------------------------------------------------------------------- + +Mark Leisher <mleisher@crl.nmsu.edu> +29 March 1997 + +=========================================================================== + +CHANGES +------- + +Version: 0.5 +Date : 21 September 1999 +========================== + 1. Added copyright stuff and put in CVS. |