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93 lines
3.4 KiB
C
93 lines
3.4 KiB
C
/*************************************************
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* Unicode Property Table handler *
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*************************************************/
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#ifndef _UCPINTERNAL_H
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#define _UCPINTERNAL_H
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/* Internal header file defining the layout of the bits in each pair of 32-bit
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words that form a data item in the table. */
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typedef struct cnode {
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pcre_uint32 f0;
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pcre_uint32 f1;
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} cnode;
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/* Things for the f0 field */
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#define f0_scriptmask 0xff000000 /* Mask for script field */
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#define f0_scriptshift 24 /* Shift for script value */
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#define f0_rangeflag 0x00f00000 /* Flag for a range item */
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#define f0_charmask 0x001fffff /* Mask for code point value */
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/* Things for the f1 field */
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#define f1_typemask 0xfc000000 /* Mask for char type field */
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#define f1_typeshift 26 /* Shift for the type field */
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#define f1_rangemask 0x0000ffff /* Mask for a range offset */
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#define f1_casemask 0x0000ffff /* Mask for a case offset */
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#define f1_caseneg 0xffff8000 /* Bits for negation */
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/* The data consists of a vector of structures of type cnode. The two unsigned
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32-bit integers are used as follows:
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(f0) (1) The most significant byte holds the script number. The numbers are
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defined by the enum in ucp.h.
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(2) The 0x00800000 bit is set if this entry defines a range of characters.
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It is not set if this entry defines a single character
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(3) The 0x00600000 bits are spare.
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(4) The 0x001fffff bits contain the code point. No Unicode code point will
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ever be greater than 0x0010ffff, so this should be OK for ever.
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(f1) (1) The 0xfc000000 bits contain the character type number. The numbers are
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defined by an enum in ucp.h.
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(2) The 0x03ff0000 bits are spare.
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(3) The 0x0000ffff bits contain EITHER the unsigned offset to the top of
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range if this entry defines a range, OR the *signed* offset to the
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character's "other case" partner if this entry defines a single
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character. There is no partner if the value is zero.
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-------------------------------------------------------------------------------
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| script (8) |.|.|.| codepoint (21) || type (6) |.|.| spare (8) | offset (16) |
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-------------------------------------------------------------------------------
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| | | | |
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| | |-> spare | |-> spare
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| | |
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| |-> spare |-> spare
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|-> range flag
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The upper/lower casing information is set only for characters that come in
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pairs. The non-one-to-one mappings in the Unicode data are ignored.
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When searching the data, proceed as follows:
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(1) Set up for a binary chop search.
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(2) If the top is not greater than the bottom, the character is not in the
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table. Its type must therefore be "Cn" ("Undefined").
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(3) Find the middle vector element.
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(4) Extract the code point and compare. If equal, we are done.
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(5) If the test character is smaller, set the top to the current point, and
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goto (2).
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(6) If the current entry defines a range, compute the last character by adding
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the offset, and see if the test character is within the range. If it is,
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we are done.
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(7) Otherwise, set the bottom to one element past the current point and goto
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(2).
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*/
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#endif /* _UCPINTERNAL_H */
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/* End of ucpinternal.h */
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