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pcre16

       #include <pcre.h>


PCRE 16-BIT API BASIC FUNCTIONS


       pcre16 *pcre16_compile(PCRE_SPTR16 pattern, int options,
            const char **errptr, int *erroffset,
            const unsigned char *tableptr);

       pcre16 *pcre16_compile2(PCRE_SPTR16 pattern, int options,
            int *errorcodeptr,
            const char **errptr, int *erroffset,
            const unsigned char *tableptr);

       pcre16_extra *pcre16_study(const pcre16 *code, int options,
            const char **errptr);

       void pcre16_free_study(pcre16_extra *extra);

       int pcre16_exec(const pcre16 *code, const pcre16_extra *extra,
            PCRE_SPTR16 subject, int length, int startoffset,
            int options, int *ovector, int ovecsize);

       int pcre16_dfa_exec(const pcre16 *code, const pcre16_extra *extra,
            PCRE_SPTR16 subject, int length, int startoffset,
            int options, int *ovector, int ovecsize,
            int *workspace, int wscount);


PCRE 16-BIT API STRING EXTRACTION FUNCTIONS


       int pcre16_copy_named_substring(const pcre16 *code,
            PCRE_SPTR16 subject, int *ovector,
            int stringcount, PCRE_SPTR16 stringname,
            PCRE_UCHAR16 *buffer, int buffersize);

       int pcre16_copy_substring(PCRE_SPTR16 subject, int *ovector,
            int stringcount, int stringnumber, PCRE_UCHAR16 *buffer,
            int buffersize);

       int pcre16_get_named_substring(const pcre16 *code,
            PCRE_SPTR16 subject, int *ovector,
            int stringcount, PCRE_SPTR16 stringname,
            PCRE_SPTR16 *stringptr);

       int pcre16_get_stringnumber(const pcre16 *code,
            PCRE_SPTR16 name);

       int pcre16_get_stringtable_entries(const pcre16 *code,
            PCRE_SPTR16 name, PCRE_UCHAR16 **first, PCRE_UCHAR16 **last);

       int pcre16_get_substring(PCRE_SPTR16 subject, int *ovector,
            int stringcount, int stringnumber,
            PCRE_SPTR16 *stringptr);

       void pcre16_assign_jit_stack(pcre16_extra *extra,
            pcre16_jit_callback callback, void *data);

       const unsigned char *pcre16_maketables(void);

       int pcre16_fullinfo(const pcre16 *code, const pcre16_extra *extra,
            int what, void *where);

       int pcre16_refcount(pcre16 *code, int adjust);

       int pcre16_config(int what, void *where);

       const char *pcre16_version(void);

       int pcre16_pattern_to_host_byte_order(pcre16 *code,
            pcre16_extra *extra, const unsigned char *tables);


PCRE 16-BIT API INDIRECTED FUNCTIONS


       void *(*pcre16_malloc)(size_t);

       void (*pcre16_free)(void *);

       void *(*pcre16_stack_malloc)(size_t);

       void (*pcre16_stack_free)(void *);

       int (*pcre16_callout)(pcre16_callout_block *);


PCRE 16-BIT API 16-BIT-ONLY FUNCTION


       int pcre16_utf16_to_host_byte_order(PCRE_UCHAR16 *output,
            PCRE_SPTR16 input, int length, int *byte_order,
            int keep_boms);


THE PCRE 16-BIT LIBRARY


       Starting  with  release  8.30, it is possible to compile a PCRE library
       that supports 16-bit character strings, including  UTF-16  strings,  as
       well  as  or instead of the original 8-bit library. The majority of the
       work to make  this  possible  was  done  by  Zoltan  Herczeg.  The  two
       libraries contain identical sets of functions, used in exactly the same
       way. Only the names of the functions and the data types of their  argu-
       ments  and results are different. To avoid over-complication and reduce
       the documentation maintenance load,  most  of  the  PCRE  documentation
       describes  the  8-bit  library,  with only occasional references to the
       16-bit library. This page describes what is different when you use  the
       16-bit library.

       WARNING:  A  single  application can be linked with both libraries, but
       you must take care when processing any particular pattern to use  func-
       tions  from  just one library. For example, if you want to study a pat-
       application that uses PCRE.


STRING TYPES


       In the 8-bit library, strings are passed to PCRE library  functions  as
       vectors  of  bytes  with  the  C  type "char *". In the 16-bit library,
       strings are passed as vectors of unsigned 16-bit quantities. The  macro
       PCRE_UCHAR16  specifies  an  appropriate  data type, and PCRE_SPTR16 is
       defined as "const PCRE_UCHAR16 *". In very  many  environments,  "short
       int" is a 16-bit data type. When PCRE is built, it defines PCRE_UCHAR16
       as "unsigned short int", but checks that it really  is  a  16-bit  data
       type.  If  it is not, the build fails with an error message telling the
       maintainer to modify the definition appropriately.


STRUCTURE TYPES


       The types of the opaque structures that are used  for  compiled  16-bit
       patterns  and  JIT stacks are pcre16 and pcre16_jit_stack respectively.
       The  type  of  the  user-accessible  structure  that  is  returned   by
       pcre16_study()  is  pcre16_extra, and the type of the structure that is
       used for passing data to a callout  function  is  pcre16_callout_block.
       These structures contain the same fields, with the same names, as their
       8-bit counterparts. The only difference is that pointers  to  character
       strings are 16-bit instead of 8-bit types.


16-BIT FUNCTIONS


       For  every function in the 8-bit library there is a corresponding func-
       tion in the 16-bit library with a name that starts with pcre16_ instead
       of  pcre_.  The  prototypes are listed above. In addition, there is one
       extra function, pcre16_utf16_to_host_byte_order(). This  is  a  utility
       function  that converts a UTF-16 character string to host byte order if
       necessary. The other 16-bit  functions  expect  the  strings  they  are
       passed to be in host byte order.

       The input and output arguments of pcre16_utf16_to_host_byte_order() may
       point to the same address, that is, conversion in place  is  supported.
       The output buffer must be at least as long as the input.

       The  length  argument  specifies the number of 16-bit data units in the
       input string; a negative value specifies a zero-terminated string.

       If byte_order is NULL, it is assumed that the string starts off in host
       byte  order. This may be changed by byte-order marks (BOMs) anywhere in
       the string (commonly as the first character).

       If byte_order is not NULL, a non-zero value of the integer to which  it
       points  means  that  the input starts off in host byte order, otherwise
       the opposite order is assumed. Again, BOMs in  the  string  can  change
       this. The final byte order is passed back at the end of processing.

       If  keep_boms  is  not  zero,  byte-order  mark characters (0xfeff) are
       patterns uses 16-bit characters.  The  pcre16_get_stringtable_entries()
       function returns the length of each entry in the table as the number of
       16-bit data units.


OPTION NAMES


       There   are   two   new   general   option   names,   PCRE_UTF16    and
       PCRE_NO_UTF16_CHECK,     which     correspond    to    PCRE_UTF8    and
       PCRE_NO_UTF8_CHECK in the 8-bit library. In  fact,  these  new  options
       define  the  same bits in the options word. There is a discussion about
       the validity of UTF-16 strings in the pcreunicode page.

       For the pcre16_config() function there is an  option  PCRE_CONFIG_UTF16
       that  returns  1  if UTF-16 support is configured, otherwise 0. If this
       option  is  given  to  pcre_config()  or  pcre32_config(),  or  if  the
       PCRE_CONFIG_UTF8  or  PCRE_CONFIG_UTF32  option is given to pcre16_con-
       fig(), the result is the PCRE_ERROR_BADOPTION error.


CHARACTER CODES


       In 16-bit mode, when  PCRE_UTF16  is  not  set,  character  values  are
       treated in the same way as in 8-bit, non UTF-8 mode, except, of course,
       that they can range from 0 to 0xffff instead of 0  to  0xff.  Character
       types  for characters less than 0xff can therefore be influenced by the
       locale in the same way as before.  Characters greater  than  0xff  have
       only one case, and no "type" (such as letter or digit).

       In  UTF-16  mode,  the  character  code  is  Unicode, in the range 0 to
       0x10ffff, with the exception of values in the range  0xd800  to  0xdfff
       because  those  are "surrogate" values that are used in pairs to encode
       values greater than 0xffff.

       A UTF-16 string can indicate its endianness by special code knows as  a
       byte-order mark (BOM). The PCRE functions do not handle this, expecting
       strings  to  be  in  host  byte  order.  A  utility   function   called
       pcre16_utf16_to_host_byte_order()  is  provided  to help with this (see
       above).


ERROR NAMES


       The errors PCRE_ERROR_BADUTF16_OFFSET and PCRE_ERROR_SHORTUTF16  corre-
       spond  to  their  8-bit  counterparts.  The error PCRE_ERROR_BADMODE is
       given when a compiled pattern is passed to a  function  that  processes
       patterns  in  the  other  mode, for example, if a pattern compiled with
       pcre_compile() is passed to pcre16_exec().

       There are new error codes whose names  begin  with  PCRE_UTF16_ERR  for
       invalid  UTF-16  strings,  corresponding to the PCRE_UTF8_ERR codes for
       UTF-8 strings that are described in the section entitled "Reason  codes
       for  invalid UTF-8 strings" in the main pcreapi page. The UTF-16 errors
       are:

       callout function point to 16-bit vectors.


TESTING


       The  pcretest  program continues to operate with 8-bit input and output
       files, but it can be used for testing the 16-bit library. If it is  run
       with the command line option -16, patterns and subject strings are con-
       verted from 8-bit to 16-bit before being passed to PCRE, and the 16-bit
       library  functions  are used instead of the 8-bit ones. Returned 16-bit
       strings are converted to 8-bit for output. If both the  8-bit  and  the
       32-bit libraries were not compiled, pcretest defaults to 16-bit and the
       -16 option is ignored.

       When PCRE is being built, the RunTest script that is  called  by  "make
       check"  uses  the  pcretest  -C  option to discover which of the 8-bit,
       16-bit and 32-bit libraries has been built, and runs the  tests  appro-
       priately.


NOT SUPPORTED IN 16-BIT MODE


       Not all the features of the 8-bit library are available with the 16-bit
       library. The C++ and POSIX wrapper functions  support  only  the  8-bit
       library, and the pcregrep program is at present 8-bit only.


AUTHOR


       Philip Hazel
       University Computing Service
       Cambridge CB2 3QH, England.


REVISION


       Last updated: 08 November 2012
       Copyright (c) 1997-2012 University of Cambridge.


PCRE 8.32 08 November 2012 PCRE(3)



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