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revision 954 by ph10, Sat Mar 31 18:09:26 2012 UTC revision 1055 by chpe, Tue Oct 16 15:53:30 2012 UTC
# Line 1  Line 1 
1  .TH PCREPRECOMPILE 3 "10 January 2012" "PCRE 8.30"  .TH PCREPRECOMPILE 3 "24 June 2012" "PCRE 8.30"
2  .SH NAME  .SH NAME
3  PCRE - Perl-compatible regular expressions  PCRE - Perl-compatible regular expressions
4  .SH "SAVING AND RE-USING PRECOMPILED PCRE PATTERNS"  .SH "SAVING AND RE-USING PRECOMPILED PCRE PATTERNS"
# Line 18  JIT data. Line 18  JIT data.
18  .P  .P
19  If you save compiled patterns to a file, you can copy them to a different host  If you save compiled patterns to a file, you can copy them to a different host
20  and run them there. If the two hosts have different endianness (byte order),  and run them there. If the two hosts have different endianness (byte order),
21  you should run the \fBpcre[16]_pattern_to_host_byte_order()\fP function on the  you should run the \fBpcre[16|32]_pattern_to_host_byte_order()\fP function on the
22  new host before trying to match the pattern. The matching functions return  new host before trying to match the pattern. The matching functions return
23  PCRE_ERROR_BADENDIANNESS if they detect a pattern with the wrong endianness.  PCRE_ERROR_BADENDIANNESS if they detect a pattern with the wrong endianness.
24  .P  .P
# Line 30  restoring a compiled pattern loses any J Line 30  restoring a compiled pattern loses any J
30  .SH "SAVING A COMPILED PATTERN"  .SH "SAVING A COMPILED PATTERN"
31  .rs  .rs
32  .sp  .sp
33  The value returned by \fBpcre[16]_compile()\fP points to a single block of  The value returned by \fBpcre[16|32]_compile()\fP points to a single block of
34  memory that holds the compiled pattern and associated data. You can find the  memory that holds the compiled pattern and associated data. You can find the
35  length of this block in bytes by calling \fBpcre[16]_fullinfo()\fP with an  length of this block in bytes by calling \fBpcre[16|32]_fullinfo()\fP with an
36  argument of PCRE_INFO_SIZE. You can then save the data in any appropriate  argument of PCRE_INFO_SIZE. You can then save the data in any appropriate
37  manner. Here is sample code for the 8-bit library that compiles a pattern and  manner. Here is sample code for the 8-bit library that compiles a pattern and
38  writes it to a file. It assumes that the variable \fIfd\fP refers to a file  writes it to a file. It assumes that the variable \fIfd\fP refers to a file
# Line 68  If the pattern has been studied, it is a Line 68  If the pattern has been studied, it is a
68  data in a similar way to the compiled pattern itself. However, if the  data in a similar way to the compiled pattern itself. However, if the
69  PCRE_STUDY_JIT_COMPILE was used, the just-in-time data that is created cannot  PCRE_STUDY_JIT_COMPILE was used, the just-in-time data that is created cannot
70  be saved because it is too dependent on the current environment. When studying  be saved because it is too dependent on the current environment. When studying
71  generates additional information, \fBpcre[16]_study()\fP returns a pointer to a  generates additional information, \fBpcre[16|32]_study()\fP returns a pointer to a
72  \fBpcre[16]_extra\fP data block. Its format is defined in the  \fBpcre[16|32]_extra\fP data block. Its format is defined in the
73  .\" HTML <a href="pcreapi.html#extradata">  .\" HTML <a href="pcreapi.html#extradata">
74  .\" </a>  .\" </a>
75  section on matching a pattern  section on matching a pattern
# Line 79  in the Line 79  in the
79  \fBpcreapi\fP  \fBpcreapi\fP
80  .\"  .\"
81  documentation. The \fIstudy_data\fP field points to the binary study data, and  documentation. The \fIstudy_data\fP field points to the binary study data, and
82  this is what you must save (not the \fBpcre[16]_extra\fP block itself). The  this is what you must save (not the \fBpcre[16|32]_extra\fP block itself). The
83  length of the study data can be obtained by calling \fBpcre[16]_fullinfo()\fP  length of the study data can be obtained by calling \fBpcre[16|32]_fullinfo()\fP
84  with an argument of PCRE_INFO_STUDYSIZE. Remember to check that  with an argument of PCRE_INFO_STUDYSIZE. Remember to check that
85  \fBpcre[16]_study()\fP did return a non-NULL value before trying to save the  \fBpcre[16|32]_study()\fP did return a non-NULL value before trying to save the
86  study data.  study data.
87  .  .
88  .  .
# Line 90  study data. Line 90  study data.
90  .rs  .rs
91  .sp  .sp
92  Re-using a precompiled pattern is straightforward. Having reloaded it into main  Re-using a precompiled pattern is straightforward. Having reloaded it into main
93  memory, called \fBpcre[16]_pattern_to_host_byte_order()\fP if necessary,  memory, called \fBpcre[16|32]_pattern_to_host_byte_order()\fP if necessary,
94  you pass its pointer to \fBpcre[16]_exec()\fP or \fBpcre[16]_dfa_exec()\fP in  you pass its pointer to \fBpcre[16|32]_exec()\fP or \fBpcre[16|32]_dfa_exec()\fP in
95  the usual way.  the usual way.
96  .P  .P
97  However, if you passed a pointer to custom character tables when the pattern  However, if you passed a pointer to custom character tables when the pattern
98  was compiled (the \fItableptr\fP argument of \fBpcre[16]_compile()\fP), you  was compiled (the \fItableptr\fP argument of \fBpcre[16|32]_compile()\fP), you
99  must now pass a similar pointer to \fBpcre[16]_exec()\fP or  must now pass a similar pointer to \fBpcre[16|32]_exec()\fP or
100  \fBpcre[16]_dfa_exec()\fP, because the value saved with the compiled pattern  \fBpcre[16|32]_dfa_exec()\fP, because the value saved with the compiled pattern
101  will obviously be nonsense. A field in a \fBpcre[16]_extra()\fP block is used  will obviously be nonsense. A field in a \fBpcre[16|32]_extra()\fP block is used
102  to pass this data, as described in the  to pass this data, as described in the
103  .\" HTML <a href="pcreapi.html#extradata">  .\" HTML <a href="pcreapi.html#extradata">
104  .\" </a>  .\" </a>
# Line 116  functions to use PCRE's internal tables. Line 116  functions to use PCRE's internal tables.
116  special action at run time in this case.  special action at run time in this case.
117  .P  .P
118  If you saved study data with the compiled pattern, you need to create your own  If you saved study data with the compiled pattern, you need to create your own
119  \fBpcre[16]_extra\fP data block and set the \fIstudy_data\fP field to point to the  \fBpcre[16|32]_extra\fP data block and set the \fIstudy_data\fP field to point to the
120  reloaded study data. You must also set the PCRE_EXTRA_STUDY_DATA bit in the  reloaded study data. You must also set the PCRE_EXTRA_STUDY_DATA bit in the
121  \fIflags\fP field to indicate that study data is present. Then pass the  \fIflags\fP field to indicate that study data is present. Then pass the
122  \fBpcre[16]_extra\fP block to the matching function in the usual way. If the  \fBpcre[16|32]_extra\fP block to the matching function in the usual way. If the
123  pattern was studied for just-in-time optimization, that data cannot be saved,  pattern was studied for just-in-time optimization, that data cannot be saved,
124  and so is lost by a save/restore cycle.  and so is lost by a save/restore cycle.
125  .  .
# Line 146  Cambridge CB2 3QH, England. Line 146  Cambridge CB2 3QH, England.
146  .rs  .rs
147  .sp  .sp
148  .nf  .nf
149  Last updated: 10 January 2012  Last updated: 24 June 2012
150  Copyright (c) 1997-2012 University of Cambridge.  Copyright (c) 1997-2012 University of Cambridge.
151  .fi  .fi

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