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revision 691 by ph10, Sun Sep 11 14:31:21 2011 UTC revision 861 by ph10, Tue Jan 10 14:54:28 2012 UTC
# Line 13  If you are not using any private charact Line 13  If you are not using any private charact
13  .\"  .\"
14  documentation), this is relatively straightforward. If you are using private  documentation), this is relatively straightforward. If you are using private
15  tables, it is a little bit more complicated. However, if you are using the  tables, it is a little bit more complicated. However, if you are using the
16  just-in-time optimization feature of \fBpcre_study()\fP, it is not possible to  just-in-time optimization feature, it is not possible to save and reload the
17  save and reload the JIT data.  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. This works even if the new host has the opposite endianness  and run them there. If the two hosts have different endianness (byte order),
21  to the one on which the patterns were compiled. There may be a small  you should run the \fBpcre[16]_pattern_to_host_byte_order()\fP function on the
22  performance penalty, but it should be insignificant. However, compiling regular  new host before trying to match the pattern. The matching functions return
23  expressions with one version of PCRE for use with a different version is not  PCRE_ERROR_BADENDIANNESS if they detect a pattern with the wrong endianness.
24  guaranteed to work and may cause crashes, and saving and restoring a compiled  .P
25  pattern loses any JIT optimization data.  Compiling regular expressions with one version of PCRE for use with a different
26    version is not guaranteed to work and may cause crashes, and saving and
27    restoring a compiled pattern loses any JIT optimization data.
28  .  .
29  .  .
30  .SH "SAVING A COMPILED PATTERN"  .SH "SAVING A COMPILED PATTERN"
31  .rs  .rs
32  .sp  .sp
33  The value returned by \fBpcre_compile()\fP points to a single block of memory  The value returned by \fBpcre[16]_compile()\fP points to a single block of
34  that holds the compiled pattern and associated data. You can find the length of  memory that holds the compiled pattern and associated data. You can find the
35  this block in bytes by calling \fBpcre_fullinfo()\fP with an argument of  length of this block in bytes by calling \fBpcre[16]_fullinfo()\fP with an
36  PCRE_INFO_SIZE. You can then save the data in any appropriate manner. Here is  argument of PCRE_INFO_SIZE. You can then save the data in any appropriate
37  sample code that compiles a pattern and writes it to a file. It assumes that  manner. Here is sample code for the 8-bit library that compiles a pattern and
38  the variable \fIfd\fP refers to a file that is open for output:  writes it to a file. It assumes that the variable \fIfd\fP refers to a file
39    that is open for output:
40  .sp  .sp
41    int erroroffset, rc, size;    int erroroffset, rc, size;
42    char *error;    char *error;
# Line 65  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_study()\fP returns a pointer to a  generates additional information, \fBpcre[16]_study()\fP returns a pointer to a
72  \fBpcre_extra\fP data block. Its format is defined in the  \fBpcre[16]_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 76  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_extra\fP block itself). The length  this is what you must save (not the \fBpcre[16]_extra\fP block itself). The
83  of the study data can be obtained by calling \fBpcre_fullinfo()\fP with an  length of the study data can be obtained by calling \fBpcre[16]_fullinfo()\fP
84  argument of PCRE_INFO_STUDYSIZE. Remember to check that \fBpcre_study()\fP did  with an argument of PCRE_INFO_STUDYSIZE. Remember to check that
85  return a non-NULL value before trying to save the study data.  \fBpcre[16]_study()\fP did return a non-NULL value before trying to save the
86    study data.
87  .  .
88  .  .
89  .SH "RE-USING A PRECOMPILED PATTERN"  .SH "RE-USING A PRECOMPILED PATTERN"
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, you pass its pointer to \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP in  memory, called \fBpcre[16]_pattern_to_host_byte_order()\fP if necessary,
94  the usual way. This should work even on another host, and even if that host has  you pass its pointer to \fBpcre[16]_exec()\fP or \fBpcre[16]_dfa_exec()\fP in
95  the opposite endianness to the one where the pattern was compiled.  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_compile()\fP), you must  was compiled (the \fItableptr\fP argument of \fBpcre[16]_compile()\fP), you
99  now pass a similar pointer to \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP,  must now pass a similar pointer to \fBpcre[16]_exec()\fP or
100  because the value saved with the compiled pattern will obviously be nonsense. A  \fBpcre[16]_dfa_exec()\fP, because the value saved with the compiled pattern
101  field in a \fBpcre_extra()\fP block is used to pass this data, as described in  will obviously be nonsense. A field in a \fBpcre[16]_extra()\fP block is used
102  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>
105  section on matching a pattern  section on matching a pattern
# Line 107  in the Line 111  in the
111  documentation.  documentation.
112  .P  .P
113  If you did not provide custom character tables when the pattern was compiled,  If you did not provide custom character tables when the pattern was compiled,
114  the pointer in the compiled pattern is NULL, which causes \fBpcre_exec()\fP to  the pointer in the compiled pattern is NULL, which causes the matching
115  use PCRE's internal tables. Thus, you do not need to take any special action at  functions to use PCRE's internal tables. Thus, you do not need to take any
116  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_extra\fP data block and set the \fIstudy_data\fP field to point to the  \fBpcre[16]_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_extra\fP block to \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP in the  \fBpcre[16]_extra\fP block to the matching function in the usual way. If the
123  usual way. If the pattern was studied for just-in-time optimization, that data  pattern was studied for just-in-time optimization, that data cannot be saved,
124  cannot be saved, and so is lost by a save/restore cycle.  and so is lost by a save/restore cycle.
125  .  .
126  .  .
127  .SH "COMPATIBILITY WITH DIFFERENT PCRE RELEASES"  .SH "COMPATIBILITY WITH DIFFERENT PCRE RELEASES"
# Line 142  Cambridge CB2 3QH, England. Line 146  Cambridge CB2 3QH, England.
146  .rs  .rs
147  .sp  .sp
148  .nf  .nf
149  Last updated: 26 August 2011  Last updated: 10 January 2012
150  Copyright (c) 1997-2011 University of Cambridge.  Copyright (c) 1997-2012 University of Cambridge.
151  .fi  .fi

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