1 <!-- $Id: tools.xml,v 1.43 2004-12-13 20:17:41 adam Exp $ -->
2 <chapter id="tools"><title>Supporting Tools</title>
5 In support of the service API - primarily the ASN module, which
6 provides the pro-grammatic interface to the Z39.50 APDUs, &yaz; contains
7 a collection of tools that support the development of applications.
10 <sect1 id="tools.query"><title>Query Syntax Parsers</title>
13 Since the type-1 (RPN) query structure has no direct, useful string
14 representation, every origin application needs to provide some form of
15 mapping from a local query notation or representation to a
16 <token>Z_RPNQuery</token> structure. Some programmers will prefer to
17 construct the query manually, perhaps using
18 <function>odr_malloc()</function> to simplify memory management.
19 The &yaz; distribution includes three separate, query-generating tools
20 that may be of use to you.
23 <sect2 id="PQF"><title>Prefix Query Format</title>
26 Since RPN or reverse polish notation is really just a fancy way of
27 describing a suffix notation format (operator follows operands), it
28 would seem that the confusion is total when we now introduce a prefix
29 notation for RPN. The reason is one of simple laziness - it's somewhat
30 simpler to interpret a prefix format, and this utility was designed
31 for maximum simplicity, to provide a baseline representation for use
32 in simple test applications and scripting environments (like Tcl). The
33 demonstration client included with YAZ uses the PQF.
38 The PQF have been adopted by other parties developing Z39.50
39 software. It is often referred to as Prefix Query Notation
44 The PQF is defined by the pquery module in the YAZ library.
45 There are two sets of function that have similar behavior. First
46 set operates on a PQF parser handle, second set doesn't. First set
47 set of functions are more flexible than the second set. Second set
48 is obsolete and is only provided to ensure backwards compatibility.
51 First set of functions all operate on a PQF parser handle:
54 #include <yaz/pquery.h>
56 YAZ_PQF_Parser yaz_pqf_create (void);
58 void yaz_pqf_destroy (YAZ_PQF_Parser p);
60 Z_RPNQuery *yaz_pqf_parse (YAZ_PQF_Parser p, ODR o, const char *qbuf);
62 Z_AttributesPlusTerm *yaz_pqf_scan (YAZ_PQF_Parser p, ODR o,
63 Odr_oid **attributeSetId, const char *qbuf);
66 int yaz_pqf_error (YAZ_PQF_Parser p, const char **msg, size_t *off);
69 A PQF parser is created and destructed by functions
70 <function>yaz_pqf_create</function> and
71 <function>yaz_pqf_destroy</function> respectively.
72 Function <function>yaz_pqf_parse</function> parses query given
73 by string <literal>qbuf</literal>. If parsing was successful,
74 a Z39.50 RPN Query is returned which is created using ODR stream
75 <literal>o</literal>. If parsing failed, a NULL pointer is
77 Function <function>yaz_pqf_scan</function> takes a scan query in
78 <literal>qbuf</literal>. If parsing was successful, the function
79 returns attributes plus term pointer and modifies
80 <literal>attributeSetId</literal> to hold attribute set for the
81 scan request - both allocated using ODR stream <literal>o</literal>.
82 If parsing failed, yaz_pqf_scan returns a NULL pointer.
83 Error information for bad queries can be obtained by a call to
84 <function>yaz_pqf_error</function> which returns an error code and
85 modifies <literal>*msg</literal> to point to an error description,
86 and modifies <literal>*off</literal> to the offset within last
87 query were parsing failed.
90 The second set of functions are declared as follows:
93 #include <yaz/pquery.h>
95 Z_RPNQuery *p_query_rpn (ODR o, oid_proto proto, const char *qbuf);
97 Z_AttributesPlusTerm *p_query_scan (ODR o, oid_proto proto,
98 Odr_oid **attributeSetP, const char *qbuf);
100 int p_query_attset (const char *arg);
103 The function <function>p_query_rpn()</function> takes as arguments an
104 &odr; stream (see section <link linkend="odr">The ODR Module</link>)
105 to provide a memory source (the structure created is released on
106 the next call to <function>odr_reset()</function> on the stream), a
107 protocol identifier (one of the constants <token>PROTO_Z3950</token> and
108 <token>PROTO_SR</token>), an attribute set reference, and
109 finally a null-terminated string holding the query string.
112 If the parse went well, <function>p_query_rpn()</function> returns a
113 pointer to a <literal>Z_RPNQuery</literal> structure which can be
114 placed directly into a <literal>Z_SearchRequest</literal>.
115 If parsing failed, due to syntax error, a NULL pointer is returned.
118 The <literal>p_query_attset</literal> specifies which attribute set
119 to use if the query doesn't specify one by the
120 <literal>@attrset</literal> operator.
121 The <literal>p_query_attset</literal> returns 0 if the argument is a
122 valid attribute set specifier; otherwise the function returns -1.
126 The grammar of the PQF is as follows:
130 query ::= top-set query-struct.
132 top-set ::= [ '@attrset' string ]
134 query-struct ::= attr-spec | simple | complex | '@term' term-type query
136 attr-spec ::= '@attr' [ string ] string query-struct
138 complex ::= operator query-struct query-struct.
140 operator ::= '@and' | '@or' | '@not' | '@prox' proximity.
142 simple ::= result-set | term.
144 result-set ::= '@set' string.
148 proximity ::= exclusion distance ordered relation which-code unit-code.
150 exclusion ::= '1' | '0' | 'void'.
152 distance ::= integer.
154 ordered ::= '1' | '0'.
156 relation ::= integer.
158 which-code ::= 'known' | 'private' | integer.
160 unit-code ::= integer.
162 term-type ::= 'general' | 'numeric' | 'string' | 'oid' | 'datetime' | 'null'.
166 You will note that the syntax above is a fairly faithful
167 representation of RPN, except for the Attribute, which has been
168 moved a step away from the term, allowing you to associate one or more
169 attributes with an entire query structure. The parser will
170 automatically apply the given attributes to each term as required.
174 The @attr operator is followed by an attribute specification
175 (<literal>attr-spec</literal> above). The specification consists
176 of an optional attribute set, an attribute type-value pair and
177 a sub-query. The attribute type-value pair is packed in one string:
178 an attribute type, an equals sign, and an attribute value, like this:
179 <literal>@attr 1=1003</literal>.
180 The type is always an integer but the value may be either an
181 integer or a string (if it doesn't start with a digit character).
182 A string attribute-value is encoded as a Type-1 ``complex''
183 attribute with the list of values containing the single string
184 specified, and including no semantic indicators.
188 Version 3 of the Z39.50 specification defines various encoding of terms.
189 Use <literal>@term </literal> <replaceable>type</replaceable>
190 <replaceable>string</replaceable>,
191 where type is one of: <literal>general</literal>,
192 <literal>numeric</literal> or <literal>string</literal>
193 (for InternationalString).
194 If no term type has been given, the <literal>general</literal> form
195 is used. This is the only encoding allowed in both versions 2 and 3
196 of the Z39.50 standard.
199 <sect3 id="PQF-prox">
200 <title>Using Proximity Operators with PQF</title>
203 This is an advanced topic, describing how to construct
204 queries that make very specific requirements on the
205 relative location of their operands.
206 You may wish to skip this section and go straight to
207 <link linkend="pqf-examples">the example PQF queries</link>.
212 Most Z39.50 servers do not support proximity searching, or
213 support only a small subset of the full functionality that
214 can be expressed using the PQF proximity operator. Be
215 aware that the ability to <emphasis>express</emphasis> a
216 query in PQF is no guarantee that any given server will
217 be able to <emphasis>execute</emphasis> it.
223 The proximity operator <literal>@prox</literal> is a special
224 and more restrictive version of the conjunction operator
225 <literal>@and</literal>. Its semantics are described in
226 section 3.7.2 (Proximity) of Z39.50 the standard itself, which
227 can be read on-line at
228 <ulink url="http://lcweb.loc.gov/z3950/agency/markup/09.html"/>
231 In PQF, the proximity operation is represented by a sequence
234 @prox <replaceable>exclusion</replaceable> <replaceable>distance</replaceable> <replaceable>ordered</replaceable> <replaceable>relation</replaceable> <replaceable>which-code</replaceable> <replaceable>unit-code</replaceable>
236 in which the meanings of the parameters are as described in in
237 the standard, and they can take the following values:
239 <listitem><formalpara><title>exclusion</title><para>
240 0 = false (i.e. the proximity condition specified by the
241 remaining parameters must be satisfied) or
242 1 = true (the proximity condition specified by the
243 remaining parameters must <emphasis>not</emphasis> be
245 </para></formalpara></listitem>
246 <listitem><formalpara><title>distance</title><para>
247 An integer specifying the difference between the locations
248 of the operands: e.g. two adjacent words would have
249 distance=1 since their locations differ by one unit.
250 </para></formalpara></listitem>
251 <listitem><formalpara><title>ordered</title><para>
252 1 = ordered (the operands must occur in the order the
253 query specifies them) or
254 0 = unordered (they may appear in either order).
255 </para></formalpara></listitem>
256 <listitem><formalpara><title>relation</title><para>
257 Recognised values are
261 4 (greaterThanOrEqual),
264 </para></formalpara></listitem>
265 <listitem><formalpara><title>which-code</title><para>
266 <literal>known</literal>
269 (the unit-code parameter is taken from the well-known list
270 of alternatives described in below) or
271 <literal>private</literal>
274 (the unit-code paramater has semantics specific to an
275 out-of-band agreement such as a profile).
276 </para></formalpara></listitem>
277 <listitem><formalpara><title>unit-code</title><para>
278 If the which-code parameter is <literal>known</literal>
279 then the recognised values are
291 If which-code is <literal>private</literal> then the
292 acceptable values are determined by the profile.
293 </para></formalpara></listitem>
295 (The numeric values of the relation and well-known unit-code
296 parameters are taken straight from
297 <ulink url="http://lcweb.loc.gov/z3950/agency/asn1.html#ProximityOperator"
298 >the ASN.1</ulink> of the proximity structure in the standard.)
302 <sect3 id="pqf-examples"><title>PQF queries</title>
304 <example><title>PQF queries using simple terms</title>
312 <example><title>PQF boolean operators</title>
315 @or "dylan" "zimmerman"
316 @and @or dylan zimmerman when
317 @and when @or dylan zimmerman
321 <example><title>PQF references to result sets</title>
329 <example><title>Attributes for terms</title>
333 @attr 1=4 @attr 4=1 "self portrait"
334 @attrset exp1 @attr 1=1 CategoryList
335 @attr gils 1=2008 Copenhagen
336 @attr 1=/book/title computer
340 <example><title>PQF Proximity queries</title>
343 @prox 0 3 1 2 k 2 dylan zimmerman
346 Here the parameters 0, 3, 1, 2, k and 2 represent exclusion,
347 distance, ordered, relation, which-code and unit-code, in that
351 exclusion = 0: the proximity condition must hold
354 distance = 3: the terms must be three units apart
357 ordered = 1: they must occur in the order they are specified
360 relation = 2: lessThanOrEqual (to the distance of 3 units)
363 which-code is ``known'', so the standard unit-codes are used
369 So the whole proximity query means that the words
370 <literal>dylan</literal> and <literal>zimmerman</literal> must
371 both occur in the record, in that order, differing in position
372 by three or fewer words (i.e. with two or fewer words between
373 them.) The query would find ``Bob Dylan, aka. Robert
374 Zimmerman'', but not ``Bob Dylan, born as Robert Zimmerman''
375 since the distance in this case is four.
379 <example><title>PQF specification of search term</title>
382 @term string "a UTF-8 string, maybe?"
386 <example><title>PQF mixed queries</title>
389 @or @and bob dylan @set Result-1
391 @attr 4=1 @and @attr 1=1 "bob dylan" @attr 1=4 "slow train coming"
393 @and @attr 2=4 @attr gils 1=2038 -114 @attr 2=2 @attr gils 1=2039 -109
397 The last of these examples is a spatial search: in
398 <ulink url="http://www.gils.net/prof_v2.html#sec_7_4"
399 >the GILS attribute set</ulink>,
401 2038 indicates West Bounding Coordinate and
402 2030 indicates East Bounding Coordinate,
403 so the query is for areas extending from -114 degrees
404 to no more than -109 degrees.
411 <sect2 id="CCL"><title>CCL</title>
414 Not all users enjoy typing in prefix query structures and numerical
415 attribute values, even in a minimalistic test client. In the library
416 world, the more intuitive Common Command Language - CCL (ISO 8777)
417 has enjoyed some popularity - especially before the widespread
418 availability of graphical interfaces. It is still useful in
419 applications where you for some reason or other need to provide a
420 symbolic language for expressing boolean query structures.
424 The EUROPAGATE research project working under the Libraries programme
425 of the European Commission's DG XIII has, amongst other useful tools,
426 implemented a general-purpose CCL parser which produces an output
427 structure that can be trivially converted to the internal RPN
428 representation of &yaz; (The <literal>Z_RPNQuery</literal> structure).
429 Since the CCL utility - along with the rest of the software
430 produced by EUROPAGATE - is made freely available on a liberal
431 license, it is included as a supplement to &yaz;.
434 <sect3><title>CCL Syntax</title>
437 The CCL parser obeys the following grammar for the FIND argument.
438 The syntax is annotated by in the lines prefixed by
439 <literal>‐‐</literal>.
443 CCL-Find ::= CCL-Find Op Elements
446 Op ::= "and" | "or" | "not"
447 -- The above means that Elements are separated by boolean operators.
449 Elements ::= '(' CCL-Find ')'
452 | Qualifiers Relation Terms
453 | Qualifiers Relation '(' CCL-Find ')'
454 | Qualifiers '=' string '-' string
455 -- Elements is either a recursive definition, a result set reference, a
456 -- list of terms, qualifiers followed by terms, qualifiers followed
457 -- by a recursive definition or qualifiers in a range (lower - upper).
459 Set ::= 'set' = string
460 -- Reference to a result set
462 Terms ::= Terms Prox Term
464 -- Proximity of terms.
468 -- This basically means that a term may include a blank
470 Qualifiers ::= Qualifiers ',' string
472 -- Qualifiers is a list of strings separated by comma
474 Relation ::= '=' | '>=' | '<=' | '<>' | '>' | '<'
475 -- Relational operators. This really doesn't follow the ISO8777
479 -- Proximity operator
483 <example><title>CCL queries</title>
485 The following queries are all valid:
497 (dylan and bob) or set=1
501 Assuming that the qualifiers <literal>ti</literal>,
502 <literal>au</literal>
503 and <literal>date</literal> are defined we may use:
509 au=(bob dylan and slow train coming)
511 date>1980 and (ti=((self portrait)))
517 <sect3><title>CCL Qualifiers</title>
520 Qualifiers are used to direct the search to a particular searchable
521 index, such as title (ti) and author indexes (au). The CCL standard
522 itself doesn't specify a particular set of qualifiers, but it does
523 suggest a few short-hand notations. You can customize the CCL parser
524 to support a particular set of qualifiers to reflect the current target
525 profile. Traditionally, a qualifier would map to a particular
526 use-attribute within the BIB-1 attribute set. It is also
527 possible to set other attributes, such as the structure
532 A CCL profile is a set of predefined CCL qualifiers that may be
533 read from a file or set in the CCL API.
534 The YAZ client reads its CCL qualifiers from a file named
535 <filename>default.bib</filename>. There are four types of
536 lines in a CCL profile: qualifier specification,
537 qualifier alias, comments and directives.
539 <sect4><title id="qualifier-specification">Qualifier specification</title>
541 A qualifier specification is of the form:
545 <replaceable>qualifier-name</replaceable>
546 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable>
547 [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable> ...
551 where <replaceable>qualifier-name</replaceable> is the name of the
552 qualifier to be used (eg. <literal>ti</literal>),
553 <replaceable>type</replaceable> is attribute type in the attribute
554 set (Bib-1 is used if no attribute set is given) and
555 <replaceable>val</replaceable> is attribute value.
556 The <replaceable>type</replaceable> can be specified as an
557 integer or as it be specified either as a single-letter:
558 <literal>u</literal> for use,
559 <literal>r</literal> for relation,<literal>p</literal> for position,
560 <literal>s</literal> for structure,<literal>t</literal> for truncation
561 or <literal>c</literal> for completeness.
562 The attributes for the special qualifier name <literal>term</literal>
563 are used when no CCL qualifier is given in a query.
564 <table><title>Common Bib-1 attributes</title>
566 <colspec colwidth="2*" colname="type"></colspec>
567 <colspec colwidth="9*" colname="description"></colspec>
571 <entry>Description</entry>
576 <entry><literal>u=</literal><replaceable>value</replaceable></entry>
578 Use attribute (1). Common use attributes are
579 1 Personal-name, 4 Title, 7 ISBN, 8 ISSN, 30 Date,
580 62 Subject, 1003 Author), 1016 Any. Specify value
586 <entry><literal>r=</literal><replaceable>value</replaceable></entry>
588 Relation attribute (2). Common values are
589 1 <, 2 <=, 3 =, 4 >=, 5 >, 6 <>,
590 100 phonetic, 101 stem, 102 relevance, 103 always matches.
595 <entry><literal>p=</literal><replaceable>value</replaceable></entry>
597 Position attribute (3). Values: 1 first in field, 2
598 first in any subfield, 3 any position in field.
603 <entry><literal>s=</literal><replaceable>value</replaceable></entry>
605 Structure attribute (4). Values: 1 phrase, 2 word,
606 3 key, 4 year, 5 date, 6 word list, 100 date (un),
607 101 name (norm), 102 name (un), 103 structure, 104 urx,
608 105 free-form-text, 106 document-text, 107 local-number,
609 108 string, 109 numeric string.
614 <entry><literal>t=</literal><replaceable>value</replaceable></entry>
616 Truncation attribute (5). Values: 1 right, 2 left,
617 3 left& right, 100 none, 101 process #, 102 regular-1,
618 103 regular-2, 104 CCL.
623 <entry><literal>c=</literal><replaceable>value</replaceable></entry>
625 Completeness attribute (6). Values: 1 incomplete subfield,
626 2 complete subfield, 3 complete field.
635 The complete list of Bib-1 attributes can be found
636 <ulink url="http://lcweb.loc.gov/z3950/agency/defns/bib1.html">
641 It is also possible to specify non-numeric attribute values,
642 which are used in combination with certain types.
643 The special combinations are:
645 <table><title>Special attribute combos</title>
647 <colspec colwidth="2*" colname="name"></colspec>
648 <colspec colwidth="9*" colname="description"></colspec>
652 <entry>Description</entry>
657 <entry><literal>s=pw</literal></entry><entry>
658 The structure is set to either word or phrase depending
659 on the number of tokens in a term (phrase-word).
663 <entry><literal>s=al</literal></entry><entry>
664 Each token in the term is ANDed. (and-list).
665 This does not set the structure at all.
669 <row><entry><literal>s=ol</literal></entry><entry>
670 Each token in the term is ORed. (or-list).
671 This does not set the structure at all.
675 <row><entry><literal>r=o</literal></entry><entry>
676 Allows ranges and the operators greather-than, less-than, ...
678 This sets Bib-1 relation attribute accordingly (relation
679 ordered). A query construct is only treated as a range if
680 dash is used and that is surrounded by white-space. So
681 <literal>-1980</literal> is treated as term
682 <literal>"-1980"</literal> not <literal><= 1980</literal>.
683 If <literal>- 1980</literal> is used, however, that is
688 <row><entry><literal>r=r</literal></entry><entry>
689 Similar to <literal>r=o</literal> but assumes that terms
690 are non-negative (not prefixed with <literal>-</literal>).
691 Thus, a dash will always be treated as a range.
692 The construct <literal>1980-1990</literal> is
693 treated as a range with <literal>r=r</literal> but as a
694 single term <literal>"1980-1990"</literal> with
695 <literal>r=o</literal>. The special attribute
696 <literal>r=r</literal> is available in YAZ 2.0.24 or later.
700 <row><entry><literal>t=l</literal></entry><entry>
701 Allows term to be left-truncated.
702 If term is of the form <literal>?x</literal>, the resulting
703 Type-1 term is <literal>x</literal> and truncation is left.
707 <row><entry><literal>t=r</literal></entry><entry>
708 Allows term to be right-truncated.
709 If term is of the form <literal>x?</literal>, the resulting
710 Type-1 term is <literal>x</literal> and truncation is right.
714 <row><entry><literal>t=n</literal></entry><entry>
715 If term is does not include <literal>?</literal>, the
716 truncation attribute is set to none (100).
720 <row><entry><literal>t=b</literal></entry><entry>
721 Allows term to be both left&right truncated.
722 If term is of the form <literal>?x?</literal>, the
723 resulting term is <literal>x</literal> and trunctation is
724 set to both left&right.
731 <example><title>CCL profile</title>
733 Consider the following definition:
744 <literal>ti</literal> and <literal>au</literal> both set
745 structure attribute to phrase (s=1).
746 <literal>ti</literal>
747 sets the use-attribute to 4. <literal>au</literal> sets the
749 When no qualifiers are used in the query the structure-attribute is
750 set to free-form-text (105) (rule for <literal>term</literal>).
751 The <literal>date</literal> sets the relation attribute to
752 the relation used in the CCL query and sets the use attribute
756 You can combine attributes. To Search for "ranked title" you
759 ti,ranked=knuth computer
761 which will set relation=ranked, use=title, structure=phrase.
768 is a valid query. But
776 <sect4><title>Qualifier alias</title>
778 A qualifier alias is of the form:
781 <replaceable>q</replaceable>
782 <replaceable>q1</replaceable> <replaceable>q2</replaceable> ..
785 which declares <replaceable>q</replaceable> to
786 be an alias for <replaceable>q1</replaceable>,
787 <replaceable>q2</replaceable>... such that the CCL
788 query <replaceable>q=x</replaceable> is equivalent to
789 <replaceable>q1=x or q2=x or ...</replaceable>.
793 <sect4><title>Comments</title>
795 Lines with white space or lines that begin with
796 character <literal>#</literal> are treated as comments.
800 <sect4><title>Directives</title>
802 Directive specifications takes the form
804 <para><literal>@</literal><replaceable>directive</replaceable> <replaceable>value</replaceable>
806 <table><title>CCL directives</title>
808 <colspec colwidth="2*" colname="name"></colspec>
809 <colspec colwidth="8*" colname="description"></colspec>
810 <colspec colwidth="1*" colname="default"></colspec>
814 <entry>Description</entry>
815 <entry>Default</entry>
820 <entry>truncation</entry>
821 <entry>Truncation character</entry>
822 <entry><literal>?</literal></entry>
826 <entry>Specifies how multiple fields are to be
827 combined. There are two modes: <literal>or</literal>:
828 multiple qualifier fields are ORed,
829 <literal>merge</literal>: attributes for the qualifier
830 fields are merged and assigned to one term.
832 <entry><literal>merge</literal></entry>
836 <entry>Specificies if CCL operatores and qualifiers should be
837 compared with case sensitivity or not. Specify 0 for
838 case sensitive; 1 for case insensitive.</entry>
839 <entry><literal>0</literal></entry>
844 <entry>Specifies token for CCL operator AND.</entry>
845 <entry><literal>and</literal></entry>
850 <entry>Specifies token for CCL operator OR.</entry>
851 <entry><literal>or</literal></entry>
856 <entry>Specifies token for CCL operator NOT.</entry>
857 <entry><literal>not</literal></entry>
862 <entry>Specifies token for CCL operator SET.</entry>
863 <entry><literal>set</literal></entry>
870 <sect3><title>CCL API</title>
872 All public definitions can be found in the header file
873 <filename>ccl.h</filename>. A profile identifier is of type
874 <literal>CCL_bibset</literal>. A profile must be created with the call
875 to the function <function>ccl_qual_mk</function> which returns a profile
876 handle of type <literal>CCL_bibset</literal>.
880 To read a file containing qualifier definitions the function
881 <function>ccl_qual_file</function> may be convenient. This function
882 takes an already opened <literal>FILE</literal> handle pointer as
883 argument along with a <literal>CCL_bibset</literal> handle.
887 To parse a simple string with a FIND query use the function
890 struct ccl_rpn_node *ccl_find_str (CCL_bibset bibset, const char *str,
891 int *error, int *pos);
894 which takes the CCL profile (<literal>bibset</literal>) and query
895 (<literal>str</literal>) as input. Upon successful completion the RPN
896 tree is returned. If an error occur, such as a syntax error, the integer
897 pointed to by <literal>error</literal> holds the error code and
898 <literal>pos</literal> holds the offset inside query string in which
903 An English representation of the error may be obtained by calling
904 the <literal>ccl_err_msg</literal> function. The error codes are
905 listed in <filename>ccl.h</filename>.
909 To convert the CCL RPN tree (type
910 <literal>struct ccl_rpn_node *</literal>)
911 to the Z_RPNQuery of YAZ the function <function>ccl_rpn_query</function>
912 must be used. This function which is part of YAZ is implemented in
913 <filename>yaz-ccl.c</filename>.
914 After calling this function the CCL RPN tree is probably no longer
915 needed. The <literal>ccl_rpn_delete</literal> destroys the CCL RPN tree.
919 A CCL profile may be destroyed by calling the
920 <function>ccl_qual_rm</function> function.
924 The token names for the CCL operators may be changed by setting the
925 globals (all type <literal>char *</literal>)
926 <literal>ccl_token_and</literal>, <literal>ccl_token_or</literal>,
927 <literal>ccl_token_not</literal> and <literal>ccl_token_set</literal>.
928 An operator may have aliases, i.e. there may be more than one name for
929 the operator. To do this, separate each alias with a space character.
933 <sect2 id="tools.cql"><title>CQL</title>
935 <ulink url="http://www.loc.gov/z3950/agency/zing/cql/">CQL</ulink>
936 - Common Query Language - was defined for the
937 <ulink url="http://www.loc.gov/z3950/agency/zing/srw/">SRW</ulink>
939 In many ways CQL has a similar syntax to CCL.
940 The objective of CQL is different. Where CCL aims to be
941 an end-user language, CQL is <emphasis>the</emphasis> protocol
942 query language for SRW.
946 If you are new to CQL, read the
947 <ulink url="http://zing.z3950.org/cql/intro.html">Gentle
948 Introduction</ulink>.
952 The CQL parser in &yaz; provides the following:
956 It parses and validates a CQL query.
961 It generates a C structure that allows you to convert
962 a CQL query to some other query language, such as SQL.
967 The parser converts a valid CQL query to PQF, thus providing a
968 way to use CQL for both SRW/SRU servers and Z39.50 targets at the
974 The parser converts CQL to
975 <ulink url="http://www.loc.gov/z3950/agency/zing/cql/xcql.html">
977 XCQL is an XML representation of CQL.
978 XCQL is part of the SRW specification. However, since SRU
979 supports CQL only, we don't expect XCQL to be widely used.
980 Furthermore, CQL has the advantage over XCQL that it is
986 <sect3 id="tools.cql.parsing"><title>CQL parsing</title>
988 A CQL parser is represented by the <literal>CQL_parser</literal>
989 handle. Its contents should be considered &yaz; internal (private).
991 #include <yaz/cql.h>
993 typedef struct cql_parser *CQL_parser;
995 CQL_parser cql_parser_create(void);
996 void cql_parser_destroy(CQL_parser cp);
998 A parser is created by <function>cql_parser_create</function> and
999 is destroyed by <function>cql_parser_destroy</function>.
1002 To parse a CQL query string, the following function
1005 int cql_parser_string(CQL_parser cp, const char *str);
1007 A CQL query is parsed by the <function>cql_parser_string</function>
1008 which takes a query <parameter>str</parameter>.
1009 If the query was valid (no syntax errors), then zero is returned;
1010 otherwise -1 is returned to indicate a syntax error.
1014 int cql_parser_stream(CQL_parser cp,
1015 int (*getbyte)(void *client_data),
1016 void (*ungetbyte)(int b, void *client_data),
1019 int cql_parser_stdio(CQL_parser cp, FILE *f);
1021 The functions <function>cql_parser_stream</function> and
1022 <function>cql_parser_stdio</function> parses a CQL query
1023 - just like <function>cql_parser_string</function>.
1024 The only difference is that the CQL query can be
1025 fed to the parser in different ways.
1026 The <function>cql_parser_stream</function> uses a generic
1027 byte stream as input. The <function>cql_parser_stdio</function>
1028 uses a <literal>FILE</literal> handle which is opened for reading.
1032 <sect3 id="tools.cql.tree"><title>CQL tree</title>
1034 The the query string is valid, the CQL parser
1035 generates a tree representing the structure of the
1040 struct cql_node *cql_parser_result(CQL_parser cp);
1042 <function>cql_parser_result</function> returns the
1043 a pointer to the root node of the resulting tree.
1046 Each node in a CQL tree is represented by a
1047 <literal>struct cql_node</literal>.
1048 It is defined as follows:
1050 #define CQL_NODE_ST 1
1051 #define CQL_NODE_BOOL 2
1061 struct cql_node *modifiers;
1065 struct cql_node *left;
1066 struct cql_node *right;
1067 struct cql_node *modifiers;
1072 There are two node types: search term (ST) and boolean (BOOL).
1073 A modifier is treated as a search term too.
1076 The search term node has five members:
1080 <literal>index</literal>: index for search term.
1081 If an index is unspecified for a search term,
1082 <literal>index</literal> will be NULL.
1085 <literal>index_uri</literal>: index URi for search term
1086 or NULL if none could be resolved for the index.
1091 <literal>term</literal>: the search term itself.
1096 <literal>relation</literal>: relation for search term.
1101 <literal>relation_uri</literal>: relation URI for search term.
1106 <literal>modifiers</literal>: relation modifiers for search
1107 term. The <literal>modifiers</literal> list itself of cql_nodes
1108 each of type <literal>ST</literal>.
1115 The boolean node represents both <literal>and</literal>,
1116 <literal>or</literal>, not as well as
1121 <literal>left</literal> and <literal>right</literal>: left
1122 - and right operand respectively.
1127 <literal>modifiers</literal>: proximity arguments.
1134 <sect3 id="tools.cql.pqf"><title>CQL to PQF conversion</title>
1136 Conversion to PQF (and Z39.50 RPN) is tricky by the fact
1137 that the resulting RPN depends on the Z39.50 target
1138 capabilities (combinations of supported attributes).
1139 In addition, the CQL and SRW operates on index prefixes
1140 (URI or strings), whereas the RPN uses Object Identifiers
1144 The CQL library of &yaz; defines a <literal>cql_transform_t</literal>
1145 type. It represents a particular mapping between CQL and RPN.
1146 This handle is created and destroyed by the functions:
1148 cql_transform_t cql_transform_open_FILE (FILE *f);
1149 cql_transform_t cql_transform_open_fname(const char *fname);
1150 void cql_transform_close(cql_transform_t ct);
1152 The first two functions create a tranformation handle from
1153 either an already open FILE or from a filename respectively.
1156 The handle is destroyed by <function>cql_transform_close</function>
1157 in which case no further reference of the handle is allowed.
1160 When a <literal>cql_transform_t</literal> handle has been created
1161 you can convert to RPN.
1163 int cql_transform_buf(cql_transform_t ct,
1164 struct cql_node *cn, char *out, int max);
1166 This function converts the CQL tree <literal>cn</literal>
1167 using handle <literal>ct</literal>.
1168 For the resulting PQF, you supply a buffer <literal>out</literal>
1169 which must be able to hold at at least <literal>max</literal>
1173 If conversion failed, <function>cql_transform_buf</function>
1174 returns a non-zero SRW error code; otherwise zero is returned
1175 (conversion successful). The meanings of the numeric error
1176 codes are listed in the SRW specifications at
1177 <ulink url="http://www.loc.gov/srw/diagnostic-list.html"/>
1180 If conversion fails, more information can be obtained by calling
1182 int cql_transform_error(cql_transform_t ct, char **addinfop);
1184 This function returns the most recently returned numeric
1185 error-code and sets the string-pointer at
1186 <literal>*addinfop</literal> to point to a string containing
1187 additional information about the error that occurred: for
1188 example, if the error code is 15 (``Illegal or unsupported context
1189 set''), the additional information is the name of the requested
1190 context set that was not recognised.
1193 The SRW error-codes may be translated into brief human-readable
1194 error messages using
1196 const char *cql_strerror(int code);
1200 If you wish to be able to produce a PQF result in a different
1201 way, there are two alternatives.
1203 void cql_transform_pr(cql_transform_t ct,
1204 struct cql_node *cn,
1205 void (*pr)(const char *buf, void *client_data),
1208 int cql_transform_FILE(cql_transform_t ct,
1209 struct cql_node *cn, FILE *f);
1211 The former function produces output to a user-defined
1212 output stream. The latter writes the result to an already
1213 open <literal>FILE</literal>.
1216 <sect3 id="tools.cql.map">
1217 <title>Specification of CQL to RPN mapping</title>
1219 The file supplied to functions
1220 <function>cql_transform_open_FILE</function>,
1221 <function>cql_transform_open_fname</function> follows
1222 a structure found in many Unix utilities.
1223 It consists of mapping specifications - one per line.
1224 Lines starting with <literal>#</literal> are ignored (comments).
1227 Each line is of the form
1229 <replaceable>CQL pattern</replaceable><literal> = </literal> <replaceable> RPN equivalent</replaceable>
1233 An RPN pattern is a simple attribute list. Each attribute pair
1236 [<replaceable>set</replaceable>] <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>
1238 The attribute <replaceable>set</replaceable> is optional.
1239 The <replaceable>type</replaceable> is the attribute type,
1240 <replaceable>value</replaceable> the attribute value.
1243 The following CQL patterns are recognized:
1245 <varlistentry><term>
1246 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
1250 This pattern is invoked when a CQL index, such as
1251 dc.title is converted. <replaceable>set</replaceable>
1252 and <replaceable>name</replaceable> are the context set and index
1254 Typically, the RPN specifies an equivalent use attribute.
1257 For terms not bound by an index the pattern
1258 <literal>index.cql.serverChoice</literal> is used.
1259 Here, the prefix <literal>cql</literal> is defined as
1260 <literal>http://www.loc.gov/zing/cql/cql-indexes/v1.0/</literal>.
1261 If this pattern is not defined, the mapping will fail.
1265 <varlistentry><term>
1266 <literal>qualifier.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
1271 For backwards compatibility, this is recognised as a synonym of
1272 <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
1276 <varlistentry><term>
1277 <literal>relation.</literal><replaceable>relation</replaceable>
1281 This pattern specifies how a CQL relation is mapped to RPN.
1282 <replaceable>pattern</replaceable> is name of relation
1283 operator. Since <literal>=</literal> is used as
1284 separator between CQL pattern and RPN, CQL relations
1285 including <literal>=</literal> cannot be
1286 used directly. To avoid a conflict, the names
1287 <literal>ge</literal>,
1288 <literal>eq</literal>,
1289 <literal>le</literal>,
1290 must be used for CQL operators, greater-than-or-equal,
1291 equal, less-than-or-equal respectively.
1292 The RPN pattern is supposed to include a relation attribute.
1295 For terms not bound by a relation, the pattern
1296 <literal>relation.scr</literal> is used. If the pattern
1297 is not defined, the mapping will fail.
1300 The special pattern, <literal>relation.*</literal> is used
1301 when no other relation pattern is matched.
1306 <varlistentry><term>
1307 <literal>relationModifier.</literal><replaceable>mod</replaceable>
1311 This pattern specifies how a CQL relation modifier is mapped to RPN.
1312 The RPN pattern is usually a relation attribute.
1317 <varlistentry><term>
1318 <literal>structure.</literal><replaceable>type</replaceable>
1322 This pattern specifies how a CQL structure is mapped to RPN.
1323 Note that this CQL pattern is somewhat to similar to
1324 CQL pattern <literal>relation</literal>.
1325 The <replaceable>type</replaceable> is a CQL relation.
1328 The pattern, <literal>structure.*</literal> is used
1329 when no other structure pattern is matched.
1330 Usually, the RPN equivalent specifies a structure attribute.
1335 <varlistentry><term>
1336 <literal>position.</literal><replaceable>type</replaceable>
1340 This pattern specifies how the anchor (position) of
1341 CQL is mapped to RPN.
1342 The <replaceable>type</replaceable> is one
1343 of <literal>first</literal>, <literal>any</literal>,
1344 <literal>last</literal>, <literal>firstAndLast</literal>.
1347 The pattern, <literal>position.*</literal> is used
1348 when no other position pattern is matched.
1353 <varlistentry><term>
1354 <literal>set.</literal><replaceable>prefix</replaceable>
1358 This specification defines a CQL context set for a given prefix.
1359 The value on the right hand side is the URI for the set -
1360 <emphasis>not</emphasis> RPN. All prefixes used in
1361 index patterns must be defined this way.
1367 <example><title>CQL to RPN mapping file</title>
1369 This simple file defines two context sets, three indexes and three
1370 relations, a position pattern and a default structure.
1372 <programlisting><![CDATA[
1373 set.cql = http://www.loc.gov/zing/cql/context-sets/cql/v1.1/
1374 set.dc = http://www.loc.gov/zing/cql/dc-indexes/v1.0/
1376 index.cql.serverChoice = 1=1016
1377 index.dc.title = 1=4
1378 index.dc.subject = 1=21
1384 position.any = 3=3 6=1
1390 With the mappings above, the CQL query
1394 is converted to the PQF:
1396 @attr 1=1016 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "computer"
1398 by rules <literal>index.cql.serverChoice</literal>,
1399 <literal>relation.scr</literal>, <literal>structure.*</literal>,
1400 <literal>position.any</literal>.
1407 is rejected, since <literal>position.right</literal> is
1413 >my = "http://www.loc.gov/zing/cql/dc-indexes/v1.0/" my.title = x
1417 @attr 1=4 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "x"
1422 <sect3 id="tools.cql.xcql"><title>CQL to XCQL conversion</title>
1424 Conversion from CQL to XCQL is trivial and does not
1425 require a mapping to be defined.
1426 There three functions to choose from depending on the
1427 way you wish to store the resulting output (XML buffer
1430 int cql_to_xml_buf(struct cql_node *cn, char *out, int max);
1431 void cql_to_xml(struct cql_node *cn,
1432 void (*pr)(const char *buf, void *client_data),
1434 void cql_to_xml_stdio(struct cql_node *cn, FILE *f);
1436 Function <function>cql_to_xml_buf</function> converts
1437 to XCQL and stores result in a user supplied buffer of a given
1441 <function>cql_to_xml</function> writes the result in
1442 a user defined output stream.
1443 <function>cql_to_xml_stdio</function> writes to a
1449 <sect1 id="tools.oid"><title>Object Identifiers</title>
1452 The basic YAZ representation of an OID is an array of integers,
1453 terminated with the value -1. The &odr; module provides two
1454 utility-functions to create and copy this type of data elements:
1458 Odr_oid *odr_getoidbystr(ODR o, char *str);
1462 Creates an OID based on a string-based representation using dots (.)
1463 to separate elements in the OID.
1467 Odr_oid *odr_oiddup(ODR odr, Odr_oid *o);
1471 Creates a copy of the OID referenced by the <emphasis>o</emphasis>
1473 Both functions take an &odr; stream as parameter. This stream is used to
1474 allocate memory for the data elements, which is released on a
1475 subsequent call to <function>odr_reset()</function> on that stream.
1479 The OID module provides a higher-level representation of the
1480 family of object identifiers which describe the Z39.50 protocol and its
1481 related objects. The definition of the module interface is given in
1482 the <filename>oid.h</filename> file.
1486 The interface is mainly based on the <literal>oident</literal> structure.
1487 The definition of this structure looks like this:
1491 typedef struct oident
1496 int oidsuffix[OID_SIZE];
1502 The proto field takes one of the values
1511 Use <literal>PROTO_Z3950</literal> for Z39.50 Object Identifers,
1512 <literal>PROTO_GENERAL</literal> for other types (such as
1513 those associated with ILL).
1517 The oclass field takes one of the values
1539 corresponding to the OID classes defined by the Z39.50 standard.
1541 Finally, the value field takes one of the values
1599 again, corresponding to the specific OIDs defined by the standard.
1601 <ulink url="http://lcweb.loc.gov/z3950/agency/defns/oids.html">
1602 Registry of Z39.50 Object Identifiers</ulink> for the
1607 The desc field contains a brief, mnemonic name for the OID in question.
1615 struct oident *oid_getentbyoid(int *o);
1619 takes as argument an OID, and returns a pointer to a static area
1620 containing an <literal>oident</literal> structure. You typically use
1621 this function when you receive a PDU containing an OID, and you wish
1622 to branch out depending on the specific OID value.
1630 int *oid_ent_to_oid(struct oident *ent, int *dst);
1634 Takes as argument an <literal>oident</literal> structure - in which
1635 the <literal>proto</literal>, <literal>oclass</literal>/, and
1636 <literal>value</literal> fields are assumed to be set correctly -
1637 and returns a pointer to a the buffer as given by <literal>dst</literal>
1639 representation of the corresponding OID. The function returns
1640 NULL and the array dst is unchanged if a mapping couldn't place.
1641 The array <literal>dst</literal> should be at least of size
1642 <literal>OID_SIZE</literal>.
1646 The <function>oid_ent_to_oid()</function> function can be used whenever
1647 you need to prepare a PDU containing one or more OIDs. The separation of
1648 the <literal>protocol</literal> element from the remainder of the
1649 OID-description makes it simple to write applications that can
1650 communicate with either Z39.50 or OSI SR-based applications.
1658 oid_value oid_getvalbyname(const char *name);
1662 takes as argument a mnemonic OID name, and returns the
1663 <literal>/value</literal> field of the first entry in the database that
1664 contains the given name in its <literal>desc</literal> field.
1668 Three utility functions are provided for translating OIDs'
1669 symbolic names (e.g. <literal>Usmarc</literal> into OID structures
1670 (int arrays) and strings containing the OID in dotted notation
1671 (e.g. <literal>1.2.840.10003.9.5.1</literal>). They are:
1675 int *oid_name_to_oid(oid_class oclass, const char *name, int *oid);
1676 char *oid_to_dotstring(const int *oid, char *oidbuf);
1677 char *oid_name_to_dotstring(oid_class oclass, const char *name, char *oidbuf);
1681 <literal>oid_name_to_oid()</literal>
1682 translates the specified symbolic <literal>name</literal>,
1683 interpreted as being of class <literal>oclass</literal>. (The
1684 class must be specified as many symbolic names exist within
1685 multiple classes - for example, <literal>Zthes</literal> is the
1686 symbolic name of an attribute set, a schema and a tag-set.) The
1687 sequence of integers representing the OID is written into the
1688 area <literal>oid</literal> provided by the caller; it is the
1689 caller's responsibility to ensure that this area is large enough
1690 to contain the translated OID. As a convenience, the address of
1691 the buffer (i.e. the value of <literal>oid</literal>) is
1695 <literal>oid_to_dotstring()</literal>
1696 Translates the int-array <literal>oid</literal> into a dotted
1697 string which is written into the area <literal>oidbuf</literal>
1698 supplied by the caller; it is the caller's responsibility to
1699 ensure that this area is large enough. The address of the buffer
1703 <literal>oid_name_to_dotstring()</literal>
1704 combines the previous two functions to derive a dotted string
1705 representing the OID specified by <literal>oclass</literal> and
1706 <literal>name</literal>, writing it into the buffer passed as
1707 <literal>oidbuf</literal> and returning its address.
1711 Finally, the module provides the following utility functions, whose
1712 meaning should be obvious:
1716 void oid_oidcpy(int *t, int *s);
1717 void oid_oidcat(int *t, int *s);
1718 int oid_oidcmp(int *o1, int *o2);
1719 int oid_oidlen(int *o);
1724 The OID module has been criticized - and perhaps rightly so
1725 - for needlessly abstracting the
1726 representation of OIDs. Other toolkits use a simple
1727 string-representation of OIDs with good results. In practice, we have
1728 found the interface comfortable and quick to work with, and it is a
1729 simple matter (for what it's worth) to create applications compatible
1730 with both ISO SR and Z39.50. Finally, the use of the
1731 <literal>/oident</literal> database is by no means mandatory.
1732 You can easily create your own system for representing OIDs, as long
1733 as it is compatible with the low-level integer-array representation
1740 <sect1 id="tools.nmem"><title>Nibble Memory</title>
1743 Sometimes when you need to allocate and construct a large,
1744 interconnected complex of structures, it can be a bit of a pain to
1745 release the associated memory again. For the structures describing the
1746 Z39.50 PDUs and related structures, it is convenient to use the
1747 memory-management system of the &odr; subsystem (see
1748 <xref linkend="odr.use"/>). However, in some circumstances
1749 where you might otherwise benefit from using a simple nibble memory
1750 management system, it may be impractical to use
1751 <function>odr_malloc()</function> and <function>odr_reset()</function>.
1752 For this purpose, the memory manager which also supports the &odr;
1753 streams is made available in the NMEM module. The external interface
1754 to this module is given in the <filename>nmem.h</filename> file.
1758 The following prototypes are given:
1762 NMEM nmem_create(void);
1763 void nmem_destroy(NMEM n);
1764 void *nmem_malloc(NMEM n, int size);
1765 void nmem_reset(NMEM n);
1766 int nmem_total(NMEM n);
1767 void nmem_init(void);
1768 void nmem_exit(void);
1772 The <function>nmem_create()</function> function returns a pointer to a
1773 memory control handle, which can be released again by
1774 <function>nmem_destroy()</function> when no longer needed.
1775 The function <function>nmem_malloc()</function> allocates a block of
1776 memory of the requested size. A call to <function>nmem_reset()</function>
1777 or <function>nmem_destroy()</function> will release all memory allocated
1778 on the handle since it was created (or since the last call to
1779 <function>nmem_reset()</function>. The function
1780 <function>nmem_total()</function> returns the number of bytes currently
1781 allocated on the handle.
1785 The nibble memory pool is shared amongst threads. POSIX
1786 mutex'es and WIN32 Critical sections are introduced to keep the
1787 module thread safe. Function <function>nmem_init()</function>
1788 initializes the nibble memory library and it is called automatically
1789 the first time the <literal>YAZ.DLL</literal> is loaded. &yaz; uses
1790 function <function>DllMain</function> to achieve this. You should
1791 <emphasis>not</emphasis> call <function>nmem_init</function> or
1792 <function>nmem_exit</function> unless you're absolute sure what
1793 you're doing. Note that in previous &yaz; versions you'd have to call
1794 <function>nmem_init</function> yourself.
1799 <sect1 id="tools.log"><title>Log</title>
1801 &yaz; has evolved a fairly complex log system which should be useful both
1802 for debugging &yaz; itself, debugging applications that use &yaz;, and for
1803 production use of those applications.
1806 The log functions are declared in header <filename>yaz/log.h</filename>
1807 and implemented in <filename>src/log.c</filename>.
1808 Due to name clash with syslog and some math utilities the logging
1809 interface has been modified as of YAZ 2.0.29. The obsolete interface
1810 is still available if in header file <filename>yaz/log.h</filename>.
1811 The key points of the interface are:
1814 void yaz_log(int level, const char *fmt, ...)
1816 void yaz_log_init(int level, const char *prefix, const char *name);
1817 void yaz_log_init_file(const char *fname);
1818 void yaz_log_init_level(int level);
1819 void yaz_log_init_prefix(const char *prefix);
1820 void yaz_log_time_format(const char *fmt);
1821 void yaz_log_init_max_size(int mx);
1823 int yaz_log_mask_str(const char *str);
1824 int yaz_log_module_level(const char *name);
1828 The reason for the whole log module is the <function>yaz_log</function>
1829 function. It takes a bitmask indicating the log levels, a
1830 <literal>printf</literal>-like format string, and a variable number of
1835 The <literal>log level</literal> is a bit mask, that says on which level(s)
1836 the log entry should be made, and optionally set some behaviour of the
1837 logging. In the most simple cases, it can be one of <literal>YLOG_FATAL,
1838 YLOG_DEBUG, YLOG_WARN, YLOG_LOG</literal>. Those can be combined with bits
1839 that modify the way the log entry is written:<literal>YLOG_ERRNO,
1840 YLOG_NOTIME, YLOG_FLUSH</literal>.
1841 Most of the rest of the bits are deprecated, and should not be used. Use
1842 the dynamic log levels instead.
1846 Applications that use &yaz;, should not use the LOG_LOG for ordinary
1847 messages, but should make use of the dynamic loglevel system. This consists
1848 of two parts, defining the loglevel and checking it.
1852 To define the log levels, the (main) program should pass a string to
1853 <function>yaz_log_mask_str</function> to define which log levels are to be
1854 logged. This string should be a comma-separated list of log level names,
1855 and can contain both hard-coded names and dynamic ones. The log level
1856 calculation starts with <literal>YLOG_DEFAULT_LEVEL</literal> and adds a bit
1857 for each word it meets, unless the word starts with a '-', in which case it
1858 clears the bit. If the string <literal>'none'</literal> is found,
1859 all bits are cleared. Typically this string comes from the command-line,
1860 often identified by <literal>-v</literal>. The
1861 <function>yaz_log_mask_str</function> returns a log level that should be
1862 passed to <function>yaz_log_init_level</function> for it to take effect.
1866 Each module should check what log bits it should be used, by calling
1867 <function>yaz_log_module_level</function> with a suitable name for the
1868 module. The name is cleared from a preceding path and an extension, if any,
1869 so it is quite possible to use <literal>__FILE__</literal> for it. If the
1870 name has been passed to <function>yaz_log_mask_str</function>, the routine
1871 returns a non-zero bitmask, which should then be used in consequent calls
1872 to yaz_log. (It can also be tested, so as to avoid unnecessary calls to
1873 yaz_log, in time-critical places, or when the log entry would take time
1878 Yaz uses the following dynamic log levels:
1879 <literal>server, session, request, requestdetail</literal> for the server
1881 <literal>zoom</literal> for the zoom client api.
1882 <literal>ztest</literal> for the simple test server.
1883 <literal>malloc, nmem, odr, eventl</literal> for internal debugging of yaz itself.
1884 Of course, any program using yaz is welcome to define as many new ones, as
1889 By default the log is written to stderr, but this can be changed by a call
1890 to <function>yaz_log_init_file</function> or
1891 <function>yaz_log_init</function>. If the log is directed to a file, the
1892 file size is checked at every write, and if it exceeds the limit given in
1893 <function>yaz_log_init_max_size</function>, the log is rotated. The
1894 rotation keeps one old version (with a <literal>.1</literal> appended to
1895 the name). The size defaults to 1GB. Setting it to zero will disable the
1900 A typical yaz-log looks like this
1901 13:23:14-23/11 yaz-ztest(1) [session] Starting session from tcp:127.0.0.1 (pid=30968)
1902 13:23:14-23/11 yaz-ztest(1) [request] Init from 'YAZ' (81) (ver 2.0.28) OK
1903 13:23:17-23/11 yaz-ztest(1) [request] Search Z: @attrset Bib-1 foo OK:7 hits
1904 13:23:22-23/11 yaz-ztest(1) [request] Present: [1] 2+2 OK 2 records returned
1905 13:24:13-23/11 yaz-ztest(1) [request] Close OK
1909 The log entries start with a time stamp. This can be omitted by setting the
1910 <literal>YLOG_NOTIME</literal> bit in the loglevel. This way automatic tests
1911 can be hoped to produce identical log files, that are easy to diff. The
1912 format of the time stamp can be set with
1913 <function>yaz_log_time_format</function>, which takes a format string just
1914 like <function>strftime</function>.
1918 Next in a log line comes the prefix, often the name of the program. For
1919 yaz-based servers, it can also contain the session number. Then
1920 comes one or more logbits in square brackets, depending on the logging
1921 level set by <function>yaz_log_init_level</function> and the loglevel
1922 passed to <function>yaz_log_init_level</function>. Finally comes the format
1923 string and additional values passed to <function>yaz_log</function>
1927 The log level <literal>YLOG_LOGLVL</literal>, enabled by the string
1928 <literal>loglevel</literal>, will log all the log-level affecting
1929 operations. This can come in handy if you need to know what other log
1930 levels would be useful. Grep the logfile for <literal>[loglevel]</literal>.
1934 The log system is almost independent of the rest of &yaz;, the only
1935 important dependence is of <filename>nmem</filename>, and that only for
1936 using the semaphore definition there.
1940 The dynamic log levels and log rotation were introduced in &yaz; 2.0.28. At
1941 the same time, the log bit names were changed from
1942 <literal>LOG_something</literal> to <literal>YLOG_something</literal>,
1943 to avoid collision with <filename>syslog.h</filename>.
1948 <sect1 id="tools.marc"><title>MARC</title>
1951 YAZ provides a fast utility that decodes MARC records and
1952 encodes to a varity of output formats. The MARC records must
1953 be encoded in ISO2709.
1956 #include <yaz/marcdisp.h>
1958 /* create handler */
1959 yaz_marc_t yaz_marc_create(void);
1961 void yaz_marc_destroy(yaz_marc_t mt);
1963 /* set XML mode YAZ_MARC_LINE, YAZ_MARC_SIMPLEXML, ... */
1964 void yaz_marc_xml(yaz_marc_t mt, int xmlmode);
1965 #define YAZ_MARC_LINE 0
1966 #define YAZ_MARC_SIMPLEXML 1
1967 #define YAZ_MARC_OAIMARC 2
1968 #define YAZ_MARC_MARCXML 3
1969 #define YAZ_MARC_ISO2709 4
1971 /* supply iconv handle for character set conversion .. */
1972 void yaz_marc_iconv(yaz_marc_t mt, yaz_iconv_t cd);
1974 /* set debug level, 0=none, 1=more, 2=even more, .. */
1975 void yaz_marc_debug(yaz_marc_t mt, int level);
1977 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
1978 On success, result in *result with size *rsize. */
1979 int yaz_marc_decode_buf (yaz_marc_t mt, const char *buf, int bsize,
1980 char **result, int *rsize);
1982 /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
1983 On success, result in WRBUF */
1984 int yaz_marc_decode_wrbuf (yaz_marc_t mt, const char *buf,
1985 int bsize, WRBUF wrbuf);
1989 A MARC conversion handle must be created by using
1990 <function>yaz_marc_create</function> and destroyed
1991 by calling <function>yaz_marc_destroy</function>.
1994 All other function operate on a <literal>yaz_marc_t</literal> handle.
1995 The output is specified by a call to <function>yaz_marc_xml</function>.
1996 The <literal>xmlmode</literal> must be one of
1999 <term>YAZ_MARC_LINE</term>
2002 A simple line-by-line format suitable for display but not
2003 recommend for further (machine) processing.
2009 <term>YAZ_MARC_MARXML</term>
2012 The resulting record is converted to MARCXML.
2018 <term>YAZ_MARC_ISO2709</term>
2021 The resulting record is converted to ISO2709 (MARC).
2028 The actual conversion functions are
2029 <function>yaz_marc_decode_buf</function> and
2030 <function>yaz_marc_decode_wrbuf</function> which decodes and encodes
2031 a MARC record. The former function operates on simple buffers, the
2032 stores the resulting record in a WRBUF handle (WRBUF is a simple string
2036 <title>Display of MARC record</title>
2038 The followint program snippet illustrates how the MARC API may
2039 be used to convert a MARC record to the line-by-line format:
2040 <programlisting><![CDATA[
2041 void print_marc(const char *marc_buf, int marc_buf_size)
2043 char *result; /* for result buf */
2044 int result_len; /* for size of result */
2045 yaz_marc_t mt = yaz_marc_create();
2046 yaz_marc_xml(mt, YAZ_MARC_LINE);
2047 yaz_marc_decode_buf(mt, marc_buf, marc_buf_size,
2048 &result, &result_len);
2049 fwrite(result, result_len, 1, stdout);
2050 yaz_marc_destroy(mt); /* note that result is now freed... */
2060 <!-- Keep this comment at the end of the file
2065 sgml-minimize-attributes:nil
2066 sgml-always-quote-attributes:t
2069 sgml-parent-document: "yaz.xml"
2070 sgml-local-catalogs: nil
2071 sgml-namecase-general:t