Package SAX for XML C APIs

7 Package SAX for XML C APIs

SAX is a standard interface for event-based XML parsing, developed collaboratively by the members of the XML-DEV mailing list. To use SAX, an xmlsaxcb structure is initialized with function pointers and passed to one of the XmlLoadSax calls. A pointer to a user-defined context structure is also provided, and will be passed to each SAX function.

For event-based schema validation APIs, refer to Package Event APIs for C.

The following table summarizes the methods available through the SAX interface for XML C APIs.

Table 7-1 Summary of SAX Methods for XML C Implementation

Function	Summary
XmlSaxAttributeDecl()	Receives SAX notification of an attribute's declaration.
XmlSaxCDATA()	Receives SAX notification of `CDATA`. Oracle extension.
XmlSaxCharacters()	Receives SAX notification of character data
XmlSaxComment()	Receives SAX notification of a comment.
XmlSaxElementDecl()	Receives SAX notification of an element's declaration. Oracle extension.
XmlSaxEndDocument()	Receives SAX end-of-document notification.
XmlSaxEndElement()	Receives SAX end-of-element notification.
XmlSaxNotationDecl()	Receives SAX notification of a notation declaration.
XmlSaxPI()	Receives SAX notification of a processing instruction.
XmlSaxParsedEntityDecl()	Receives SAX notification of a parsed entity declaration. Oracle extension.
XmlSaxStartDocument()	Receives SAX start-of-document notification.
XmlSaxStartElement()	Receives SAX start-of-element notification.
XmlSaxStartElementNS()	Receives SAX namespace-aware start-of-element notification.
XmlSaxUnparsedEntityDecl()	Receives SAX notification of an unparsed entity declaration.
XmlSaxWhitespace()	Receives SAX notification of ignorable (whitespace) data.
XmlSaxXmlDecl()	Receives SAX notification of an XML declaration. Oracle extension.

XmlSaxAttributeDecl()

This event marks an element declaration in the DTD. The element's name and content will be in the data encoding. Note that an attribute may be declared before the element it belongs to!

Syntax

xmlerr XmlSaxAttributeDecl(
   void *ctx, 
   oratext *elem, 
   oratext *attr, 
   oratext *body);

Parameter	In/Out	Description
ctx	IN	user's SAX context
elem	IN	element for which the attribute is declared; data encoding
attr	IN	attribute's name; data encoding
body	IN	body of an attribute declaration

Returns

(xmlerr) error code, XMLERR_OK [0] for success

See Also:

XmlSaxAttributeDecl()

XmlSaxBeginGen()

This call creates an XML generation context from the specified XML meta context. This context is uded by the SAX calls to generate an incremental XML document.

Syntax

void *XmlSaxBeginGen(
   XmlCtx *xctx);

Parameter	In/Out	Description
xctx	IN	the XML meta contextt

XmlSaxCDATA()

This event handles CDATA, as distinct from Text. If no XmlSaxCDATA callback is provided, the Text callback will be invoked. The data will be in the data encoding, and the returned length is in characters, not bytes. See also XmlSaxWhitespace, which receiving notification about ignorable (whitespace formatting) character data.

Syntax

xmlerr XmlSaxCDATA(
   void *ctx, 
   oratext *ch, 
   size_t len);

Parameter	In/Out	Description
ctx	IN	user's SAX context
ch	IN	pointer to `CDATA`; data encoding
len	IN	length of `CDATA`, in characters

Returns

(xmlerr) error code, XMLERR_OK [0] for success

See Also:

XmlSaxWhitespace()

XmlSaxCharacters()

This event marks character data, either Text or CDATA. If an XmlSaxCDATA callback is provided, then CDATA will be send to that instead; with no XmlSaxCDATA callback, both Text and CDATA go to the XmlSaxCharacters callback. The data will be in the data encoding, and the returned length is in characters, not bytes. See also XmlSaxWhitespace, which receiving notification about ignorable (whitespace formatting) character data.

Syntax

xmlerr XmlSaxCharacters(
   void *ctx, 
   oratext *ch, 
   size_t len);

Parameter	In/Out	Description
ctx	IN	user's SAX context
ch	IN	pointer to data; data encoding
len	IN	length of data, in characters

Returns

(xmlerr) error code, XMLERR_OK [0] for success

See Also:

XmlSaxWhitespace()

XmlSaxComment()

This event marks a comment in the XML document. The comment's data will be in the data encoding. Oracle extension, not in SAX standard.

Syntax

xmlerr XmlSaxComment(
   void *ctx, 
   oratext *data);

Parameter	In/Out	Description
ctx	IN	user's SAX context
data	IN	comment's data; data encoding

Returns

(xmlerr) error code, XMLERR_OK [0] for success

XmlSaxElementDecl()

This event marks an element declaration in the DTD. The element's name and content will be in the data encoding.

Syntax

xmlerr XmlSaxElementDecl(
   void *ctx, 
   oratext *name, 
   oratext *content);

Parameter	In/Out	Description
ctx	IN	user's SAX context
name	IN	element's name
content	IN	element's context model

Returns

(xmlerr) error code, XMLERR_OK [0] for success

See Also:

XmlSaxAttributeDecl()

XmlSaxEndDocument()

The last SAX event, called once for each document, indicating the end of the document. Matching event is XmlSaxStartDocument.

Syntax

xmlerr XmlSaxEndDocument(
   void *ctx);

Parameter	In/Out	Description
ctx	IN	user's SAX context

Returns

(xmlerr) error code, XMLERR_OK [0] for success

See Also:

XmlSaxStartDocument()

XmlSaxEndElement()

This event marks the close of an element; it matches the XmlSaxStartElement or XmlSaxStartElementNS events. The name is the tagName of the element (which may be a qualified name for namespace-aware elements) and is in the data encoding.

XmlSaxEndGen()

Completes the generation of an incrementally constructed XML document, and returns it to the application.

Syntax

orastream *XmlSaxEndGen(
   void *genCtx);

Parameter	In/Out	Description
genCtx	IN	the generation context used to create the XML document; see XmlSaxBeginGen()XmlSaxBeginGen()t

Return

(orastream*) the stream containing the generated XML document

XmlSaxNotationDecl()

The even marks the declaration of a notation in the DTD. The notation's name, public ID, and system ID will all be in the data encoding. Both IDs are optional and may be NULL.

XmlSaxPI()

This event marks a ProcessingInstruction. The ProcessingInstructions target and data will be in the data encoding. There is always a target, but the data may be NULL.

Syntax

xmlerr XmlSaxPI(
   void *ctx, 
   oratext *target, 
   oratext *data);

Parameter	In/Out	Description
ctx	IN	user's SAX context
target	IN	PI's target; data encoding
data	IN	PI's data as data encoding, or `NULL`

Returns

(xmlerr) error code, XMLERR_OK [0] for success

XmlSaxParsedEntityDecl()

Marks an parsed entity declaration in the DTD. The parsed entity's name, public ID, system ID, and notation name will all be in the data encoding.

Syntax

xmlerr XmlSaxParsedEntityDecl(
   void *ctx, 
   oratext *name, 
   oratext *value, 
   oratext *pubId, 
   oratext *sysId, 
   boolean general);

Parameter	In/Out	Description
ctx	IN	user's SAX context
name	IN	entity's name; data encoding
value	IN	entity's value; data encoding
pubId	IN	entity's public ID as data encoding, or `NULL`
sysId	IN	entity's system ID; data encoding
general	IN	`TRUE` if general entity, `FALSE` if parameter entity

Returns

(xmlerr) error code, XMLERR_OK [0] for success

See Also:

XmlSaxUnparsedEntityDecl()

XmlSaxStartDocument()

The first SAX event, called once for each document, indicating the start of the document. Matching event is XmlSaxEndDocument.

Syntax

xmlerr XmlSaxStartDocument(
   void *ctx);

Parameter	In/Out	Description
ctx	IN	user's SAX context

Returns

(xmlerr) error code, XMLERR_OK [0] for success

See Also:

XmlSaxEndDocument()

XmlSaxStartElement()

This event marks the start of an element. Note this is the original SAX 1 non-namespace-aware version; XmlSaxStartElementNS is the SAX 2 namespace-aware version. If both are registered, only the NS version will be called. The element's name will be in the data encoding, as are all the attribute parts. See the functions in the NamedNodeMap interface for operating on the attributes map. The matching function is XmlSaxEndElement (there is no namespace aware version of this function).

Syntax

xmlerr XmlSaxStartElement(
   void *ctx, 
   oratext *name, 
   xmlnodelist *attrs);

Parameter	In/Out	Description
ctx	IN	user's SAX context
name	IN	element's name; data encoding
attrs	IN	`NamedNodeMap` of element's attributes

Returns

(xmlerr) error code, XMLERR_OK [0] for success

XmlSaxStartElementNS()

This event marks the start of an element. Note this is the new SAX 2 namespace-aware version; XmlSaxStartElement is the SAX 1 non-namespace-aware version. If both are registered, only the NS version will be called. The element's qualified name, local name, and namespace URI will be in the data encoding, as are all the attribute parts. See the functions in the NamedNodeMap interface for operating on the attributes map. The matching function is XmlSaxEndElement (there is no namespace aware version of this function).

Syntax

xmlerr XmlSaxStartElementNS(
   void *ctx, 
   oratext *qname, 
   oratext *local, 
   oratext *nsp, 
   xmlnodelist *attrs);

Parameter	In/Out	Description
ctx	IN	user's SAX context
qname	IN	element's qualified name; data encoding
local	IN	element's namespace local name; data encoding
nsp	IN	element's namespace URI; data encoding
attrs	IN	`NodeList` of element's attributes, or `NULL`

Returns

(xmlerr) error code, XMLERR_OK [0] for success

XmlSaxUnparsedEntityDecl()

Marks an unparsed entity declaration in the DTD, see XmlSaxParsedEntityDecl for the parsed entity version. The unparsed entity's name, public ID, system ID, and notation name will all be in the data encoding.

Syntax

xmlerr XmlSaxUnparsedEntityDecl(
   void *ctx, 
   oratext *name, 
   oratext *pubId, 
   oratext *sysId, 
   oratext *note);

Parameter	In/Out	Description
ctx	IN	user's SAX context
name	IN	entity's name; data encoding
pubId	IN	entity's public ID as data encoding, or `NULL`
sysId	IN	entity's system ID; data encoding
note	IN	entity's notation name; data encoding

Returns

(xmlerr) error code, XMLERR_OK [0] for success

See Also:

XmlSaxParsedEntityDecl()

XmlSaxWhitespace()

This event marks ignorable whitespace data such as newlines, and indentation between lines. The matching function is XmlSaxCharacters, which receives notification of normal character data. The data is in the data encoding, and the returned length is in characters, not bytes.

Syntax

xmlerr XmlSaxWhitespace(
   void *ctx, 
   oratext *ch, 
   size_t len);

Parameter	In/Out	Description
ctx	IN	user's SAX context
ch	IN	pointer to data; data encoding
len	IN	length of data, in characters

Returns

(xmlerr) error code, XMLERR_OK [0] for success

See Also:

XmlSaxCharacters()

XmlSaxXmlDecl()

This event marks an XML declaration. The XmlSaxStartDocument event is always first; if this callback is registered and an XMLDecl exists, it will be the second event. The encoding flag says whether an encoding was specified. Since the document's own encoding specification may be overridden (or wrong), and the input will be converted to the data encoding anyway, the actual encoding specified in the document is not provided. For the standalone flag, -1 will be returned if it was not specified, otherwise 0 for FALSE, 1 for TRUE.

Syntax

xmlerr XmlSaxXmlDecl(
   void *ctx, 
   oratext *version, 
   boolean encoding, 
   sword standalone);

Parameter	In/Out	Description
ctx	IN	user's SAX context
version	IN	version string from XMLDecl; data encoding
encoding	IN	whether encoding was specified
standalone	IN	value of the standalone document; `< 0` if not specified

Returns

(xmlerr) error code, XMLERR_OK [0] for success