You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
169 lines
5.5 KiB
169 lines
5.5 KiB
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
|
|
<HTML>
|
|
<HEAD>
|
|
<TITLE>Mini-XML Programmers Manual, Version 2.2.1</TITLE>
|
|
<META NAME="author" CONTENT="Michael Sweet">
|
|
<META NAME="copyright" CONTENT="Copyright 2003-2005">
|
|
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=iso-iso-8859-1">
|
|
<LINK REL="Start" HREF="index.html">
|
|
<LINK REL="Contents" HREF="toc.html">
|
|
<LINK REL="Prev" HREF="SaveCallbacks.html">
|
|
<LINK REL="Next" HREF="ChangingNodeValues.html">
|
|
<STYLE TYPE="text/css"><!--
|
|
BODY { font-family: serif }
|
|
H1 { font-family: sans-serif }
|
|
H2 { font-family: sans-serif }
|
|
H3 { font-family: sans-serif }
|
|
H4 { font-family: sans-serif }
|
|
H5 { font-family: sans-serif }
|
|
H6 { font-family: sans-serif }
|
|
SUB { font-size: smaller }
|
|
SUP { font-size: smaller }
|
|
PRE { font-family: monospace }
|
|
--></STYLE>
|
|
</HEAD>
|
|
<BODY>
|
|
<A HREF="toc.html">Contents</A>
|
|
<A HREF="SaveCallbacks.html">Previous</A>
|
|
<A HREF="ChangingNodeValues.html">Next</A>
|
|
<HR NOSHADE>
|
|
<H2><A NAME="4_3">Custom Data Types</A></H2>
|
|
<P>Mini-XML supports custom data types via global load and save
|
|
callbacks. Only a single set of callbacks can be active at any time,
|
|
however your callbacks can store additional information in order to
|
|
support multiple custom data types as needed. The <TT>MXML_CUSTOM</TT>
|
|
node type identifies custom data nodes.</P>
|
|
<P>The load callback receives a pointer to the current data node and a
|
|
string of opaque character data from the XML source with character
|
|
entities converted to the corresponding UTF-8 characters. For example,
|
|
if we wanted to support a custom date/time type whose value is encoded
|
|
as "yyyy-mm-ddThh:mm:ssZ" (ISO format), the load callback would look
|
|
like the following:</P>
|
|
<PRE>
|
|
typedef struct
|
|
{
|
|
unsigned year, /* Year */
|
|
month, /* Month */
|
|
day, /* Day */
|
|
hour, /* Hour */
|
|
minute, /* Minute */
|
|
second; /* Second */
|
|
time_t unix; /* UNIX time value */
|
|
} iso_date_time_t;
|
|
|
|
int /* I - 0 on success, -1 on error */
|
|
load_custom(mxml_node_t *node, /* I - Node */
|
|
const char *data) /* I - Value */
|
|
{
|
|
iso_date_time_t *dt; /* Date/time value */
|
|
struct tm tmdata; /* UNIX time data */
|
|
|
|
|
|
/*
|
|
* Allocate data structure...
|
|
*/
|
|
|
|
dt = calloc(1, sizeof(iso_date_time_t));
|
|
|
|
/*
|
|
* Try reading 6 unsigned integers from the data string...
|
|
*/
|
|
|
|
if (sscanf(data, "%u-%u-%uT%u:%u:%uZ",
|
|
&(dt->year), &(dt->month), &(dt->day),
|
|
&(dt->hour), &(dt->minute), &(dt->second)) != 6)
|
|
{
|
|
/*
|
|
* Unable to read numbers, free the data structure and return an
|
|
* error...
|
|
*/
|
|
|
|
free(dt);
|
|
|
|
return (-1);
|
|
}
|
|
|
|
/*
|
|
* Range check values...
|
|
*/
|
|
|
|
if (dt->month <1 || dt->month > 12 ||
|
|
dt->day <1 || dt->day > 31 ||
|
|
dt->hour <0 || dt->hour > 23 ||
|
|
dt->minute <0 || dt->minute > 59 ||
|
|
dt->second <0 || dt->second > 59)
|
|
{
|
|
/*
|
|
* Date information is out of range...
|
|
*/
|
|
|
|
free(dt);
|
|
|
|
return (-1);
|
|
}
|
|
|
|
/*
|
|
* Convert ISO time to UNIX time in seconds...
|
|
*/
|
|
|
|
tmdata.tm_year = dt->year - 1900;
|
|
tmdata.tm_mon = dt->month - 1;
|
|
tmdata.tm_day = dt->day;
|
|
tmdata.tm_hour = dt->hour;
|
|
tmdata.tm_min = dt->minute;
|
|
tmdata.tm_sec = dt->second;
|
|
|
|
dt->unix = gmtime(&tmdata);
|
|
|
|
/*
|
|
* Assign custom node data and destroy function pointers...
|
|
*/
|
|
|
|
node->value.custom.data = dt;
|
|
node->value.custom.destroy = free;
|
|
|
|
/*
|
|
* Return with no errors...
|
|
*/
|
|
|
|
return (0);
|
|
}
|
|
</PRE>
|
|
<P>The function itself can return 0 on success or -1 if it is unable to
|
|
decode the custom data or the data contains an error. Custom data nodes
|
|
contain a <TT>void</TT> pointer to the allocated custom data for the
|
|
node and a pointer to a destructor function which will free the custom
|
|
data when the node is deleted.</P>
|
|
|
|
<!-- NEED 3in -->
|
|
<P>The save callback receives the node pointer and returns an allocated
|
|
string containing the custom data value. The following save callback
|
|
could be used for our ISO date/time type:</P>
|
|
<PRE>
|
|
char * /* I - Allocated string */
|
|
save_custom(mxml_node_t *node) /* I - Node */
|
|
{
|
|
char data[255]; /* Data string */
|
|
iso_date_time_t *dt; /* ISO date/time pointer */
|
|
|
|
|
|
dt = (iso_date_time_t *)node->custom.data;
|
|
|
|
snprintf(data, sizeof(data), "%04u-%02u-%02uT%02u:%02u:%02uZ",
|
|
dt->year, dt->month, dt->day, dt->hour,
|
|
dt->minute, dt->second);
|
|
|
|
return (strdup(data));
|
|
}
|
|
</PRE>
|
|
<P>You register the callback functions using the <A href="mxmlSetCustomHandlers.html#mxmlSetCustomHandlers">
|
|
<TT>mxmlSetCustomHandlers()</TT></A> function:</P>
|
|
<PRE>
|
|
mxmlSetCustomHandlers(load_custom, save_custom);
|
|
</PRE>
|
|
<HR NOSHADE>
|
|
<A HREF="toc.html">Contents</A>
|
|
<A HREF="SaveCallbacks.html">Previous</A>
|
|
<A HREF="ChangingNodeValues.html">Next</A>
|
|
</BODY>
|
|
</HTML>
|
|
|