mxml

Tiny XML library.

michaelrsweet
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163
C

Mini-XML - Tiny XML Parsing Library v4

Version
Apache 2.0
Build
Coverity Scan Status

Mini-XML is a small XML parsing library that you can use to read XML data files
or strings in your application without requiring large non-standard libraries.
Mini-XML only requires a “make” program and a C99 compatible compiler - GCC
works, as do most vendors’ C compilers.

Mini-XML provides the following functionality:

  • Reading of UTF-8 and UTF-16 and writing of UTF-8 encoded XML files and
    strings.
  • Data is stored in a linked-list tree structure, preserving the XML data
    hierarchy.
  • SAX (streamed) reading of XML files and strings to minimize memory usage.
  • Supports arbitrary element names, attributes, and attribute values with no
    preset limits, just available memory.
  • Supports integer, real, opaque, text, and custom data types in “leaf” nodes.
  • Functions for creating and managing trees of data.
  • “Find” and “walk” functions for easily locating and navigating trees of data.
  • Support for custom string memory management functions to implement string
    pools and other schemes for reducing memory usage.

Mini-XML doesn’t do validation or other types of processing on the data
based upon schema files or other sources of definition information.

Building Mini-XML

Mini-XML comes with an autoconf-based configure script; just type the
following command to get things going:

./configure

The default install prefix is /usr/local, which can be overridden using the
--prefix option:

./configure --prefix=/foo

Other configure options can be found using the --help option:

./configure --help

Once you have configured the software, type make to do the build and run
the test program to verify that things are working, as follows:

make

If you are using Mini-XML under Microsoft Windows with Visual C++, use the
included project files in the vcnet subdirectory to build the library
instead. Note: The static library on Windows is NOT thread-safe.

Installing Mini-XML

The install target will install Mini-XML in the lib and include
directories:

sudo make install

Once you have installed it, use the -lmxml option to link your application
against it.

Documentation

The documentation is available in the doc subdirectory in the files
mxml.html (HTML) and mxml.epub (EPUB). You can also look at the
testmxml.c source file for examples of using Mini-XML.

Mini-XML provides a single header file which you include:

#include <mxml.h>

Nodes (elements, comments, declarations, integers, opaque strings, processing
instructions, real numbers, and text strings) are represented by mxml_node_t
pointers. New nodes can be created using the mxmlNewXxx functions. The top
node must be the <?xml ...?> processing instruction.

You load an XML file using the mxmlLoadFilename function:

mxml_node_t *tree;

tree = mxmlLoadFilename(/*top*/NULL, /*options*/NULL,
                        "example.xml");

Similarly, you save an XML file using the mxmlSaveFilename function:

mxml_node_t *tree;

mxmlSaveFilename(tree, /*options*/NULL,
                 "filename.xml");

There are variations of these functions for loading from or saving to file
descriptors, FILE pointers, strings, and IO callbacks.

You can find a named element/node using the mxmlFindElement function:

mxml_node_t *node = mxmlFindElement(tree, tree, "name", "attr",
				"value", MXML_DESCEND_ALL);

The name, attr, and value arguments can be passed as NULL to act as
wildcards, e.g.:

/* Find the first "a" element */
node = mxmlFindElement(tree, tree, "a", NULL, NULL, MXML_DESCEND_ALL);

/* Find the first "a" element with "href" attribute */
node = mxmlFindElement(tree, tree, "a", "href", NULL, MXML_DESCEND_ALL);

/* Find the first "a" element with "href" to a URL */
node = mxmlFindElement(tree, tree, "a", "href",
                       "https://www.msweet.org/mxml", MXML_DESCEND_ALL);

/* Find the first element with a "src" attribute*/
node = mxmlFindElement(tree, tree, NULL, "src", NULL, MXML_DESCEND_ALL);

/* Find the first element with a "src" = "foo.jpg" */
node = mxmlFindElement(tree, tree, NULL, "src", "foo.jpg",
                       MXML_DESCEND_ALL);

You can also iterate with the same function:

mxml_node_t *node;

for (node = mxmlFindElement(tree, tree, "name", NULL, NULL,
			MXML_DESCEND_ALL);
 node != NULL;
 node = mxmlFindElement(node, tree, "name", NULL, NULL,
			MXML_DESCEND_ALL))
{
  ... do something ...
}

The mxmlFindPath function finds the (first) value node under a specific
element using an XPath:

mxml_node_t *value = mxmlFindPath(tree, "path/to/*/foo/bar");

The mxmlGetInteger, mxmlGetOpaque, mxmlGetReal, and mxmlGetText functions
retrieve the corresponding value from a node:

mxml_node_t *node;

int intvalue = mxmlGetInteger(node);

const char *opaquevalue = mxmlGetOpaque(node);

double realvalue = mxmlGetReal(node);

bool whitespacevalue;
const char *textvalue = mxmlGetText(node, &whitespacevalue);

Finally, once you are done with the XML data, use the mxmlDelete function to
recursively free the memory that is used for a particular node or the entire
tree:

mxmlDelete(tree);

Getting Help And Reporting Problems

The Mini-XML project page provides access to the
current version of this software, documentation, and Github issue tracking page.

Legal Stuff

Copyright © 2003-2024 by Michael R Sweet

The Mini-XML library is licensed under the Apache License Version 2.0 with an
optional exception to allow linking against GPL2/LGPL2-only software. See the
files “LICENSE” and “NOTICE” for more information.

Note: The exception listed in the NOTICE file only applies when linking
against GPL2/LGPL2-only software. Some Apache License purists have objected
to linking Apache Licensed code against Mini-XML with these exceptions on the
grounds that it makes Mini-XML somehow incompatible with the Apache License.
For that reason, people wishing to retain their Apache License purity may
omit the exception from their copy of Mini-XML.

Note 2: IANAL, but I am beginning to dislike them!