libextractor man page

libextractor — meta-information extraction library 1.0.0

Synopsis

#include <extractor.h>

const char *EXTRACTOR_metatype_to_string (enum EXTRACTOR_MetaType type);

const char *EXTRACTOR_metatype_to_description (enum EXTRACTOR_MetaType type);

enum EXTRACTOR_MetaTypeEXTRACTOR_metatype_get_max (void);

struct EXTRACTOR_PluginList *EXTRACTOR_plugin_add_defaults (enum EXTRACTOR_Options flags);

struct EXTRACTOR_PluginList *EXTRACTOR_plugin_add (struct EXTRACTOR_PluginList *prev, const char *library, const char *options, enum EXTRACTOR_Options flags);

struct EXTRACTOR_PluginList *EXTRACTOR_plugin_add_last (struct EXTRACTOR_PluginList *prev, const char *library, const char *options, enum EXTRACTOR_Options flags);

struct EXTRACTOR_PluginList *EXTRACTOR_plugin_add_config (struct EXTRACTOR_PluginList *prev, const char *config, enum EXTRACTOR_Options flags); struct EXTRACTOR_PluginList *EXTRACTOR_plugin_remove (struct EXTRACTOR_PluginList *prev, const char *library);

void EXTRACTOR_plugin_remove_all (struct EXTRACTOR_PluginList *plugins);

void EXTRACTOR_extract (struct EXTRACTOR_PluginList *plugins, const char *filename, const void *data, size_t size, EXTRACTOR_MetaDataProcessor proc, void *proc_cls);

int EXTRACTOR_meta_data_prin t(void *handle, const char *plugin_name, enum EXTRACTOR_MetaType type, enum EXTRACTOR_MetaFormat format, const char *data_mime_type, const char *data, size_t data_len);

EXTRACTOR_VERSION

Description

GNU libextractor is a simple library for keyword extraction. libextractor does not support all formats but supports a simple plugging mechanism such that you can quickly add extractors for additional formats, even without recompiling libextractor. libextractor typically ships with dozens of plugins that can be used to obtain meta data from common file-types. If you want to write your own plugin for some filetype, all you need to do is write a little library that implements a single method with this signature:

void EXTRACTOR_XXX_extract_method (struct EXTRACTOR_ExtractContext *ec);

ec contains function pointers for reading, seeking, getting the overall file size and returning meta data. There is also a field with options for the plugin. New plugins will be automatically located and used once they are installed in the respective directory (typically something like /usr/lib/libextractor/).

The application extract gives an example how to use libextractor.

The basic use of libextractor is to load the plugins (for example with EXTRACTOR_plugin_add_defaults), then to extract the keyword list using EXTRACTOR_extract, and finally unloading the plugins (with EXTRACTOR_plugin_remove_all).

Textual meta data obtained from libextractor is supposed to be UTF-8 encoded if the text encoding is known. Plugins are supposed to convert meta-data to UTF-8 if necessary. The EXTRACTOR_meta_data_print function converts the UTF-8 keywords to the character set from the current locale before printing them.

See Also

extract(1)

Bugs

A couple of file-formats (on the order of 10^3) are not recognized...

Authors

extract was originally written by Christian Grothoff <christian@grothoff.org> and Vidyut Samanta <vids@cs.ucla.edu>. Use <libextractor@gnu.org> to contact the current maintainer(s).

Availability

You can obtain the original author's latest version from http://www.gnu.org/software/libextracto….

Referenced By

doodle(1), libdoodle(3), libextractor-extract(1).

Sept 4, 2012 GNU libextractor 1.0.0