LIBEXTRACTOR(3)LIBEXTRACTOR(3)NAMElibextractor - 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 EXTRAC‐
TOR_PluginList *prev, const char *library, const char *options, enum
EXTRACTOR_Options flags);
struct EXTRACTOR_PluginList *EXTRACTOR_plugin_add_last (struct EXTRAC‐
TOR_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 *plug‐
ins);
void EXTRACTOR_extract (struct EXTRACTOR_PluginList *plugins, const
char *filename, const void *data, size_t size, EXTRACTOR_MetaDataPro‐
cessor 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. libex‐
tractor does not support all formats but supports a simple plugging
mechanism such that you can quickly add extractors for additional for‐
mats, 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 file‐
type, 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 some‐
thing 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 EXTRAC‐
TOR_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 func‐
tion converts the UTF-8 keywords to the character set from the current
locale before printing them.
SEE ALSOextract(1)LEGAL NOTICElibextractor is released under the GPL and a GNU package
(http://www.gnu.org/).
BUGS
A couple of file-formats (on the order of 10^3) are not recognized...
AUTHORS
extract was originally written by Christian Grothoff <chris‐
tian@grothoff.org> and Vidyut Samanta <vids@cs.ucla.edu>. Use <libex‐
tractor@gnu.org> to contact the current maintainer(s).
AVAILABILITY
You can obtain the original author's latest version from
http://www.gnu.org/software/libextractor/.
GNU libextractor 1.0.0 Sept 4, 2012 LIBEXTRACTOR(3)
