kannel-dev 1.4.4-2build1 / usr / include / kannel / gwlib / charset.h

/* ==================================================================== 
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/*
 * gwlib/charset.h - character set conversions
 *
 * This header defines some utility functions for converting between
 * character sets.  Approximations are made when necessary, so avoid
 * needless conversions.
 *
 * Currently only GSM and Latin-1 are supported with Kannel specific
 * functions. This module contains also wrappers for libxml2 character
 * set conversion functions that work either from or to UTF-8. More
 * about libxml2's character set support on the header file
 * <libxml/encoding.h> or the implementation file encoding.c. Short
 * version: it has a few basic character set supports built in; for
 * the rest iconv is used.
 *
 * Richard Braakman
 * Tuomas Luttinen
 */

#ifndef CHARSET_H
#define CHARSET_H

#include <libxml/encoding.h>
#include <libxml/tree.h>

/*
 * Initialize the charset subsystem.
 */
void charset_init(void);

/*
 * Shutdown the charset subsystem.
 */
void charset_shutdown(void);

/**
 * Convert octet string in GSM format to UTF-8.
 * Every GSM character can be represented with unicode, hence nothing will
 * be lost. Escaped charaters will be translated into appropriate UTF-8 character.
 */
void charset_gsm_to_utf8(Octstr *ostr);

/**
 * Convert octet string in UTF-8 format to GSM 03.38.
 * Because not all UTF-8 charater can be converted to GSM 03.38 non
 * convertable character replaces with NRP character (see define above).
 * Special characters will be formed into escape sequences.
 * Incomplete UTF-8 characters at the end of the string will be skipped.
 */
void charset_utf8_to_gsm(Octstr *ostr);

/*
 * Convert from GSM default character set to NRC ISO 21 (German)
 * and vise versa.
 */
void charset_gsm_to_nrc_iso_21_german(Octstr *ostr);
void charset_nrc_iso_21_german_to_gsm(Octstr *ostr);

/* Trunctate a string of GSM characters to a maximum length.
 * Make sure the last remaining character is a whole character,
 * and not half of an escape sequence.
 * Return 1 if any characters were removed, otherwise 0.
 */
int charset_gsm_truncate(Octstr *gsm, long max);

/* Convert a string in the GSM default character set (GSM 03.38)
 * to ISO-8859-1.  A series of Greek characters (codes 16, 18-26)
 * are not representable and are converted to '?' characters.
 * GSM default is a 7-bit alphabet.  Characters with the 8th bit
 * set are left unchanged. */
void charset_gsm_to_latin1(Octstr *gsm);

/* Convert a string in the ISO-8859-1 character set to the GSM 
 * default character set (GSM 03.38).  A large number of characters
 * are not representable.  Approximations are made in some cases
 * (accented characters to their unaccented versions, for example),
 * and the rest are converted to '?' characters. */
void charset_latin1_to_gsm(Octstr *latin1);

/* Convert a string from  character set specified by charset_from into
 * UTF-8 character set. The result is stored in the octet string *to that 
 * is allocated by the function. The function returns the number of bytes 
 * written for success, -1 for general error, -2 for an transcoding error 
 * (the input string wasn't valid string in the character set it was said 
 * to be or there was no converter found for the character set).
 */
int charset_to_utf8(Octstr *from, Octstr **to, Octstr *charset_from);

/* Convert a string from UTF-8 character set into another character set 
 * specified by charset_from. The result is stored in the octet string *to
 * that is allocated by the function. The function returns the number of 
 * bytes written for success, -1 for general error, -2 for an transcoding 
 * error (the input string wasn't valid string in the character set it 
 * was said to be or there was no converter found for the character set).
 */
int charset_from_utf8(Octstr *utf8, Octstr **to, Octstr *charset_to);

/* use iconv library to convert an Octstr in place, from source character set to
 * destination character set
 */
int charset_convert(Octstr* string, char* charset_from, char* charset_to);

#endif