/*
 * encoding.h : interface for the encoding conversion functions needed for
 *              XML
 *
 * Related specs: 
 * rfc2044        (UTF-8 and UTF-16) F. Yergeau Alis Technologies
 * [ISO-10646]    UTF-8 and UTF-16 in Annexes
 * [ISO-8859-1]   ISO Latin-1 characters codes.
 * [UNICODE]      The Unicode Consortium, "The Unicode Standard --
 *                Worldwide Character Encoding -- Version 1.0", Addison-
 *                Wesley, Volume 1, 1991, Volume 2, 1992.  UTF-8 is
 *                described in Unicode Technical Report #4.
 * [US-ASCII]     Coded Character Set--7-bit American Standard Code for
 *                Information Interchange, ANSI X3.4-1986.
 *
 * See Copyright for the status of this software.
 *
 * Daniel.Veillard@w3.org
 */

#ifndef __XML_CHAR_ENCODING_H__
#define __XML_CHAR_ENCODING_H__

#include <libxml/xmlversion.h>
#ifdef LIBXML_ICONV_ENABLED
#include <iconv.h>
#endif
#include <libxml/tree.h>

#ifdef __cplusplus
extern "C" {
#endif

/**
 * Predefined values for some standard encodings
 * Libxml don't do beforehand translation on UTF8, ISOLatinX
 * It also support UTF16 (LE and BE) by default.
 *
 * Anything else would have to be translated to UTF8 before being
 * given to the parser itself. The BOM for UTF16 and the encoding
 * declaration are looked at and a converter is looked for at that
 * point. If not found the parser stops here as asked by the XML REC
 * Converter can be registered by the user using xmlRegisterCharEncodingHandler
 * but the currentl form doesn't allow stateful transcoding (a serious
 * problem agreed !). If iconv has been found it will be used
 * automatically and allow stateful transcoding, the simplest is then
 * to be sure to enable icon and to provide iconv libs for the encoding
 * support needed.
 */
typedef enum {
    XML_CHAR_ENCODING_ERROR=   -1, /* No char encoding detected */
    XML_CHAR_ENCODING_NONE=	0, /* No char encoding detected */
    XML_CHAR_ENCODING_UTF8=	1, /* UTF-8 */
    XML_CHAR_ENCODING_UTF16LE=	2, /* UTF-16 little endian */
    XML_CHAR_ENCODING_UTF16BE=	3, /* UTF-16 big endian */
    XML_CHAR_ENCODING_UCS4LE=	4, /* UCS-4 little endian */
    XML_CHAR_ENCODING_UCS4BE=	5, /* UCS-4 big endian */
    XML_CHAR_ENCODING_EBCDIC=	6, /* EBCDIC uh! */
    XML_CHAR_ENCODING_UCS4_2143=7, /* UCS-4 unusual ordering */
    XML_CHAR_ENCODING_UCS4_3412=8, /* UCS-4 unusual ordering */
    XML_CHAR_ENCODING_UCS2=	9, /* UCS-2 */
    XML_CHAR_ENCODING_8859_1=	10,/* ISO-8859-1 ISO Latin 1 */
    XML_CHAR_ENCODING_8859_2=	11,/* ISO-8859-2 ISO Latin 2 */
    XML_CHAR_ENCODING_8859_3=	12,/* ISO-8859-3 */
    XML_CHAR_ENCODING_8859_4=	13,/* ISO-8859-4 */
    XML_CHAR_ENCODING_8859_5=	14,/* ISO-8859-5 */
    XML_CHAR_ENCODING_8859_6=	15,/* ISO-8859-6 */
    XML_CHAR_ENCODING_8859_7=	16,/* ISO-8859-7 */
    XML_CHAR_ENCODING_8859_8=	17,/* ISO-8859-8 */
    XML_CHAR_ENCODING_8859_9=	18,/* ISO-8859-9 */
    XML_CHAR_ENCODING_2022_JP=  19,/* ISO-2022-JP */
    XML_CHAR_ENCODING_SHIFT_JIS=20,/* Shift_JIS */
    XML_CHAR_ENCODING_EUC_JP=   21,/* EUC-JP */
    XML_CHAR_ENCODING_ASCII=    22 /* pure ASCII */
} xmlCharEncoding;

/**
 * xmlCharEncodingInputFunc:
 * @out:  a pointer ot an array of bytes to store the UTF-8 result
 * @outlen:  the lenght of @out
 * @in:  a pointer ot an array of chars in the original encoding
 * @inlen:  the lenght of @in
 *
 * Take a block of chars in the original encoding and try to convert
 * it to an UTF-8 block of chars out.
 *
 * Returns the number of byte written, or -1 by lack of space, or -2
 *     if the transcoding failed.
 * The value of @inlen after return is the number of octets consumed
 *     as the return value is positive, else unpredictiable.
 * The value of @outlen after return is the number of ocetes consumed.
 */
typedef int (* xmlCharEncodingInputFunc)(unsigned char* out, int *outlen,
                                         const unsigned char* in, int *inlen);


/**
 * xmlCharEncodingOutputFunc:
 * @out:  a pointer ot an array of bytes to store the result
 * @outlen:  the lenght of @out
 * @in:  a pointer ot an array of UTF-8 chars
 * @inlen:  the lenght of @in
 *
 * Take a block of UTF-8 chars in and try to convert it to an other
 * encoding.
 * Note: a first call designed to produce heading info is called with
 * in = NULL. If stateful this should also initialize the encoder state
 *
 * Returns the number of byte written, or -1 by lack of space, or -2
 *     if the transcoding failed.
 * The value of @inlen after return is the number of octets consumed
 *     as the return value is positive, else unpredictiable.
 * The value of @outlen after return is the number of ocetes consumed.
 */
typedef int (* xmlCharEncodingOutputFunc)(unsigned char* out, int *outlen,
                                          const unsigned char* in, int *inlen);


/*
 * Block defining the handlers for non UTF-8 encodings.
 * If iconv is supported, there is two extra fields 
 */

typedef struct _xmlCharEncodingHandler xmlCharEncodingHandler;
typedef xmlCharEncodingHandler *xmlCharEncodingHandlerPtr;
struct _xmlCharEncodingHandler {
    char                       *name;
    xmlCharEncodingInputFunc   input;
    xmlCharEncodingOutputFunc  output;
#ifdef LIBXML_ICONV_ENABLED
    iconv_t                    iconv_in;
    iconv_t                    iconv_out;
#endif /* LIBXML_ICONV_ENABLED */
};

/*
 * Interfaces for encoding handlers
 */
void	xmlInitCharEncodingHandlers	(void);
void	xmlCleanupCharEncodingHandlers	(void);
void	xmlRegisterCharEncodingHandler	(xmlCharEncodingHandlerPtr handler);
xmlCharEncodingHandlerPtr
	xmlGetCharEncodingHandler	(xmlCharEncoding enc);
xmlCharEncodingHandlerPtr
	xmlFindCharEncodingHandler	(const char *name);


/*
 * Interfaces for encoding names and aliases
 */
int	xmlAddEncodingAlias		(const char *name,
					 const char *alias);
int	xmlDelEncodingAlias		(const char *alias);
const char *
	xmlGetEncodingAlias		(const char *alias);
void	xmlCleanupEncodingAliases	(void);
xmlCharEncoding
	xmlParseCharEncoding		(const char* name);
const char*
	xmlGetCharEncodingName		(xmlCharEncoding enc);

/*
 * Interfaces directly used by the parsers.
 */
xmlCharEncoding
	xmlDetectCharEncoding		(const unsigned char* in,
					 int len);

int	xmlCheckUTF8			(const unsigned char *utf);

int	xmlCharEncOutFunc		(xmlCharEncodingHandler *handler,
					 xmlBufferPtr out,
					 xmlBufferPtr in);

int	xmlCharEncInFunc		(xmlCharEncodingHandler *handler,
					 xmlBufferPtr out,
					 xmlBufferPtr in);
int	xmlCharEncFirstLine		(xmlCharEncodingHandler *handler,
					 xmlBufferPtr out,
					 xmlBufferPtr in);
int	xmlCharEncCloseFunc		(xmlCharEncodingHandler *handler);

#ifdef __cplusplus
}
#endif

#endif /* __XML_CHAR_ENCODING_H__ */