/**********************************************************************

  transcode_data.h -

  $Author$
  $Date$
  created at: Mon 10 Dec 2007 14:01:47 JST 2007

  Copyright (C) 2007 Martin Duerst

**********************************************************************/

#include "ruby/ruby.h"

#ifndef RUBY_TRANSCODE_DATA_H
#define RUBY_TRANSCODE_DATA_H 1

typedef unsigned char base_element;

typedef struct byte_lookup {
    const base_element *base;
    const struct byte_lookup *const *info;
} BYTE_LOOKUP;

#ifndef PType
/* data file needs to treat this as a pointer, to remove warnings */
#define PType (const BYTE_LOOKUP *)
#endif

#define NOMAP   (PType 0x01)   /* single byte direct map */
#define ONEbt   (0x02)   /* one byte payload */
#define TWObt   (0x03)   /* two bytes payload */
#define THREEbt (0x05)   /* three bytes payload */
#define FOURbt  (0x06)   /* four bytes payload, UTF-8 only, macros start at getBT0 */
#define ILLEGAL (PType 0x07)   /* illegal byte sequence */
#define UNDEF   (PType 0x09)   /* legal but undefined */
#define ZERObt  (PType 0x0A)   /* zero bytes of payload, i.e. remove */

#define o1(b1)          ((const BYTE_LOOKUP *)((((unsigned char)(b1))<<8)|ONEbt))
#define o2(b1,b2)       ((const BYTE_LOOKUP *)((((unsigned char)(b1))<<8)|(((unsigned char)(b2))<<16)|TWObt))
#define o3(b1,b2,b3)    ((const BYTE_LOOKUP *)((((unsigned char)(b1))<<8)|(((unsigned char)(b2))<<16)|(((unsigned char)(b3))<<24)|THREEbt))
#define o4(b0,b1,b2,b3) ((const BYTE_LOOKUP *)((((unsigned char)(b1))<< 8)|(((unsigned char)(b2))<<16)|(((unsigned char)(b3))<<24)|((((unsigned char)(b0))&0x07)<<5)|FOURbt))

#define getBT1(a)      (((a)>> 8)&0xFF)
#define getBT2(a)      (((a)>>16)&0xFF)
#define getBT3(a)      (((a)>>24)&0xFF)
#define getBT0(a)      ((((a)>> 5)&0x07)|0xF0)   /* for UTF-8 only!!! */

/* do we need these??? maybe not, can be done with simple tables */
#define ONETRAIL       /* legal but undefined if one more trailing UTF-8 */
#define TWOTRAIL       /* legal but undefined if two more trailing UTF-8 */
#define THREETRAIL     /* legal but undefined if three more trailing UTF-8 */

/* dynamic structure, one per conversion (similar to iconv_t) */
/* may carry conversion state (e.g. for iso-2022-jp) */
typedef struct rb_transcoding {
    VALUE ruby_string_dest; /* the String used as the conversion destination,
			       or NULL if something else is being converted */
    char *(*flush_func)(struct rb_transcoding*, int, int);
} rb_transcoding;

/* static structure, one per supported encoding pair */
typedef struct rb_transcoder {
    const char *from_encoding;
    const char *to_encoding;
    const BYTE_LOOKUP *conv_tree_start;
    int max_output;
    int from_utf8;
    void (*preprocessor)(char**, char**, char*, char*,
			 struct rb_transcoder *, struct rb_transcoding *);
    void (*postprocessor)(char**, char**, char*, char*,
			 struct rb_transcoder *, struct rb_transcoding *);
} rb_transcoder;

void rb_declare_transcoder(const char *enc1, const char *enc2, const char *lib);
void rb_register_transcoder(const rb_transcoder *);

#endif /* RUBY_TRANSCODE_DATA_H */