/* Copyright 2009 Daniel Martin                                             */
/*                                                                          */
/* Licensed under the Apache License, Version 2.0 (the "License");          */
/* you may not use this file except in compliance with the License.         */
/* You may obtain a copy of the License at                                  */
/*                                                                          */
/*     http://www.apache.org/licenses/LICENSE-2.0                           */
/*                                                                          */
/* Unless required by applicable law or agreed to in writing, software      */
/* distributed under the License is distributed on an "AS IS" BASIS,        */
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. */
/* See the License for the specific language governing permissions and      */
/* limitations under the License.                                           */

#include <stdint.h>

#ifndef _UTF8CHECKER_H_
#define _UTF8CHECKER_H_ 1

/* Ways a UTF stream can screw up */
#define MISSING_CONTINUATION 1 /* a multibyte sequence without as many continuation bytes as expected.  e.g. [ef 81] 48 */
#define UNEXPECTED_CONTINUATION 2 /* A continuation byte when not expected */
#define OVERLONG_FORM 3 /* A full multibyte sequence encoding something that should have been encoded shorter */
#define OUT_OF_RANGE 4 /* A full multibyte sequence encoding something larger than 10FFFF */
#define BAD_SCALAR_VALUE 5 /* A full multibyte sequence encoding something in the range U+D800..U+DFFF */
#define INVALID 6 /* bytes 0xFE or 0xFF */

/* called with: errorCode, bytes_so_far, unichars_so_far, invalid_byte_buf, invalid_byte_buf_len */
/* NOTE: treat passed byte buffer as a constant, and as something that vanishes after this call returns! */
typedef void (*error_handler)(int, int, int, uint8_t *, int);

/* called with: unicode character, bytes_so_far, unichars_so_far, byte_buf, byte_buf_len */
/* NOTE: treat passed byte buffer as a constant, and as something that vanishes after this call returns! */
typedef void (*unicode_handler)(uint32_t, int, int, uint8_t *, int);

typedef struct {
    uint8_t working[6];
    int working_len;
    int unichars_so_far;
    int bytes_so_far;
    int expecting_continuation;
} utf8_decoder_state_struct;

typedef utf8_decoder_state_struct *utf8_decoder_state;

utf8_decoder_state init_utf8_decoder_state(utf8_decoder_state state);
void process_byte(uint8_t incoming, utf8_decoder_state state, unicode_handler unih, error_handler errh);
void end_processing(utf8_decoder_state state, error_handler errh);

#endif