xref: /third_party/icu/icu4c/source/tools/genrb/rle.h (revision 2e5b6d6d)
1// © 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/*
4*******************************************************************************
5*
6*   Copyright (C) 2000, International Business Machines
7*   Corporation and others.  All Rights Reserved.
8*
9*******************************************************************************
10*
11* File writejava.c
12*
13* Modification History:
14*
15*   Date        Name        Description
16*   01/11/02    Ram        Creation.
17*******************************************************************************
18*/
19
20#ifndef RLE_H
21#define RLE_H 1
22
23#include "unicode/utypes.h"
24#include "unicode/ustring.h"
25
26U_CDECL_BEGIN
27/**
28 * Construct a string representing a byte array.  Use run-length encoding.
29 * Two bytes are packed into a single char, with a single extra zero byte at
30 * the end if needed.  A byte represents itself, unless it is the
31 * ESCAPE_BYTE.  Then the following notations are possible:
32 *   ESCAPE_BYTE ESCAPE_BYTE   ESCAPE_BYTE literal
33 *   ESCAPE_BYTE n b           n instances of byte b
34 * Since an encoded run occupies 3 bytes, we only encode runs of 4 or
35 * more bytes.  Thus we have n > 0 and n != ESCAPE_BYTE and n <= 0xFF.
36 * If we encounter a run where n == ESCAPE_BYTE, we represent this as:
37 *   b ESCAPE_BYTE n-1 b
38 * The ESCAPE_BYTE value is chosen so as not to collide with commonly
39 * seen values.
40 */
41int32_t
42byteArrayToRLEString(const uint8_t* src,int32_t srcLen, uint16_t* buffer,int32_t bufLen, UErrorCode* status);
43
44
45/**
46 * Construct a string representing a char array.  Use run-length encoding.
47 * A character represents itself, unless it is the ESCAPE character.  Then
48 * the following notations are possible:
49 *   ESCAPE ESCAPE   ESCAPE literal
50 *   ESCAPE n c      n instances of character c
51 * Since an encoded run occupies 3 characters, we only encode runs of 4 or
52 * more characters.  Thus we have n > 0 and n != ESCAPE and n <= 0xFFFF.
53 * If we encounter a run where n == ESCAPE, we represent this as:
54 *   c ESCAPE n-1 c
55 * The ESCAPE value is chosen so as not to collide with commonly
56 * seen values.
57 */
58int32_t
59usArrayToRLEString(const uint16_t* src,int32_t srcLen,uint16_t* buffer, int32_t bufLen,UErrorCode* status);
60
61/**
62 * Construct an array of bytes from a run-length encoded string.
63 */
64int32_t
65rleStringToByteArray(uint16_t* src, int32_t srcLen, uint8_t* target, int32_t tgtLen, UErrorCode* status);
66/**
67 * Construct an array of shorts from a run-length encoded string.
68 */
69int32_t
70rleStringToUCharArray(uint16_t* src, int32_t srcLen, uint16_t* target, int32_t tgtLen, UErrorCode* status);
71
72U_CDECL_END
73
74#endif
75