icuSources/tools/genrb/rle.h

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