1 // Copyright (c) 2005-2009 Nokia Corporation and/or its subsidiary(-ies).

     2 // All rights reserved.

     3 // This component and the accompanying materials are made available

     4 // under the terms of the License "Eclipse Public License v1.0"

     5 // which accompanies this distribution, and is available

     6 // at the URL "http://www.eclipse.org/legal/epl-v10.html".

     7 //

     8 // Initial Contributors:

     9 // Nokia Corporation - initial contribution.

    10 //

    11 // Contributors:

    12 //

    13 // Description:

    14 // e32\kernel\byte_pair.cpp

    15 // 

    16 //

    17 

    18 #include <e32cia.h>

    19 #include "u32std.h"

    20 

    21 TInt BytePairDecompress(TUint8* dst, TInt dstSize, TUint8* src, TInt srcSize, TUint8*& srcNext)

    22 	{

    23 	TUint8* dstStart = dst;

    24 	TUint8* dstEnd = dst+dstSize;

    25 	TUint8* srcEnd = src+srcSize;

    26 

    27 	TUint32 LUT[0x100/2];

    28 	TUint8* LUT0 = (TUint8*)LUT;

    29 	TUint8* LUT1 = LUT0+0x100;

    30 

    31 	TUint8 stack[0x100];

    32 	TUint8* stackStart = stack+sizeof(stack);

    33 	TUint8* sp = stackStart;

    34 

    35 	TUint32 marker = ~0u;

    36 	TInt numTokens;

    37 	TUint32 p1;

    38 	TUint32 p2;

    39 

    40 	TUint32* l = (TUint32*)LUT;

    41 	TUint32 b = 0x03020100;

    42 	TUint32 step = 0x04040404;

    43 	do

    44 		{

    45 		*l++ = b;

    46 		b += step;

    47 		}

    48 	while(b>step);

    49 

    50 	if(src>=srcEnd)

    51 		goto error;

    52 	numTokens = *src++;

    53 	if(numTokens)

    54 		{

    55 		if(src>=srcEnd)

    56 			goto error;

    57 		marker = *src++;

    58 		LUT0[marker] = (TUint8)~marker;

    59 

    60 		if(numTokens<32)

    61 			{

    62 			TUint8* tokenEnd = src+3*numTokens;

    63 			if(tokenEnd>srcEnd)

    64 				goto error;

    65 			do

    66 				{

    67 				TInt b = *src++;

    68 				TInt p1 = *src++;

    69 				TInt p2 = *src++;

    70 				LUT0[b] = (TUint8)p1;

    71 				LUT1[b] = (TUint8)p2;

    72 				}

    73 			while(src<tokenEnd);

    74 			}

    75 		else

    76 			{

    77 			TUint8* bitMask = src;

    78 			src += 32;

    79 			if(src>srcEnd)

    80 				goto error;

    81 			TInt b=0;

    82 			do

    83 				{

    84 				TUint8 mask = bitMask[b>>3];

    85 				if(mask&(1<<(b&7)))

    86 					{

    87 					if(src>=srcEnd)

    88 						goto error;

    89 					TInt p1 = *src++;

    90 					if(src>=srcEnd)

    91 						goto error;

    92 					TInt p2 = *src++;

    93 					LUT0[b] = (TUint8)p1;

    94 					LUT1[b] = (TUint8)p2;		

    95 					--numTokens;

    96 					}

    97 				++b;

    98 				}

    99 			while(b<0x100);

   100 			if(numTokens)

   101 				goto error;

   102 			}

   103 		}

   104 

   105 	if(src>=srcEnd)

   106 		goto error;

   107 	b = *src++;

   108 	if(dst>=dstEnd)

   109 		goto error;

   110 	p1 = LUT0[b];

   111 	if(p1!=b)

   112 		goto not_single;

   113 next:

   114 	if(src>=srcEnd)

   115 		goto done_s;

   116 	b = *src++;

   117 	*dst++ = (TUint8)p1;

   118 	if(dst>=dstEnd)

   119 		goto done_d;

   120 	p1 = LUT0[b];

   121 	if(p1==b)

   122 		goto next;

   123 

   124 not_single:

   125 	if(b==marker)

   126 		goto do_marker;

   127 

   128 do_pair:

   129 	p2 = LUT1[b];

   130 	b = p1;

   131 	p1 = LUT0[b];

   132 	if(sp<=stack)

   133 		goto error;

   134 	*--sp = (TUint8)p2;

   135 

   136 recurse:

   137 	if(b!=p1)

   138 		goto do_pair;

   139 

   140 	if(sp==stackStart)

   141 		goto next;

   142 	b = *sp++;

   143 	*dst++ = (TUint8)p1;

   144 	if(dst>=dstEnd)

   145 		goto error;

   146 	p1 = LUT0[b];

   147 	goto recurse;

   148 

   149 do_marker:

   150 	if(src>=srcEnd)

   151 		goto error;

   152 	p1 = *src++;

   153 	goto next;

   154 

   155 error:

   156 	srcNext = 0;

   157 	return KErrCorrupt;

   158 

   159 done_s:

   160 	*dst++ = (TUint8)p1;

   161 	srcNext = src;

   162 	return dst-dstStart;

   163 

   164 done_d:

   165 	--src;

   166 	srcNext = src;

   167 	return dst-dstStart;

   168 	}

   169 

   170