baseuefidecompresslib.c

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/*++

Copyright (c) 2004 - 2006, Intel Corporation                                                         
All rights reserved. This program and the accompanying materials                          
are licensed and made available under the terms and conditions of the BSD License         
which accompanies this distribution.  The full text of the license may be found at        
http://opensource.org/licenses/bsd-license.php                                            
                                                                                          
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.  


Module Name:

  BaseUefiDecompressLib.c
  
Abstract: 

  UEFI Decompress Library.

--*/

#include "EdkIIGlueBase.h"

//
// Decompression algorithm begins here
//
#define BITBUFSIZ 32
#define MAXMATCH  256
#define THRESHOLD 3
#define CODE_BIT  16
#define BAD_TABLE - 1

//
// C: Char&Len Set; P: Position Set; T: exTra Set
//
#define NC      (0xff + MAXMATCH + 2 - THRESHOLD)
#define CBIT    9
#define MAXPBIT 5
#define TBIT    5
#define MAXNP   ((1U << MAXPBIT) - 1)
#define NT      (CODE_BIT + 3)
#if NT > MAXNP
#define NPT NT
#else
#define NPT MAXNP
#endif

typedef struct {
  UINT8   *mSrcBase;  ///< Starting address of compressed data
  UINT8   *mDstBase;  ///< Starting address of decompressed data
  UINT32  mOutBuf;
  UINT32  mInBuf;

  UINT16  mBitCount;
  UINT32  mBitBuf;
  UINT32  mSubBitBuf;
  UINT16  mBlockSize;
  UINT32  mCompSize;
  UINT32  mOrigSize;

  UINT16  mBadTableFlag;

  UINT16  mLeft[2 * NC - 1];
  UINT16  mRight[2 * NC - 1];
  UINT8   mCLen[NC];
  UINT8   mPTLen[NPT];
  UINT16  mCTable[4096];
  UINT16  mPTTable[256];

  ///
  /// The length of the field 'Position Set Code Length Array Size' in Block Header.
  /// For EFI 1.1 de/compression algorithm, mPBit = 4
  /// For Tiano de/compression algorithm, mPBit = 5
  ///
  UINT8   mPBit;
} SCRATCH_DATA;

/**
  Read NumOfBit of bits from source into mBitBuf

  Shift mBitBuf NumOfBits left. Read in NumOfBits of bits from source.

  @param  Sd        The global scratch data
  @param  NumOfBits The number of bits to shift and read.

**/
VOID
GlueFillBuf (
  IN  SCRATCH_DATA  *Sd,
  IN  UINT16        NumOfBits
  )
{
  //
  // Left shift NumOfBits of bits in advance
  //
  Sd->mBitBuf = (UINT32) (Sd->mBitBuf << NumOfBits);

  //
  // Copy data needed in bytes into mSbuBitBuf
  //
  while (NumOfBits > Sd->mBitCount) {

    Sd->mBitBuf |= (UINT32) (Sd->mSubBitBuf << (NumOfBits = (UINT16) (NumOfBits - Sd->mBitCount)));

    if (Sd->mCompSize > 0) {
      //
      // Get 1 byte into SubBitBuf
      //
      Sd->mCompSize--;
      Sd->mSubBitBuf  = Sd->mSrcBase[Sd->mInBuf++];
      Sd->mBitCount   = 8;

    } else {
      //
      // No more bits from the source, just pad zero bit.
      //
      Sd->mSubBitBuf  = 0;
      Sd->mBitCount   = 8;

    }
  }

  //
  // Caculate additional bit count read to update mBitCount
  //
  Sd->mBitCount = (UINT16) (Sd->mBitCount - NumOfBits);
  
  //
  // Copy NumOfBits of bits from mSubBitBuf into mBitBuf
  //
  Sd->mBitBuf |= Sd->mSubBitBuf >> Sd->mBitCount;
}

/**
  Get NumOfBits of bits out from mBitBuf

  Get NumOfBits of bits out from mBitBuf. Fill mBitBuf with subsequent 
  NumOfBits of bits from source. Returns NumOfBits of bits that are 
  popped out.

  @param  Sd        The global scratch data.
  @param  NumOfBits The number of bits to pop and read.

  @return The bits that are popped out.

**/
UINT32
GlueGetBits (
  IN  SCRATCH_DATA  *Sd,
  IN  UINT16        NumOfBits
  )
{
  UINT32  OutBits;

  //
  // Pop NumOfBits of Bits from Left
  //  
  OutBits = (UINT32) (Sd->mBitBuf >> (BITBUFSIZ - NumOfBits));

  //
  // Fill up mBitBuf from source
  //
  FillBuf (Sd, NumOfBits);

  return OutBits;
}

/**
  Creates Huffman Code mapping table according to code length array.

  Creates Huffman Code mapping table for Extra Set, Char&Len Set 
  and Position Set according to code length array.

  @param  Sd        The global scratch data
  @param  NumOfChar Number of symbols in the symbol set
  @param  BitLen    Code length array
  @param  TableBits The width of the mapping table
  @param  Table     The table

  @retval  0 OK.
  @retval  BAD_TABLE The table is corrupted.

**/
UINT16
GlueMakeTable (
  IN  SCRATCH_DATA  *Sd,
  IN  UINT16        NumOfChar,
  IN  UINT8         *BitLen,
  IN  UINT16        TableBits,
  OUT UINT16        *Table
  )
{
  UINT16  Count[17];
  UINT16  Weight[17];
  UINT16  Start[18];
  UINT16  *Pointer;
  UINT16  Index3;
  volatile UINT16  Index;
  UINT16  Len;
  UINT16  Char;
  UINT16  JuBits;
  UINT16  Avail;
  UINT16  NextCode;
  UINT16  Mask;

  for (Index = 1; Index <= 16; Index++) {
    Count[Index] = 0;
  }

  for (Index = 0; Index < NumOfChar; Index++) {
    Count[BitLen[Index]]++;
  }

  Start[1] = 0;

  for (Index = 1; Index <= 16; Index++) {
    Start[Index + 1] = (UINT16) (Start[Index] + (Count[Index] << (16 - Index)));
  }

  if (Start[17] != 0) {
    /*(1U << 16)*/
    return (UINT16) BAD_TABLE;
  }

  JuBits = (UINT16) (16 - TableBits);

  for (Index = 1; Index <= TableBits; Index++) {
    Start[Index] >>= JuBits;
    Weight[Index] = (UINT16) (1U << (TableBits - Index));
  }

  while (Index <= 16) {
    Weight[Index] = (UINT16) (1U << (16 - Index));
    Index++;    
  }

  Index = (UINT16) (Start[TableBits + 1] >> JuBits);

  if (Index != 0) {
    Index3 = (UINT16) (1U << TableBits);
    while (Index != Index3) {
      Table[Index++] = 0;
    }
  }

  Avail = NumOfChar;
  Mask  = (UINT16) (1U << (15 - TableBits));

  for (Char = 0; Char < NumOfChar; Char++) {

    Len = BitLen[Char];
    if (Len == 0) {
      continue;
    }

    NextCode = (UINT16) (Start[Len] + Weight[Len]);

    if (Len <= TableBits) {

      for (Index = Start[Len]; Index < NextCode; Index++) {
        Table[Index] = Char;
      }

    } else {

      Index3  = Start[Len];
      Pointer = &Table[Index3 >> JuBits];
      Index   = (UINT16) (Len - TableBits);

      while (Index != 0) {
        if (*Pointer == 0) {
          Sd->mRight[Avail]                     = Sd->mLeft[Avail] = 0;
          *Pointer = Avail++;
        }

        if (Index3 & Mask) {
          Pointer = &Sd->mRight[*Pointer];
        } else {
          Pointer = &Sd->mLeft[*Pointer];
        }

        Index3 <<= 1;
        Index--;
      }

      *Pointer = Char;

    }

    Start[Len] = NextCode;
  }
  //
  // Succeeds
  //
  return 0;
}

/**
  Decodes a position value.

  Get a position value according to Position Huffman Table.
  
  @param  Sd the global scratch data

  @return The position value decoded.

**/
UINT32
GlueDecodeP (
  IN  SCRATCH_DATA  *Sd
  )
{
  UINT16  Val;
  UINT32  Mask;
  UINT32  Pos;

  Val = Sd->mPTTable[Sd->mBitBuf >> (BITBUFSIZ - 8)];

  if (Val >= MAXNP) {
    Mask = 1U << (BITBUFSIZ - 1 - 8);

    do {

      if (Sd->mBitBuf & Mask) {
        Val = Sd->mRight[Val];
      } else {
        Val = Sd->mLeft[Val];
      }

      Mask >>= 1;
    } while (Val >= MAXNP);
  }
  //
  // Advance what we have read
  //
  FillBuf (Sd, Sd->mPTLen[Val]);

  Pos = Val;
  if (Val > 1) {
    Pos = (UINT32) ((1U << (Val - 1)) + GetBits (Sd, (UINT16) (Val - 1)));
  }

  return Pos;
}

/**
  Reads code lengths for the Extra Set or the Position Set.

  Read in the Extra Set or Pointion Set Length Arrary, then
  generate the Huffman code mapping for them.

  @param  Sd      The global scratch data.
  @param  nn      Number of symbols.
  @param  nbit    Number of bits needed to represent nn.
  @param  Special The special symbol that needs to be taken care of.

  @retval  0 OK.
  @retval  BAD_TABLE Table is corrupted.

**/
UINT16
GlueReadPTLen (
  IN  SCRATCH_DATA  *Sd,
  IN  UINT16        nn,
  IN  UINT16        nbit,
  IN  UINT16        Special
  )
{
  UINT16  Number;
  UINT16  CharC;
  volatile UINT16  Index;
  UINT32  Mask;

  //
  // Read Extra Set Code Length Array size 
  //
  Number = (UINT16) GetBits (Sd, nbit);

  if (Number == 0) {
    //
    // This represents only Huffman code used
    //
    CharC = (UINT16) GetBits (Sd, nbit);

    for (Index = 0; Index < 256; Index++) {
      Sd->mPTTable[Index] = CharC;
    }

    for (Index = 0; Index < nn; Index++) {
      Sd->mPTLen[Index] = 0;
    }

    return 0;
  }

  Index = 0;

  while (Index < Number) {

    CharC = (UINT16) (Sd->mBitBuf >> (BITBUFSIZ - 3));

    //
    // If a code length is less than 7, then it is encoded as a 3-bit
    // value. Or it is encoded as a series of "1"s followed by a 
    // terminating "0". The number of "1"s = Code length - 4.
    //
    if (CharC == 7) {
      Mask = 1U << (BITBUFSIZ - 1 - 3);
      while (Mask & Sd->mBitBuf) {
        Mask >>= 1;
        CharC += 1;
      }
    }
    
    FillBuf (Sd, (UINT16) ((CharC < 7) ? 3 : CharC - 3));

    Sd->mPTLen[Index++] = (UINT8) CharC;
 
    //
    // For Code&Len Set, 
    // After the third length of the code length concatenation,
    // a 2-bit value is used to indicated the number of consecutive 
    // zero lengths after the third length.
    //