From 1ea5ca46c7eefe66a01cb4db3b72fc0e5a04e2cb Mon Sep 17 00:00:00 2001 From: vanjeff Date: Wed, 19 Jul 2006 17:37:07 +0000 Subject: 1. added functions header for BaseUefiDecompressLi 2. added some internal functions header for BaseLib 3. added EFIAPI for some internal assembly files declare git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@1050 6f19259b-4bc3-4df7-8a09-765794883524 --- .../BaseUefiDecompressLib/BaseUefiDecompressLib.c | 191 +++++++++++++++++---- 1 file changed, 160 insertions(+), 31 deletions(-) (limited to 'MdePkg/Library/BaseUefiDecompressLib') diff --git a/MdePkg/Library/BaseUefiDecompressLib/BaseUefiDecompressLib.c b/MdePkg/Library/BaseUefiDecompressLib/BaseUefiDecompressLib.c index ee832f0b2f..c0c79c7c4a 100644 --- a/MdePkg/Library/BaseUefiDecompressLib/BaseUefiDecompressLib.c +++ b/MdePkg/Library/BaseUefiDecompressLib/BaseUefiDecompressLib.c @@ -69,9 +69,11 @@ typedef struct { } 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 Sd The global scratch data @param NumOfBits The number of bits to shift and read. **/ @@ -81,8 +83,14 @@ FillBuf ( 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))); @@ -92,7 +100,6 @@ FillBuf ( // Get 1 byte into SubBitBuf // Sd->mCompSize--; - Sd->mSubBitBuf = 0; Sd->mSubBitBuf = Sd->mSrcBase[Sd->mInBuf++]; Sd->mBitCount = 8; @@ -106,16 +113,25 @@ FillBuf ( } } + // + // 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 Sd The global scratch data. @param NumOfBits The number of bits to pop and read. @return The bits that are popped out. @@ -129,8 +145,14 @@ GetBits ( { UINT32 OutBits; + // + // Pop NumOfBits of Bits from Left + // OutBits = (UINT32) (Sd->mBitBuf >> (BITBUFSIZ - NumOfBits)); + // + // Fill up mBitBuf from source + // FillBuf (Sd, NumOfBits); return OutBits; @@ -139,11 +161,14 @@ GetBits ( /** Creates Huffman Code mapping table according to code length array. - @param Sd The global scratch data + 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 BitLen Code length array @param TableBits The width of the mapping table - @param Table The table + @param Table The table @retval 0 OK. @retval BAD_TABLE The table is corrupted. @@ -266,6 +291,8 @@ MakeTable ( /** Decodes a position value. + Get a position value according to Position Huffman Table. + @param Sd the global scratch data @return The position value decoded. @@ -312,9 +339,12 @@ DecodeP ( /** Reads code lengths for the Extra Set or the Position Set. - @param Sd The global scratch data. - @param nn Number of symbols. - @param nbit Number of bits needed to represent nn. + 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. @@ -334,9 +364,15 @@ ReadPTLen ( 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++) { @@ -356,6 +392,11 @@ ReadPTLen ( 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) { @@ -363,11 +404,17 @@ ReadPTLen ( 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. + // if (Index == Special) { CharC = (UINT16) GetBits (Sd, 2); while ((INT16) (--CharC) >= 0) { @@ -379,12 +426,15 @@ ReadPTLen ( while (Index < nn) { Sd->mPTLen[Index++] = 0; } - + return MakeTable (Sd, nn, Sd->mPTLen, 8, Sd->mPTTable); } /** Reads code lengths for Char&Len Set. + + Read in and decode the Char&Len Set Code Length Array, then + generate the Huffman Code mapping table for the Char&Len Set. @param Sd the global scratch data @@ -394,14 +444,17 @@ ReadCLen ( SCRATCH_DATA *Sd ) { - UINT16 Number; - UINT16 CharC; + UINT16 Number; + UINT16 CharC; volatile UINT16 Index; - UINT32 Mask; + UINT32 Mask; Number = (UINT16) GetBits (Sd, CBIT); if (Number == 0) { + // + // This represents only Huffman code used + // CharC = (UINT16) GetBits (Sd, CBIT); for (Index = 0; Index < NC; Index++) { @@ -417,7 +470,6 @@ ReadCLen ( Index = 0; while (Index < Number) { - CharC = Sd->mPTTable[Sd->mBitBuf >> (BITBUFSIZ - 8)]; if (CharC >= NT) { Mask = 1U << (BITBUFSIZ - 1 - 8); @@ -471,6 +523,10 @@ ReadCLen ( /** Decode a character/length value. + + Read one value from mBitBuf, Get one code from mBitBuf. If it is at block boundary, generates + Huffman code mapping table for Extra Set, Code&Len Set and + Position Set. @param Sd The global scratch data. @@ -488,21 +544,38 @@ DecodeC ( if (Sd->mBlockSize == 0) { // // Starting a new block - // + // Read BlockSize from block header + // Sd->mBlockSize = (UINT16) GetBits (Sd, 16); + + // + // Read in the Extra Set Code Length Arrary, + // Generate the Huffman code mapping table for Extra Set. + // Sd->mBadTableFlag = ReadPTLen (Sd, NT, TBIT, 3); if (Sd->mBadTableFlag != 0) { return 0; } + // + // Read in and decode the Char&Len Set Code Length Arrary, + // Generate the Huffman code mapping table for Char&Len Set. + // ReadCLen (Sd); + // + // Read in the Position Set Code Length Arrary, + // Generate the Huffman code mapping table for the Position Set. + // Sd->mBadTableFlag = ReadPTLen (Sd, MAXNP, Sd->mPBit, (UINT16) (-1)); if (Sd->mBadTableFlag != 0) { return 0; } } + // + // Get one code according to Code&Set Huffman Table + // Sd->mBlockSize--; Index2 = Sd->mCTable[Sd->mBitBuf >> (BITBUFSIZ - 12)]; @@ -530,6 +603,8 @@ DecodeC ( /** Decode the source data and put the resulting data into the destination buffer. + Decode the source data and put the resulting data into the destination buffer. + @param Sd The global scratch data **/ @@ -547,6 +622,9 @@ Decode ( DataIdx = 0; for (;;) { + // + // Get one code from mBitBuf + // CharC = DecodeC (Sd); if (Sd->mBadTableFlag != 0) { return ; @@ -559,6 +637,9 @@ Decode ( if (Sd->mOutBuf >= Sd->mOrigSize) { return ; } else { + // + // Write orignal character into mDstBase + // Sd->mDstBase[Sd->mOutBuf++] = (UINT8) CharC; } @@ -567,11 +648,20 @@ Decode ( // Process a Pointer // CharC = (UINT16) (CharC - (UINT8_MAX + 1 - THRESHOLD)); - + + // + // Get string length + // BytesRemain = CharC; + // + // Locate string position + // DataIdx = Sd->mOutBuf - DecodeP (Sd) - 1; + // + // Write BytesRemain of bytes into mDstBase + // BytesRemain--; while ((INT16) (BytesRemain) >= 0) { Sd->mDstBase[Sd->mOutBuf++] = Sd->mDstBase[DataIdx++]; @@ -588,14 +678,35 @@ Decode ( } /** - The internal implementation of *_DECOMPRESS_PROTOCOL.GetInfo(). - - @param Source The source buffer containing the compressed data. - @param SourceSize The size of source buffer - @param DestinationSize The size of destination buffer. - @param ScratchSize The size of scratch buffer. - - @retval RETURN_SUCCESS The size of destination buffer and the size of scratch buffer are successull retrieved. + Retrieves the size of the uncompressed buffer and the size of the scratch buffer. + + Retrieves the size of the uncompressed buffer and the temporary scratch buffer + required to decompress the buffer specified by Source and SourceSize. + If the size of the uncompressed buffer or the size of the scratch buffer cannot + be determined from the compressed data specified by Source and SourceData, + then RETURN_INVALID_PARAMETER is returned. Otherwise, the size of the uncompressed + buffer is returned in DestinationSize, the size of the scratch buffer is returned + in ScratchSize, and RETURN_SUCCESS is returned. + This function does not have scratch buffer available to perform a thorough + checking of the validity of the source data. It just retrieves the "Original Size" + field from the beginning bytes of the source data and output it as DestinationSize. + And ScratchSize is specific to the decompression implementation. + + If Source is NULL, then ASSERT(). + If DestinationSize is NULL, then ASSERT(). + If ScratchSize is NULL, then ASSERT(). + + @param Source The source buffer containing the compressed data. + @param SourceSize The size, in bytes, of the source buffer. + @param DestinationSize A pointer to the size, in bytes, of the uncompressed buffer + that will be generated when the compressed buffer specified + by Source and SourceSize is decompressed.. + @param ScratchSize A pointer to the size, in bytes, of the scratch buffer that + is required to decompress the compressed buffer specified + by Source and SourceSize. + + @retval RETURN_SUCCESS The size of destination buffer and the size of scratch + buffer are successull retrieved. @retval RETURN_INVALID_PARAMETER The source data is corrupted **/ @@ -631,12 +742,27 @@ UefiDecompressGetInfo ( } /** - The internal implementation of *_DECOMPRESS_PROTOCOL.Decompress(). - - @param Source The source buffer containing the compressed data. + Decompresses a compressed source buffer. + + This function is designed so that the decompression algorithm can be implemented + without using any memory services. As a result, this function is not allowed to + call any memory allocation services in its implementation. It is the caller¡¯s r + esponsibility to allocate and free the Destination and Scratch buffers. + If the compressed source data specified by Source is sucessfully decompressed + into Destination, then RETURN_SUCCESS is returned. If the compressed source data + specified by Source is not in a valid compressed data format, + then RETURN_INVALID_PARAMETER is returned. + + If Source is NULL, then ASSERT(). + If Destination is NULL, then ASSERT(). + If the required scratch buffer size > 0 and Scratch is NULL, then ASSERT(). + + @param Source The source buffer containing the compressed data. @param Destination The destination buffer to store the decompressed data - @param Scratch The buffer used internally by the decompress routine. This buffer is needed to store intermediate data. - + @param Scratch A temporary scratch buffer that is used to perform the decompression. + This is an optional parameter that may be NULL if the + required scratch buffer size is 0. + @retval RETURN_SUCCESS Decompression is successfull @retval RETURN_INVALID_PARAMETER The source data is corrupted @@ -688,6 +814,9 @@ UefiDecompress ( Sd->mPBit = 4; Sd->mSrcBase = (UINT8 *)Src; Sd->mDstBase = Dst; + // + // CompSize and OrigSize are caculated in bytes + // Sd->mCompSize = CompSize; Sd->mOrigSize = OrigSize; -- cgit v1.2.3