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authorvanjeff <vanjeff@6f19259b-4bc3-4df7-8a09-765794883524>2006-07-19 17:37:07 +0000
committervanjeff <vanjeff@6f19259b-4bc3-4df7-8a09-765794883524>2006-07-19 17:37:07 +0000
commit1ea5ca46c7eefe66a01cb4db3b72fc0e5a04e2cb (patch)
tree11db61e6d73e5a6b0bca974e7e4a8e29f1344a49 /MdePkg/Library/BaseUefiDecompressLib
parentebfe209ec07c4105baba33576457a4bd6c798a2b (diff)
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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
Diffstat (limited to 'MdePkg/Library/BaseUefiDecompressLib')
-rw-r--r--MdePkg/Library/BaseUefiDecompressLib/BaseUefiDecompressLib.c191
1 files changed, 160 insertions, 31 deletions
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;