1087 lines
24 KiB
C++
1087 lines
24 KiB
C++
///////////////////////////////////////////////////////////////////////////
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//
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// Copyright (c) 2002, Industrial Light & Magic, a division of Lucas
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// Digital Ltd. LLC
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Industrial Light & Magic nor the names of
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// its contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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///////////////////////////////////////////////////////////////////////////
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//-----------------------------------------------------------------------------
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//
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// 16-bit Huffman compression and decompression.
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//
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// The source code in this file is derived from the 8-bit
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// Huffman compression and decompression routines written
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// by Christian Rouet for his PIZ image file format.
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//
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//-----------------------------------------------------------------------------
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#include <ImfHuf.h>
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#include <ImfInt64.h>
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#include <ImfAutoArray.h>
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#include "Iex.h"
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#include <string.h>
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#include <assert.h>
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#include <algorithm>
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using namespace std;
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using namespace Iex;
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namespace Imf {
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namespace {
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const int HUF_ENCBITS = 16; // literal (value) bit length
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const int HUF_DECBITS = 14; // decoding bit size (>= 8)
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const int HUF_ENCSIZE = (1 << HUF_ENCBITS) + 1; // encoding table size
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const int HUF_DECSIZE = 1 << HUF_DECBITS; // decoding table size
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const int HUF_DECMASK = HUF_DECSIZE - 1;
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struct HufDec
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{ // short code long code
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//-------------------------------
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int len:8; // code length 0
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int lit:24; // lit p size
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int * p; // 0 lits
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};
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void
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invalidNBits ()
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{
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throw InputExc ("Error in header for Huffman-encoded data "
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"(invalid number of bits).");
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}
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void
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tooMuchData ()
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{
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throw InputExc ("Error in Huffman-encoded data "
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"(decoded data are longer than expected).");
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}
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void
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notEnoughData ()
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{
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throw InputExc ("Error in Huffman-encoded data "
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"(decoded data are shorter than expected).");
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}
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void
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invalidCode ()
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{
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throw InputExc ("Error in Huffman-encoded data "
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"(invalid code).");
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}
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void
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invalidTableSize ()
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{
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throw InputExc ("Error in Huffman-encoded data "
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"(invalid code table size).");
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}
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void
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unexpectedEndOfTable ()
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{
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throw InputExc ("Error in Huffman-encoded data "
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"(unexpected end of code table data).");
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}
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void
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tableTooLong ()
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{
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throw InputExc ("Error in Huffman-encoded data "
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"(code table is longer than expected).");
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}
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void
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invalidTableEntry ()
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{
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throw InputExc ("Error in Huffman-encoded data "
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"(invalid code table entry).");
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}
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inline Int64
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hufLength (Int64 code)
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{
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return code & 63;
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}
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inline Int64
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hufCode (Int64 code)
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{
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return code >> 6;
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}
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inline void
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outputBits (int nBits, Int64 bits, Int64 &c, int &lc, char *&out)
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{
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c <<= nBits;
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lc += nBits;
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c |= bits;
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while (lc >= 8)
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*out++ = (c >> (lc -= 8));
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}
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inline Int64
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getBits (int nBits, Int64 &c, int &lc, const char *&in)
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{
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while (lc < nBits)
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{
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c = (c << 8) | *(unsigned char *)(in++);
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lc += 8;
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}
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lc -= nBits;
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return (c >> lc) & ((1 << nBits) - 1);
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}
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//
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// ENCODING TABLE BUILDING & (UN)PACKING
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//
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//
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// Build a "canonical" Huffman code table:
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// - for each (uncompressed) symbol, hcode contains the length
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// of the corresponding code (in the compressed data)
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// - canonical codes are computed and stored in hcode
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// - the rules for constructing canonical codes are as follows:
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// * shorter codes (if filled with zeroes to the right)
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// have a numerically higher value than longer codes
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// * for codes with the same length, numerical values
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// increase with numerical symbol values
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// - because the canonical code table can be constructed from
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// symbol lengths alone, the code table can be transmitted
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// without sending the actual code values
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// - see http://www.compressconsult.com/huffman/
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//
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void
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hufCanonicalCodeTable (Int64 hcode[HUF_ENCSIZE])
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{
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Int64 n[59];
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//
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// For each i from 0 through 58, count the
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// number of different codes of length i, and
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// store the count in n[i].
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//
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for (int i = 0; i <= 58; ++i)
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n[i] = 0;
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for (int i = 0; i < HUF_ENCSIZE; ++i)
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n[hcode[i]] += 1;
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//
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// For each i from 58 through 1, compute the
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// numerically lowest code with length i, and
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// store that code in n[i].
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//
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Int64 c = 0;
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for (int i = 58; i > 0; --i)
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{
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Int64 nc = ((c + n[i]) >> 1);
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n[i] = c;
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c = nc;
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}
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//
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// hcode[i] contains the length, l, of the
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// code for symbol i. Assign the next available
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// code of length l to the symbol and store both
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// l and the code in hcode[i].
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//
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for (int i = 0; i < HUF_ENCSIZE; ++i)
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{
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int l = hcode[i];
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if (l > 0)
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hcode[i] = l | (n[l]++ << 6);
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}
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}
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//
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// Compute Huffman codes (based on frq input) and store them in frq:
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// - code structure is : [63:lsb - 6:msb] | [5-0: bit length];
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// - max code length is 58 bits;
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// - codes outside the range [im-iM] have a null length (unused values);
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// - original frequencies are destroyed;
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// - encoding tables are used by hufEncode() and hufBuildDecTable();
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//
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struct FHeapCompare
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{
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bool operator () (Int64 *a, Int64 *b) {return *a > *b;}
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};
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void
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hufBuildEncTable
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(Int64* frq, // io: input frequencies [HUF_ENCSIZE], output table
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int* im, // o: min frq index
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int* iM) // o: max frq index
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{
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//
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// This function assumes that when it is called, array frq
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// indicates the frequency of all possible symbols in the data
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// that are to be Huffman-encoded. (frq[i] contains the number
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// of occurrences of symbol i in the data.)
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//
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// The loop below does three things:
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//
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// 1) Finds the minimum and maximum indices that point
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// to non-zero entries in frq:
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//
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// frq[im] != 0, and frq[i] == 0 for all i < im
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// frq[iM] != 0, and frq[i] == 0 for all i > iM
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//
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// 2) Fills array fHeap with pointers to all non-zero
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// entries in frq.
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//
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// 3) Initializes array hlink such that hlink[i] == i
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// for all array entries.
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//
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AutoArray <int, HUF_ENCSIZE> hlink;
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AutoArray <Int64 *, HUF_ENCSIZE> fHeap;
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*im = 0;
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while (!frq[*im])
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(*im)++;
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int nf = 0;
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for (int i = *im; i < HUF_ENCSIZE; i++)
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{
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hlink[i] = i;
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if (frq[i])
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{
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fHeap[nf] = &frq[i];
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nf++;
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*iM = i;
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}
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}
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//
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// Add a pseudo-symbol, with a frequency count of 1, to frq;
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// adjust the fHeap and hlink array accordingly. Function
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// hufEncode() uses the pseudo-symbol for run-length encoding.
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//
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(*iM)++;
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frq[*iM] = 1;
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fHeap[nf] = &frq[*iM];
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nf++;
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//
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// Build an array, scode, such that scode[i] contains the number
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// of bits assigned to symbol i. Conceptually this is done by
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// constructing a tree whose leaves are the symbols with non-zero
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// frequency:
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//
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// Make a heap that contains all symbols with a non-zero frequency,
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// with the least frequent symbol on top.
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//
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// Repeat until only one symbol is left on the heap:
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//
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// Take the two least frequent symbols off the top of the heap.
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// Create a new node that has first two nodes as children, and
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// whose frequency is the sum of the frequencies of the first
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// two nodes. Put the new node back into the heap.
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//
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// The last node left on the heap is the root of the tree. For each
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// leaf node, the distance between the root and the leaf is the length
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// of the code for the corresponding symbol.
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//
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// The loop below doesn't actually build the tree; instead we compute
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// the distances of the leaves from the root on the fly. When a new
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// node is added to the heap, then that node's descendants are linked
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// into a single linear list that starts at the new node, and the code
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// lengths of the descendants (that is, their distance from the root
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// of the tree) are incremented by one.
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//
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make_heap (&fHeap[0], &fHeap[nf], FHeapCompare());
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AutoArray <Int64, HUF_ENCSIZE> scode;
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memset (scode, 0, sizeof (Int64) * HUF_ENCSIZE);
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while (nf > 1)
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{
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//
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// Find the indices, mm and m, of the two smallest non-zero frq
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// values in fHeap, add the smallest frq to the second-smallest
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// frq, and remove the smallest frq value from fHeap.
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//
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int mm = fHeap[0] - frq;
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pop_heap (&fHeap[0], &fHeap[nf], FHeapCompare());
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--nf;
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int m = fHeap[0] - frq;
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pop_heap (&fHeap[0], &fHeap[nf], FHeapCompare());
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frq[m ] += frq[mm];
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push_heap (&fHeap[0], &fHeap[nf], FHeapCompare());
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//
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// The entries in scode are linked into lists with the
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// entries in hlink serving as "next" pointers and with
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// the end of a list marked by hlink[j] == j.
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//
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// Traverse the lists that start at scode[m] and scode[mm].
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// For each element visited, increment the length of the
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// corresponding code by one bit. (If we visit scode[j]
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// during the traversal, then the code for symbol j becomes
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// one bit longer.)
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//
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// Merge the lists that start at scode[m] and scode[mm]
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// into a single list that starts at scode[m].
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//
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//
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// Add a bit to all codes in the first list.
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//
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for (int j = m; true; j = hlink[j])
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{
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scode[j]++;
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assert (scode[j] <= 58);
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if (hlink[j] == j)
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{
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//
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// Merge the two lists.
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//
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hlink[j] = mm;
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break;
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}
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}
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//
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// Add a bit to all codes in the second list
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//
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for (int j = mm; true; j = hlink[j])
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{
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scode[j]++;
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assert (scode[j] <= 58);
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if (hlink[j] == j)
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break;
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}
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}
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//
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// Build a canonical Huffman code table, replacing the code
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// lengths in scode with (code, code length) pairs. Copy the
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// code table from scode into frq.
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//
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hufCanonicalCodeTable (scode);
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memcpy (frq, scode, sizeof (Int64) * HUF_ENCSIZE);
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}
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//
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// Pack an encoding table:
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// - only code lengths, not actual codes, are stored
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// - runs of zeroes are compressed as follows:
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//
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// unpacked packed
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// --------------------------------
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// 1 zero 0 (6 bits)
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// 2 zeroes 59
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// 3 zeroes 60
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// 4 zeroes 61
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// 5 zeroes 62
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// n zeroes (6 or more) 63 n-6 (6 + 8 bits)
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//
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const int SHORT_ZEROCODE_RUN = 59;
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const int LONG_ZEROCODE_RUN = 63;
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const int SHORTEST_LONG_RUN = 2 + LONG_ZEROCODE_RUN - SHORT_ZEROCODE_RUN;
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const int LONGEST_LONG_RUN = 255 + SHORTEST_LONG_RUN;
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void
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hufPackEncTable
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(const Int64* hcode, // i : encoding table [HUF_ENCSIZE]
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int im, // i : min hcode index
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int iM, // i : max hcode index
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char** pcode) // o: ptr to packed table (updated)
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{
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char *p = *pcode;
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Int64 c = 0;
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int lc = 0;
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for (; im <= iM; im++)
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{
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int l = hufLength (hcode[im]);
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if (l == 0)
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{
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int zerun = 1;
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while ((im < iM) && (zerun < LONGEST_LONG_RUN))
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{
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if (hufLength (hcode[im+1]) > 0 )
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break;
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im++;
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zerun++;
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}
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if (zerun >= 2)
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{
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if (zerun >= SHORTEST_LONG_RUN)
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{
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outputBits (6, LONG_ZEROCODE_RUN, c, lc, p);
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outputBits (8, zerun - SHORTEST_LONG_RUN, c, lc, p);
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}
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else
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{
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outputBits (6, SHORT_ZEROCODE_RUN + zerun - 2, c, lc, p);
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}
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continue;
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}
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}
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outputBits (6, l, c, lc, p);
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}
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if (lc > 0)
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*p++ = (unsigned char) (c << (8 - lc));
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*pcode = p;
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}
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//
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// Unpack an encoding table packed by hufPackEncTable():
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//
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void
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hufUnpackEncTable
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(const char** pcode, // io: ptr to packed table (updated)
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int ni, // i : input size (in bytes)
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int im, // i : min hcode index
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int iM, // i : max hcode index
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Int64* hcode) // o: encoding table [HUF_ENCSIZE]
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{
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memset (hcode, 0, sizeof (Int64) * HUF_ENCSIZE);
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const char *p = *pcode;
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Int64 c = 0;
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int lc = 0;
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for (; im <= iM; im++)
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{
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if (p - *pcode > ni)
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unexpectedEndOfTable();
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Int64 l = hcode[im] = getBits (6, c, lc, p); // code length
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if (l == (Int64) LONG_ZEROCODE_RUN)
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{
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if (p - *pcode > ni)
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unexpectedEndOfTable();
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int zerun = getBits (8, c, lc, p) + SHORTEST_LONG_RUN;
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if (im + zerun > iM + 1)
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tableTooLong();
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while (zerun--)
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hcode[im++] = 0;
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im--;
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}
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else if (l >= (Int64) SHORT_ZEROCODE_RUN)
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{
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int zerun = l - SHORT_ZEROCODE_RUN + 2;
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if (im + zerun > iM + 1)
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tableTooLong();
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while (zerun--)
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hcode[im++] = 0;
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im--;
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}
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}
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*pcode = (char *) p;
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hufCanonicalCodeTable (hcode);
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}
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//
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// DECODING TABLE BUILDING
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//
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//
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// Clear a newly allocated decoding table so that it contains only zeroes.
|
|
//
|
|
|
|
void
|
|
hufClearDecTable
|
|
(HufDec * hdecod) // io: (allocated by caller)
|
|
// decoding table [HUF_DECSIZE]
|
|
{
|
|
memset (hdecod, 0, sizeof (HufDec) * HUF_DECSIZE);
|
|
}
|
|
|
|
|
|
//
|
|
// Build a decoding hash table based on the encoding table hcode:
|
|
// - short codes (<= HUF_DECBITS) are resolved with a single table access;
|
|
// - long code entry allocations are not optimized, because long codes are
|
|
// unfrequent;
|
|
// - decoding tables are used by hufDecode();
|
|
//
|
|
|
|
void
|
|
hufBuildDecTable
|
|
(const Int64* hcode, // i : encoding table
|
|
int im, // i : min index in hcode
|
|
int iM, // i : max index in hcode
|
|
HufDec * hdecod) // o: (allocated by caller)
|
|
// decoding table [HUF_DECSIZE]
|
|
{
|
|
//
|
|
// Init hashtable & loop on all codes.
|
|
// Assumes that hufClearDecTable(hdecod) has already been called.
|
|
//
|
|
|
|
for (; im <= iM; im++)
|
|
{
|
|
Int64 c = hufCode (hcode[im]);
|
|
int l = hufLength (hcode[im]);
|
|
|
|
if (c >> l)
|
|
{
|
|
//
|
|
// Error: c is supposed to be an l-bit code,
|
|
// but c contains a value that is greater
|
|
// than the largest l-bit number.
|
|
//
|
|
|
|
invalidTableEntry();
|
|
}
|
|
|
|
if (l > HUF_DECBITS)
|
|
{
|
|
//
|
|
// Long code: add a secondary entry
|
|
//
|
|
|
|
HufDec *pl = hdecod + (c >> (l - HUF_DECBITS));
|
|
|
|
if (pl->len)
|
|
{
|
|
//
|
|
// Error: a short code has already
|
|
// been stored in table entry *pl.
|
|
//
|
|
|
|
invalidTableEntry();
|
|
}
|
|
|
|
pl->lit++;
|
|
|
|
if (pl->p)
|
|
{
|
|
int *p = pl->p;
|
|
pl->p = new int [pl->lit];
|
|
|
|
for (int i = 0; i < pl->lit - 1; ++i)
|
|
pl->p[i] = p[i];
|
|
|
|
delete [] p;
|
|
}
|
|
else
|
|
{
|
|
pl->p = new int [1];
|
|
}
|
|
|
|
pl->p[pl->lit - 1]= im;
|
|
}
|
|
else if (l)
|
|
{
|
|
//
|
|
// Short code: init all primary entries
|
|
//
|
|
|
|
HufDec *pl = hdecod + (c << (HUF_DECBITS - l));
|
|
|
|
for (Int64 i = 1 << (HUF_DECBITS - l); i > 0; i--, pl++)
|
|
{
|
|
if (pl->len || pl->p)
|
|
{
|
|
//
|
|
// Error: a short code or a long code has
|
|
// already been stored in table entry *pl.
|
|
//
|
|
|
|
invalidTableEntry();
|
|
}
|
|
|
|
pl->len = l;
|
|
pl->lit = im;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
//
|
|
// Free the long code entries of a decoding table built by hufBuildDecTable()
|
|
//
|
|
|
|
void
|
|
hufFreeDecTable (HufDec *hdecod) // io: Decoding table
|
|
{
|
|
for (int i = 0; i < HUF_DECSIZE; i++)
|
|
{
|
|
if (hdecod[i].p)
|
|
{
|
|
delete [] hdecod[i].p;
|
|
hdecod[i].p = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
//
|
|
// ENCODING
|
|
//
|
|
|
|
inline void
|
|
outputCode (Int64 code, Int64 &c, int &lc, char *&out)
|
|
{
|
|
outputBits (hufLength (code), hufCode (code), c, lc, out);
|
|
}
|
|
|
|
|
|
inline void
|
|
sendCode (Int64 sCode, int runCount, Int64 runCode,
|
|
Int64 &c, int &lc, char *&out)
|
|
{
|
|
static const int RLMIN = 32; // min count to activate run-length coding
|
|
|
|
if (runCount > RLMIN)
|
|
{
|
|
outputCode (sCode, c, lc, out);
|
|
outputCode (runCode, c, lc, out);
|
|
outputBits (8, runCount, c, lc, out);
|
|
}
|
|
else
|
|
{
|
|
while (runCount-- >= 0)
|
|
outputCode (sCode, c, lc, out);
|
|
}
|
|
}
|
|
|
|
|
|
//
|
|
// Encode (compress) ni values based on the Huffman encoding table hcode:
|
|
//
|
|
|
|
int
|
|
hufEncode // return: output size (in bits)
|
|
(const Int64* hcode, // i : encoding table
|
|
const unsigned short* in, // i : uncompressed input buffer
|
|
const int ni, // i : input buffer size (in bytes)
|
|
int rlc, // i : rl code
|
|
char* out) // o: compressed output buffer
|
|
{
|
|
char *outStart = out;
|
|
Int64 c = 0; // bits not yet written to out
|
|
int lc = 0; // number of valid bits in c (LSB)
|
|
int s = in[0];
|
|
int cs = 0;
|
|
|
|
//
|
|
// Loop on input values
|
|
//
|
|
|
|
for (int i = 1; i < ni; i++)
|
|
{
|
|
//
|
|
// Count same values or send code
|
|
//
|
|
|
|
if (s == in[i] && cs < 255)
|
|
{
|
|
cs++;
|
|
}
|
|
else
|
|
{
|
|
sendCode (hcode[s], cs, hcode[rlc], c, lc, out);
|
|
cs=0;
|
|
}
|
|
|
|
s = in[i];
|
|
}
|
|
|
|
//
|
|
// Send remaining code
|
|
//
|
|
|
|
sendCode (hcode[s], cs, hcode[rlc], c, lc, out);
|
|
|
|
if (lc)
|
|
*out = (c << (8 - lc)) & 0xff;
|
|
|
|
return (out - outStart) * 8 + lc;
|
|
}
|
|
|
|
|
|
//
|
|
// DECODING
|
|
//
|
|
|
|
//
|
|
// In order to force the compiler to inline them,
|
|
// getChar() and getCode() are implemented as macros
|
|
// instead of "inline" functions.
|
|
//
|
|
|
|
#define getChar(c, lc, in) \
|
|
{ \
|
|
c = (c << 8) | *(unsigned char *)(in++); \
|
|
lc += 8; \
|
|
}
|
|
|
|
|
|
#define getCode(po, rlc, c, lc, in, out, oe) \
|
|
{ \
|
|
if (po == rlc) \
|
|
{ \
|
|
if (lc < 8) \
|
|
getChar(c, lc, in); \
|
|
\
|
|
lc -= 8; \
|
|
\
|
|
unsigned char cs = (c >> lc); \
|
|
\
|
|
if (out + cs > oe) \
|
|
tooMuchData(); \
|
|
\
|
|
unsigned short s = out[-1]; \
|
|
\
|
|
while (cs-- > 0) \
|
|
*out++ = s; \
|
|
} \
|
|
else if (out < oe) \
|
|
{ \
|
|
*out++ = po; \
|
|
} \
|
|
else \
|
|
{ \
|
|
tooMuchData(); \
|
|
} \
|
|
}
|
|
|
|
|
|
//
|
|
// Decode (uncompress) ni bits based on encoding & decoding tables:
|
|
//
|
|
|
|
void
|
|
hufDecode
|
|
(const Int64 * hcode, // i : encoding table
|
|
const HufDec * hdecod, // i : decoding table
|
|
const char* in, // i : compressed input buffer
|
|
int ni, // i : input size (in bits)
|
|
int rlc, // i : run-length code
|
|
int no, // i : expected output size (in bytes)
|
|
unsigned short* out) // o: uncompressed output buffer
|
|
{
|
|
Int64 c = 0;
|
|
int lc = 0;
|
|
unsigned short * outb = out;
|
|
unsigned short * oe = out + no;
|
|
const char * ie = in + (ni + 7) / 8; // input byte size
|
|
|
|
//
|
|
// Loop on input bytes
|
|
//
|
|
|
|
while (in < ie)
|
|
{
|
|
getChar (c, lc, in);
|
|
|
|
//
|
|
// Access decoding table
|
|
//
|
|
|
|
while (lc >= HUF_DECBITS)
|
|
{
|
|
const HufDec pl = hdecod[(c >> (lc-HUF_DECBITS)) & HUF_DECMASK];
|
|
|
|
if (pl.len)
|
|
{
|
|
//
|
|
// Get short code
|
|
//
|
|
|
|
lc -= pl.len;
|
|
getCode (pl.lit, rlc, c, lc, in, out, oe);
|
|
}
|
|
else
|
|
{
|
|
if (!pl.p)
|
|
invalidCode(); // wrong code
|
|
|
|
//
|
|
// Search long code
|
|
//
|
|
|
|
int j;
|
|
|
|
for (j = 0; j < pl.lit; j++)
|
|
{
|
|
int l = hufLength (hcode[pl.p[j]]);
|
|
|
|
while (lc < l && in < ie) // get more bits
|
|
getChar (c, lc, in);
|
|
|
|
if (lc >= l)
|
|
{
|
|
if (hufCode (hcode[pl.p[j]]) ==
|
|
((c >> (lc - l)) & ((Int64(1) << l) - 1)))
|
|
{
|
|
//
|
|
// Found : get long code
|
|
//
|
|
|
|
lc -= l;
|
|
getCode (pl.p[j], rlc, c, lc, in, out, oe);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (j == pl.lit)
|
|
invalidCode(); // Not found
|
|
}
|
|
}
|
|
}
|
|
|
|
//
|
|
// Get remaining (short) codes
|
|
//
|
|
|
|
int i = (8 - ni) & 7;
|
|
c >>= i;
|
|
lc -= i;
|
|
|
|
while (lc > 0)
|
|
{
|
|
const HufDec pl = hdecod[(c << (HUF_DECBITS - lc)) & HUF_DECMASK];
|
|
|
|
if (pl.len)
|
|
{
|
|
lc -= pl.len;
|
|
getCode (pl.lit, rlc, c, lc, in, out, oe);
|
|
}
|
|
else
|
|
{
|
|
invalidCode(); // wrong (long) code
|
|
}
|
|
}
|
|
|
|
if (out - outb != no)
|
|
notEnoughData ();
|
|
}
|
|
|
|
|
|
void
|
|
countFrequencies (Int64 freq[HUF_ENCSIZE],
|
|
const unsigned short data[/*n*/],
|
|
int n)
|
|
{
|
|
for (int i = 0; i < HUF_ENCSIZE; ++i)
|
|
freq[i] = 0;
|
|
|
|
for (int i = 0; i < n; ++i)
|
|
++freq[data[i]];
|
|
}
|
|
|
|
|
|
void
|
|
writeUInt (char buf[4], unsigned int i)
|
|
{
|
|
unsigned char *b = (unsigned char *) buf;
|
|
|
|
b[0] = i;
|
|
b[1] = i >> 8;
|
|
b[2] = i >> 16;
|
|
b[3] = i >> 24;
|
|
}
|
|
|
|
|
|
unsigned int
|
|
readUInt (const char buf[4])
|
|
{
|
|
const unsigned char *b = (const unsigned char *) buf;
|
|
|
|
return ( b[0] & 0x000000ff) |
|
|
((b[1] << 8) & 0x0000ff00) |
|
|
((b[2] << 16) & 0x00ff0000) |
|
|
((b[3] << 24) & 0xff000000);
|
|
}
|
|
|
|
} // namespace
|
|
|
|
|
|
//
|
|
// EXTERNAL INTERFACE
|
|
//
|
|
|
|
|
|
int
|
|
hufCompress (const unsigned short raw[],
|
|
int nRaw,
|
|
char compressed[])
|
|
{
|
|
if (nRaw == 0)
|
|
return 0;
|
|
|
|
AutoArray <Int64, HUF_ENCSIZE> freq;
|
|
|
|
countFrequencies (freq, raw, nRaw);
|
|
|
|
int im, iM;
|
|
hufBuildEncTable (freq, &im, &iM);
|
|
|
|
char *tableStart = compressed + 20;
|
|
char *tableEnd = tableStart;
|
|
hufPackEncTable (freq, im, iM, &tableEnd);
|
|
int tableLength = tableEnd - tableStart;
|
|
|
|
char *dataStart = tableEnd;
|
|
int nBits = hufEncode (freq, raw, nRaw, iM, dataStart);
|
|
int dataLength = (nBits + 7) / 8;
|
|
|
|
writeUInt (compressed, im);
|
|
writeUInt (compressed + 4, iM);
|
|
writeUInt (compressed + 8, tableLength);
|
|
writeUInt (compressed + 12, nBits);
|
|
writeUInt (compressed + 16, 0); // room for future extensions
|
|
|
|
return dataStart + dataLength - compressed;
|
|
}
|
|
|
|
|
|
void
|
|
hufUncompress (const char compressed[],
|
|
int nCompressed,
|
|
unsigned short raw[],
|
|
int nRaw)
|
|
{
|
|
if (nCompressed == 0)
|
|
{
|
|
if (nRaw != 0)
|
|
notEnoughData();
|
|
|
|
return;
|
|
}
|
|
|
|
int im = readUInt (compressed);
|
|
int iM = readUInt (compressed + 4);
|
|
// int tableLength = readUInt (compressed + 8);
|
|
int nBits = readUInt (compressed + 12);
|
|
|
|
if (im < 0 || im >= HUF_ENCSIZE || iM < 0 || iM >= HUF_ENCSIZE)
|
|
invalidTableSize();
|
|
|
|
const char *ptr = compressed + 20;
|
|
|
|
AutoArray <Int64, HUF_ENCSIZE> freq;
|
|
AutoArray <HufDec, HUF_DECSIZE> hdec;
|
|
|
|
hufClearDecTable (hdec);
|
|
|
|
hufUnpackEncTable (&ptr, nCompressed - (ptr - compressed), im, iM, freq);
|
|
|
|
try
|
|
{
|
|
if (nBits > 8 * (nCompressed - (ptr - compressed)))
|
|
invalidNBits();
|
|
|
|
hufBuildDecTable (freq, im, iM, hdec);
|
|
hufDecode (freq, hdec, ptr, nBits, iM, nRaw, raw);
|
|
}
|
|
catch (...)
|
|
{
|
|
hufFreeDecTable (hdec);
|
|
throw;
|
|
}
|
|
|
|
hufFreeDecTable (hdec);
|
|
}
|
|
|
|
|
|
} // namespace Imf
|