CountryFlags:

renamed to .cpp

git-svn-id: http://svn.miranda-ng.org/main/trunk@541 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c

1 files changed, 0 insertions, 506 deletions

diff --git a/plugins/CountryFlags/huffman.c b/plugins/CountryFlags/huffman.c
deleted file mode 100644
index c460e9a66e..0000000000
--- a/plugins/CountryFlags/huffman.c
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-/*************************************************************************

-* Name:        huffman.c

-* Author:      Marcus Geelnard

-* Description: Huffman coder/decoder implementation.

-* Reentrant:   Yes

-*

-* This is a very straight forward implementation of a Huffman coder and

-* decoder.

-*

-* Primary flaws with this primitive implementation are:

-*  - Slow bit stream implementation

-*  - Maximum tree depth of 32 (the coder aborts if any code exceeds a

-*    size of 32 bits). If I'm not mistaking, this should not be possible

-*    unless the input buffer is larger than 2^32 bytes, which is not

-*    supported by the coder anyway (max 2^32-1 bytes can be specified with

-*    an unsigned 32-bit integer).

-*

-* On the other hand, there are a few advantages of this implementation:

-*  - The Huffman tree is stored in a very compact form, requiring only

-*    10 bits per symbol (for 8 bit symbols), meaning a maximum of 320

-*    bytes overhead.

-*  - The code should be fairly easy to follow, if you are familiar with

-*    how the Huffman compression algorithm works.

-*

-* Possible improvements (probably not worth it):

-*  - Partition the input data stream into blocks, where each block has

-*    its own Huffman tree. With variable block sizes, it should be

-*    possible to find locally optimal Huffman trees, which in turn could

-*    reduce the total size.

-*  - Allow for a few different predefined Huffman trees, which could

-*    reduce the size of a block even further.

-*-------------------------------------------------------------------------

-* Copyright (c) 2003-2006 Marcus Geelnard

-*

-* This software is provided 'as-is', without any express or implied

-* warranty. In no event will the authors be held liable for any damages

-* arising from the use of this software.

-*

-* Permission is granted to anyone to use this software for any purpose,

-* including commercial applications, and to alter it and redistribute it

-* freely, subject to the following restrictions:

-*

-* 1. The origin of this software must not be misrepresented; you must not

-*    claim that you wrote the original software. If you use this software

-*    in a product, an acknowledgment in the product documentation would

-*    be appreciated but is not required.

-*

-* 2. Altered source versions must be plainly marked as such, and must not

-*    be misrepresented as being the original software.

-*

-* 3. This notice may not be removed or altered from any source

-*    distribution.

-*

-* Marcus Geelnard

-* marcus.geelnard at home.se

-*************************************************************************/

-

-

-/*************************************************************************

-* Types used for Huffman coding

-*************************************************************************/

-

-typedef struct {

-    unsigned char *BytePtr;

-    unsigned int  BitPos;

-} huff_bitstream_t;

-

-typedef struct {

-    int Symbol;

-    unsigned int Count;

-    unsigned int Code;

-    unsigned int Bits;

-} huff_sym_t;

-

-typedef struct huff_encodenode_struct huff_encodenode_t;

-

-struct huff_encodenode_struct {

-    huff_encodenode_t *ChildA, *ChildB;

-    int Count;

-    int Symbol;

-};

-

-typedef struct huff_decodenode_struct huff_decodenode_t;

-

-struct huff_decodenode_struct {

-    huff_decodenode_t *ChildA, *ChildB;

-    int Symbol;

-};

-

-

-/*************************************************************************

-* Constants for Huffman decoding

-*************************************************************************/

-

-/* The maximum number of nodes in the Huffman tree is 2^(8+1)-1 = 511 */

-#define MAX_TREE_NODES 511

-

-

-/*************************************************************************

-* _Huffman_InitBitstream() - Initialize a bitstream.

-*************************************************************************/

-

-static void _Huffman_InitBitstream( huff_bitstream_t *stream,

-    unsigned char *buf )

-{

-  stream->BytePtr  = buf;

-  stream->BitPos   = 0;

-}

-

-

-/*************************************************************************

-* _Huffman_ReadBit() - Read one bit from a bitstream.

-*************************************************************************/

-

-static unsigned int _Huffman_ReadBit( huff_bitstream_t *stream )

-{

-  unsigned int  x, bit;

-  unsigned char *buf;

-

-  /* Get current stream state */

-  buf = stream->BytePtr;

-  bit = stream->BitPos;

-

-  /* Extract bit */

-  x = (*buf & (1<<(7-bit))) ? 1 : 0;

-  bit = (bit+1) & 7;

-  if ( !bit )

-  {

-    ++ buf;

-  }

-

-  /* Store new stream state */

-  stream->BitPos = bit;

-  stream->BytePtr = buf;

-

-  return x;

-}

-

-

-/*************************************************************************

-* _Huffman_Read8Bits() - Read eight bits from a bitstream.

-*************************************************************************/

-

-static unsigned int _Huffman_Read8Bits( huff_bitstream_t *stream )

-{

-  unsigned int  x, bit;

-  unsigned char *buf;

-

-  /* Get current stream state */

-  buf = stream->BytePtr;

-  bit = stream->BitPos;

-

-  /* Extract byte */

-  x = (*buf << bit) | (buf[1] >> (8-bit));

-  ++ buf;

-

-  /* Store new stream state */

-  stream->BytePtr = buf;

-

-  return x;

-}

-

-

-/*************************************************************************

-* _Huffman_WriteBits() - Write bits to a bitstream.

-*************************************************************************/

-

-#ifdef HUFFMAN_ENCODE

-static void _Huffman_WriteBits( huff_bitstream_t *stream, unsigned int x,

-  unsigned int bits )

-{

-  unsigned int  bit, count;

-  unsigned char *buf;

-  unsigned int  mask;

-

-  /* Get current stream state */

-  buf = stream->BytePtr;

-  bit = stream->BitPos;

-

-  /* Append bits */

-  mask = 1 << (bits-1);

-  for ( count = 0; count < bits; ++ count )

-  {

-    *buf = (unsigned char)((*buf & (0xff^(1<<(7-bit)))) +

-            ((x & mask ? 1 : 0) << (7-bit)));

-    x <<= 1;

-    bit = (bit+1) & 7;

-    if ( !bit )

-    {

-      ++ buf;

-    }

-  }

-

-  /* Store new stream state */

-  stream->BytePtr = buf;

-  stream->BitPos  = bit;

-}

-#endif

-

-

-/*************************************************************************

-* _Huffman_Hist() - Calculate (sorted) histogram for a block of data.

-*************************************************************************/

-

-#ifdef HUFFMAN_ENCODE

-static void _Huffman_Hist( unsigned char *in, huff_sym_t *sym,

-  unsigned int size )

-{

-  int k;

-

-  /* Clear/init histogram */

-  for ( k = 0; k < 256; ++ k )

-  {

-    sym[k].Symbol = k;

-    sym[k].Count  = 0;

-    sym[k].Code   = 0;

-    sym[k].Bits   = 0;

-  }

-

-  /* Build histogram */

-  for ( k = size; k; -- k )

-  {

-    sym[*in ++].Count ++;

-  }

-}

-#endif

-

-

-/*************************************************************************

-* _Huffman_StoreTree() - Store a Huffman tree in the output stream and

-* in a look-up-table (a symbol array).

-*************************************************************************/

-

-#ifdef HUFFMAN_ENCODE

-static void _Huffman_StoreTree( huff_encodenode_t *node, huff_sym_t *sym,

-  huff_bitstream_t *stream, unsigned int code, unsigned int bits )

-{

-  unsigned int sym_idx;

-

-  /* Is this a leaf node? */

-  if ( node->Symbol >= 0 )

-  {

-    /* Append symbol to tree description */

-    _Huffman_WriteBits( stream, 1, 1 );

-    _Huffman_WriteBits( stream, node->Symbol, 8 );

-

-    /* Find symbol index */

-    for ( sym_idx = 0; sym_idx < 256; ++ sym_idx )

-    {

-      if ( sym[sym_idx].Symbol == node->Symbol ) break;

-    }

-

-    /* Store code info in symbol array */

-    sym[sym_idx].Code = code;

-    sym[sym_idx].Bits = bits;

-    return;

-  }

-  else

-  {

-    /* This was not a leaf node */

-    _Huffman_WriteBits( stream, 0, 1 );

-  }

-

-  /* Branch A */

-  _Huffman_StoreTree( node->ChildA, sym, stream, (code<<1)+0, bits+1 );

-

-  /* Branch B */

-  _Huffman_StoreTree( node->ChildB, sym, stream, (code<<1)+1, bits+1 );

-}

-#endif

-

-

-/*************************************************************************

-* _Huffman_MakeTree() - Generate a Huffman tree.

-*************************************************************************/

-

-#ifdef HUFFMAN_ENCODE

-static void _Huffman_MakeTree( huff_sym_t *sym, huff_bitstream_t *stream )

-{

-  huff_encodenode_t nodes[MAX_TREE_NODES], *node_1, *node_2, *root;

-  unsigned int k, num_symbols, nodes_left, next_idx;

-

-   /* Initialize all leaf nodes */

-  num_symbols = 0;

-  for ( k = 0; k < 256; ++ k )

-  {

-    if ( sym[k].Count > 0 )

-    {

-      nodes[num_symbols].Symbol = sym[k].Symbol;

-      nodes[num_symbols].Count = sym[k].Count;

-      nodes[num_symbols].ChildA = (huff_encodenode_t *) 0;

-      nodes[num_symbols].ChildB = (huff_encodenode_t *) 0;

-      ++ num_symbols;

-    }

-  }

-

-  /* Build tree by joining the lightest nodes until there is only

-     one node left (the root node). */

-  root = (huff_encodenode_t *) 0;

-  nodes_left = num_symbols;

-  next_idx = num_symbols;

-  while( nodes_left > 1 )

-  {

-    /* Find the two lightest nodes */

-    node_1 = (huff_encodenode_t *) 0;

-    node_2 = (huff_encodenode_t *) 0;

-    for ( k = 0; k < next_idx; ++ k )

-    {

-      if ( nodes[k].Count > 0 )

-      {

-        if ( !node_1 || (nodes[k].Count <= node_1->Count))

-        {

-          node_2 = node_1;

-          node_1 = &nodes[k];

-        }

-        else if ( !node_2 || (nodes[k].Count <= node_2->Count))

-        {

-          node_2 = &nodes[k];

-        }

-      }

-    }

-

-    /* Join the two nodes into a new parent node */

-    root = &nodes[next_idx];

-    root->ChildA = node_1;

-    root->ChildB = node_2;

-    root->Count = node_1->Count + node_2->Count;

-    root->Symbol = -1;

-    node_1->Count = 0;

-    node_2->Count = 0;

-    ++ next_idx;

-    -- nodes_left;

-  }

-

-  /* Store the tree in the output stream, and in the sym[] array (the

-      latter is used as a look-up-table for faster encoding) */

-  if ( root )

-  {

-    _Huffman_StoreTree( root, sym, stream, 0, 0 );

-  }

-  else

-  {

-    /* Special case: only one symbol => no binary tree */

-    root = &nodes[0];

-    _Huffman_StoreTree( root, sym, stream, 0, 1 );

-  }

-}

-#endif

-

-

-/*************************************************************************

-* _Huffman_RecoverTree() - Recover a Huffman tree from a bitstream.

-*************************************************************************/

-

-static huff_decodenode_t * _Huffman_RecoverTree( huff_decodenode_t *nodes,

-  huff_bitstream_t *stream, unsigned int *nodenum )

-{

-  huff_decodenode_t * this_node;

-

-  /* Pick a node from the node array */

-  this_node = &nodes[*nodenum];

-  *nodenum = *nodenum + 1;

-

-  /* Clear the node */

-  this_node->Symbol = -1;

-  this_node->ChildA = (huff_decodenode_t *) 0;

-  this_node->ChildB = (huff_decodenode_t *) 0;

-

-  /* Is this a leaf node? */

-  if ( _Huffman_ReadBit( stream ))

-  {

-    /* Get symbol from tree description and store in lead node */

-    this_node->Symbol = _Huffman_Read8Bits( stream );

-

-    return this_node;

-  }

-

-  /* Get branch A */

-  this_node->ChildA = _Huffman_RecoverTree( nodes, stream, nodenum );

-

-  /* Get branch B */

-  this_node->ChildB = _Huffman_RecoverTree( nodes, stream, nodenum );

-

-  return this_node;

-}

-

-

-

-/*************************************************************************

-*                            PUBLIC FUNCTIONS                            *

-*************************************************************************/

-

-

-/*************************************************************************

-* Huffman_Compress() - Compress a block of data using a Huffman coder.

-*  in     - Input (uncompressed) buffer.

-*  out    - Output (compressed) buffer. This buffer must be 384 bytes

-*           larger than the input buffer.

-*  insize - Number of input bytes.

-* The function returns the size of the compressed data.

-*************************************************************************/

-

-#ifdef HUFFMAN_ENCODE

-int Huffman_Compress( unsigned char *in, unsigned char *out,

-  unsigned int insize )

-{

-  huff_sym_t       sym[256], tmp;

-  huff_bitstream_t stream;

-  unsigned int     k, total_bytes, swaps, symbol;

-

-  /* Do we have anything to compress? */

-  if ( insize < 1 ) return 0;

-

-  /* Initialize bitstream */

-  _Huffman_InitBitstream( &stream, out );

-

-  /* Calculate and sort histogram for input data */

-  _Huffman_Hist( in, sym, insize );

-

-  /* Build Huffman tree */

-  _Huffman_MakeTree( sym, &stream );

-

-  /* Sort histogram - first symbol first (bubble sort) */

-  do

-  {

-    swaps = 0;

-    for ( k = 0; k < 255; ++ k )

-    {

-      if ( sym[k].Symbol > sym[k+1].Symbol )

-      {

-        tmp      = sym[k];

-        sym[k]   = sym[k+1];

-        sym[k+1] = tmp;

-        swaps    = 1;

-      }

-    }

-  }

-  while( swaps );

-

-  /* Encode input stream */

-  for ( k = 0; k < insize; ++ k )

-  {

-    symbol = in[k];

-    _Huffman_WriteBits( &stream, sym[symbol].Code,

-                        sym[symbol].Bits );

-  }

-

-  /* Calculate size of output data */

-  total_bytes = (int)(stream.BytePtr - out);

-  if ( stream.BitPos > 0 )

-  {

-    ++ total_bytes;

-  }

-

-  return total_bytes;

-}

-#endif

-

-

-/*************************************************************************

-* Huffman_Uncompress() - Uncompress a block of data using a Huffman

-* decoder.

-*  in      - Input (compressed) buffer.

-*  out     - Output (uncompressed) buffer. This buffer must be large

-*            enough to hold the uncompressed data.

-*  insize  - Number of input bytes.

-*  outsize - Number of output bytes.

-*************************************************************************/

-

-void Huffman_Uncompress( unsigned char *in, unsigned char *out,

-  unsigned int insize, unsigned int outsize )

-{

-  huff_decodenode_t nodes[MAX_TREE_NODES], *root, *node;

-  huff_bitstream_t  stream;

-  unsigned int      k, node_count;

-  unsigned char     *buf;

-

-  /* Do we have anything to decompress? */

-  if ( insize < 1 ) return;

-

-  /* Initialize bitstream */

-  _Huffman_InitBitstream( &stream, in );

-

-  /* Recover Huffman tree */

-  node_count = 0;

-  root = _Huffman_RecoverTree( nodes, &stream, &node_count );

-

-  /* Decode input stream */

-  buf = out;

-  for ( k = 0; k < outsize; ++ k )

-  {

-    /* Traverse tree until we find a matching leaf node */

-    node = root;

-    while( node->Symbol < 0 )

-    {

-      /* Get next node */

-      if ( _Huffman_ReadBit( &stream ))

-        node = node->ChildB;

-      else

-        node = node->ChildA;

-    }

-

-    /* We found the matching leaf node and have the symbol */

-    *buf ++ = (unsigned char) node->Symbol;

-  }

-}