+/*
+FreeSat Huffman decoder for VDR
+Copyright (C) 2008 DOM http://www.rst38.org.uk/vdr/
+Port to C++ / Enigma 2
+Copyright (C) 2008 Martin Croome
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+*/
+#include "freesatv2.h"
+#ifdef FREESATV2_DEBUG
+# include "eerror.h"
+#endif
+#include <asm/types.h>
+
+#define START '\0'
+#define STOP '\0'
+#define ESCAPE '\1'
+
+#ifndef DATADIR
+# define DATADIR "/usr/share"
+#endif
+
+#ifndef FREESAT_DATA_DIRECTORY
+#define FREESAT_DATA_DIRECTORY DATADIR
+#endif
+#define TABLE1_FILENAME FREESAT_DATA_DIRECTORY "/enigma2/freesat.t1"
+#define TABLE2_FILENAME FREESAT_DATA_DIRECTORY "/enigma2/freesat.t2"
+
+static void loadFile(huffTableEntry **table, const char *filename);
+
+
+struct huffTableEntry
+{
+ uint32_t value;
+ uint16_t bits;
+ char next;
+ huffTableEntry * nextEntry;
+
+ huffTableEntry(unsigned int value, short bits, char next) : value(value), bits(bits), next(next), nextEntry(NULL)
+ { }
+};
+
+freesatHuffmanDecoder::freesatHuffmanDecoder()
+{
+ memset(m_tables, 0, sizeof(m_tables));
+ loadFile(&m_tables[0][0], TABLE1_FILENAME);
+ loadFile(&m_tables[1][0], TABLE2_FILENAME);
+}
+
+freesatHuffmanDecoder::~freesatHuffmanDecoder()
+{
+ int i, j;
+ huffTableEntry *currentEntry, *nextEntry;
+ for ( j = 0 ; j < 2; j++ )
+ {
+ for ( i = 0 ; i < 256; i++ )
+ {
+ currentEntry = m_tables[j][i];
+ while ( currentEntry != NULL )
+ {
+ nextEntry = currentEntry->nextEntry;
+ delete currentEntry;
+ currentEntry = nextEntry;
+ }
+ m_tables[j][i] = NULL;
+ }
+ }
+}
+
+
+/** \brief Convert a textual character description into a value
+*
+* \param str - Encoded (in someway) string
+*
+* \return Raw character
+*/
+static unsigned char resolveChar(const char *str)
+{
+ const char *p = str;
+ unsigned c0 = *p++, c1 = *p++;
+ if (c1)
+ switch(c0|c1<<8)
+ {
+ case '0'|'x'<<8:
+ if ( sscanf(p,"%02x", &c1) == 1 )
+ c0 = c1;
+ break;
+ case 'E'|'S'<<8:
+ if ( !strcmp(p,"CAPE") )
+ c0 = ESCAPE;
+ break;
+ case 'S'|'T'<<8:
+ if ( !strcmp(p,"OP") )
+ c0 = STOP;
+ else if ( !strcmp(p,"ART") )
+ c0 = START;
+ break;
+ }
+ return c0;
+}
+
+
+/** \brief Decode a binary string into a value
+*
+* \param binary - Binary string to decode
+*
+* \return Decoded value
+*/
+static unsigned long decodeBinary(const char *binary)
+{
+ unsigned long mask = 0x80000000;
+ unsigned long val = 0;
+
+ while (*binary)
+ {
+ if ( *binary == '1' )
+ {
+ val |= mask;
+ }
+ mask >>= 1;
+ ++binary;
+ }
+ return val;
+}
+
+static void loadFile(huffTableEntry **table, const char *filename)
+{
+ char buf[1024];
+ char *from;
+ char *to;
+ char *binary;
+ char *colon;
+
+ FILE *fp = fopen(filename, "r");
+ if ( fp )
+ {
+ while ( fgets(buf,sizeof(buf),fp) != NULL )
+ {
+ // Tokenize string "in place"
+ from = buf;
+ colon = strchr(buf, ':');
+ if (colon == NULL)
+ continue;
+ binary = colon + 1;
+ *colon = 0;
+ colon = strchr(binary, ':');
+ if (colon == NULL)
+ continue;
+ *colon = 0;
+ to = colon + 1;
+ colon = strchr(to, ':');
+ if (colon != NULL)
+ *colon = 0;
+ {
+ int bin_len = strlen(binary);
+ int from_char = resolveChar(from);
+ char to_char = resolveChar(to);
+ unsigned long bin = decodeBinary(binary);
+
+ // Add entry to end of bucket
+ huffTableEntry **pCurrent = &table[from_char];
+ while ( *pCurrent != NULL )
+ {
+ pCurrent = &((*pCurrent)->nextEntry);
+ }
+ *pCurrent = new huffTableEntry(bin, bin_len, to_char);
+ }
+ }
+ fclose(fp);
+ }
+#ifdef FREESATV2_DEBUG
+ else
+ {
+ eDebug("[FREESAT] Cannot load '%s'",filename);
+ }
+#endif
+}
+
+
+/** \brief Decode an EPG string as necessary
+*
+* \param src - Possibly encoded string
+* \param size - Size of the buffer
+*
+* \retval NULL - Can't decode
+* \return A decoded string
+*/
+std::string freesatHuffmanDecoder::decode(const unsigned char *src, size_t size)
+{
+ std::string uncompressed;
+
+ if (src[0] != 0x1f)
+ return uncompressed;
+
+ const unsigned int table_index = src[1] - 1;
+
+ if (table_index <= 1)
+ {
+ huffTableEntry **table = &m_tables[table_index][0];
+ unsigned int value = 0;
+ unsigned int byte = 2;
+ unsigned int bit = 0;
+ int lastch = START;
+
+ while (byte < 6 && byte < size)
+ {
+ value |= src[byte] << ((5-byte) * 8);
+ byte++;
+ }
+
+ do
+ {
+ int found = 0;
+ unsigned bitShift = 0;
+ if (lastch == ESCAPE)
+ {
+ char nextCh = (value >> 24) & 0xff;
+ found = 1;
+ // Encoded in the next 8 bits.
+ // Terminated by the first ASCII character.
+ bitShift = 8;
+ if ((nextCh & 0x80) == 0)
+ lastch = nextCh;
+ uncompressed.append(&nextCh, 1);
+ }
+ else
+ {
+ huffTableEntry * currentEntry = table[lastch];
+ while ( currentEntry != NULL )
+ {
+ unsigned mask = 0, maskbit = 0x80000000;
+ short kk;
+ for ( kk = 0; kk < currentEntry->bits; kk++)
+ {
+ mask |= maskbit;
+ maskbit >>= 1;
+ }
+ if ((value & mask) == currentEntry->value)
+ {
+ char nextCh = currentEntry->next;
+ bitShift = currentEntry->bits;
+ if (nextCh != STOP && nextCh != ESCAPE)
+ {
+ uncompressed.append(&nextCh, 1);
+ }
+ found = 1;
+ lastch = nextCh;
+ break;
+ }
+ currentEntry = currentEntry->nextEntry;
+ }
+ }
+ if (found)
+ {
+ // Shift up by the number of bits.
+ unsigned b;
+ for ( b = 0; b < bitShift; b++)
+ {
+ value = (value << 1) & 0xfffffffe;
+ if (byte < size)
+ value |= (src[byte] >> (7-bit)) & 1;
+ if (bit == 7)
+ {
+ bit = 0;
+ byte++;
+ }
+ else bit++;
+ }
+ }
+ else
+ {
+#ifdef FREESATV2_DEBUG
+ eDebug("[FREESAT] Missing table %d entry: <%s>", table_index + 1, uncompressed.c_str());
+#endif
+ return uncompressed;
+ }
+ } while (lastch != STOP && value != 0);
+ }
+ return uncompressed;
+}
projects / vuplus_dvbapp / blobdiff