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P25 Interleaver final commit

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dennis.sheirer
2014-11-08 15:08:20 +00:00
parent b979fc75de
commit 7b89c614e7
1 changed files with 58 additions and 17 deletions
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75
src/decode/p25/P25Interleave.java
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@@ -8,25 +8,36 @@ import org.slf4j.LoggerFactory;
import bits.BitSetBuffer;
/**
* Utility class to deinterleave P25 packet blocks of 196-bit length.
* Utility class to process interleave of P25 196-bit packet blocks.
*/
public class P25Interleave
{
private final static Logger mLog =
LoggerFactory.getLogger( P25Interleave.class );
private static int[] MATRIX = new int[] { 0,1,2,3,16,17,18,19,32,33,34,35,
48,49,50,51,64,65,66,67,80,81,82,83,96,97,98,99,112,113,114,115,
128,129,130,131,144,145,146,147,160,161,162,163,176,177,178,179,
192,193,194,195,4,5,6,7,20,21,22,23,36,37,38,39,52,53,54,55,68,
69,70,71,84,85,86,87,100,101,102,103,116,117,118,119,132,133,
134,135,148,149,150,151,164,165,166,167,180,181,182,183,8,9,10,
11,24,25,26,27,40,41,42,43,56,57,58,59,72,73,74,75,88,89,90,91,
104,105,106,107,120,121,122,123,136,137,138,139,152,153,154,155,
168,169,170,171,184,185,186,187,12,13,14,15,28,29,30,31,44,45,
46,47,60,61,62,63,76,77,78,79,92,93,94,95,108,109,110,111,124,
125,126,127,140,141,142,143,156,157,158,159,172,173,174,175,188,
189,190,191 };
private static int[] INTERLEAVE = new int[] { 0,1,2,3,52,53,54,55,100,101,
102,103,148,149,150,151,4,5,6,7,56,57,58,59,104,105,106,107,152,153,154,
155,8,9,10,11,60,61,62,63,108,109,110,111,156,157,158,159,12,13,14,15,
64,65,66,67,112,113,114,115,160,161,162,163,16,17,18,19,68,69,70,71,116,
117,118,119,164,165,166,167,20,21,22,23,72,73,74,75,120,121,122,123,168,
169,170,171,24,25,26,27,76,77,78,79,124,125,126,127,172,173,174,175,28,
29,30,31,80,81,82,83,128,129,130,131,176,177,178,179,32,33,34,35,84,85,
86,87,132,133,134,135,180,181,182,183,36,37,38,39,88,89,90,91,136,137,
138,139,184,185,186,187,40,41,42,43,92,93,94,95,140,141,142,143,188,189,
190,191,44,45,46,47,96,97,98,99,144,145,146,147,192,193,194,195,48,49,
50,51 };
private static int[] DEINTERLEAVE = new int[] { 0,1,2,3,16,17,18,19,32,33,
34,35,48,49,50,51,64,65,66,67,80,81,82,83,96,97,98,99,112,113,114,115,
128,129,130,131,144,145,146,147,160,161,162,163,176,177,178,179,192,193,
194,195,4,5,6,7,20,21,22,23,36,37,38,39,52,53,54,55,68,69,70,71,84,85,
86,87,100,101,102,103,116,117,118,119,132,133,134,135,148,149,150,151,
164,165,166,167,180,181,182,183,8,9,10,11,24,25,26,27,40,41,42,43,56,57,
58,59,72,73,74,75,88,89,90,91,104,105,106,107,120,121,122,123,136,137,
138,139,152,153,154,155,168,169,170,171,184,185,186,187,12,13,14,15,28,
29,30,31,44,45,46,47,60,61,62,63,76,77,78,79,92,93,94,95,108,109,110,
111,124,125,126,127,140,141,142,143,156,157,158,159,172,173,174,175,188,
189,190,191 };
/**
* Deinterleaves the 196-bit block in message, identified by start and end
@@ -37,7 +48,7 @@ public class P25Interleave
* @param start - starting bit index for the block
* @param end - ending bit index for the block, plus 1
*/
public static void deinterleave( BitSetBuffer message, int start, int end )
public static BitSetBuffer deinterleave( BitSetBuffer message, int start, int end )
{
BitSet original = message.get( start, end );
@@ -47,10 +58,40 @@ public class P25Interleave
/* Iterate only the set bits in the original message and apply
* the deinterleave -- we don't have to evaluate the 0 bits */
for (int i = original.nextSetBit( 0 );
i >= 0 && i < MATRIX.length;
i = message.nextSetBit( i + 1 ) )
i >= 0 && i < DEINTERLEAVE.length;
i = original.nextSetBit( i + 1 ) )
{
message.set( start + MATRIX[ i ] );
message.set( start + DEINTERLEAVE[ i ] );
}
return message;
}
/**
* Interleaves the 196-bit block in message, identified by start and end
* bit positions. Note: end index (exclusive) should be one more than the
* last bit in the block.
*
* @param message - source message to interleave
* @param start - starting bit index for the block
* @param end - ending bit index for the block, plus 1
*/
public static BitSetBuffer interleave( BitSetBuffer message, int start, int end )
{
BitSet original = message.get( start, end );
/* Clear block bits in source message */
message.clear( start, end );
/* Iterate only the set bits in the original message and apply
* the deinterleave -- we don't have to evaluate the 0 bits */
for (int i = original.nextSetBit( 0 );
i >= 0 && i < INTERLEAVE.length;
i = original.nextSetBit( i + 1 ) )
{
message.set( start + INTERLEAVE[ i ] );
}
return message;
}
}