Changeset 5489

Timestamp:

10/23/07 23:40:49 (6 years ago)

Author:

jgaeddert

Message:

adding subheader encoder/decoder for PACKET_RS_512; does not yet pass check

Location:

experimental/components/Packetizer/trunk/Packetizer-metadata

Files:

• Makefile.am (modified) (1 diff)
• src/PacketizerDSP.cpp (modified) (6 diffs)
• src/PacketizerDSP.h (modified) (2 diffs)
• tests/EncodeDecodeSubheader_testsuite.h (modified) (1 diff)

experimental/components/Packetizer/trunk/Packetizer-metadata/Makefile.am

@@ -35 +35 @@
     encode_rs_char.o                \
     init_rs_char.o                  \
+    crc.o                           \
     PNCodes.o                       \
     binary_sequence.o               \

experimental/components/Packetizer/trunk/Packetizer-metadata/src/PacketizerDSP.cpp

@@ -52 +52 @@
     buf2 = new char[MAX_PACKET_SIZE];
     buf_len = MAX_PACKET_SIZE;
+
+    src_id = 0;
+    dst_id = 0;
+    port_id = 0;
+    app_id = 0;
+    packet_id = 0;
 }
 
@@ -199 +205 @@
         fec_outer = FEC_NONE;
         crc = CRC_CHECKSUM_16;
+        break;
     default:
         std::cerr << "ERROR! PacketizerBase::ConfigurePacketType() "
@@ -474 +481 @@
     case PACKET_RAW_400:
         return EncodeSubheader_PACKET_RAW_400(output, output_length, num_written);
+    case PACKET_RS_512:
+        return EncodeSubheader_PACKET_RS_512(output, output_length, num_written);
     default:
         std::cerr << "ERROR! PacketEncoder::EncodeSubheader(): unsupported packet type" << std::endl;
@@ -507 +516 @@
 }
 
+// Encode subheader for PACKET_RS_512
+bool PacketEncoder::EncodeSubheader_PACKET_RS_512(
+    char* output,
+    unsigned int output_length,
+    unsigned int &num_written)
+{
+    unsigned int nr;
+    unsigned int nw;
+
+    // 1. push 16 8-bit symbols into buf1
+    // variable     num bits
+    // ----         ----
+    // packet_id    32
+    // src_id       16
+    // dst_id       16
+    // app_id       16
+    // port_id      16
+    // expansion    64
+    buf1[0] = (packet_id >> 0)  & 0x0F;
+    buf1[1] = (packet_id >> 4)  & 0x0F;
+    buf1[2] = (packet_id >> 8)  & 0x0F;
+    buf1[3] = (packet_id >> 12) & 0x0F;
+
+    buf1[4] = (src_id >> 0 ) & 0x0F;
+    buf1[5] = (src_id >> 4 ) & 0x0F;
+
+    buf1[6] = (dst_id >> 0 ) & 0x0F;
+    buf1[7] = (dst_id >> 4 ) & 0x0F;
+
+    buf1[8] = (app_id >> 0 ) & 0x0F;
+    buf1[9] = (app_id >> 4 ) & 0x0F;
+
+    buf1[10] = (port_id >> 0 ) & 0x0F;
+    buf1[11] = (port_id >> 4 ) & 0x0F;
+
+    buf1[12] = 7;
+    buf1[13] = 7;
+    buf1[14] = 7;
+    buf1[15] = 7;
+
+    // 2. compute CRC and append to end of message
+    FastCrc crc(0x04c11db7);
+    for (unsigned int i=0; i<16; i++)
+        crc.PutByte(buf1[i]);
+    UINT32 crc_code = crc.Done();
+
+    buf1[16] = (crc_code >> 0 )  & 0x0F;
+    buf1[17] = (crc_code >> 4 )  & 0x0F;
+    buf1[18] = (crc_code >> 8 )  & 0x0F;
+    buf1[19] = (crc_code >> 12 ) & 0x0F;
+
+    // 3. repack 20 8-bit symbols (+2 bits) into 27 6-bit symbols
+    SigProc::repack_bytes(buf1, 8, 20, buf2, 2, buf_len, &nw);
+    printf("repack 8->2: nw=%d\n", nw);
+    buf2[640] = 0;
+    SigProc::repack_bytes(buf2, 2, 641, buf1, 6, buf_len, &nw);
+    printf("repack 2->6: nw=%d\n", nw);
+    
+    // 4. use 6-bit RS (63,55) punctured to (35,27)
+    //    27 symbols (uncoded)
+    // -> 35 symbols (coded)
+    int symsize = 6;
+    int npad = 28;
+    int nn = (1<<symsize)-1-npad;    // 63-28 = 35
+    int nroots = 8;
+    int kk = nn-nroots;             // 35-8 = 27
+    void *rs;
+    rs = init_rs_char(symsize,0x43,1,1,nroots,0);
+    encode_rs_char(rs, (unsigned char*) buf1, (unsigned char*) &buf1[kk]);
+
+    // 5. unpack to output buffer
+    SigProc::repack_bytes(buf1, 6, 27, output, 1, output_length, &num_written);
+    num_written += 3; // pad to 213
+    printf("PACKET_RS_512 subheader: num_written: %d (should be 213)\n", num_written);
+    return true;
+}
 
 bool PacketDecoder::FindHeader(
@@ -631 +716 @@
     case PACKET_RAW_400:
         return PacketDecoder::DecodeSubheader_PACKET_RAW_400(input, input_length);
+    case PACKET_RS_512:
+        return PacketDecoder::DecodeSubheader_PACKET_RS_512(input, input_length);
     default:;
     }
@@ -655 +742 @@
         packet_id |= ( rxy > 0 ) ? 0x01 : 0x00;
     }
+    return true;
+}
+
+bool PacketDecoder::DecodeSubheader_PACKET_RS_512(
+    char * input,
+    unsigned int input_length)
+{
+    unsigned int nr;
+    unsigned int nw;
+    
+    // 1. pack 210 bits into 35 6-bit symbols to buf2
+    SigProc::repack_bytes(input, 1, 210, buf2, 6, buf_len, &nw);
+
+    // 2. use RS 6-bit (63,55) code, punctured to (35,27)
+    int symsize = 6;
+    int npad = 28;
+    int nn = (1<<symsize)-1-npad;   // 63-28 = 35
+    int nroots = 8;
+    int kk = nn-nroots;             // 35-8 = 27
+    void *rs;
+    rs = init_rs_char(symsize,0x43,1,1,nroots,0);
+    int nerrors(0);
+    nerrors = decode_rs_char(rs, (unsigned char*) buf2, 0, 0);
+
+    // 3. repack 27 6-bit symbols (-2 bits) to 20 8-bit symbols
+    SigProc::repack_bytes(buf2, 6, 27, buf1, 2, buf_len, &nw);
+    printf("decode, unpack: nw = %d (should be 81)\n", nw);
+    SigProc::repack_bytes(buf1, 2, 80, buf2, 8, buf_len, &nw);
+    printf("decode, unpack: nw = %d (should be 20)\n", nw);
+    
+    // 4. decode and compare CRC
+    FastCrc crc(0x04c11db7);
+    for (unsigned int i=0; i<16; i++)
+        crc.PutByte( buf2[i] );
+    UINT32 crc_code = crc.Done();
+    unsigned long crc_rx(0);
+    for (unsigned int i=1; i<4; i++) {
+        crc_rx <<= 4;
+        crc_rx |= buf2[20-i-1];
+    }
+    //printf("crc_rx = %d, crc_code = %d\n", crc_rx, crc_code);
+    std::cout << "crc_rc: 0x" << std::hex << crc_rx << ", crc_code = 0x" << crc_code << std::endl;
+
+    // 5. decode 16 8-bit symbols...
+    
     return true;
 }

experimental/components/Packetizer/trunk/Packetizer-metadata/src/PacketizerDSP.h

@@ -255 +255 @@
         unsigned int &num_written);
 
+    ///
+    bool EncodeSubheader_PACKET_RS_512(
+        char * output,
+        unsigned int output_length,
+        unsigned int &num_written);
+
   protected:
     /// Array of control code pointers
@@ -350 +356 @@
     ///
     bool DecodeSubheader_PACKET_RAW_400(char * input, unsigned int input_length);
+    bool DecodeSubheader_PACKET_RS_512(char * input, unsigned int input_length);
 
   protected:

experimental/components/Packetizer/trunk/Packetizer-metadata/tests/EncodeDecodeSubheader_testsuite.h

@@ -43 +43 @@
     }
 
+    //
+    // Basic test for creating and extracting a packet of type PACKET_RS_512
+    // 
+    void test_EncodeDecodeSubheader_PACKET_RS_512_01() {
+        // Generate encoder
+        PacketEncoder enc;
+
+        // Generate decoder
+        PacketDecoder dec;
+
+        // Generate temporary output buffer
+        char buf[256];
+        unsigned int N;
+
+        // Set encoder packet id property
+        enc.packet_id = 68392;
+        enc.src_id = 859;
+        enc.dst_id = 906;
+        enc.port_id = 254;
+        enc.app_id = 211;
+        enc.ConfigurePacketType(PACKET_RS_512);
+        enc.EncodeSubheader(buf, 256, N);
+        TS_ASSERT_EQUALS(N, 213);
+
+        // try to decode subheader
+        dec.ConfigurePacketType(PACKET_RS_512);
+        dec.DecodeSubheader(buf, 256);
+
+        TS_ASSERT_EQUALS(dec.packet_id, enc.packet_id);
+        TS_ASSERT_EQUALS(dec.src_id, enc.src_id);
+        TS_ASSERT_EQUALS(dec.dst_id, enc.dst_id);
+        TS_ASSERT_EQUALS(dec.port_id, enc.port_id);
+        TS_ASSERT_EQUALS(dec.app_id, enc.app_id);
+
+    }
+
 };