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muxstuff.c File Reference

#include "muxstuff.h"

Go to the source code of this file.

Functions

int twotothe (int n)
int ** make_mt_bytes (mux_table_entry *mt, int mt_size, int num_channels, int info_bytes)
float ** make_mt_ratios (int **mt_bytes, int mt_size, int num_channels, int info_bytes)
mux_parameters * new_mux_parameters (char *name)
byte * construct_header (int mc, int pm, bch_type code, int level)
byte * construct_header_level2 (int mc, int pm, int mpl)
int deconstruct_header (byte *header, int *mc, int *pm, bch_type code, int level)
void deconstruct_header_level2 (byte *header, int *mc, int *pm, int *mpl)
byte * construct_mpl (int mpl, bch_type code)
int deconstruct_mpl (byte *mplf, int *mpl, bch_type code)
void swapbits (bytes *b, int a1, int a2)
void swapbytes (bytes *b, int a1, int a2)
void interleave_header (bytes *mux_pdu, int sync_bytes, int header_bytes, int mode)
int mux_byte_source (mux_table_entry *mte, int x)

Variables

int debug
byte sync_8 [1]
byte sync_16 [2]
byte sync_2x16 [4]
byte sync_24 [3]
byte sync_32 [4]
byte h223_headers [16]

Function Documentation

byte* construct_header (  int  mc,
int  pm,
bch_type  code,
int  level
) 
 

Definition at line 232 of file muxstuff.c.

References byte, error(), and lookup_crc().

Referenced by multiplex().

00235             : CRC is always 3 bits.  
00236       * MC is always 4 bits.
00237       * pm should be either 1 or 0, nothing else.
00238       *
00239       * compute crc field, add crc field to bits field
00240       * 
00241       * 
00242       * Bit fields look like this:
00243       *
00244       */
00245 {
00246   static byte h[8];
00247   unsigned long bits=0;
00248   unsigned int crcBits=0;
00249 
00250   if (debug) {
00251     printf("construct_header() MC = %d, %PM = %d\n", mc, pm);
00252   }
00253 
00254   if (level==1) { /* level 0 will also come here */
00255     crcBits = lookup_crc(mc); 
00256     bits = (mc << 4) | (crcBits << 1) | pm;
00257     h[0] = bits;
00258   }
00259   else
00260     error("construct_header","invalid level");
00261 
00262   return (h);
00263 }

byte* construct_header_level2 (  int  mc,
int  pm,
int  mpl
) 
 

Definition at line 265 of file muxstuff.c.

References byte, and encode_golay().

Referenced by multiplex().

00274 {
00275   static byte ret[4];
00276   long bits,encoded;
00277   
00278   bits = (mc&0xF);
00279   bits = bits << 1;
00280   bits = bits | pm&0x1;
00281   bits = bits << 7;
00282   bits = bits | (mpl&0x7F);
00283 
00284   encoded = encode_golay(bits);
00285 
00286   /* now, encoded should contain codeword in 24 lsb bits of encoded */ 
00287   ret[0] = ((encoded >> 16)&0x000000FF);
00288   ret[1] = ((encoded >> 8)&0x000000FF);
00289   ret[2] = (encoded&0x000000FF);
00290   return ret;
00291 }

byte* construct_mpl (  int  mpl,
bch_type  code
) 
 

Definition at line 345 of file muxstuff.c.

References byte, and encode_bch().

00346 {
00347   static byte mplf[8];
00348   unsigned long bits=0;
00349 
00350   bits = mpl;
00351   
00352   if (debug) {
00353     printf("construct_mpl() MPL = %d\n", mpl);
00354   }
00355   
00356   encode_bch(bits, mplf, code);
00357   
00358   return (mplf);
00359 }

int deconstruct_header (  byte *  header,
int *  mc,
int *  pm,
bch_type  code,
int  level
) 
 

Definition at line 294 of file muxstuff.c.

References decode_bch(), and lookup_crc().

Referenced by demultiplex().

00300 {
00301   unsigned long hbits=0;
00302   unsigned int recdCrcBits=0;
00303   int returnval;
00304 
00305   if (level == 1) { /* 0 will also come here */
00306     decode_bch(&hbits, header, code, 1);
00307     *pm = (hbits & 1);
00308     recdCrcBits = (hbits >> 1) & 0x07;
00309     *mc = (hbits >> 4) & 0x0F;
00310 
00311     if (recdCrcBits == lookup_crc(*mc))
00312       returnval = 1;
00313     else
00314       returnval = 0;
00315   }
00316   
00317   if (debug) {
00318     printf("deconstruct_header() MC = %d, PM = %d, CRC = %d\n",*mc,*pm,returnval);
00319   }
00320 
00321   return returnval;
00322 }

void deconstruct_header_level2 (  byte *  header,
int *  mc,
int *  pm,
int *  mpl
) 
 

Definition at line 324 of file muxstuff.c.

References codeword, and decode_golay().

Referenced by demultiplex().

00329 {
00330   long codeword,decoded;
00331 
00332   /* form long out of byte array style header for golay decoding.  mask
00333      out MSB because only 23 bit code, not 24 bit code */
00334   codeword = ((header[0] & 0x7F)<<16) | header[1]<<8 | header[2];
00335 
00336   decoded = decode_golay(codeword);
00337   
00338   *mc = (decoded>>8) & 0xF; 
00339   *pm = (decoded>>7) & 0x1;
00340   *mpl = decoded & 0x7F;
00341   if (debug)
00342     printf("deconstruct_header() MC = %d, PM = %d, MPL = %d\n",*mc,*pm,*mpl);
00343 }

int deconstruct_mpl (  byte *  mplf,
int *  mpl,
bch_type  code
) 
 

Definition at line 361 of file muxstuff.c.

References decode_bch().

Referenced by demultiplex().

00366 {
00367   unsigned long bits=0;
00368   int status;
00369 
00370   status = decode_bch(&bits, mplf, code, 1);
00371   *mpl = bits;
00372 
00373   if (debug) {
00374     printf("deconstruct_mpl() MPL = %d\n", *mpl);
00375   }
00376 
00377   return status;
00378 }

void interleave_header (  bytes *  mux_pdu,
int  sync_bytes,
int  header_bytes,
int  mode
) 
 

Definition at line 418 of file muxstuff.c.

References num_bytes(), swapbits(), and swapbytes().

00426 {
00427   int i, j;
00428   int field_length = num_bytes(mux_pdu) - sync_bytes;
00429 
00430   if (mode == BIT_INTERLEAVING) {
00431     for (i = header_bytes * 8 - 1; i > 0; i--) {
00432       j = field_length * 8 / i;
00433       swapbits(mux_pdu, i, j);
00434     }    
00435   }
00436   else if (mode == BYTE_INTERLEAVING) {
00437     for (i = header_bytes - 1; i > 0; i--) {
00438       j = field_length / i;
00439       swapbytes(mux_pdu, i, j);
00440     }
00441   }
00442 }

int** make_mt_bytes (  mux_table_entry *  mt,
int  mt_size,
int  num_channels,
int  info_bytes
) 
 

Definition at line 51 of file muxstuff.c.

References error(), med_pattern::non_repeating_part, med_pattern::non_repeating_part_length, mux_table_entry::pattern, med_pattern::repeating_part, and med_pattern::repeating_part_length.

Referenced by multiplex().

00060 {
00061   int **mt_bytes = (int **) malloc(mt_size * sizeof(int *));
00062   int i,j,k,n,repeating,towhere;
00063 
00064   if (mt_bytes != NULL) {
00065     for (i=0; i<mt_size; i++) {
00066       mt_bytes[i] = (int *) malloc(num_channels * sizeof(int));
00067       if (mt_bytes[i] != NULL) {
00068         /*
00069          * Figure out how many bytes get allocated to each channel 
00070          * per multiplex code.
00071          */
00072         for (j=0; j<num_channels; j++)
00073           mt_bytes[i][j]=0;
00074         
00075         repeating=!(mt[i].pattern->non_repeating_part_length);
00076         n=0;/* counter */
00077         for (k=0; k<info_bytes; k++) {
00078           if (!repeating) {
00079             towhere = mt[i].pattern->non_repeating_part[n++];
00080             if (towhere >= num_channels)
00081               error("make_mt_bytes","MUX table contains channels \
00082                      that are not used"); 
00083             if (n >= mt[i].pattern->non_repeating_part_length) {
00084               repeating = 1;
00085               n=0;
00086             }
00087           }
00088           else {
00089             towhere = mt[i].pattern->repeating_part[n++];
00090             if (towhere >= num_channels)
00091               error("make_mt_bytes","MUX table contains channels \
00092                      that are not used"); 
00093             if (n >= mt[i].pattern->repeating_part_length)
00094               n=0;
00095           }
00096           mt_bytes[i][towhere]++;
00097         }
00098       }
00099       else {
00100         error("make_mt_bytes", "malloc failed");
00101       }
00102     }
00103   }
00104   else {
00105     error("make_mt_bytes", "malloc failed");
00106   }
00107   return (mt_bytes);
00108 }

float** make_mt_ratios (  int **  mt_bytes,
int  mt_size,
int  num_channels,
int  info_bytes
) 
 

Definition at line 111 of file muxstuff.c.

References error().

Referenced by multiplex().

00115 {
00116   float **mt_ratios = (float **) malloc(mt_size * sizeof(float *));
00117   int i, j;
00118  
00119   int *junkblock;
00120  
00121   if (mt_ratios != NULL) {
00122     /*
00123      * Go through entire multiplex table.
00124      */
00125 
00126   /*
00127   junkblock = (int *) malloc(sizeof(int)*200);
00128   printf(" junkblock %x ...............................\n",junkblock);
00129   */
00130 
00131  for (i=0; i<mt_size; i++) {
00132       mt_ratios[i] = (float *) malloc(num_channels * sizeof(float));
00133       if (mt_ratios[i] != NULL) {
00134         if (info_bytes)
00135           for (j=0; j<num_channels; j++)
00136             mt_ratios[i][j] = (float) mt_bytes[i][j] / info_bytes;
00137       }
00138       else {
00139         error("make_mt_ratios", "malloc failed");
00140       }
00141     }
00142   }
00143   else {
00144     error("make_mt_ratios", "malloc failed");
00145   }
00146   return (mt_ratios);
00147 }

int mux_byte_source (  mux_table_entry *  mte,
int  x
) 
 

Definition at line 445 of file muxstuff.c.

References med_pattern::non_repeating_part, med_pattern::non_repeating_part_length, mux_table_entry::pattern, med_pattern::repeating_part, and med_pattern::repeating_part_length.

Referenced by demultiplex(), and multiplex().

00451 {
00452   int source;
00453   
00454   if (x < mte->pattern->non_repeating_part_length) {
00455     source = mte->pattern->non_repeating_part[x];
00456   }
00457   else {
00458     x -= mte->pattern->non_repeating_part_length;
00459     x %= mte->pattern->repeating_part_length;
00460     source = mte->pattern->repeating_part[x];
00461   }
00462   return(source);
00463 }

mux_parameters* new_mux_parameters (  char *  name  ) 
 

Definition at line 150 of file muxstuff.c.

References mux_table_entry::entry, mux_parameters::header_code, mux_parameters::info_field_length, mux_parameters::mpl_code, mux_parameters::mt_bytes, mux_parameters::mt_ratios, mux_parameters::mux_table, mux_parameters::mux_table_size, mux_table_entry::pattern, mux_parameters::payload_max, mux_parameters::payload_min, mux_parameters::sync_flag_length, mux_parameters::sync_threshold, and mux_parameters::use_mpl.

Referenced by start_config().

00155 {
00156   mux_parameters *p;
00157   int x, y, n;
00158   char str[256];
00159 
00160   p = (mux_parameters *) malloc(sizeof(mux_parameters));
00161   if (p != NULL) {
00162 
00163     p->sync_flag_length = DEF_MUX_SYNC_FLAG;
00164     p->info_field_length = DEF_INFO_FIELD_LENGTH;
00165     p->sync_threshold = DEF_MUX_SYNC_THRESH;
00166 
00167     p->use_mpl = DEF_USE_MPL;
00168     p->header_code = DEF_HEADER_CODE;
00169     p->mpl_code = DEF_MPL_CODE;
00170 
00171     p->payload_min = DEF_PAYLOAD_MIN;
00172     p->payload_max = DEF_PAYLOAD_MAX;
00173 
00174     p->mux_table_size=0;
00175     p->mt_bytes=NULL;
00176     p->mt_ratios=NULL;
00177     
00178     for (x=0; x<MUX_TABLE_SIZE; x++) {
00179       p->mux_table[x].entry=NULL;
00180       p->mux_table[x].pattern=NULL;
00181     }
00182   }
00183   return (p);
00184 }

void swapbits (  bytes *  b,
int  a1,
int  a2
) 
 

Definition at line 380 of file muxstuff.c.

References byte, get_byte(), and set_byte().

Referenced by interleave_header().

00384 {
00385   byte x = get_byte(b, (a1 / 8));
00386   byte y = get_byte(b, (a2 / 8));
00387   byte tmp = x;
00388   if (y & (1 << (a2 % 8))) {
00389     x |= (1 << (a1 % 8));
00390   }
00391   else {
00392     x &= ~(1 << (a1 % 8));
00393   }
00394   if (tmp & (1 << (a1 % 8))) {
00395     y |= (1 << (a2 % 8));
00396   }
00397   else {
00398     y &= ~(1 << (a2 % 8));
00399   }
00400   set_byte(b, (a1 / 8), x);
00401   set_byte(b, (a2 / 8), y);
00402 }

void swapbytes (  bytes *  b,
int  a1,
int  a2
) 
 

Definition at line 405 of file muxstuff.c.

References byte, get_byte(), and set_byte().

Referenced by interleave_header().

00409 {
00410   byte x1, x2;
00411   x1 = get_byte(b, a1);
00412   x2 = get_byte(b, a2);
00413   set_byte(b, a1, x2);
00414   set_byte(b, a2, x1);
00415 }

int twotothe (  int  n  )  [static]
 

Definition at line 41 of file muxstuff.c.

00042 {
00043   int r=1;
00044   while (n>0) {
00045     r *= 2;
00046     n--;
00047   }
00048   return (r);
00049 }

Variable Documentation

int debug
 

Definition at line 23 of file main.c.

byte h223_headers[16] [static]
 

Initial value:


{
  0x00,   
  0xA2,   
  0xE4,   
  0x46,   
  0x68,   
  0xCA,   
  0x8C,   
  0x2E,   
  0xD0,   
  0x72,   
  0x34,   
  0x96,   
  0xB8,   
  0x1A,   
  0x5C,   
  0xFE,   
}

Definition at line 188 of file muxstuff.c.

byte sync_16[2]
 

Initial value:

 
{
  0x4D,
  0xE1,
}

Definition at line 11 of file muxstuff.c.

byte sync_24[3]
 

Initial value:

 
{
  0x82,
  0x4E,
  0xE7,
}

Definition at line 25 of file muxstuff.c.

byte sync_2x16[4]
 

Initial value:

 
{
  0x4D,
  0xE1,
  0x4D,
  0xE1,
}

Definition at line 17 of file muxstuff.c.

byte sync_32[4]
 

Initial value:

 
{
  0x17,
  0x8A,
  0xCE,
  0x98,
}

Definition at line 32 of file muxstuff.c.

byte sync_8[1]
 

Initial value:

 
{ 
  0x7E,
}

Definition at line 6 of file muxstuff.c.

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