barak · Jan 30, 2025
diff --git a/Makefile b/Makefile
@@ -30,9 +30,10 @@ tests = mod2dense-test mod2sparse-test mod2convert-test rand-test
 
 tests: $(tests)
 
-CFLAGS += -Wall -Wno-maybe-uninitialized
+CFLAGS += -Wall -Wextra -Wpedantic -Wmissing-prototypes
 CFLAGS += -O2
 CFLAGS += -g
+CFLAGS += -std=c99
 LOADLIBES += -lm
 
 ofiles = alloc.o blockio.o channel.o check.o dec.o distrib.o enc.o	\

diff --git a/alist-to-pchk.c b/alist-to-pchk.c
@@ -16,14 +16,12 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <math.h>
 
 #include "alloc.h"
 #include "intio.h"
 #include "open.h"
 #include "mod2sparse.h"
 #include "mod2dense.h"
-#include "mod2convert.h"
 #include "rcode.h"
 
 
@@ -46,6 +44,10 @@ int main
   int tot, trans;
   int nxt;
 
+  mod2sparse *H;
+  int M;
+  int N;
+
   trans = 0;
 
   for (;;)

diff --git a/channel.c b/channel.c
@@ -14,36 +14,24 @@
  */
 
 #include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
-#include <math.h>
 
 #include "channel.h"
 
 
-/* GLOBAL VARIABLES.  Declared in channel.h. */
-
-channel_type channel;	/* Type of channel */
-
-double error_prob;	/* Error probability for BSC */
-double std_dev;		/* Noise standard deviation for AWGN */
-double lwidth;		/* Width of noise distribution for AWLN */
-
-
 /* PARSE A COMMAND-LINE SPECIFICATION OF A CHANNEL.  Takes a pointer to an
    argument list and an argument count; returns the number of arguments that 
    make up a channel specification at this point in the command line.  Returns
    zero if the argument list does not start with a channel specification.
    Returns -1 if there seems to be a channel specification here, but it's 
    invalid.
-
-   Sets the variables declared in channel.h to the type and parameters of
-   the channel.
  */
 
 int channel_parse
 ( char **argv,		/* Pointer to argument list */
-  int argc		/* Number of arguments in list */
+  int argc,		/* Number of arguments in list */
+  channel_type *channel, /* (output parameter) Type of channel */
+  double *channel_data /* (output parameter) BSC: Error probability, AWGN: Noise standard deviation, AWLN: Width of noise distribution */
 )
 { 
   char junk;
@@ -52,9 +40,9 @@ int channel_parse
 
   if (strcmp(argv[0],"bsc")==0  || strcmp(argv[0],"BSC")==0)
   { 
-    channel = BSC;
-    if (argc<2 || sscanf(argv[1],"%lf%c",&error_prob,&junk)!=1 
-     || error_prob<=0 || error_prob>=1)
+    *channel = BSC;
+    if (argc<2 || sscanf(argv[1],"%lf%c",channel_data,&junk)!=1
+     || *channel_data<=0 || *channel_data>=1)
     { return -1;
     }
     else
@@ -63,9 +51,9 @@ int channel_parse
   }
   else if (strcmp(argv[0],"awgn")==0 || strcmp(argv[0],"AWGN")==0)
   { 
-    channel = AWGN;
-    if (argc<2 || sscanf(argv[1],"%lf%c",&std_dev,&junk)!=1 
-     || std_dev<=0)
+    *channel = AWGN;
+    if (argc<2 || sscanf(argv[1],"%lf%c",channel_data,&junk)!=1
+     || *channel_data<=0)
     { return -1;
     }
     else
@@ -74,9 +62,9 @@ int channel_parse
   }
   else if (strcmp(argv[0],"awln")==0 || strcmp(argv[0],"AWLN")==0)
   {
-    channel = AWLN;
-    if (argc<2 || sscanf(argv[1],"%lf%c",&lwidth,&junk)!=1 
-     || lwidth<=0)
+    *channel = AWLN;
+    if (argc<2 || sscanf(argv[1],"%lf%c",channel_data,&junk)!=1
+     || *channel_data<=0)
     { return -1;
     }
     else
@@ -85,7 +73,7 @@ int channel_parse
   }
   else if (strcmp(argv[0],"misc")==0 || strcmp(argv[0],"MISC")==0)
   {
-    channel = MISC;
+    *channel = MISC;
     return 2;
   }
   else

diff --git a/channel.h b/channel.h
@@ -14,19 +14,12 @@
  */
 
 
-/* TYPES OF CHANNEL, AND CHANNEL PARAMETERS.  The global variables declared
-   here are located in channel.c. */
+/* TYPES OF CHANNEL */
 
 typedef enum { BSC, AWGN, AWLN , MISC} channel_type;
 
-extern channel_type channel;	/* Type of channel */
-
-extern double error_prob;	/* Error probability for BSC */
-extern double std_dev;		/* Noise standard deviation for AWGN */
-extern double lwidth;		/* Width of noise distributoin for AWLN */
-
 
 /* PROCEDURES TO DO WITH CHANNELS. */
 
-int  channel_parse (char **, int);
+int  channel_parse (char **, int, channel_type *channel, double *channel_data);
 void channel_usage (void);
diff --git a/check.c b/check.c
@@ -13,7 +13,6 @@
  * risk.
  */
 
-#include <stdlib.h>
 #include <stdio.h>
 #include <math.h>
 

diff --git a/dec.c b/dec.c
@@ -24,25 +24,12 @@
 #include "alloc.h"
 #include "mod2sparse.h"
 #include "mod2dense.h"
-#include "mod2convert.h"
-#include "rand.h"
 #include "rcode.h"
 #include "check.h"
 #include "dec.h"
 #include "enc.h"
 
 
-/* GLOBAL VARIABLES.  Declared in dec.h. */
-
-decoding_method dec_method;	/* Decoding method to use */
-
-int table;	/* Trace option, 2 for a table of decoding details */
-int block_no;	/* Number of current block, from zero */
-
-int max_iter;	/* Maximum number of iteratons of decoding to do */
-char *gen_file;	/* Generator file for Enum_block and Enum_bit */
-
-
 /* DECODE BY EXHAUSTIVE ENUMERATION.  Decodes by trying all possible source
    messages (and hence all possible codewords, unless the parity check matrix
    was redundant).  If the last argument is 1, it sets dblk to the most likely
@@ -54,22 +41,23 @@ char *gen_file;	/* Generator file for Enum_block and Enum_bit */
    will be the same for all blocks).  The return valued is "unsigned" because
    it might conceivably be as big as 2^31.
 
-   The parity check matrix and other data are taken from the global variables
-   declared in rcode.h.
-
    The number of message bits should not be greater than 31 for this procedure.
    The setup procedure immediately below checks this, reads the generator file,
    and outputs headers for the detailed trace file, if required.
  */
 
-void enum_decode_setup(void)
+void enum_decode_setup(
+  gen_matrix *gm,
+  int table,		/* Trace option, 2 for a table of decoding details */
+  char *gen_file		/* Generator file for Enum_block and Enum_bit */
+)
 {
-  read_gen(gen_file,0,0);
+  read_gen(gen_file,0,0, gm);
 
-  if (N-M>31)
+  if (gm->dim.N-gm->dim.M>31)
   { fprintf(stderr,
 "Trying to decode messages with %d bits by exhaustive enumeration is absurd!\n",
-      N-M);
+      gm->dim.N-gm->dim.M);
     exit(1);  
   }
 
@@ -82,7 +70,11 @@ unsigned enum_decode
 ( double *lratio,	/* Likelihood ratios for bits */
   char *dblk, 		/* Place to stored decoded message */
   double *bitpr,	/* Place to store marginal bit probabilities */
-  int max_block		/* Maximize probability of whole block being correct? */
+  int max_block,		/* Maximize probability of whole block being correct? */
+  mod2sparse *H,		/* Parity check matrix */
+  gen_matrix *gm,		/* Generator matrix */
+  int table,		/* Trace option, 2 for a table of decoding details */
+  int block_no		/* Number of current block, from zero */
 )
 {
   mod2dense *u, *v;
@@ -93,84 +85,89 @@ unsigned enum_decode
   unsigned d;
   int i, j;
 
-  if (N-M>31) abort();
+  if (gm->dim.N-gm->dim.M>31) abort();
 
   /* Allocate needed space. */
 
   bpr = bitpr;
   if (bpr==0 && max_block==0)
-  { bpr = chk_alloc (N, sizeof *bpr);
+  { bpr = chk_alloc (gm->dim.N, sizeof *bpr);
   }
 
-  cblk = chk_alloc (N, sizeof *cblk);
+  cblk = chk_alloc (gm->dim.N, sizeof *cblk);
 
-  if (type=='d')
-  { u = mod2dense_allocate(N-M,1);
-    v = mod2dense_allocate(M,1);
+  if (gm->type=='d')
+  { u = mod2dense_allocate(gm->dim.N-gm->dim.M,1);
+    v = mod2dense_allocate(gm->dim.M,1);
   }
 
-  if (type=='m')
-  { u = mod2dense_allocate(M,1);
-    v = mod2dense_allocate(M,1);
+  else if (gm->type=='m')
+  { u = mod2dense_allocate(gm->dim.M,1);
+    v = mod2dense_allocate(gm->dim.M,1);
+  } 
+
+  else
+  { u = NULL;
+    v = NULL;
   }
 
-  lk0 = chk_alloc (N, sizeof *lk0);
-  lk1 = chk_alloc (N, sizeof *lk1);
+  lk0 = chk_alloc (gm->dim.N, sizeof *lk0);
+  lk1 = chk_alloc (gm->dim.N, sizeof *lk1);
 
   /* Pre-compute likelihoods for bits. */
 
-  for (j = 0; j<N; j++)
+  for (j = 0; j<gm->dim.N; j++)
   { lk0[j] = 1/(1+lratio[j]);
     lk1[j] = 1 - lk0[j];
   }
 
   /* Initialize marginal bit probabilities. */
 
   if (bpr)
-  { for (j = 0; j<N; j++) bpr[j] = 0.0;
+  { for (j = 0; j<gm->dim.N; j++) bpr[j] = 0.0;
   }
 
   /* Exhaustively try all possible decoded messages. */
 
   tpr = 0.0;
 
-  for (d = 0; d<=(1u<<(N-M))-1; d++)
+  for (d = 0; d<=(1u<<(gm->dim.N-gm->dim.M))-1; d++)
   {
     /* Unpack message into source block. */
 
-    for (i = N-M-1; i>=0; i--)
+    for (i = gm->dim.N-gm->dim.M-1; i>=0; i--)
     { sblk[i] = (d>>i)&1;
     }
 
     /* Find full codeword for this message. */
 
-    switch (type)
+    switch (gm->type)
     { case 's':
-      { sparse_encode (sblk, cblk);
+      { sparse_encode (sblk, cblk, H, gm);
         break;
       }
       case 'd':
-      { dense_encode (sblk, cblk, u, v);
+      { dense_encode (sblk, cblk, u, v, gm);
         break;
       }
       case 'm':
-      { mixed_encode (sblk, cblk, u, v);
+      { mixed_encode (sblk, cblk, u, v, H, gm);
         break;
       }
     }
 
     /* Compute likelihood for this decoding. */
 
     lk = 1;
-    for (j = 0; j<N; j++)
+    for (j = 0; j<gm->dim.N; j++)
     { lk *= cblk[j]==0 ? lk0[j] : lk1[j];
     }
 
     /* Update maximum likelihood decoding. */
 
     if (max_block)
     { if (d==0 || lk>maxlk)
-      { for (j = 0; j<N; j++)
+      { for (j = 0; j<gm->dim.N; j++)
         { dblk[j] = cblk[j];
         }
         maxlk = lk;
@@ -180,7 +177,7 @@ unsigned enum_decode
     /* Update bit probabilities. */
 
     if (bpr)
-    { for (j = 0; j<N; j++) 
+    { for (j = 0; j<gm->dim.N; j++)
       { if (cblk[j]==1) 
         { bpr[j] += lk;
         }
@@ -198,14 +195,14 @@ unsigned enum_decode
   /* Normalize bit probabilities. */
 
   if (bpr)
-  { for (j = 0; j<N; j++) bpr[j] /= tpr;
+  { for (j = 0; j<gm->dim.N; j++) bpr[j] /= tpr;
   }
 
   /* Decoding to maximize bit-by-bit success, if that's what's wanted. 
      In case of a tie, decode to a 1. */
 
   if (!max_block)
-  { for (j = 0; j<N; j++) 
+  { for (j = 0; j<gm->dim.N; j++)
     { dblk[j] = bpr[j]>=0.5;
     }
   }
@@ -217,7 +214,7 @@ unsigned enum_decode
   free(lk0);
   free(lk1);
 
-  return 1<<(N-M);
+  return 1<<(gm->dim.N-gm->dim.M);
 }
 
 
@@ -240,7 +237,7 @@ unsigned enum_decode
    file, if required.
 */
 
-void prprp_decode_setup (void)
+void prprp_decode_setup (int table)
 {
   if (table==2)
   { printf(
@@ -253,7 +250,10 @@ unsigned prprp_decode
   double *lratio,	/* Likelihood ratios for bits */
   char *dblk,		/* Place to store decoding */
   char *pchk,		/* Place to store parity checks */
-  double *bprb		/* Place to store bit probabilities */
+  double *bprb,		/* Place to store bit probabilities */
+  int table,		/* Trace option, 2 for a table of decoding details */
+  int block_no,		/* Number of current block, from zero */
+  int max_iter		/* Maximum number of iterations of decoding to do */
 )
 { 
   int N, n, c;