Initial Commit

lib/ldpc/make-pchk.c

@@ -0,0 +1,93 @@
+/* MAKE-PCHK.C - Make a parity check matrix explicitly. */
+
+/* Copyright (c) 1995-2012 by Radford M. Neal.
+ *
+ * Permission is granted for anyone to copy, use, modify, and distribute
+ * these programs and accompanying documents for any purpose, provided
+ * this copyright notice is retained and prominently displayed, and note
+ * is made of any changes made to these programs.  These programs and
+ * documents are distributed without any warranty, express or implied.
+ * As the programs were written for research purposes only, they have not
+ * been tested to the degree that would be advisable in any important
+ * application.  All use of these programs is entirely at the user's own
+ * risk.
+ */
+
+#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"
+
+
+void usage(void);
+
+
+/* MAIN PROGRAM. */
+
+int main
+( int argc,
+  char **argv
+)
+{
+  char **bit_specs;
+  char *file;
+  FILE *f;
+  int i, j, k;
+  char junk;
+
+  if (!(file = argv[1]) 
+   || !argv[2] || sscanf(argv[2],"%d%c",&M,&junk)!=1 || M<=0
+   || !argv[3] || sscanf(argv[3],"%d%c",&N,&junk)!=1 || N<=0)
+  { usage();
+  }
+
+  bit_specs = argv+4;
+
+  if (bit_specs[0]==0) 
+  { usage();
+  }
+
+  H = mod2sparse_allocate(M,N);
+
+  for (k = 0; bit_specs[k]!=0; k++)
+  { if (sscanf(bit_specs[k],"%d:%d%c",&i,&j,&junk)!=2 || i<0 || j<0) 
+    { usage();
+    }
+    if (i>=M || j>=N)
+    { fprintf(stderr,"Bit %d:%d is out of range\n",i,j);
+      exit(1);
+    }
+    mod2sparse_insert(H,i,j);
+  }
+
+  f = open_file_std(file,"wb");
+  if (f==NULL) 
+  { fprintf(stderr,"Can't create parity check file: %s\n",file);
+    exit(1);
+  }
+
+  intio_write(f,('P'<<8)+0x80);
+  
+  if (ferror(f) || !mod2sparse_write(f,H) || fclose(f)!=0)
+  { fprintf(stderr,"Error writing to parity check file %s\n",file);
+    exit(1);
+  }
+
+  return 0;
+}
+
+
+/* PRINT USAGE MESSAGE AND EXIT. */
+
+void usage(void)
+{ fprintf(stderr,"Usage: make-pchk pchk-file n-checks n-bits row:col ...\n");
+  exit(1);
+}