1 files changed, 113 insertions, 0 deletions
diff --git a/ipl/packs/loadfunc/cspgen.c b/ipl/packs/loadfunc/cspgen.c
new file mode 100644
index 0000000..3a88ee0
--- /dev/null
+++ b/ipl/packs/loadfunc/cspgen.c
@@ -0,0 +1,113 @@
+/*
+ *  cspgen(image, cycle) - calculate next "cyclic space" generation
+ *
+ *  The image is considered a torus, with top and bottom connected directly
+ *  and with sides connected using a shift of one row.
+ */
+
+/*
+ *  internal buffer layout:
+ *
+ *	image header
+ *	copy of last row
+ *	original array
+ *	copy of first row
+ *	
+ *  new array is stored atop old array, but directly after the header.
+ */
+
+
+#include <stdlib.h>
+#include <string.h>
+#include "icall.h"
+
+
+int cspgen(int argc, descriptor *argv)
+{
+   int ulength, period, i;
+   char *ustring, *udata, *cycle;
+   char *old, *new;
+   char o, x;
+
+   int w, h, n;				/* width, height, total pixels */
+
+   char hbuf[20];			/* image header buffer */
+   int hlen;				/* header length */
+
+   static char *ibuf;			/* image buffer */
+   static int ilen;			/* buffer length */
+   int ineed;				/* buffer length needed */
+
+   static char map[256];		/* mapping from one char to next */
+
+   /*
+    * Get the parameters.
+    */
+   ArgString(1);			/* validate types */
+   ArgString(2);
+   ustring = StringAddr(argv[1]);	/* universe string and length */
+   ulength = StringLen(argv[1]);
+   cycle = StringAddr(argv[2]);		/* cycle and length */
+   period = StringLen(argv[2]);
+   sscanf(ustring, "%d", &w);		/* row width */
+
+   /*
+    * Build the generation mapping table.
+    */
+   map[cycle[period-1] & 0xFF] = cycle[0];	/* last maps to first */
+   for (i = 1; i < period; i++)
+      map[cycle[i-1] & 0xFF] = cycle[i];
+
+   /*
+    * Copy the image header (through the second comma) to hbuf.
+    */
+   old = ustring;
+   new = hbuf;
+   while ((*new++ = *old++) != ',')
+      ;
+   while ((*new++ = *old++) != ',')
+      ;
+   udata = old;
+   hlen = udata - ustring;		/* header length */
+
+   /*
+    * Allocate the image buffer.
+    */
+   n = ulength - hlen;			/* number of pixels */
+   if (n % w != 0)
+      Error(205);
+   h = n / w;				/* image height */
+
+   ineed = hlen + n + 2 * w;		/* buffer size needed */
+   if (ilen < ineed)
+      if (!(ibuf = realloc(ibuf, ilen = ineed)))
+	 Error(305);
+
+   /*
+    * Copy the image into the buffer.  Allow for the possibility that
+    * the image already be *in* the buffer.
+    */
+   new = ibuf + hlen;
+   old = new + w;
+   memmove(old, udata, n);		/* main image, leaving room */
+   memcpy(old - w, old + n - w, w);	/* dup last row first first */
+   memcpy(old + n, old, w);		/* dup first row beyond last */
+
+   /*
+    * Create the new image.
+    */
+   memcpy(ibuf, hbuf, hlen);
+   for (i = 0; i < n; i++) {
+      o = *old;
+      x = map[o & 0xFF];
+      if (old[-1] == x || old[1] == x || old[-w] == x || old[w] == x)
+	 o = x;
+      *new++ = o;
+      old++;
+      }
+
+   /*
+    * Return the result.
+    */
+   RetConstStringN(ibuf, ulength);
+}