1 files changed, 106 insertions, 0 deletions
diff --git a/systems/knuth/local/web/tangext.c b/systems/knuth/local/web/tangext.c
new file mode 100644
index 0000000000..2a8a88d292
--- /dev/null
+++ b/systems/knuth/local/web/tangext.c
@@ -0,0 +1,106 @@
+/* External procedures for tangle/weave */
+/* Written by Don Knuth, 29 April 2000, based on Howard Trickey's code of 83 */
+
+/* Note: The input files are read directly with C routines, instead
+  of using the Pascal runtime system. So we do our own EOF testing.
+  The GNU Pascal routines are used only to open ("reset") the files. */
+
+#define BUF_SIZE 500 /* should agree with long_buf_size in weave.web */
+#define max_file_name_length 60 /* should agree with tangle.ch */
+
+#include "GPCtypes.h" /* defines GNU Pascal I/O structure */
+#include <string.h>
+
+void Argv(int n, char* str)
+{
+  register char *s,*t;
+  if (n<0 || n>=_p_argc) return;
+  s=_p_argv[n];
+  if (strlen(s) >= max_file_name_length-5) {
+    str[0]='\0'; return; /* TANGLE doesn't want it too long */
+  }
+  for (t=str; *s; s++,t++) *t=*s;
+  *t='\0';
+}
+
+void Flushstdout()
+{
+  fflush(stdout);
+}
+
+#define buffer Buffer /* GNU Pascal likes to capitalize */
+#define xord Xord
+#define xchr Xchr
+#define limit Limit
+
+unsigned char buffer[BUF_SIZE+1];  /* 0..BUF_SIZE.  Input goes here */
+unsigned char xord[256];
+unsigned char xchr[256];	/* character translation arrays */
+int limit;	/* index into buffer */
+
+/*
+ * lineread reads from the Pascal text file with iorec pointer filep
+ * into buffer[0], buffer[1],..., buffer[limit-1] (and
+ * setting "limit").
+ * Characters are read until a newline is found (which isn't put in the
+ * buffer) or until the next character would go into buffer[BUF_SIZE].
+ * And trailing blanks are to be ignored, so limit is really set to
+ * one past the last non-blank.
+ * The characters need to be translated, so really xord[c] is put into
+ * the buffer when c is read.
+ * If end-of-file is encountered, the FilSta field of *filep is set
+ * appropriately.
+ */
+void Lineread(FDR filep)
+{
+	register int	c;
+	register unsigned char	*cs;	/* points to where next char goes */
+	register unsigned char	*cnb;	/* last non-blank character input */
+	register FILE *iop;	/* stdio-style FILE pointer */
+	register int	l;	/* how many chars before buffer overflow */
+
+	iop = filep->FilJfn;
+	cnb = cs = &buffer[0];
+	l = BUF_SIZE;
+
+	/* overflow when next char would go into buffer[BUF_SIZE] */
+	while ((--l >= 0) && ((c = getc(iop)) != EOF) && (c != '\n')) {
+		if ((*cs++ = xord[c]) != ' ')
+			cnb = cs;
+	}
+
+	if (c == EOF)
+		filep->FilSta |= FiEof;	/* we hit end-of-file */
+        /* actually that wasn't necessary, since testeof uses feof */
+
+	limit = (cnb - &buffer[0]);
+}
+
+/*
+ *	testeof(filep)
+ *
+ *  Test whether or not the Pascal text file with iorec pointer filep
+ *  has reached end-of-file (when the only I/O on it is done with
+ *  lineread, above).
+ *  We may have to read the next character and unget it to see if perhaps
+ *  the end-of-file is next.
+ */
+bool Testeof(FDR filep)
+{
+  register int c;
+  register FILE *iop; /* stdio-style FILE pointer */
+
+  iop = filep->FilJfn;
+  if (feof(iop)) return TRUE;
+  c = getc(iop);
+  if (c == EOF) return TRUE;
+  else {
+    ungetc(c,iop);
+    return FALSE;
+  }
+}
+
+void Exit(int c)
+{
+  exit(c);
+}