From a5bf64b061d73dddf7f2393e4042715553be0a3a Mon Sep 17 00:00:00 2001
From: Glen Whitney <gwhitney@post.harvard.edu>
Date: Mon, 29 Jul 2019 13:22:15 -0400
Subject: [PATCH] Add bitwise logical functions

---
 doc/teapot.lyx    | 81 ++++++++++++++++++++++++++++++++++++++++++++---
 src/common/func.c | 38 ++++++++++++++++++++++
 2 files changed, 114 insertions(+), 5 deletions(-)

diff --git a/doc/teapot.lyx b/doc/teapot.lyx
index 694bdf7..86b5361 100644
--- a/doc/teapot.lyx
+++ b/doc/teapot.lyx
@@ -5546,7 +5546,7 @@ abs
 
 x
 \emph default
-) 
+)
 \series default
  
 \end_layout
@@ -5775,7 +5775,78 @@ x
 x
 \emph default
  is given in radians.
- 
+\end_layout
+
+\begin_layout Description
+
+\series medium
+int
+\begin_inset space ~
+\end_inset
+
+
+\series default
+bitand
+\series medium
+(int
+\emph on
+
+\begin_inset space ~
+\end_inset
+
+v1,
+\begin_inset space ~
+\end_inset
+
+...
+\emph default
+) evaluates to the bitwise 
+\begin_inset Quotes eld
+\end_inset
+
+and
+\begin_inset Quotes erd
+\end_inset
+
+ of all the supplied values.
+\end_layout
+
+\begin_layout Description
+
+\series medium
+int
+\begin_inset space ~
+\end_inset
+
+
+\series default
+bitor
+\series medium
+(int
+\emph on
+
+\begin_inset space ~
+\end_inset
+
+v
+\emph default
+1,
+\emph on
+
+\begin_inset space ~
+\end_inset
+
+
+\emph default
+...) evaluates to the bitwise 
+\begin_inset Quotes eld
+\end_inset
+
+or
+\begin_inset Quotes erd
+\end_inset
+
+ of all the supplied values.
 \end_layout
 
 \begin_layout Description
@@ -6788,7 +6859,7 @@ string
 
 x
 \emph default
-) 
+)
 \series default
  
 \end_layout
@@ -7084,7 +7155,7 @@ x
 
 l
 \emph default
-]) 
+])
 \series default
  
 \end_layout
@@ -7108,7 +7179,7 @@ y
 
 l
 \emph default
-]) 
+])
 \series default
  
 \end_layout
diff --git a/src/common/func.c b/src/common/func.c
index 8621a9f..5b35490 100644
--- a/src/common/func.c
+++ b/src/common/func.c
@@ -511,6 +511,42 @@ static Token z_func(int argc, const Token argv[])
 }
 /*}}}*/
 
+typedef enum { LOG_AND, LOG_OR } LogicalFunction;
+
+static Token bitwise_func(int argc, const Token argv[], LogicalFunction lop)
+{
+  Token result;
+  int accum;
+  if (lop == LOG_AND) accum = -1;
+  else accum = 0;
+  for (size_t i = 0; i < argc; ++i) {
+    if (!INTPATIBLE(argv[i]))
+    {
+      result.type = EEK;
+      result.u.err =
+	mystrmalloc(_("Bitwise functions operate only on integers."));
+      return result;
+    }
+    int val = 0;
+    if (argv[i].type == INT) val = argv[i].u.integer;
+    if (lop == LOG_AND) accum = accum & val;
+    else accum = accum | val;
+  }
+  result.type = INT;
+  result.u.integer = accum;
+  return result;
+}
+
+static Token bitand_func(int argc, const Token argv[])
+{
+  return bitwise_func(argc, argv, LOG_AND);
+}
+
+static Token bitor_func(int argc, const Token argv[])
+{
+  return bitwise_func(argc, argv, LOG_OR);
+}
+
 /* e */ /*{{{*/
 static Token e_func(int argc, const Token argv[])
 {
@@ -1451,6 +1487,8 @@ Tfunc tfunc[]=
   { "substr", substr_func },
   { "strptime", strptime_func },
   { "time", time_func },
+  { "bitand", bitand_func },
+  { "bitor", bitor_func },
   { "", (Token (*)(int, const Token[]))0 }
 };
 /*}}}*/