Change return value spec for base64 stream functions.

* filter.c (base64_stream_enc, base64_stream_dec):
Count bytes encoded or decoded (using a fast integral
counter which efficiently overflows to a Lisp value that may
be a bignum).

* txr.1: Doc updated.

2 files changed, 27 insertions, 9 deletions

diff --git a/filter.c b/filter.c
index 5c7d47f9..11637a29 100644
--- a/filter.c
+++ b/filter.c
@@ -743,7 +743,8 @@ val base64_stream_enc(val out, val in, val nbytes, val wrap_cols)
   int ulim = nilp(default_null_arg(nbytes));
   cnum col = 0;
   cnum nb = if3(ulim, 0, c_num(nbytes));
-  cnum nb_orig = nb;
+  cnum count = 0;
+  val ret = zero;
   cnum wcol = c_num(default_arg(wrap_cols, zero));
 
   for (; ulim || nb > 0; ulim ? --nb : 0) {
@@ -760,6 +761,7 @@ val base64_stream_enc(val out, val in, val nbytes, val wrap_cols)
       put_char(chr(b64[(word >> 12) & 0x3F]), out); col_check(&col, wcol, out);
       put_char(chr(b64[(word >>  6) & 0x3F]), out); col_check(&col, wcol, out);
       put_char(chr(b64[(word      ) & 0x3F]), out); col_check(&col, wcol, out);
+      count += 3;
     } else if (bv1) {
       cnum b0 = c_num(bv0);
       cnum b1 = c_num(bv1);
@@ -768,6 +770,7 @@ val base64_stream_enc(val out, val in, val nbytes, val wrap_cols)
       put_char(chr(b64[(word >> 12) & 0x3F]), out); col_check(&col, wcol, out);
       put_char(chr(b64[(word >>  6) & 0x3F]), out); col_check(&col, wcol, out);
       put_char(chr('='), out);                      col_check(&col, wcol, out);
+      count += 2;
       break;
     } else if (bv0) {
       cnum b0 = c_num(bv0);
@@ -776,16 +779,22 @@ val base64_stream_enc(val out, val in, val nbytes, val wrap_cols)
       put_char(chr(b64[(word >> 12) & 0x3F]), out); col_check(&col, wcol, out);
       put_char(chr('='), out);                      col_check(&col, wcol, out);
       put_char(chr('='), out);                      col_check(&col, wcol, out);
+      count++;
       break;
     } else {
       break;
     }
+
+    if (count > NUM_MAX / 2) {
+      ret = plus(ret, num_fast(count));
+      count = 0;
+    }
   }
 
   if (wcol && col > 0)
     put_char(chr('\n'), out);
 
-  return if3(ulim, t, num(nb_orig - nb));
+  return plus(ret, num_fast(count));
 }
 
 val base64_encode(val str, val wrap_cols)
@@ -833,6 +842,9 @@ INLINE int b64_code(cnum c)
 
 val base64_stream_dec(val out, val in)
 {
+  val ret = zero;
+  cnum count = 0;
+
   for (;;) {
     cnum c0 = get_base64_char(in);
     cnum c1 = c0 ? get_base64_char(in) : 0;
@@ -849,6 +861,7 @@ val base64_stream_dec(val out, val in)
       put_byte(num_fast((word >> 16)       ), out);
       put_byte(num_fast((word >>  8) & 0xff), out);
       put_byte(num_fast( word        & 0xff), out);
+      count += 3;
     } else if (c2) {
       long f0 = b64_code(c0);
       long f1 = b64_code(c1);
@@ -857,19 +870,26 @@ val base64_stream_dec(val out, val in)
 
       put_byte(num_fast((word >> 16)       ), out);
       put_byte(num_fast((word >>  8) & 0xff), out);
+      count += 2;
       break;
     } else if (c0 || c1) {
       long f0 = b64_code(c0);
       long f1 = b64_code(c1);
       long word = (f0 << 18) | (f1 << 12);
       put_byte(num_fast((word >> 16)       ), out);
+      count += 1;
       break;
     } else {
       break;
     }
+
+    if (count > NUM_MAX / 2) {
+      ret = plus(ret, num_fast(count));
+      count = 0;
+    }
   }
 
-  return t;
+  return plus(ret, num_fast(count));
 }
 
 val base64_decode(val str)
diff --git a/txr.1 b/txr.1
index 911143dd..b0d3ecb8 100644
--- a/txr.1
+++ b/txr.1
@@ -52518,12 +52518,10 @@ stream.
 
 The
 .code base64-stream-enc
-function returns
-.code t
-if the
-.meta nbytes
-argument is omitted. If the argument is specified,
-it returns the number of bytes that have been encoded.
+function returns the number of bytes encoded;
+the
+.code base64-stream-dec
+function returns the number of bytes decoded.
 
 .SS* Filter Module
 The filter module provides a trie (pronounced "try") data structure,