format: ~x/~X specifiers support buffers.

* buf.c (buf_hex): New function.

* buf.h (buf_hex): Declared.

* stream.c (formatv): Support printing of buffers in hex
via temporary buffer containing hex characters, similarly
to how bignums are handled.

* tests/018/format.tl: New file, providing some coverage over
new and affected code.

5 files changed, 84 insertions, 18 deletions

diff --git a/buf.c b/buf.c
index 5d0fb268..1804733a 100644
--- a/buf.c
+++ b/buf.c
@@ -834,6 +834,20 @@ val buf_pprint(val buf, val stream_in)
   return t;
 }
 
+void buf_hex(val buf, char *hex, size_t sz, int caps)
+{
+  val self = lit("buf-hex");
+  struct buf *b = buf_handle(buf, self);
+  size_t i;
+  unsigned char *data = b->data;
+  const char *fmt = caps ? "%02X" : "%02x";
+
+  *hex = 0;
+
+  for (i = 0; i < sz - 1; i += 2)
+    hex += sprintf(hex, fmt, *data++);
+}
+
 struct buf_strm {
   struct strm_base a;
   utf8_decoder_t ud;
diff --git a/buf.h b/buf.h
index 1805f3b8..89c543e5 100644
--- a/buf.h
+++ b/buf.h
@@ -113,6 +113,8 @@ val buf_get_cptr(val buf, val pos);
 val buf_print(val buf, val stream);
 val buf_pprint(val buf, val stream);
 
+void buf_hex(val buf, char *, size_t, int);
+
 val make_buf_stream(val buf_opt);
 val get_buf_from_stream(val stream);
 
diff --git a/stream.c b/stream.c
index 52389245..b565b57e 100644
--- a/stream.c
+++ b/stream.c
@@ -3407,19 +3407,41 @@ val formatv(val stream_in, val fmtstr, struct args *al)
           obj = args_get_checked(self, al, &arg_ix);
           typ = type(obj);
         hex:
-          if (typ == BGNUM) {
-            int nchars = mp_radix_size(mp(obj), 16);
-            if (nchars >= convert(int, sizeof (num_buf)))
-              pnum = coerce(char *, chk_malloc(nchars + 1));
-            mp_toradix_case(mp(obj), coerce(unsigned char *, pnum), 16, ch == 'x');
-          } else {
-            const char *fmt = ch == 'x' ? num_fmt->hex : num_fmt->HEX;
-            value = c_num(obj, self);
-            if (value < 0) {
-              num_buf[0] = '-';
-              sprintf(num_buf + 1, fmt, -value);
-            } else {
-              sprintf(num_buf, fmt, value);
+          switch (typ) {
+          case BGNUM:
+            {
+              int nchars = mp_radix_size(mp(obj), 16);
+              if (nchars >= convert(int, sizeof (num_buf)))
+                pnum = coerce(char *, chk_malloc(nchars + 1));
+              mp_toradix_case(mp(obj), coerce(unsigned char *, pnum), 16, ch == 'x');
+            }
+            break;
+          case BUF:
+            {
+              ucnum len = c_unum(length_buf(obj), self);
+              ucnum nchars = 2 * len + 1;
+
+              if (len >= INT_PTR_MAX)
+                uw_throwf(error_s, lit("~a: ~~~a conversion given "
+                                       "too large a buf argument"),
+                          self, chr(ch), nao);
+
+              pnum = coerce(char *, chk_malloc(nchars));
+              buf_hex(obj, pnum, nchars, ch == 'X');
+            }
+            break;
+          case NUM:
+          case CHR:
+          default:
+            {
+              const char *fmt = ch == 'x' ? num_fmt->hex : num_fmt->HEX;
+              value = c_num(obj, self);
+              if (value < 0) {
+                num_buf[0] = '-';
+                sprintf(num_buf + 1, fmt, -value);
+              } else {
+                sprintf(num_buf, fmt, value);
+              }
             }
           }
           goto output_num;
diff --git a/tests/018/format.tl b/tests/018/format.tl
new file mode 100644
index 00000000..3e9e4f5b
--- /dev/null
+++ b/tests/018/format.tl
@@ -0,0 +1,29 @@
+(load "../common")
+
+(mtest
+  (fmt "~x" #b'') ""
+  (fmt "~4x" #b'') "    "
+  (fmt "~4,02x" #b'') "  00"
+  (fmt "~x" #b'AF') "af"
+  (fmt "~4x" #b'AF') "  af"
+  (fmt "~-4x" #b'AF') "af  "
+  (fmt "~4,03x" #b'AF') " 0af"
+  (fmt "~-4,03X" #b'AF') "0AF ")
+
+(mtest
+  (fmt "~x" #\xaf) "af"
+  (fmt "~4x" #\xaf) "  af"
+  (fmt "~-4x" #\xaf) "af  "
+  (fmt "~4,03x" #\xaf) " 0af"
+  (fmt "~-4,03X" #\xaf) "0AF ")
+
+(mtest
+  (fmt "~x" #xaf) "af"
+  (fmt "~4x" #xaf) "  af"
+  (fmt "~-4x" #xaf) "af  "
+  (fmt "~4,03x" #xaf) " 0af"
+  (fmt "~-4,03X" #xaf) "0AF ")
+
+(test
+  (fmt "~x" (sha256 "abc"))
+  "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad")
diff --git a/txr.1 b/txr.1
index cbf7f97c..bbe1560d 100644
--- a/txr.1
+++ b/txr.1
@@ -53534,14 +53534,13 @@ Requires an argument of integer or character type type. The integer
 value or character code is printed in decimal.
 
 .coIP x
-Requires an argument of character or integer type. The integer value or
-character code is printed in hexadecimal, using lowercase letters
-for the digits
+Requires an argument of character, integer or buffer type. The integer value,
+character code, or buffer contents are printed in hexadecimal, using lowercase
+letters for the digits
 .code a
 through
 .codn f .
-Width and precision semantics
-are as described for the
+Width and precision semantics are as described for the
 .code a
 format directive, for integers.