Avoid need for base64_init and extra table

Simplify the code by assuming C99 initializers.
* src/list.c (base_64_digits): Remove.
(base64_map): Now a constant.  Now has its (old value + 1) % 65,
as that’s the only easy portable way to do it with a static
initializer (even on platforms where CHAR_BIT != 8); all uses changed.
(base64_init): Remove; only use removed.
(from_header): Adjust to new values in base64_map.

* src/list.c (base_64_digits): Remove; no longer needed.
(base64_map): Now const, initialized statically, and with
invalid entries being 0 not 64, and with valid entries
being 1 greater than before.

diff --git a/src/list.c b/src/list.c
index 04005092e909aecf128f2cb4b8be923641eefded..0026378fd15e6fcc64c0168a801bea6d62964d8c 100644 (file)
--- a/src/list.c
+++ b/src/list.c
@@ -51,29 +51,30 @@ static uid_t uid_from_header (const char *buf, size_t size);
 static intmax_t from_header (const char *, size_t, const char *,
                             intmax_t, uintmax_t, bool, bool);
 
-/* Base 64 digits; see Internet RFC 2045 Table 1.  */
-static char const base_64_digits[64] =
-{
-  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
-  'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
-  'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
-  'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
-  '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
+/* Table of base-64 digit values + 1, indexed by unsigned chars.
+   See Internet RFC 2045 Table 1.
+   Zero entries are for unsigned chars that are not base-64 digits.  */
+static char const base64_map[UCHAR_MAX + 1] = {
+  ['A'] =  0 + 1, ['B'] =  1 + 1, ['C'] =  2 + 1, ['D'] =  3 + 1,
+  ['E'] =  4 + 1, ['F'] =  5 + 1, ['G'] =  6 + 1, ['H'] =  7 + 1,
+  ['I'] =  8 + 1, ['J'] =  9 + 1, ['K'] = 10 + 1, ['L'] = 11 + 1,
+  ['M'] = 12 + 1, ['N'] = 13 + 1, ['O'] = 14 + 1, ['P'] = 15 + 1,
+  ['Q'] = 16 + 1, ['R'] = 17 + 1, ['S'] = 18 + 1, ['T'] = 19 + 1,
+  ['U'] = 20 + 1, ['V'] = 21 + 1, ['W'] = 22 + 1, ['X'] = 23 + 1,
+  ['Y'] = 24 + 1, ['Z'] = 25 + 1,
+  ['a'] = 26 + 1, ['b'] = 27 + 1, ['c'] = 28 + 1, ['d'] = 29 + 1,
+  ['e'] = 30 + 1, ['f'] = 31 + 1, ['g'] = 32 + 1, ['h'] = 33 + 1,
+  ['i'] = 34 + 1, ['j'] = 35 + 1, ['k'] = 36 + 1, ['l'] = 37 + 1,
+  ['m'] = 38 + 1, ['n'] = 39 + 1, ['o'] = 40 + 1, ['p'] = 41 + 1,
+  ['q'] = 42 + 1, ['r'] = 43 + 1, ['s'] = 44 + 1, ['t'] = 45 + 1,
+  ['u'] = 46 + 1, ['v'] = 47 + 1, ['w'] = 48 + 1, ['x'] = 49 + 1,
+  ['y'] = 50 + 1, ['z'] = 51 + 1,
+  ['0'] = 52 + 1, ['1'] = 53 + 1, ['2'] = 54 + 1, ['3'] = 55 + 1,
+  ['4'] = 56 + 1, ['5'] = 57 + 1, ['6'] = 58 + 1, ['7'] = 59 + 1,
+  ['8'] = 60 + 1, ['9'] = 61 + 1,
+  ['+'] = 62 + 1, ['/'] = 63 + 1,
 };
 
-/* Table of base-64 digit values indexed by unsigned chars.
-   The value is 64 for unsigned chars that are not base-64 digits.  */
-static char base64_map[UCHAR_MAX + 1];
-
-static void
-base64_init (void)
-{
-  int i;
-  memset (base64_map, 64, sizeof base64_map);
-  for (i = 0; i < 64; i++)
-    base64_map[(int) base_64_digits[i]] = i;
-}
-
 static char *
 decode_xform (char *file_name, void *data)
 {
@@ -171,7 +172,6 @@ read_and (void (*do_something) (void))
   enum read_header prev_status;
   struct timespec mtime;
 
-  base64_init ();
   name_gather ();
 
   open_archive (ACCESS_READ);
@@ -843,8 +843,8 @@ from_header (char const *where0, size_t digs, char const *type,
       while (where != lim)
        {
          unsigned char uc = *where;
-         int dig = base64_map[uc];
-         if (64 <= dig)
+         char dig = base64_map[uc];
+         if (dig <= 0)
            break;
          if (ckd_mul (&value, value, 64))
            {
@@ -854,7 +854,7 @@ from_header (char const *where0, size_t digs, char const *type,
                        quote_mem (where0, digs), type));
              return -1;
            }
-         value |= dig;
+         value |= dig - 1;
          where++;
        }
     }
@@ -1427,7 +1427,6 @@ skim_member (bool must_copy)
 void
 test_archive_label (void)
 {
-  base64_init ();
   name_gather ();
 
   open_archive (ACCESS_READ);