Convert hex digits more systematically

This makes the code a bit smaller and presumably faster, as
it substitutes a single lookup for conditional jumps.
* src/character.c (hexdigit): New constant.
(syms_of_character) [HEXDIGIT_IS_CONST]: Initialize it.
* src/character.h (HEXDIGIT_CONST, HEXDIGIT_IS_CONST): New macros.
(hexdigit): New decl.
(char_hexdigit): New inline function.
* src/charset.c: Do not include c-ctype.h.
* src/charset.c (read_hex):
* src/editfns.c (styled_format):
* src/image.c (xbm_scan):
* src/lread.c (read_escape):
* src/regex.c (ISXDIGIT) [emacs]:
Use char_hexdigit insted of doing it by hand.

1 files changed, 2 insertions, 4 deletions

diff --git a/src/editfns.c b/src/editfns.c
index da99c055b54..d599fcfec80 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -4704,10 +4704,8 @@ styled_format (ptrdiff_t nargs, Lisp_Object *args, bool message)
                   char src0 = src[0];
                   int exponent_bytes = 0;
                   bool signedp = src0 == '-' || src0 == '+' || src0 == ' ';
-                  if (zero_flag
-                      && ((src[signedp] >= '0' && src[signedp] <= '9')
-                          || (src[signedp] >= 'a' && src[signedp] <= 'f')
-                          || (src[signedp] >= 'A' && src[signedp] <= 'F')))
+                  unsigned char after_sign = src[signedp];
+                  if (zero_flag && 0 <= char_hexdigit (after_sign))
                     {
                       leading_zeros += padding;
                       padding = 0;