[Findutils-patches] [PATCH 6/7] Refactor insert_fprintf to minimise calls to make_segment.

[James Youngman]

* find/print.c (get_format_flags_length): Factor out of
insert_fprintf; computes the length of the format flags for a
format specifier (that is everything after the % but before the
format control character).
(get_format_specifer_length): Also factored out of insert_fprintf;
returns the number of format control characters (e.g. 2 for %A@)
or 0 for error.
(insert_fprintf): Keep fmt_editpos and fmt_inpos more closely in
step, instead of initialising fmt_inpos only when we need it (the
idea eventually will be to make fmt_inpos the loop control
variable).  Call get_format_specifer_length and
get_format_flags_length when needed. Reduce the number of
different calls to make_segment.  We now have one for each KIND_
value plus one for the error case.
---
 ChangeLog    |   18 +++++++++
 find/print.c |  116 ++++++++++++++++++++++++++++++++++++----------------------
 2 files changed, 90 insertions(+), 44 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 0bd6aaf..2e477d3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,21 @@
+2011-06-28  James Youngman  <address@hidden>
+
+       Refactor insert_fprintf to minimise calls to make_segment.
+       * find/print.c (get_format_flags_length): Factor out of
+       insert_fprintf; computes the length of the format flags for a
+       format specifier (that is everything after the % but before the
+       format control character).
+       (get_format_specifer_length): Also factored out of insert_fprintf;
+       returns the number of format control characters (e.g. 2 for %A@)
+       or 0 for error.
+       (insert_fprintf): Keep fmt_editpos and fmt_inpos more closely in
+       step, instead of initialising fmt_inpos only when we need it (the
+       idea eventually will be to make fmt_inpos the loop control
+       variable).  Call get_format_specifer_length and
+       get_format_flags_length when needed. Reduce the number of
+       different calls to make_segment.  We now have one for each KIND_
+       value plus one for the error case.
+
 2011-06-27  James Youngman  <address@hidden>
 
        Factor some of the code out of insert_fprintf.
diff --git a/find/print.c b/find/print.c
index fc72591..862be43 100644
--- a/find/print.c
+++ b/find/print.c
@@ -272,6 +272,41 @@ parse_escape_char(const char ch)
 }
 
 
+static size_t
+get_format_flags_length(const char *p)
+{
+  size_t n = 0;
+  /* Scan past flags, width and precision, to verify kind. */
+  for (; p[++n] && strchr ("-+ #", p[n]);)
+    {
+      /* Do nothing. */
+    }
+  while (ISDIGIT (p[n]))
+    n++;
+  if (p[n] == '.')
+    for (n++; ISDIGIT (p[n]); n++)
+      /* Do nothing. */ ;
+  return n;
+}
+
+static size_t
+get_format_specifer_length(char ch)
+{
+  if (strchr ("abcdDfFgGhHiklmMnpPsStuUyYZ%", ch))
+    {
+      return 1;
+    }
+  else if (strchr ("ABCT", ch))
+    {
+      return 2;
+    }
+  else
+    {
+      return 0;
+    }
+}
+
+
 bool
 insert_fprintf (struct format_val *vec,
                const struct parser_table *entry,
@@ -335,72 +370,65 @@ insert_fprintf (struct format_val *vec,
        }
       else if (fmt_editpos[0] == '%')
        {
-         if (fmt_editpos[1] == '%')
-           {
-             /* % escapes itself.  That is, %% produces just %. */
-             fmt_inpos = fmt_editpos+1;
-           }
-         else if (fmt_editpos[1] == 0)
+         size_t len;
+         fmt_inpos = fmt_editpos;
+         if (fmt_inpos[1] == 0)
            {
              /* Trailing %.  We don't like those. */
              error (EXIT_FAILURE, 0,
-                    _("error: %s at end of format string"), fmt_editpos);
+                    _("error: %s at end of format string"), fmt_inpos);
            }
+
+         if (fmt_inpos[1] == '%') /* %% produces just %. */
+           len = 1;
          else
+           len = get_format_flags_length(fmt_inpos);
+         fmt_inpos += len;
+         fmt_editpos += len;
+
+         assert (fmt_inpos == fmt_editpos);
+         len = get_format_specifer_length (fmt_inpos[0]);
+         if (len && (fmt_inpos[len-1]))
            {
-             /* Scan past flags, width and precision, to verify kind. */
-             for (fmt_inpos = fmt_editpos;
-                  *++fmt_inpos && strchr ("-+ #", *fmt_inpos);)
-               {
-                 /* Do nothing. */
-               }
-             while (ISDIGIT (*fmt_inpos))
-               fmt_inpos++;
-             if (*fmt_inpos == '.')
-               for (fmt_inpos++; ISDIGIT (*fmt_inpos); fmt_inpos++)
-                 /* Do nothing. */ ;
-           }
-         if (strchr ("abcdDfFgGhHiklmMnpPsStuUyYZ%", *fmt_inpos))
-           {
-             segmentp = make_segment (segmentp, segstart, fmt_inpos - segstart,
-                                      KIND_FORMAT, *fmt_inpos, 0,
-                                      our_pred);
-             fmt_editpos = fmt_inpos;
-             segstart = fmt_editpos + 1;
-           }
-         else if (strchr ("ABCT", *fmt_inpos) && fmt_inpos[1])
-           {
-             segmentp = make_segment (segmentp, segstart, fmt_inpos - segstart,
-                                      KIND_FORMAT, fmt_inpos[0], fmt_inpos[1],
+             const char fmt2 = (len == 2) ? fmt_inpos[1] : 0;
+             segmentp = make_segment (segmentp, segstart,
+                                      fmt_editpos - segstart,
+                                      KIND_FORMAT, *fmt_inpos, fmt2,
                                       our_pred);
-             fmt_editpos = fmt_inpos + 1;
-             segstart = fmt_editpos + 1;
+             fmt_editpos += (len - 1);
+             fmt_inpos += (len - 1);
            }
          else
            {
-             switch (*fmt_inpos)
+             if (strchr ("{[(", *fmt_inpos))
                {
-               case '{':
-               case '[':
-               case '(':
                  error (EXIT_FAILURE, 0,
                         _("error: the format directive `%%%c' is reserved for 
future use"),
                         (int)*fmt_inpos);
                  /*NOTREACHED*/
-                 break;
+               }
 
-               default:
+             if (len == 2 && !fmt_inpos[1])
+               {
+                 error (0, 0,
+                        _("warning: format directive `%%%c' "
+                          "should be followed by another character"),
+                        *fmt_inpos);
+               }
+             else
+               {
                  /* An unrecognized % escape.  Print the char after the %. */
                  error (0, 0,
                         _("warning: unrecognized format directive `%%%c'"),
                         *fmt_inpos);
-                 segmentp = make_segment (segmentp,
-                                          segstart, fmt_editpos - segstart,
-                                          KIND_PLAIN, 0, 0,
-                                          our_pred);
-                 segstart = fmt_editpos + 1;
                }
+             ++fmt_inpos;
+             segmentp = make_segment (segmentp,
+                                      segstart, fmt_inpos - segstart,
+                                      KIND_PLAIN, 0, 0,
+                                      our_pred);
            }
+         segstart = fmt_editpos + 1;
        }
     }
 
-- 
1.7.2.5