svn commit: r1345878 - /subversion/trunk/subversion/libsvn_subr/config_file.c

[st...@apache.org]

Author: stefan2
Date: Mon Jun  4 08:59:24 2012
New Revision: 1345878

URL: http://svn.apache.org/viewvc?rev=1345878&view=rev
Log:
Continue Bert's work on config parsing performance.

* subversion/libsvn_subr/config_file.c
  (parser_getc_plain): inline-able, low overhead variant of parser_getc
  (skip_whitespace, skip_to_eoln): use new func; optimize condition order

Modified:
    subversion/trunk/subversion/libsvn_subr/config_file.c

Modified: subversion/trunk/subversion/libsvn_subr/config_file.c
URL: http://svn.apache.org/viewvc/subversion/trunk/subversion/libsvn_subr/config_file.c?rev=1345878&r1=1345877&r2=1345878&view=diff
==============================================================================
--- subversion/trunk/subversion/libsvn_subr/config_file.c (original)
+++ subversion/trunk/subversion/libsvn_subr/config_file.c Mon Jun  4 08:59:24 2012
@@ -120,6 +120,27 @@ parser_getc(parse_context_t *ctx, int *c
   return SVN_NO_ERROR;
 }
 
+/* Simplified version of parser_getc() to be used inside skipping loops.
+ * It will not check for 'ungotton' chars and may or may not ignore '\r'.
+ *
+ * In a 'while(cond) getc();' loop, the first iteration must call
+ * parser_getc to handle all the special cases.  Later iterations should
+ * use parser_getc_plain for maximum performance.
+ */
+static APR_INLINE svn_error_t *
+parser_getc_plain(parse_context_t *ctx, int *c)
+{
+  if (ctx->buffer_pos < ctx->buffer_size)
+    {
+      *c = ctx->parser_buffer[ctx->buffer_pos];
+      ctx->buffer_pos++;
+
+      return SVN_NO_ERROR;
+    }
+
+  return parser_getc(ctx, c);
+}
+
 /* Emulate ungetc() because streams don't support it.
  *
  * Use CTX to store the ungotten character C.
@@ -143,10 +164,10 @@ skip_whitespace(parse_context_t *ctx, in
   int count = 0;
 
   SVN_ERR(parser_getc(ctx, &ch));
-  while (ch != EOF && ch != '\n' && svn_ctype_isspace(ch))
+  while (svn_ctype_isspace(ch) && ch != '\n' && ch != EOF)
     {
       ++count;
-      SVN_ERR(parser_getc(ctx, &ch));
+      SVN_ERR(parser_getc_plain(ctx, &ch));
     }
   *pcount = count;
   *c = ch;
@@ -162,8 +183,8 @@ skip_to_eoln(parse_context_t *ctx, int *
   int ch;
 
   SVN_ERR(parser_getc(ctx, &ch));
-  while (ch != EOF && ch != '\n')
-    SVN_ERR(parser_getc(ctx, &ch));
+  while (ch != '\n' && ch != EOF)
+    SVN_ERR(parser_getc_plain(ctx, &ch));
 
   *c = ch;
   return SVN_NO_ERROR;