Op Mon, 30 May 2005 09:47:34 +0100 schreef James Youngman
in <[EMAIL PROTECTED]>:
: On Mon, May 30, 2005 at 04:31:52AM +0200, Buzz wrote:
:
: > * I really tried to get this patch as small as possible.
: > * The case-folding /can/ be done less often.
:
: Yes. The old code used to do the case-folding on only the new
: characters read out of the database (that is, each filename character
: read from the database would be case-folded at most once). However,
: when I refactored the code to use the Visitor pattern, I sacrificed
: that optimisation.
That is not what I meant. I meant currently there are multiple copies
of the case-folded string kept. (one per pattern).
I include a patch for this issue.
: If you can actually measure the performance impact of the current
: slightly stupid implementation of visit_substring_match_casefold(),
: I'll certainly consider applying an optimisation patch.
The following patch does not address this. Testing for it might be
difficult and time-consuming, considering the --basename option.
: > * These changes prepare a path towards a ``--and'' (``-a'') option.
:
: Are you envisaging this option as a single-use option (indicating that
: all patterns must match) or as a conjunction as used in "find"? For
: example are you suggesting...
:
: locate foo -a bar -o baz
The former.
Example:
locate -iaE foo bar 'b?z'
: I suppose you can already achieve something similar with
:
: ( locate 'foo.*bar' 'bar.*foo' ; locate baz ) | sort -u
The above would be harder to code, and definitely slower...
: What does the rest of the list think about "-a"?
:
: > * It is possible to allow reading a db from stdin.
: > * Much of the ``main'' loop can be moved into ``visitor''s.
:
: If you're talking about refactoring locate(), then yes, it is a bit
: too long. I'm not sure the current "Visitor" pattern is appropriate
: for this though.
I am. The "Visistor" pattern seems fine to me. (Except maybe the
{munged,original}_filename might be entered into a structure,
providing space for more parameters. (This should improve speed
for fastcall-compiled code))
Now for the casefolding-patch:
Suggested ChangeLog entry:
2005-05-30 Bas van Gompel <[EMAIL PROTECTED]>
* locate/locate.c: Fold case once, only when needed.
diff --exclude='*~' -Ndrup curr/findutils/locate/locate.c
mine2/findutils/locate/locate.c
--- findutils/locate/locate.c 2005-05-30 15:13:34.000000000 +0200
+++ findutils/locate/locate.c 2005-05-30 20:08:10.000000000 +0200
@@ -266,11 +266,20 @@ struct locate_stats
static struct locate_stats statistics;
-struct casefolder
+struct stringbuf
{
- const char *pattern;
char *buffer;
size_t buffersize;
+ size_t *soffs;
+ size_t *preqlen;
+};
+static struct stringbuf casebuf;
+
+
+struct casefolder
+{
+ const char *pattern;
+ struct stringbuf *pbuf;
};
struct regular_expression
@@ -381,6 +390,24 @@ visit_justprint(const char *munged_filen
return VISIT_CONTINUE;
}
+static int
+visit_casefold(const char *munged_filename,
+ const char *original_filename,
+ void *context)
+{
+ struct stringbuf *b = context;
+ (void) original_filename;
+
+ if (*b->preqlen+1 > b->buffersize)
+ {
+ b->buffer = xrealloc(b->buffer, *b->preqlen+1); /* XXX: consider using
extendbuf(). */
+ b->buffersize = *b->preqlen+1;
+ }
+ lc_strcpy(b->buffer, munged_filename);
+
+ return VISIT_CONTINUE;
+}
+
/* visit_existing_follow implements -L -e */
static int
visit_existing_follow(const char *munged_filename,
@@ -500,19 +527,12 @@ visit_substring_match_casefold(const cha
const char *original_filename,
void *context)
{
- struct casefolder * p = context;
- size_t len = strlen(munged_filename);
-
+ const struct casefolder * p = context;
+ const struct stringbuf * b = p->pbuf;
+ (void) munged_filename;
(void) original_filename;
- if (len+1 > p->buffersize)
- {
- p->buffer = xrealloc(p->buffer, len+1); /* XXX: consider using
extendbuf(). */
- p->buffersize = len+1;
- }
- lc_strcpy(p->buffer, munged_filename);
-
-
- if (NULL != strstr(p->buffer, p->pattern))
+
+ if (NULL != strstr(b->buffer, p->pattern))
return VISIT_ACCEPTED;
else
return VISIT_REJECTED;
@@ -656,6 +676,7 @@ locate (int argc,
{
char *pathpart; /* A pattern to consider. */
int argn; /* Index to current pattern in argv. */
+ int need_fold; /* Set when folding and any pattern is non-glob. */
FILE *fp; /* The pathname database. */
int c; /* An input byte. */
int nread; /* number of bytes read from an entry. */
@@ -681,6 +702,25 @@ locate (int argc,
past_pat_inspector = NULL;
+ /* See if we need fold. */
+ if (ignore_case && !regex)
+ for ( argn = 0; argn < argc; argn++ )
+ {
+ pathpart = argv[argn];
+ if (!contains_metacharacter(pathpart))
+ {
+ need_fold = 1;
+ break;
+ }
+ }
+
+ if (need_fold)
+ {
+ add_visitor(visit_casefold, &casebuf);
+ casebuf.preqlen = &pathsize;
+ casebuf.soffs = &count;
+ }
+
/* Add an inspector for each pattern we're looking for. */
for ( argn = 0; argn < argc; argn++ )
{
@@ -719,8 +759,7 @@ locate (int argc,
{
struct casefolder * cf = xmalloc(sizeof(*cf));
cf->pattern = pathpart;
- cf->buffer = NULL;
- cf->buffersize = 0;
+ cf->pbuf = &casebuf;
add_visitor(visit_substring_match_casefold, cf);
/* If we ignore case, convert it to lower now so we don't have to
* do it every time
L8r,
Buzz.
--
) | | ---/ ---/ Yes, this | This message consists of true | I do not
-- | | / / really is | and false bits entirely. | mail for
) | | / / a 72 by 4 +-------------------------------+ any1 but
-- \--| /--- /--- .sigfile. | |perl -pe "s.u(z)\1.as." | me. 4^re
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