Merged revisions 77241 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r77241 | antoine.pitrou | 2010-01-02 22:12:58 +0100 (sam., 02 janv. 2010) | 4 lines
Issue #7462: Implement the stringlib fast search algorithm for the `rfind`,
`rindex`, `rsplit` and `rpartition` methods. Patch by Florent Xicluna.
........
diff --git a/Objects/stringlib/README.txt b/Objects/stringlib/README.txt
index aec3441..c884ec3 100644
--- a/Objects/stringlib/README.txt
+++ b/Objects/stringlib/README.txt
@@ -15,10 +15,6 @@
a PyObject representing the empty string
-int STRINGLIB_CMP(STRINGLIB_CHAR*, STRINGLIB_CHAR*, Py_ssize_t)
-
- compares two strings. returns 0 if they match, and non-zero if not.
-
Py_ssize_t STRINGLIB_LEN(PyObject*)
returns the length of the given string object (which must be of the
diff --git a/Objects/stringlib/fastsearch.h b/Objects/stringlib/fastsearch.h
index 23bccfb..7b9dd47 100644
--- a/Objects/stringlib/fastsearch.h
+++ b/Objects/stringlib/fastsearch.h
@@ -5,7 +5,7 @@
/* fast search/count implementation, based on a mix between boyer-
moore and horspool, with a few more bells and whistles on the top.
- for some more background, see: http://effbot.org/stringlib.htm */
+ for some more background, see: http://effbot.org/zone/stringlib.htm */
/* note: fastsearch may access s[n], which isn't a problem when using
Python's ordinary string types, but may cause problems if you're
@@ -16,6 +16,7 @@
#define FAST_COUNT 0
#define FAST_SEARCH 1
+#define FAST_RSEARCH 2
Py_LOCAL_INLINE(Py_ssize_t)
fastsearch(const STRINGLIB_CHAR* s, Py_ssize_t n,
@@ -41,51 +42,92 @@
if (s[i] == p[0])
count++;
return count;
- } else {
+ } else if (mode == FAST_SEARCH) {
for (i = 0; i < n; i++)
if (s[i] == p[0])
return i;
+ } else { /* FAST_RSEARCH */
+ for (i = n - 1; i > -1; i--)
+ if (s[i] == p[0])
+ return i;
}
return -1;
}
mlast = m - 1;
-
- /* create compressed boyer-moore delta 1 table */
skip = mlast - 1;
- /* process pattern[:-1] */
- for (mask = i = 0; i < mlast; i++) {
- mask |= (1 << (p[i] & 0x1F));
- if (p[i] == p[mlast])
- skip = mlast - i - 1;
- }
- /* process pattern[-1] outside the loop */
- mask |= (1 << (p[mlast] & 0x1F));
- for (i = 0; i <= w; i++) {
- /* note: using mlast in the skip path slows things down on x86 */
- if (s[i+m-1] == p[m-1]) {
- /* candidate match */
- for (j = 0; j < mlast; j++)
- if (s[i+j] != p[j])
- break;
- if (j == mlast) {
- /* got a match! */
- if (mode != FAST_COUNT)
- return i;
- count++;
- i = i + mlast;
- continue;
+ if (mode != FAST_RSEARCH) {
+
+ /* create compressed boyer-moore delta 1 table */
+
+ /* process pattern[:-1] */
+ for (mask = i = 0; i < mlast; i++) {
+ mask |= (1 << (p[i] & 0x1F));
+ if (p[i] == p[mlast])
+ skip = mlast - i - 1;
+ }
+ /* process pattern[-1] outside the loop */
+ mask |= (1 << (p[mlast] & 0x1F));
+
+ for (i = 0; i <= w; i++) {
+ /* note: using mlast in the skip path slows things down on x86 */
+ if (s[i+m-1] == p[m-1]) {
+ /* candidate match */
+ for (j = 0; j < mlast; j++)
+ if (s[i+j] != p[j])
+ break;
+ if (j == mlast) {
+ /* got a match! */
+ if (mode != FAST_COUNT)
+ return i;
+ count++;
+ i = i + mlast;
+ continue;
+ }
+ /* miss: check if next character is part of pattern */
+ if (!(mask & (1 << (s[i+m] & 0x1F))))
+ i = i + m;
+ else
+ i = i + skip;
+ } else {
+ /* skip: check if next character is part of pattern */
+ if (!(mask & (1 << (s[i+m] & 0x1F))))
+ i = i + m;
}
- /* miss: check if next character is part of pattern */
- if (!(mask & (1 << (s[i+m] & 0x1F))))
- i = i + m;
- else
- i = i + skip;
- } else {
- /* skip: check if next character is part of pattern */
- if (!(mask & (1 << (s[i+m] & 0x1F))))
- i = i + m;
+ }
+ } else { /* FAST_RSEARCH */
+
+ /* create compressed boyer-moore delta 1 table */
+
+ /* process pattern[0] outside the loop */
+ mask = (1 << (p[0] & 0x1F));
+ /* process pattern[:0:-1] */
+ for (i = mlast; i > 0; i--) {
+ mask |= (1 << (p[i] & 0x1F));
+ if (p[i] == p[0])
+ skip = i - 1;
+ }
+
+ for (i = w; i >= 0; i--) {
+ if (s[i] == p[0]) {
+ /* candidate match */
+ for (j = mlast; j > 0; j--)
+ if (s[i+j] != p[j])
+ break;
+ if (j == 0)
+ /* got a match! */
+ return i;
+ /* miss: check if previous character is part of pattern */
+ if (!(mask & (1 << (s[i-1] & 0x1F))))
+ i = i - m;
+ else
+ i = i - skip;
+ } else {
+ /* skip: check if previous character is part of pattern */
+ if (!(mask & (1 << (s[i-1] & 0x1F))))
+ i = i - m;
+ }
}
}
diff --git a/Objects/stringlib/find.h b/Objects/stringlib/find.h
index bf06530..bf27d6a 100644
--- a/Objects/stringlib/find.h
+++ b/Objects/stringlib/find.h
@@ -32,20 +32,19 @@
const STRINGLIB_CHAR* sub, Py_ssize_t sub_len,
Py_ssize_t offset)
{
- /* XXX - create reversefastsearch helper! */
- if (sub_len == 0) {
- if (str_len < 0)
- return -1;
- return str_len + offset;
- } else {
- Py_ssize_t j, pos = -1;
- for (j = str_len - sub_len; j >= 0; --j)
- if (STRINGLIB_CMP(str+j, sub, sub_len) == 0) {
- pos = j + offset;
- break;
- }
- return pos;
- }
+ Py_ssize_t pos;
+
+ if (str_len < 0)
+ return -1;
+ if (sub_len == 0)
+ return str_len + offset;
+
+ pos = fastsearch(str, str_len, sub, sub_len, FAST_RSEARCH);
+
+ if (pos >= 0)
+ pos += offset;
+
+ return pos;
}
Py_LOCAL_INLINE(Py_ssize_t)
@@ -64,10 +63,7 @@
if (end < 0)
end = 0;
- return stringlib_find(
- str + start, end - start,
- sub, sub_len, start
- );
+ return stringlib_find(str + start, end - start, sub, sub_len, start);
}
Py_LOCAL_INLINE(Py_ssize_t)
diff --git a/Objects/stringlib/partition.h b/Objects/stringlib/partition.h
index 105ba31..2f26212 100644
--- a/Objects/stringlib/partition.h
+++ b/Objects/stringlib/partition.h
@@ -58,7 +58,7 @@
)
{
PyObject* out;
- Py_ssize_t pos, j;
+ Py_ssize_t pos;
if (sep_len == 0) {
PyErr_SetString(PyExc_ValueError, "empty separator");
@@ -69,20 +69,14 @@
if (!out)
return NULL;
- /* XXX - create reversefastsearch helper! */
- pos = -1;
- for (j = str_len - sep_len; j >= 0; --j)
- if (STRINGLIB_CMP(str+j, sep, sep_len) == 0) {
- pos = j;
- break;
- }
+ pos = fastsearch(str, str_len, sep, sep_len, FAST_RSEARCH);
if (pos < 0) {
Py_INCREF(STRINGLIB_EMPTY);
PyTuple_SET_ITEM(out, 0, (PyObject*) STRINGLIB_EMPTY);
Py_INCREF(STRINGLIB_EMPTY);
PyTuple_SET_ITEM(out, 1, (PyObject*) STRINGLIB_EMPTY);
- Py_INCREF(str_obj);
+ Py_INCREF(str_obj);
PyTuple_SET_ITEM(out, 2, (PyObject*) str_obj);
return out;
}
diff --git a/Objects/stringlib/stringdefs.h b/Objects/stringlib/stringdefs.h
index f85357f..8a650fe 100644
--- a/Objects/stringlib/stringdefs.h
+++ b/Objects/stringlib/stringdefs.h
@@ -22,7 +22,6 @@
#define STRINGLIB_RESIZE _PyBytes_Resize
#define STRINGLIB_CHECK PyBytes_Check
#define STRINGLIB_CHECK_EXACT PyBytes_CheckExact
-#define STRINGLIB_CMP memcmp
#define STRINGLIB_TOSTR PyObject_Str
#define STRINGLIB_GROUPING _PyBytes_InsertThousandsGrouping
#define STRINGLIB_GROUPING_LOCALE _PyBytes_InsertThousandsGroupingLocale
diff --git a/Objects/stringlib/unicodedefs.h b/Objects/stringlib/unicodedefs.h
index c23c392..a4d2144 100644
--- a/Objects/stringlib/unicodedefs.h
+++ b/Objects/stringlib/unicodedefs.h
@@ -35,23 +35,4 @@
#define STRINGLIB_WANT_CONTAINS_OBJ 1
-/* STRINGLIB_CMP was defined as:
-
-Py_LOCAL_INLINE(int)
-STRINGLIB_CMP(const Py_UNICODE* str, const Py_UNICODE* other, Py_ssize_t len)
-{
- if (str[0] != other[0])
- return 1;
- return memcmp((void*) str, (void*) other, len * sizeof(Py_UNICODE));
-}
-
-but unfortunately that gives a error if the function isn't used in a file that
-includes this file. So, reluctantly convert it to a macro instead. */
-
-#define STRINGLIB_CMP(str, other, len) \
- (((str)[0] != (other)[0]) ? \
- 1 : \
- memcmp((void*) (str), (void*) (other), (len) * sizeof(Py_UNICODE)))
-
-
#endif /* !STRINGLIB_UNICODEDEFS_H */