Merged revisions 77461 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r77461 | antoine.pitrou | 2010-01-13 08:55:48 +0100 (mer., 13 janv. 2010) | 5 lines

  Issue #7622: Improve the split(), rsplit(), splitlines() and replace()
  methods of bytes, bytearray and unicode objects by using a common
  implementation based on stringlib's fast search.  Patch by Florent Xicluna.
........

1 files changed, 788 insertions, 0 deletions

diff --git a/Objects/stringlib/split.h b/Objects/stringlib/split.h
new file mode 100644
index 0000000..00b29b3
--- /dev/null
+++ b/Objects/stringlib/split.h
@@ -0,0 +1,788 @@
+/* stringlib: split implementation */
+
+#ifndef STRINGLIB_SPLIT_H
+#define STRINGLIB_SPLIT_H
+
+#ifndef STRINGLIB_FASTSEARCH_H
+#error must include "stringlib/fastsearch.h" before including this module
+#endif
+
+/* Overallocate the initial list to reduce the number of reallocs for small
+   split sizes.  Eg, "A A A A A A A A A A".split() (10 elements) has three
+   resizes, to sizes 4, 8, then 16.  Most observed string splits are for human
+   text (roughly 11 words per line) and field delimited data (usually 1-10
+   fields).  For large strings the split algorithms are bandwidth limited
+   so increasing the preallocation likely will not improve things.*/
+
+#define MAX_PREALLOC 12
+
+/* 5 splits gives 6 elements */
+#define PREALLOC_SIZE(maxsplit) \
+    (maxsplit >= MAX_PREALLOC ? MAX_PREALLOC : maxsplit+1)
+
+#define SPLIT_APPEND(data, left, right)         \
+    sub = STRINGLIB_NEW((data) + (left),        \
+                        (right) - (left));      \
+    if (sub == NULL)                            \
+        goto onError;                           \
+    if (PyList_Append(list, sub)) {             \
+        Py_DECREF(sub);                         \
+        goto onError;                           \
+    }                                           \
+    else                                        \
+        Py_DECREF(sub);
+
+#define SPLIT_ADD(data, left, right) {          \
+    sub = STRINGLIB_NEW((data) + (left),        \
+                        (right) - (left));      \
+    if (sub == NULL)                            \
+        goto onError;                           \
+    if (count < MAX_PREALLOC) {                 \
+        PyList_SET_ITEM(list, count, sub);      \
+    } else {                                    \
+        if (PyList_Append(list, sub)) {         \
+            Py_DECREF(sub);                     \
+            goto onError;                       \
+        }                                       \
+        else                                    \
+            Py_DECREF(sub);                     \
+    }                                           \
+    count++; }
+
+
+/* Always force the list to the expected size. */
+#define FIX_PREALLOC_SIZE(list) Py_SIZE(list) = count
+
+Py_LOCAL_INLINE(PyObject *)
+stringlib_split_whitespace(PyObject* str_obj,
+                           const STRINGLIB_CHAR* str, Py_ssize_t str_len,
+                           Py_ssize_t maxcount)
+{
+    Py_ssize_t i, j, count=0;
+    PyObject *list = PyList_New(PREALLOC_SIZE(maxcount));
+    PyObject *sub;
+
+    if (list == NULL)
+        return NULL;
+
+    i = j = 0;
+    while (maxcount-- > 0) {
+        while (i < str_len && STRINGLIB_ISSPACE(str[i]))
+            i++;
+        if (i == str_len) break;
+        j = i; i++;
+        while (i < str_len && !STRINGLIB_ISSPACE(str[i]))
+            i++;
+#ifndef STRINGLIB_MUTABLE
+        if (j == 0 && i == str_len && STRINGLIB_CHECK_EXACT(str_obj)) {
+            /* No whitespace in str_obj, so just use it as list[0] */
+            Py_INCREF(str_obj);
+            PyList_SET_ITEM(list, 0, (PyObject *)str_obj);
+            count++;
+            break;
+        }
+#endif
+        SPLIT_ADD(str, j, i);
+    }
+
+    if (i < str_len) {
+        /* Only occurs when maxcount was reached */
+        /* Skip any remaining whitespace and copy to end of string */
+        while (i < str_len && STRINGLIB_ISSPACE(str[i]))
+            i++;
+        if (i != str_len)
+            SPLIT_ADD(str, i, str_len);
+    }
+    FIX_PREALLOC_SIZE(list);
+    return list;
+
+  onError:
+    Py_DECREF(list);
+    return NULL;
+}
+
+Py_LOCAL_INLINE(PyObject *)
+stringlib_split_char(PyObject* str_obj,
+                     const STRINGLIB_CHAR* str, Py_ssize_t str_len,
+                     const STRINGLIB_CHAR ch,
+                     Py_ssize_t maxcount)
+{
+    Py_ssize_t i, j, count=0;
+    PyObject *list = PyList_New(PREALLOC_SIZE(maxcount));
+    PyObject *sub;
+
+    if (list == NULL)
+        return NULL;
+
+    i = j = 0;
+    while ((j < str_len) && (maxcount-- > 0)) {
+        for(; j < str_len; j++) {
+            /* I found that using memchr makes no difference */
+            if (str[j] == ch) {
+                SPLIT_ADD(str, i, j);
+                i = j = j + 1;
+                break;
+            }
+        }
+    }
+#ifndef STRINGLIB_MUTABLE
+    if (count == 0 && STRINGLIB_CHECK_EXACT(str_obj)) {
+        /* ch not in str_obj, so just use str_obj as list[0] */
+        Py_INCREF(str_obj);
+        PyList_SET_ITEM(list, 0, (PyObject *)str_obj);
+        count++;
+    } else
+#endif
+    if (i <= str_len) {
+        SPLIT_ADD(str, i, str_len);
+    }
+    FIX_PREALLOC_SIZE(list);
+    return list;
+
+  onError:
+    Py_DECREF(list);
+    return NULL;
+}
+
+Py_LOCAL_INLINE(PyObject *)
+stringlib_split(PyObject* str_obj,
+                const STRINGLIB_CHAR* str, Py_ssize_t str_len,
+                const STRINGLIB_CHAR* sep, Py_ssize_t sep_len,
+                Py_ssize_t maxcount)
+{
+    Py_ssize_t i, j, pos, count=0;
+    PyObject *list, *sub;
+
+    if (sep_len == 0) {
+        PyErr_SetString(PyExc_ValueError, "empty separator");
+        return NULL;
+    }
+    else if (sep_len == 1)
+        return stringlib_split_char(str_obj, str, str_len, sep[0], maxcount);
+
+    list = PyList_New(PREALLOC_SIZE(maxcount));
+    if (list == NULL)
+        return NULL;
+
+    i = j = 0;
+    while (maxcount-- > 0) {
+        pos = fastsearch(str+i, str_len-i, sep, sep_len, -1, FAST_SEARCH);
+        if (pos < 0)
+            break;
+        j = i + pos;
+        SPLIT_ADD(str, i, j);
+        i = j + sep_len;
+    }
+#ifndef STRINGLIB_MUTABLE
+    if (count == 0 && STRINGLIB_CHECK_EXACT(str_obj)) {
+        /* No match in str_obj, so just use it as list[0] */
+        Py_INCREF(str_obj);
+        PyList_SET_ITEM(list, 0, (PyObject *)str_obj);
+        count++;
+    } else
+#endif
+    {
+        SPLIT_ADD(str, i, str_len);
+    }
+    FIX_PREALLOC_SIZE(list);
+    return list;
+
+  onError:
+    Py_DECREF(list);
+    return NULL;
+}
+
+Py_LOCAL_INLINE(PyObject *)
+stringlib_rsplit_whitespace(PyObject* str_obj,
+                            const STRINGLIB_CHAR* str, Py_ssize_t str_len,
+                            Py_ssize_t maxcount)
+{
+    Py_ssize_t i, j, count=0;
+    PyObject *list = PyList_New(PREALLOC_SIZE(maxcount));
+    PyObject *sub;
+
+    if (list == NULL)
+        return NULL;
+
+    i = j = str_len - 1;
+    while (maxcount-- > 0) {
+        while (i >= 0 && STRINGLIB_ISSPACE(str[i]))
+            i--;
+        if (i < 0) break;
+        j = i; i--;
+        while (i >= 0 && !STRINGLIB_ISSPACE(str[i]))
+            i--;
+#ifndef STRINGLIB_MUTABLE
+        if (j == str_len - 1 && i < 0 && STRINGLIB_CHECK_EXACT(str_obj)) {
+            /* No whitespace in str_obj, so just use it as list[0] */
+            Py_INCREF(str_obj);
+            PyList_SET_ITEM(list, 0, (PyObject *)str_obj);
+            count++;
+            break;
+        }
+#endif
+        SPLIT_ADD(str, i + 1, j + 1);
+    }
+
+    if (i >= 0) {
+        /* Only occurs when maxcount was reached */
+        /* Skip any remaining whitespace and copy to beginning of string */
+        while (i >= 0 && STRINGLIB_ISSPACE(str[i]))
+            i--;
+        if (i >= 0)
+            SPLIT_ADD(str, 0, i + 1);
+    }
+    FIX_PREALLOC_SIZE(list);
+    if (PyList_Reverse(list) < 0)
+        goto onError;
+    return list;
+
+  onError:
+    Py_DECREF(list);
+    return NULL;
+}
+
+Py_LOCAL_INLINE(PyObject *)
+stringlib_rsplit_char(PyObject* str_obj,
+                      const STRINGLIB_CHAR* str, Py_ssize_t str_len,
+                      const STRINGLIB_CHAR ch,
+                      Py_ssize_t maxcount)
+{
+    Py_ssize_t i, j, count=0;
+    PyObject *list = PyList_New(PREALLOC_SIZE(maxcount));
+    PyObject *sub;
+
+    if (list == NULL)
+        return NULL;
+
+    i = j = str_len - 1;
+    while ((i >= 0) && (maxcount-- > 0)) {
+        for(; i >= 0; i--) {
+            if (str[i] == ch) {
+                SPLIT_ADD(str, i + 1, j + 1);
+                j = i = i - 1;
+                break;
+            }
+        }
+    }
+#ifndef STRINGLIB_MUTABLE
+    if (count == 0 && STRINGLIB_CHECK_EXACT(str_obj)) {
+        /* ch not in str_obj, so just use str_obj as list[0] */
+        Py_INCREF(str_obj);
+        PyList_SET_ITEM(list, 0, (PyObject *)str_obj);
+        count++;
+    } else
+#endif
+    if (j >= -1) {
+        SPLIT_ADD(str, 0, j + 1);
+    }
+    FIX_PREALLOC_SIZE(list);
+    if (PyList_Reverse(list) < 0)
+        goto onError;
+    return list;
+
+  onError:
+    Py_DECREF(list);
+    return NULL;
+}
+
+Py_LOCAL_INLINE(PyObject *)
+stringlib_rsplit(PyObject* str_obj,
+                 const STRINGLIB_CHAR* str, Py_ssize_t str_len,
+                 const STRINGLIB_CHAR* sep, Py_ssize_t sep_len,
+                 Py_ssize_t maxcount)
+{
+    Py_ssize_t j, pos, count=0;
+    PyObject *list, *sub;
+
+    if (sep_len == 0) {
+        PyErr_SetString(PyExc_ValueError, "empty separator");
+        return NULL;
+    }
+    else if (sep_len == 1)
+        return stringlib_rsplit_char(str_obj, str, str_len, sep[0], maxcount);
+
+    list = PyList_New(PREALLOC_SIZE(maxcount));
+    if (list == NULL)
+        return NULL;
+
+    j = str_len;
+    while (maxcount-- > 0) {
+        pos = fastsearch(str, j, sep, sep_len, -1, FAST_RSEARCH);
+        if (pos < 0)
+            break;
+        SPLIT_ADD(str, pos + sep_len, j);
+        j = pos;
+    }
+#ifndef STRINGLIB_MUTABLE
+    if (count == 0 && STRINGLIB_CHECK_EXACT(str_obj)) {
+        /* No match in str_obj, so just use it as list[0] */
+        Py_INCREF(str_obj);
+        PyList_SET_ITEM(list, 0, (PyObject *)str_obj);
+        count++;
+    } else
+#endif
+    {
+        SPLIT_ADD(str, 0, j);
+    }
+    FIX_PREALLOC_SIZE(list);
+    if (PyList_Reverse(list) < 0)
+        goto onError;
+    return list;
+
+  onError:
+    Py_DECREF(list);
+    return NULL;
+}
+
+Py_LOCAL_INLINE(PyObject *)
+stringlib_splitlines(PyObject* str_obj,
+                     const STRINGLIB_CHAR* str, Py_ssize_t str_len,
+                     int keepends)
+{
+    /* This does not use the preallocated list because splitlines is
+       usually run with hundreds of newlines.  The overhead of
+       switching between PyList_SET_ITEM and append causes about a
+       2-3% slowdown for that common case.  A smarter implementation
+       could move the if check out, so the SET_ITEMs are done first
+       and the appends only done when the prealloc buffer is full.
+       That's too much work for little gain.*/
+
+    register Py_ssize_t i;
+    register Py_ssize_t j;
+    PyObject *list = PyList_New(0);
+    PyObject *sub;
+
+    if (list == NULL)
+        return NULL;
+
+    for (i = j = 0; i < str_len; ) {
+        Py_ssize_t eol;
+
+        /* Find a line and append it */
+        while (i < str_len && !STRINGLIB_ISLINEBREAK(str[i]))
+            i++;
+
+        /* Skip the line break reading CRLF as one line break */
+        eol = i;
+        if (i < str_len) {
+            if (str[i] == '\r' && i + 1 < str_len && str[i+1] == '\n')
+                i += 2;
+            else
+                i++;
+            if (keepends)
+                eol = i;
+        }
+#ifndef STRINGLIB_MUTABLE
+        if (j == 0 && eol == str_len && STRINGLIB_CHECK_EXACT(str_obj)) {
+            /* No linebreak in str_obj, so just use it as list[0] */
+            if (PyList_Append(list, str_obj))
+                goto onError;
+            break;
+        }
+#endif
+        SPLIT_APPEND(str, j, eol);
+        j = i;
+    }
+    return list;
+
+  onError:
+    Py_DECREF(list);
+    return NULL;
+}
+
+#endif
+/* stringlib: split implementation */
+
+#ifndef STRINGLIB_SPLIT_H
+#define STRINGLIB_SPLIT_H
+
+#ifndef STRINGLIB_FASTSEARCH_H
+#error must include "stringlib/fastsearch.h" before including this module
+#endif
+
+/* Overallocate the initial list to reduce the number of reallocs for small
+   split sizes.  Eg, "A A A A A A A A A A".split() (10 elements) has three
+   resizes, to sizes 4, 8, then 16.  Most observed string splits are for human
+   text (roughly 11 words per line) and field delimited data (usually 1-10
+   fields).  For large strings the split algorithms are bandwidth limited
+   so increasing the preallocation likely will not improve things.*/
+
+#define MAX_PREALLOC 12
+
+/* 5 splits gives 6 elements */
+#define PREALLOC_SIZE(maxsplit) \
+    (maxsplit >= MAX_PREALLOC ? MAX_PREALLOC : maxsplit+1)
+
+#define SPLIT_APPEND(data, left, right)         \
+    sub = STRINGLIB_NEW((data) + (left),        \
+                        (right) - (left));      \
+    if (sub == NULL)                            \
+        goto onError;                           \
+    if (PyList_Append(list, sub)) {             \
+        Py_DECREF(sub);                         \
+        goto onError;                           \
+    }                                           \
+    else                                        \
+        Py_DECREF(sub);
+
+#define SPLIT_ADD(data, left, right) {          \
+    sub = STRINGLIB_NEW((data) + (left),        \
+                        (right) - (left));      \
+    if (sub == NULL)                            \
+        goto onError;                           \
+    if (count < MAX_PREALLOC) {                 \
+        PyList_SET_ITEM(list, count, sub);      \
+    } else {                                    \
+        if (PyList_Append(list, sub)) {         \
+            Py_DECREF(sub);                     \
+            goto onError;                       \
+        }                                       \
+        else                                    \
+            Py_DECREF(sub);                     \
+    }                                           \
+    count++; }
+
+
+/* Always force the list to the expected size. */
+#define FIX_PREALLOC_SIZE(list) Py_SIZE(list) = count
+
+Py_LOCAL_INLINE(PyObject *)
+stringlib_split_whitespace(PyObject* str_obj,
+                           const STRINGLIB_CHAR* str, Py_ssize_t str_len,
+                           Py_ssize_t maxcount)
+{
+    Py_ssize_t i, j, count=0;
+    PyObject *list = PyList_New(PREALLOC_SIZE(maxcount));
+    PyObject *sub;
+
+    if (list == NULL)
+        return NULL;
+
+    i = j = 0;
+    while (maxcount-- > 0) {
+        while (i < str_len && STRINGLIB_ISSPACE(str[i]))
+            i++;
+        if (i == str_len) break;
+        j = i; i++;
+        while (i < str_len && !STRINGLIB_ISSPACE(str[i]))
+            i++;
+#ifndef STRINGLIB_MUTABLE
+        if (j == 0 && i == str_len && STRINGLIB_CHECK_EXACT(str_obj)) {
+            /* No whitespace in str_obj, so just use it as list[0] */
+            Py_INCREF(str_obj);
+            PyList_SET_ITEM(list, 0, (PyObject *)str_obj);
+            count++;
+            break;
+        }
+#endif
+        SPLIT_ADD(str, j, i);
+    }
+
+    if (i < str_len) {
+        /* Only occurs when maxcount was reached */
+        /* Skip any remaining whitespace and copy to end of string */
+        while (i < str_len && STRINGLIB_ISSPACE(str[i]))
+            i++;
+        if (i != str_len)
+            SPLIT_ADD(str, i, str_len);
+    }
+    FIX_PREALLOC_SIZE(list);
+    return list;
+
+  onError:
+    Py_DECREF(list);
+    return NULL;
+}
+
+Py_LOCAL_INLINE(PyObject *)
+stringlib_split_char(PyObject* str_obj,
+                     const STRINGLIB_CHAR* str, Py_ssize_t str_len,
+                     const STRINGLIB_CHAR ch,
+                     Py_ssize_t maxcount)
+{
+    Py_ssize_t i, j, count=0;
+    PyObject *list = PyList_New(PREALLOC_SIZE(maxcount));
+    PyObject *sub;
+
+    if (list == NULL)
+        return NULL;
+
+    i = j = 0;
+    while ((j < str_len) && (maxcount-- > 0)) {
+        for(; j < str_len; j++) {
+            /* I found that using memchr makes no difference */
+            if (str[j] == ch) {
+                SPLIT_ADD(str, i, j);
+                i = j = j + 1;
+                break;
+            }
+        }
+    }
+#ifndef STRINGLIB_MUTABLE
+    if (count == 0 && STRINGLIB_CHECK_EXACT(str_obj)) {
+        /* ch not in str_obj, so just use str_obj as list[0] */
+        Py_INCREF(str_obj);
+        PyList_SET_ITEM(list, 0, (PyObject *)str_obj);
+        count++;
+    } else
+#endif
+    if (i <= str_len) {
+        SPLIT_ADD(str, i, str_len);
+    }
+    FIX_PREALLOC_SIZE(list);
+    return list;
+
+  onError:
+    Py_DECREF(list);
+    return NULL;
+}
+
+Py_LOCAL_INLINE(PyObject *)
+stringlib_split(PyObject* str_obj,
+                const STRINGLIB_CHAR* str, Py_ssize_t str_len,
+                const STRINGLIB_CHAR* sep, Py_ssize_t sep_len,
+                Py_ssize_t maxcount)
+{
+    Py_ssize_t i, j, pos, count=0;
+    PyObject *list, *sub;
+
+    if (sep_len == 0) {
+        PyErr_SetString(PyExc_ValueError, "empty separator");
+        return NULL;
+    }
+    else if (sep_len == 1)
+        return stringlib_split_char(str_obj, str, str_len, sep[0], maxcount);
+
+    list = PyList_New(PREALLOC_SIZE(maxcount));
+    if (list == NULL)
+        return NULL;
+
+    i = j = 0;
+    while (maxcount-- > 0) {
+        pos = fastsearch(str+i, str_len-i, sep, sep_len, -1, FAST_SEARCH);
+        if (pos < 0)
+            break;
+        j = i + pos;
+        SPLIT_ADD(str, i, j);
+        i = j + sep_len;
+    }
+#ifndef STRINGLIB_MUTABLE
+    if (count == 0 && STRINGLIB_CHECK_EXACT(str_obj)) {
+        /* No match in str_obj, so just use it as list[0] */
+        Py_INCREF(str_obj);
+        PyList_SET_ITEM(list, 0, (PyObject *)str_obj);
+        count++;
+    } else
+#endif
+    {
+        SPLIT_ADD(str, i, str_len);
+    }
+    FIX_PREALLOC_SIZE(list);
+    return list;
+
+  onError:
+    Py_DECREF(list);
+    return NULL;
+}
+
+Py_LOCAL_INLINE(PyObject *)
+stringlib_rsplit_whitespace(PyObject* str_obj,
+                            const STRINGLIB_CHAR* str, Py_ssize_t str_len,
+                            Py_ssize_t maxcount)
+{
+    Py_ssize_t i, j, count=0;
+    PyObject *list = PyList_New(PREALLOC_SIZE(maxcount));
+    PyObject *sub;
+
+    if (list == NULL)
+        return NULL;
+
+    i = j = str_len - 1;
+    while (maxcount-- > 0) {
+        while (i >= 0 && STRINGLIB_ISSPACE(str[i]))
+            i--;
+        if (i < 0) break;
+        j = i; i--;
+        while (i >= 0 && !STRINGLIB_ISSPACE(str[i]))
+            i--;
+#ifndef STRINGLIB_MUTABLE
+        if (j == str_len - 1 && i < 0 && STRINGLIB_CHECK_EXACT(str_obj)) {
+            /* No whitespace in str_obj, so just use it as list[0] */
+            Py_INCREF(str_obj);
+            PyList_SET_ITEM(list, 0, (PyObject *)str_obj);
+            count++;
+            break;
+        }
+#endif
+        SPLIT_ADD(str, i + 1, j + 1);
+    }
+
+    if (i >= 0) {
+        /* Only occurs when maxcount was reached */
+        /* Skip any remaining whitespace and copy to beginning of string */
+        while (i >= 0 && STRINGLIB_ISSPACE(str[i]))
+            i--;
+        if (i >= 0)
+            SPLIT_ADD(str, 0, i + 1);
+    }
+    FIX_PREALLOC_SIZE(list);
+    if (PyList_Reverse(list) < 0)
+        goto onError;
+    return list;
+
+  onError:
+    Py_DECREF(list);
+    return NULL;
+}
+
+Py_LOCAL_INLINE(PyObject *)
+stringlib_rsplit_char(PyObject* str_obj,
+                      const STRINGLIB_CHAR* str, Py_ssize_t str_len,
+                      const STRINGLIB_CHAR ch,
+                      Py_ssize_t maxcount)
+{
+    Py_ssize_t i, j, count=0;
+    PyObject *list = PyList_New(PREALLOC_SIZE(maxcount));
+    PyObject *sub;
+
+    if (list == NULL)
+        return NULL;
+
+    i = j = str_len - 1;
+    while ((i >= 0) && (maxcount-- > 0)) {
+        for(; i >= 0; i--) {
+            if (str[i] == ch) {
+                SPLIT_ADD(str, i + 1, j + 1);
+                j = i = i - 1;
+                break;
+            }
+        }
+    }
+#ifndef STRINGLIB_MUTABLE
+    if (count == 0 && STRINGLIB_CHECK_EXACT(str_obj)) {
+        /* ch not in str_obj, so just use str_obj as list[0] */
+        Py_INCREF(str_obj);
+        PyList_SET_ITEM(list, 0, (PyObject *)str_obj);
+        count++;
+    } else
+#endif
+    if (j >= -1) {
+        SPLIT_ADD(str, 0, j + 1);
+    }
+    FIX_PREALLOC_SIZE(list);
+    if (PyList_Reverse(list) < 0)
+        goto onError;
+    return list;
+
+  onError:
+    Py_DECREF(list);
+    return NULL;
+}
+
+Py_LOCAL_INLINE(PyObject *)
+stringlib_rsplit(PyObject* str_obj,
+                 const STRINGLIB_CHAR* str, Py_ssize_t str_len,
+                 const STRINGLIB_CHAR* sep, Py_ssize_t sep_len,
+                 Py_ssize_t maxcount)
+{
+    Py_ssize_t j, pos, count=0;
+    PyObject *list, *sub;
+
+    if (sep_len == 0) {
+        PyErr_SetString(PyExc_ValueError, "empty separator");
+        return NULL;
+    }
+    else if (sep_len == 1)
+        return stringlib_rsplit_char(str_obj, str, str_len, sep[0], maxcount);
+
+    list = PyList_New(PREALLOC_SIZE(maxcount));
+    if (list == NULL)
+        return NULL;
+
+    j = str_len;
+    while (maxcount-- > 0) {
+        pos = fastsearch(str, j, sep, sep_len, -1, FAST_RSEARCH);
+        if (pos < 0)
+            break;
+        SPLIT_ADD(str, pos + sep_len, j);
+        j = pos;
+    }
+#ifndef STRINGLIB_MUTABLE
+    if (count == 0 && STRINGLIB_CHECK_EXACT(str_obj)) {
+        /* No match in str_obj, so just use it as list[0] */
+        Py_INCREF(str_obj);
+        PyList_SET_ITEM(list, 0, (PyObject *)str_obj);
+        count++;
+    } else
+#endif
+    {
+        SPLIT_ADD(str, 0, j);
+    }
+    FIX_PREALLOC_SIZE(list);
+    if (PyList_Reverse(list) < 0)
+        goto onError;
+    return list;
+
+  onError:
+    Py_DECREF(list);
+    return NULL;
+}
+
+Py_LOCAL_INLINE(PyObject *)
+stringlib_splitlines(PyObject* str_obj,
+                     const STRINGLIB_CHAR* str, Py_ssize_t str_len,
+                     int keepends)
+{
+    /* This does not use the preallocated list because splitlines is
+       usually run with hundreds of newlines.  The overhead of
+       switching between PyList_SET_ITEM and append causes about a
+       2-3% slowdown for that common case.  A smarter implementation
+       could move the if check out, so the SET_ITEMs are done first
+       and the appends only done when the prealloc buffer is full.
+       That's too much work for little gain.*/
+
+    register Py_ssize_t i;
+    register Py_ssize_t j;
+    PyObject *list = PyList_New(0);
+    PyObject *sub;
+
+    if (list == NULL)
+        return NULL;
+
+    for (i = j = 0; i < str_len; ) {
+        Py_ssize_t eol;
+
+        /* Find a line and append it */
+        while (i < str_len && !STRINGLIB_ISLINEBREAK(str[i]))
+            i++;
+
+        /* Skip the line break reading CRLF as one line break */
+        eol = i;
+        if (i < str_len) {
+            if (str[i] == '\r' && i + 1 < str_len && str[i+1] == '\n')
+                i += 2;
+            else
+                i++;
+            if (keepends)
+                eol = i;
+        }
+#ifndef STRINGLIB_MUTABLE
+        if (j == 0 && eol == str_len && STRINGLIB_CHECK_EXACT(str_obj)) {
+            /* No linebreak in str_obj, so just use it as list[0] */
+            if (PyList_Append(list, str_obj))
+                goto onError;
+            break;
+        }
+#endif
+        SPLIT_APPEND(str, j, eol);
+        j = i;
+    }
+    return list;
+
+  onError:
+    Py_DECREF(list);
+    return NULL;
+}
+
+#endif