From 413fdcea21908055cb8acad28a94b8f72eb2ffec Mon Sep 17 00:00:00 2001 From: Serhiy Storchaka Date: Sat, 14 Nov 2015 15:42:17 +0200 Subject: [PATCH] Issue #24821: Refactor STRINGLIB(fastsearch_memchr_1char) and split it on STRINGLIB(find_char) and STRINGLIB(rfind_char) that can be used independedly without special preconditions. --- Objects/bytearrayobject.c | 19 ++-- Objects/bytesobject.c | 19 ++-- Objects/stringlib/fastsearch.h | 156 +++++++++++++++++++-------------- Objects/unicodeobject.c | 33 ++++--- 4 files changed, 124 insertions(+), 103 deletions(-) diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c index 21031479b8b..131e04d5add 100644 --- a/Objects/bytearrayobject.c +++ b/Objects/bytearrayobject.c @@ -1159,16 +1159,15 @@ bytearray_find_internal(PyByteArrayObject *self, PyObject *args, int dir) ADJUST_INDICES(start, end, len); if (end - start < sub_len) res = -1; - else if (sub_len == 1 -#ifndef HAVE_MEMRCHR - && dir > 0 -#endif - ) { - unsigned char needle = *sub; - int mode = (dir > 0) ? FAST_SEARCH : FAST_RSEARCH; - res = stringlib_fastsearch_memchr_1char( - PyByteArray_AS_STRING(self) + start, end - start, - needle, needle, mode); + else if (sub_len == 1) { + if (dir > 0) + res = stringlib_find_char( + PyByteArray_AS_STRING(self) + start, end - start, + *sub); + else + res = stringlib_rfind_char( + PyByteArray_AS_STRING(self) + start, end - start, + *sub); if (res >= 0) res += start; } diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c index c10dbdfe053..6a9e06231c7 100644 --- a/Objects/bytesobject.c +++ b/Objects/bytesobject.c @@ -1937,16 +1937,15 @@ bytes_find_internal(PyBytesObject *self, PyObject *args, int dir) ADJUST_INDICES(start, end, len); if (end - start < sub_len) res = -1; - else if (sub_len == 1 -#ifndef HAVE_MEMRCHR - && dir > 0 -#endif - ) { - unsigned char needle = *sub; - int mode = (dir > 0) ? FAST_SEARCH : FAST_RSEARCH; - res = stringlib_fastsearch_memchr_1char( - PyBytes_AS_STRING(self) + start, end - start, - needle, needle, mode); + else if (sub_len == 1) { + if (dir > 0) + res = stringlib_find_char( + PyBytes_AS_STRING(self) + start, end - start, + *sub); + else + res = stringlib_rfind_char( + PyBytes_AS_STRING(self) + start, end - start, + *sub); if (res >= 0) res += start; } diff --git a/Objects/stringlib/fastsearch.h b/Objects/stringlib/fastsearch.h index cda68e77c8d..98165ad1146 100644 --- a/Objects/stringlib/fastsearch.h +++ b/Objects/stringlib/fastsearch.h @@ -32,52 +32,98 @@ #define STRINGLIB_BLOOM(mask, ch) \ ((mask & (1UL << ((ch) & (STRINGLIB_BLOOM_WIDTH -1))))) +Py_LOCAL_INLINE(Py_ssize_t) +STRINGLIB(find_char)(const STRINGLIB_CHAR* s, Py_ssize_t n, STRINGLIB_CHAR ch) +{ + const STRINGLIB_CHAR *p, *e; + + p = s; + e = s + n; + if (n > 10) { +#if STRINGLIB_SIZEOF_CHAR == 1 + p = memchr(s, ch, n); + if (p != NULL) + return (p - s); + return -1; +#else + /* use memchr if we can choose a needle without two many likely + false positives */ + unsigned char needle = ch & 0xff; + /* If looking for a multiple of 256, we'd have too + many false positives looking for the '\0' byte in UCS2 + and UCS4 representations. */ + if (needle != 0) { + while (p < e) { + void *candidate = memchr(p, needle, + (e - p) * sizeof(STRINGLIB_CHAR)); + if (candidate == NULL) + return -1; + p = (const STRINGLIB_CHAR *) + _Py_ALIGN_DOWN(candidate, sizeof(STRINGLIB_CHAR)); + if (*p == ch) + return (p - s); + /* False positive */ + p++; + } + return -1; + } +#endif + } + while (p < e) { + if (*p == ch) + return (p - s); + p++; + } + return -1; +} Py_LOCAL_INLINE(Py_ssize_t) -STRINGLIB(fastsearch_memchr_1char)(const STRINGLIB_CHAR* s, Py_ssize_t n, - STRINGLIB_CHAR ch, unsigned char needle, - int mode) +STRINGLIB(rfind_char)(const STRINGLIB_CHAR* s, Py_ssize_t n, STRINGLIB_CHAR ch) { - if (mode == FAST_SEARCH) { - const STRINGLIB_CHAR *ptr = s; - const STRINGLIB_CHAR *e = s + n; - while (ptr < e) { - void *candidate = memchr((const void *) ptr, needle, (e - ptr) * sizeof(STRINGLIB_CHAR)); - if (candidate == NULL) - return -1; - ptr = (const STRINGLIB_CHAR *) _Py_ALIGN_DOWN(candidate, sizeof(STRINGLIB_CHAR)); - if (sizeof(STRINGLIB_CHAR) == 1 || *ptr == ch) - return (ptr - s); - /* False positive */ - ptr++; - } - return -1; - } + const STRINGLIB_CHAR *p; #ifdef HAVE_MEMRCHR /* memrchr() is a GNU extension, available since glibc 2.1.91. it doesn't seem as optimized as memchr(), but is still quite - faster than our hand-written loop in FASTSEARCH below */ - else if (mode == FAST_RSEARCH) { - while (n > 0) { - const STRINGLIB_CHAR *found; - void *candidate = memrchr((const void *) s, needle, n * sizeof(STRINGLIB_CHAR)); - if (candidate == NULL) - return -1; - found = (const STRINGLIB_CHAR *) _Py_ALIGN_DOWN(candidate, sizeof(STRINGLIB_CHAR)); - n = found - s; - if (sizeof(STRINGLIB_CHAR) == 1 || *found == ch) - return n; - /* False positive */ - } - return -1; - } -#endif - else { - assert(0); /* Should never get here */ - return 0; - } + faster than our hand-written loop below */ -#undef DO_MEMCHR + if (n > 10) { +#if STRINGLIB_SIZEOF_CHAR == 1 + p = memrchr(s, ch, n); + if (p != NULL) + return (p - s); + return -1; +#else + /* use memrchr if we can choose a needle without two many likely + false positives */ + unsigned char needle = ch & 0xff; + /* If looking for a multiple of 256, we'd have too + many false positives looking for the '\0' byte in UCS2 + and UCS4 representations. */ + if (needle != 0) { + while (n > 0) { + void *candidate = memrchr(s, needle, + n * sizeof(STRINGLIB_CHAR)); + if (candidate == NULL) + return -1; + p = (const STRINGLIB_CHAR *) + _Py_ALIGN_DOWN(candidate, sizeof(STRINGLIB_CHAR)); + n = p - s; + if (*p == ch) + return n; + /* False positive */ + } + return -1; + } +#endif + } +#endif /* HAVE_MEMRCHR */ + p = s + n; + while (p > s) { + p--; + if (*p == ch) + return (p - s); + } + return -1; } Py_LOCAL_INLINE(Py_ssize_t) @@ -99,25 +145,11 @@ FASTSEARCH(const STRINGLIB_CHAR* s, Py_ssize_t n, if (m <= 0) return -1; /* use special case for 1-character strings */ - if (n > 10 && (mode == FAST_SEARCH -#ifdef HAVE_MEMRCHR - || mode == FAST_RSEARCH -#endif - )) { - /* use memchr if we can choose a needle without two many likely - false positives */ - unsigned char needle; - needle = p[0] & 0xff; -#if STRINGLIB_SIZEOF_CHAR > 1 - /* If looking for a multiple of 256, we'd have too - many false positives looking for the '\0' byte in UCS2 - and UCS4 representations. */ - if (needle != 0) -#endif - return STRINGLIB(fastsearch_memchr_1char) - (s, n, p[0], needle, mode); - } - if (mode == FAST_COUNT) { + if (mode == FAST_SEARCH) + return STRINGLIB(find_char)(s, n, p[0]); + else if (mode == FAST_RSEARCH) + return STRINGLIB(rfind_char)(s, n, p[0]); + else { /* FAST_COUNT */ for (i = 0; i < n; i++) if (s[i] == p[0]) { count++; @@ -125,14 +157,6 @@ FASTSEARCH(const STRINGLIB_CHAR* s, Py_ssize_t n, return maxcount; } return count; - } 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; } diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c index 18a30e207ad..c2b6f642c4b 100644 --- a/Objects/unicodeobject.c +++ b/Objects/unicodeobject.c @@ -811,27 +811,26 @@ Py_LOCAL_INLINE(Py_ssize_t) findchar(const void *s, int kind, Py_ssize_t size, Py_UCS4 ch, int direction) { - int mode = (direction == 1) ? FAST_SEARCH : FAST_RSEARCH; - switch (kind) { case PyUnicode_1BYTE_KIND: - { - Py_UCS1 ch1 = (Py_UCS1) ch; - if (ch1 == ch) - return ucs1lib_fastsearch((Py_UCS1 *) s, size, &ch1, 1, 0, mode); - else - return -1; - } + if ((Py_UCS1) ch != ch) + return -1; + if (direction > 0) + return ucs1lib_find_char((Py_UCS1 *) s, size, (Py_UCS1) ch); + else + return ucs1lib_rfind_char((Py_UCS1 *) s, size, (Py_UCS1) ch); case PyUnicode_2BYTE_KIND: - { - Py_UCS2 ch2 = (Py_UCS2) ch; - if (ch2 == ch) - return ucs2lib_fastsearch((Py_UCS2 *) s, size, &ch2, 1, 0, mode); - else - return -1; - } + if ((Py_UCS2) ch != ch) + return -1; + if (direction > 0) + return ucs2lib_find_char((Py_UCS2 *) s, size, (Py_UCS2) ch); + else + return ucs2lib_rfind_char((Py_UCS2 *) s, size, (Py_UCS2) ch); case PyUnicode_4BYTE_KIND: - return ucs4lib_fastsearch((Py_UCS4 *) s, size, &ch, 1, 0, mode); + if (direction > 0) + return ucs4lib_find_char((Py_UCS4 *) s, size, ch); + else + return ucs4lib_rfind_char((Py_UCS4 *) s, size, ch); default: assert(0); return -1;