A mixture of fixes and cleanup for LogKlog.cpp and friends. - sscanf calls strlen. Check if the string is missing a nul terminator, if it is, do not call sscanf. - replace NULL with nullptr for stronger typechecking. - pass by reference for simpler code. - Use ssize_t where possible to check for negative values. - fix FastCmp to add some validity checking since ASAN reports that callers are not making sure pre-conditions are met. - add fasticmp templates for completeness. - if the buffer is too small to contain a meaningful time, do not call down to log_time::strptime() because it does not limit its accesses to the buffer boundaries, instead stopping at a terminating nul or invalid match. - move strnstr to LogUtils.h, drop size checking of needle and clearly report the list of needles used with android::strnstr - replace 'sizeof(static const char[]) - 1' with strlen. Test: gTest liblog-unit-test, logd-unit-tests & logcat-unit-tests Bug: 30792935 Bug: 36536248 Bug: 35468874 Bug: 34949125 Bug: 34606909 Bug: 36075298 Bug: 36608728 Change-Id: I161bf03ba029050e809b31cceef03f729d318866
77 lines
2.9 KiB
C++
77 lines
2.9 KiB
C++
/*
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* Copyright (C) 2014-2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef _ANDROID_UTILS_FASTSTRCMP_H__
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#define _ANDROID_UTILS_FASTSTRCMP_H__
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#include <ctype.h>
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#include <string.h>
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#ifndef __predict_true
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#define __predict_true(exp) __builtin_expect((exp) != 0, 1)
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#endif
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#ifdef __cplusplus
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// Optimized for instruction cache locality
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//
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// Template class fastcmp used to create more time-efficient str*cmp
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// functions by pre-checking the first character before resorting
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// to calling the underlying string function. Profiled with a
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// measurable speedup when used in hot code. Usage is of the form:
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//
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// fastcmp<strncmp>(str1, str2, len)
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//
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// NB: use fasticmp for the case insensitive str*cmp functions.
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// NB: Returns boolean, do not use if expecting to check negative value.
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// Thus not semantically identical to the expected function behavior.
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template <int (*cmp)(const char* l, const char* r, const size_t s)>
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static inline int fastcmp(const char* l, const char* r, const size_t s) {
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const ssize_t n = s; // To help reject negative sizes, treat like zero
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return __predict_true(n > 0) &&
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((*l != *r) || (__predict_true(n > 1) && cmp(l + 1, r + 1, n - 1)));
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}
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template <int (*cmp)(const char* l, const char* r, const size_t s)>
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static inline int fasticmp(const char* l, const char* r, const size_t s) {
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const ssize_t n = s; // To help reject negative sizes, treat like zero
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return __predict_true(n > 0) &&
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((tolower(*l) != tolower(*r)) || (__predict_true(n > 1) && cmp(l + 1, r + 1, n - 1)));
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}
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template <int (*cmp)(const void* l, const void* r, const size_t s)>
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static inline int fastcmp(const void* lv, const void* rv, const size_t s) {
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const char* l = static_cast<const char*>(lv);
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const char* r = static_cast<const char*>(rv);
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const ssize_t n = s; // To help reject negative sizes, treat like zero
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return __predict_true(n > 0) &&
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((*l != *r) || (__predict_true(n > 1) && cmp(l + 1, r + 1, n - 1)));
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}
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template <int (*cmp)(const char* l, const char* r)>
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static inline int fastcmp(const char* l, const char* r) {
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return (*l != *r) || (__predict_true(*l) && cmp(l + 1, r + 1));
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}
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template <int (*cmp)(const char* l, const char* r)>
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static inline int fasticmp(const char* l, const char* r) {
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return (tolower(*l) != tolower(*r)) || (__predict_true(*l) && cmp(l + 1, r + 1));
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}
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#endif
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#endif // _ANDROID_UTILS_FASTSTRCMP_H__
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