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authorGravatar misterg <misterg@google.com>2017-09-19 16:54:40 -0400
committerGravatar misterg <misterg@google.com>2017-09-19 16:54:40 -0400
commitc2e754829628d1e9b7a16b3389cfdace76950fdf (patch)
tree5a7f056f44e27c30e10025113b644f0b3b5801fc /absl/strings/internal/memutil.cc
Initial Commit
Diffstat (limited to 'absl/strings/internal/memutil.cc')
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diff --git a/absl/strings/internal/memutil.cc b/absl/strings/internal/memutil.cc
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+// Copyright 2017 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "absl/strings/internal/memutil.h"
+
+#include <cstdlib>
+
+namespace absl {
+namespace strings_internal {
+
+int memcasecmp(const char* s1, const char* s2, size_t len) {
+ const unsigned char* us1 = reinterpret_cast<const unsigned char*>(s1);
+ const unsigned char* us2 = reinterpret_cast<const unsigned char*>(s2);
+
+ for (size_t i = 0; i < len; i++) {
+ const int diff =
+ int{static_cast<unsigned char>(absl::ascii_tolower(us1[i]))} -
+ int{static_cast<unsigned char>(absl::ascii_tolower(us2[i]))};
+ if (diff != 0) return diff;
+ }
+ return 0;
+}
+
+char* memdup(const char* s, size_t slen) {
+ void* copy;
+ if ((copy = malloc(slen)) == nullptr) return nullptr;
+ memcpy(copy, s, slen);
+ return reinterpret_cast<char*>(copy);
+}
+
+char* memrchr(const char* s, int c, size_t slen) {
+ for (const char* e = s + slen - 1; e >= s; e--) {
+ if (*e == c) return const_cast<char*>(e);
+ }
+ return nullptr;
+}
+
+size_t memspn(const char* s, size_t slen, const char* accept) {
+ const char* p = s;
+ const char* spanp;
+ char c, sc;
+
+cont:
+ c = *p++;
+ if (slen-- == 0) return p - 1 - s;
+ for (spanp = accept; (sc = *spanp++) != '\0';)
+ if (sc == c) goto cont;
+ return p - 1 - s;
+}
+
+size_t memcspn(const char* s, size_t slen, const char* reject) {
+ const char* p = s;
+ const char* spanp;
+ char c, sc;
+
+ while (slen-- != 0) {
+ c = *p++;
+ for (spanp = reject; (sc = *spanp++) != '\0';)
+ if (sc == c) return p - 1 - s;
+ }
+ return p - s;
+}
+
+char* mempbrk(const char* s, size_t slen, const char* accept) {
+ const char* scanp;
+ int sc;
+
+ for (; slen; ++s, --slen) {
+ for (scanp = accept; (sc = *scanp++) != '\0';)
+ if (sc == *s) return const_cast<char*>(s);
+ }
+ return nullptr;
+}
+
+// This is significantly faster for case-sensitive matches with very
+// few possible matches. See unit test for benchmarks.
+const char* memmatch(const char* phaystack, size_t haylen, const char* pneedle,
+ size_t neelen) {
+ if (0 == neelen) {
+ return phaystack; // even if haylen is 0
+ }
+ if (haylen < neelen) return nullptr;
+
+ const char* match;
+ const char* hayend = phaystack + haylen - neelen + 1;
+ // A static cast is used here to work around the fact that memchr returns
+ // a void* on Posix-compliant systems and const void* on Windows.
+ while ((match = static_cast<const char*>(
+ memchr(phaystack, pneedle[0], hayend - phaystack)))) {
+ if (memcmp(match, pneedle, neelen) == 0)
+ return match;
+ else
+ phaystack = match + 1;
+ }
+ return nullptr;
+}
+
+} // namespace strings_internal
+} // namespace absl