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// Copyright 2016 Google Inc.
//
// 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.
//
////////////////////////////////////////////////////////////////////////////////
#ifndef UTIL_CASE_INSENSITIVE_HASH_H_
#define UTIL_CASE_INSENSITIVE_HASH_H_
#include <ctype.h>
#include <stddef.h>
#ifndef _MSC_VER
#include <strings.h>
#endif
#include <string>
#include "util/basictypes.h"
#include "util/string_util.h"
// Functors for hashing c-strings with case-insensitive semantics.
struct CStringCaseHash {
size_t operator()(const char *str) const {
unsigned long hash_val = 0;
while (*str) {
hash_val = 5*hash_val + tolower(*str);
str++;
}
return (size_t)hash_val;
}
};
struct CStringCaseEqual {
bool operator()(const char *str1, const char *str2) const {
return !base::strcasecmp(str1, str2);
}
};
// These functors, in addition to being case-insensitive, ignore all
// non-alphanumeric characters. This is useful when we want all variants of
// a string -- where variants can differ in puncutation and whitespace -- to
// map to the same value.
struct CStringAlnumCaseHash {
size_t operator()(const char *str) const {
unsigned long hash_val = 0;
while (*str) {
if (isalnum(*str)) {
hash_val = 5*hash_val + tolower(*str);
}
str++;
}
return (size_t)hash_val;
}
};
struct CStringAlnumCaseEqual {
bool operator()(const char *str1, const char *str2) const {
while (true) {
// Skip until each pointer is pointing to an alphanumeric char or '\0'
while (!isalnum(*str1) && (*str1 != '\0')) {
str1++;
}
while (!isalnum(*str2) && (*str2 != '\0')) {
str2++;
}
if (tolower(*str1) != tolower(*str2)) {
return false; // mismatch on alphanumeric char or '\0'
}
if (*str1 == '\0') { // in which case *str2 must be '\0' as well
return true; // reached '\0' in both strings without mismatch
}
str1++;
str2++;
}
}
};
#endif // UTIL_CASE_INSENSITIVE_HASH_H_
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