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/*
* Copyright 2015 WebAssembly Community Group participants
*
* 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.
*/
// Interned String type, 100% interned on creation. Comparisons are always just a pointer comparison
#ifndef wasm_istring_h
#define wasm_istring_h
#include <unordered_set>
#include <unordered_map>
#include <set>
#include <string.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
namespace cashew {
struct IString {
const char *str;
static size_t hash_c(const char *str) { // see http://www.cse.yorku.ca/~oz/hash.html
unsigned int hash = 5381;
int c;
while ((c = *str++)) {
hash = ((hash << 5) + hash) ^ c;
}
return (size_t)hash;
}
class CStringHash : public std::hash<const char *> {
public:
size_t operator()(const char *str) const {
return IString::hash_c(str);
}
};
class CStringEqual : public std::equal_to<const char *> {
public:
bool operator()(const char *x, const char *y) const {
return strcmp(x, y) == 0;
}
};
IString() : str(nullptr) {}
IString(const char *s, bool reuse=true) { // if reuse=true, then input is assumed to remain alive; not copied
assert(s);
set(s, reuse);
}
void set(const char *s, bool reuse=true) {
typedef std::unordered_set<const char *, CStringHash, CStringEqual> StringSet;
static StringSet* strings = new StringSet();
if (reuse) {
auto result = strings->insert(s); // if already present, does nothing
str = *(result.first);
} else {
auto existing = strings->find(s);
if (existing == strings->end()) {
char *copy = (char*)malloc(strlen(s)+1); // XXX leaked
strcpy(copy, s);
s = copy;
} else {
s = *existing;
}
strings->insert(s);
str = s;
}
}
void set(const IString &s) {
str = s.str;
}
void clear() {
str = nullptr;
}
bool operator==(const IString& other) const {
//assert((str == other.str) == !strcmp(str, other.str));
return str == other.str; // fast!
}
bool operator!=(const IString& other) const {
//assert((str == other.str) == !strcmp(str, other.str));
return str != other.str; // fast!
}
bool operator<(const IString& other) const {
return strcmp(str ? str : "", other.str ? other.str : "") < 0;
}
char operator[](int x) const {
return str[x];
}
bool operator!() const { // no string, or empty string
return !str || str[0] == 0;
}
const char *c_str() const { return str; }
bool equals(const char *other) const { return !strcmp(str, other); }
bool is() { return str != nullptr; }
bool isNull() { return str == nullptr; }
};
} // namespace cashew
// Utilities for creating hashmaps/sets over IStrings
namespace std {
template <> struct hash<cashew::IString> : public unary_function<cashew::IString, size_t> {
size_t operator()(const cashew::IString& str) const {
size_t hash = size_t(str.str);
return hash = ((hash << 5) + hash) ^ 5381; /* (hash * 33) ^ c */
}
};
template <> struct equal_to<cashew::IString> : public binary_function<cashew::IString, cashew::IString, bool> {
bool operator()(const cashew::IString& x, const cashew::IString& y) const {
return x == y;
}
};
} // namespace std
namespace cashew {
// IStringSet
class IStringSet : public std::unordered_set<IString> {
public:
IStringSet() {}
IStringSet(const char *init) { // comma-delimited list
int size = strlen(init);
char *curr = new char[size+1]; // leaked!
strcpy(curr, init);
while (1) {
char *end = strchr(curr, ' ');
if (end) *end = 0;
insert(curr);
if (!end) break;
curr = end + 1;
}
}
bool has(const IString& str) {
return count(str) > 0;
}
};
class IOrderedStringSet : public std::set<IString> {
public:
bool has(const IString& str) {
return count(str) > 0;
}
};
} // namespace cashew
#endif // wasm_istring_h
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