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/*
* Copyright (C) 2018 The Android Open Source Project
*
* 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 MINIKIN_HASHER_H
#define MINIKIN_HASHER_H
#include <cstdint>
#include <string>
#include "minikin/FontFeature.h"
#include "minikin/Macros.h"
namespace minikin {
// Provides a Jenkins hash implementation.
class Hasher {
public:
Hasher() : mHash(0u) {}
IGNORE_INTEGER_OVERFLOW inline Hasher& update(uint32_t data) {
mHash += data;
mHash += (mHash << 10);
mHash ^= (mHash >> 6);
return *this;
}
inline Hasher& update(int32_t data) {
update(static_cast<uint32_t>(data));
return *this;
}
inline Hasher& update(uint64_t data) {
update(static_cast<uint32_t>(data));
update(static_cast<uint32_t>(data >> 32));
return *this;
}
inline Hasher& update(float data) {
union {
float f;
uint32_t i;
} bits;
bits.f = data;
return update(bits.i);
}
inline Hasher& update(const std::vector<FontFeature>& features) {
uint32_t size = features.size();
update(size);
for (const FontFeature& feature : features) {
update(feature);
}
return *this;
}
inline Hasher& update(const FontFeature& feature) {
update(feature.tag);
update(feature.value);
return *this;
}
inline Hasher& updateShorts(const uint16_t* data, uint32_t length) {
update(length);
uint32_t i;
for (i = 0; i < (length & -2); i += 2) {
update((uint32_t)data[i] | ((uint32_t)data[i + 1] << 16));
}
if (length & 1) {
update((uint32_t)data[i]);
}
return *this;
}
inline Hasher& updateString(const std::string& str) {
uint32_t size = str.size();
update(size);
uint32_t i;
for (i = 0; i < (size & -4); i += 4) {
update((uint32_t)str[i] | ((uint32_t)str[i + 1] << 8) | ((uint32_t)str[i + 2] << 16) |
((uint32_t)str[i + 3] << 24));
}
if (size & 3) {
uint32_t data = str[i];
data |= ((size & 3) > 1) ? ((uint32_t)str[i + 1] << 8) : 0;
data |= ((size & 3) > 2) ? ((uint32_t)str[i + 2] << 16) : 0;
update(data);
}
return *this;
}
IGNORE_INTEGER_OVERFLOW inline uint32_t hash() {
uint32_t hash = mHash;
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
return hash;
}
private:
uint32_t mHash;
};
} // namespace minikin
#endif // MINIKIN_HASHER_H
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