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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "CacheHashUtils.h"
#include "mozilla/BasePrincipal.h"
#include "plstr.h"
namespace mozilla {
namespace net {
/**
* CacheHash::Hash(const char * key, uint32_t initval)
*
* See http://burtleburtle.net/bob/hash/evahash.html for more information
* about this hash function.
*
* This algorithm is used to check the data integrity.
*/
static inline void hashmix(uint32_t& a, uint32_t& b, uint32_t& c) {
a -= b;
a -= c;
a ^= (c >> 13);
b -= c;
b -= a;
b ^= (a << 8);
c -= a;
c -= b;
c ^= (b >> 13);
a -= b;
a -= c;
a ^= (c >> 12);
b -= c;
b -= a;
b ^= (a << 16);
c -= a;
c -= b;
c ^= (b >> 5);
a -= b;
a -= c;
a ^= (c >> 3);
b -= c;
b -= a;
b ^= (a << 10);
c -= a;
c -= b;
c ^= (b >> 15);
}
CacheHash::Hash32_t CacheHash::Hash(const char* aData, uint32_t aSize,
uint32_t aInitval) {
const uint8_t* k = reinterpret_cast<const uint8_t*>(aData);
uint32_t a, b, c, len;
/* Set up the internal state */
len = aSize;
a = b = 0x9e3779b9; /* the golden ratio; an arbitrary value */
c = aInitval; /* variable initialization of internal state */
/*---------------------------------------- handle most of the key */
while (len >= 12) {
a += k[0] + (uint32_t(k[1]) << 8) + (uint32_t(k[2]) << 16) +
(uint32_t(k[3]) << 24);
b += k[4] + (uint32_t(k[5]) << 8) + (uint32_t(k[6]) << 16) +
(uint32_t(k[7]) << 24);
c += k[8] + (uint32_t(k[9]) << 8) + (uint32_t(k[10]) << 16) +
(uint32_t(k[11]) << 24);
hashmix(a, b, c);
k += 12;
len -= 12;
}
/*------------------------------------- handle the last 11 bytes */
c += aSize;
switch (len) { /* all the case statements fall through */
case 11:
c += (uint32_t(k[10]) << 24);
[[fallthrough]];
case 10:
c += (uint32_t(k[9]) << 16);
[[fallthrough]];
case 9:
c += (uint32_t(k[8]) << 8);
[[fallthrough]];
/* the low-order byte of c is reserved for the length */
case 8:
b += (uint32_t(k[7]) << 24);
[[fallthrough]];
case 7:
b += (uint32_t(k[6]) << 16);
[[fallthrough]];
case 6:
b += (uint32_t(k[5]) << 8);
[[fallthrough]];
case 5:
b += k[4];
[[fallthrough]];
case 4:
a += (uint32_t(k[3]) << 24);
[[fallthrough]];
case 3:
a += (uint32_t(k[2]) << 16);
[[fallthrough]];
case 2:
a += (uint32_t(k[1]) << 8);
[[fallthrough]];
case 1:
a += k[0];
/* case 0: nothing left to add */
}
hashmix(a, b, c);
return c;
}
CacheHash::Hash16_t CacheHash::Hash16(const char* aData, uint32_t aSize,
uint32_t aInitval) {
Hash32_t hash = Hash(aData, aSize, aInitval);
return (hash & 0xFFFF);
}
NS_IMPL_ISUPPORTS0(CacheHash)
CacheHash::CacheHash(uint32_t aInitval)
: mA(0x9e3779b9),
mB(0x9e3779b9),
mC(aInitval),
mPos(0),
mBuf(0),
mBufPos(0),
mLength(0),
mFinalized(false) {}
void CacheHash::Feed(uint32_t aVal, uint8_t aLen) {
switch (mPos) {
case 0:
mA += aVal;
mPos++;
break;
case 1:
mB += aVal;
mPos++;
break;
case 2:
mPos = 0;
if (aLen == 4) {
mC += aVal;
hashmix(mA, mB, mC);
} else {
mC += aVal << 8;
}
}
mLength += aLen;
}
void CacheHash::Update(const char* aData, uint32_t aLen) {
const uint8_t* data = reinterpret_cast<const uint8_t*>(aData);
MOZ_ASSERT(!mFinalized);
if (mBufPos) {
while (mBufPos != 4 && aLen) {
mBuf += uint32_t(*data) << 8 * mBufPos;
data++;
mBufPos++;
aLen--;
}
if (mBufPos == 4) {
mBufPos = 0;
Feed(mBuf);
mBuf = 0;
}
}
if (!aLen) return;
while (aLen >= 4) {
Feed(data[0] + (uint32_t(data[1]) << 8) + (uint32_t(data[2]) << 16) +
(uint32_t(data[3]) << 24));
data += 4;
aLen -= 4;
}
switch (aLen) {
case 3:
mBuf += data[2] << 16;
[[fallthrough]];
case 2:
mBuf += data[1] << 8;
[[fallthrough]];
case 1:
mBuf += data[0];
}
mBufPos = aLen;
}
CacheHash::Hash32_t CacheHash::GetHash() {
if (!mFinalized) {
if (mBufPos) {
Feed(mBuf, mBufPos);
}
mC += mLength;
hashmix(mA, mB, mC);
mFinalized = true;
}
return mC;
}
CacheHash::Hash16_t CacheHash::GetHash16() {
Hash32_t hash = GetHash();
return (hash & 0xFFFF);
}
OriginAttrsHash GetOriginAttrsHash(const mozilla::OriginAttributes& aOA) {
nsAutoCString suffix;
aOA.CreateSuffix(suffix);
SHA1Sum sum;
SHA1Sum::Hash hash;
sum.update(suffix.BeginReading(), suffix.Length());
sum.finish(hash);
return BigEndian::readUint64(&hash);
}
} // namespace net
} // namespace mozilla
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