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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;
// length = PL_strlen(key);
/* 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); MOZ_FALLTHROUGH;
case 10: c += (uint32_t(k[9])<<16); MOZ_FALLTHROUGH;
case 9 : c += (uint32_t(k[8])<<8); MOZ_FALLTHROUGH;
/* the low-order byte of c is reserved for the length */
case 8 : b += (uint32_t(k[7])<<24); MOZ_FALLTHROUGH;
case 7 : b += (uint32_t(k[6])<<16); MOZ_FALLTHROUGH;
case 6 : b += (uint32_t(k[5])<<8); MOZ_FALLTHROUGH;
case 5 : b += k[4]; MOZ_FALLTHROUGH;
case 4 : a += (uint32_t(k[3])<<24); MOZ_FALLTHROUGH;
case 3 : a += (uint32_t(k[2])<<16); MOZ_FALLTHROUGH;
case 2 : a += (uint32_t(k[1])<<8); MOZ_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; MOZ_FALLTHROUGH;
case 2: mBuf += data[1] << 8; MOZ_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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