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Add the code to walk to the ledger chain.

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This commit is contained in:
JoelKatz
2012-12-30 22:36:54 -08:00
parent 5009d4c3b8
commit 0c91e7e78a
1 changed files with 22 additions and 30 deletions
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52
src/cpp/ripple/Ledger.cpp
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@@ -935,55 +935,49 @@ uint256 Ledger::getLedgerHashIndex(uint32 desiredLedgerIndex)
return s.getSHA512Half();
}
int Ledger::getLedgerHashOffset(uint32 ledgerIndex)
{ // get the offset for this ledger's hash (or the first one after it) in the every-256-ledger table
return (ledgerIndex >> 8) % 256;
}
int Ledger::getLedgerHashOffset(uint32 desiredLedgerIndex, uint32 currentLedgerIndex)
{ // get the offset for this ledger's hash in the every-ledger table, -1 if not in it
if (desiredLedgerIndex >= currentLedgerIndex)
return -1;
if (currentLedgerIndex < 256)
return desiredLedgerIndex;
if (desiredLedgerIndex < (currentLedgerIndex - 256))
return -1;
return currentLedgerIndex - desiredLedgerIndex - 1;
}
uint256 Ledger::getLedgerHash(uint32 ledgerIndex)
{ // return the hash of the specified ledger, 0 if not available
// easy cases
if (ledgerIndex > mLedgerSeq)
return uint256();
if (ledgerIndex == mLedgerSeq)
return getHash();
if (ledgerIndex == (mLedgerSeq - 1))
return mParentHash;
// within 255
int offset = getLedgerHashOffset(ledgerIndex, mLedgerSeq);
if (offset != -1)
// within 256
int diff = mLedgerSeq - ledgerIndex;
if (diff <= 256)
{
SLE::pointer hashIndex = getSLE(getLedgerHashIndex());
if (hashIndex)
return hashIndex->getFieldV256(sfHashes).peekValue().at(offset);
else
assert(false);
{
assert(hashIndex->getFieldU32(sfLastLedgerSequence) == (mLedgerSeq - 1));
STVector256 vec = hashIndex->getFieldV256(sfHashes);
if (vec.size() >= diff)
return vec.at(vec.size() - diff);
}
}
if ((ledgerIndex & 0xff) != 0)
return uint256();
// in skiplist
SLE::pointer hashIndex = getSLE(getLedgerHashIndex(ledgerIndex));
if (hashIndex)
return hashIndex->getFieldV256(sfHashes).peekValue().at(getLedgerHashOffset(ledgerIndex, mLedgerSeq));
else
assert(false);
{
int lastSeq = hashIndex->getFieldU32(sfLastLedgerSequence);
assert(lastSeq >= ledgerIndex);
assert((lastSeq & 0xff) == 0);
int sDiff = (lastSeq - ledgerIndex) >> 8;
STVector256 vec = hashIndex->getFieldV256(sfHashes);
if (vec.size() > sDiff)
return vec.at(vec.size() - sDiff - 1);
}
return uint256();
}
@@ -1144,9 +1138,7 @@ void Ledger::updateSkipList()
std::vector<uint256> hashes;
if (!skipList)
{
skipList = boost::make_shared<SLE>(ltLEDGER_HASHES, hash);
}
else
hashes = skipList->getFieldV256(sfHashes).peekValue();