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Merge pull request #333 from btcdrak/112update

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Update BIP112 reference example
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Luke-Jr 2016-02-24 05:37:51 +00:00
commit 30fb3ae942
1 changed files with 98 additions and 106 deletions
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@ -229,117 +229,109 @@ The 2-way pegged sidechain requires a new REORGPROOFVERIFY opcode, the semantics
Refer to the reference implementation, reproduced below, for the precise
semantics and detailed rationale for those semantics.
/* If this flag set, CTxIn::nSequence is NOT interpreted as a
* relative lock-time. */
static const uint32_t SEQUENCE_LOCKTIME_DISABLE_FLAG = (1 << 31);
/* If CTxIn::nSequence encodes a relative lock-time and this flag
* is set, the relative lock-time has units of 512 seconds,
* otherwise it specifies blocks with a granularity of 1. */
static const uint32_t SEQUENCE_LOCKTIME_TYPE_FLAG = (1 << 22);
/* If CTxIn::nSequence encodes a relative lock-time, this mask is
* applied to extract that lock-time from the sequence field. */
static const uint32_t SEQUENCE_LOCKTIME_MASK = 0x0000ffff;
<pre>
/* Below flags apply in the context of BIP 68 */
/* If this flag set, CTxIn::nSequence is NOT interpreted as a
* relative lock-time. */
static const uint32_t SEQUENCE_LOCKTIME_DISABLE_FLAG = (1 << 31);
/* If CTxIn::nSequence encodes a relative lock-time and this flag
* is set, the relative lock-time has units of 512 seconds,
* otherwise it specifies blocks with a granularity of 1. */
static const uint32_t SEQUENCE_LOCKTIME_TYPE_FLAG = (1 << 22);
/* If CTxIn::nSequence encodes a relative lock-time, this mask is
* applied to extract that lock-time from the sequence field. */
static const uint32_t SEQUENCE_LOCKTIME_MASK = 0x0000ffff;
case OP_NOP3:
{
if (!(flags & SCRIPT_VERIFY_CHECKSEQUENCEVERIFY)) {
// not enabled; treat as a NOP3
if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS) {
return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_NOPS);
}
break;
case OP_NOP3:
{
if (!(flags & SCRIPT_VERIFY_CHECKSEQUENCEVERIFY)) {
// not enabled; treat as a NOP3
if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS) {
return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_NOPS);
}
if (stack.size() < 1)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
// Note that elsewhere numeric opcodes are limited to
// operands in the range -2**31+1 to 2**31-1, however it is
// legal for opcodes to produce results exceeding that
// range. This limitation is implemented by CScriptNum's
// default 4-byte limit.
//
// Thus as a special case we tell CScriptNum to accept up
// to 5-byte bignums, which are good until 2**39-1, well
// beyond the 2**32-1 limit of the nSequence field itself.
const CScriptNum nSequence(stacktop(-1), fRequireMinimal, 5);
// In the rare event that the argument may be < 0 due to
// some arithmetic being done first, you can always use
// 0 MAX CHECKSEQUENCEVERIFY.
if (nSequence < 0)
return set_error(serror, SCRIPT_ERR_NEGATIVE_LOCKTIME);
// To provide for future soft-fork extensibility, if the
// operand has the disabled lock-time flag set,
// CHECKSEQUENCEVERIFY behaves as a NOP.
if ((nSequence & CTxIn::SEQUENCE_LOCKTIME_DISABLE_FLAG) != 0)
break;
// Compare the specified sequence number with the input.
if (!checker.CheckSequence(nSequence))
return set_error(serror, SCRIPT_ERR_UNSATISFIED_LOCKTIME);
break;
}
bool TransactionSignatureChecker::CheckSequence(const CScriptNum& nSequence) const
{
// Relative lock times are supported by comparing the passed
// in operand to the sequence number of the input.
const int64_t txToSequence = (int64_t)txTo->vin[nIn].nSequence;
// Fail if the transaction's version number is not set high
// enough to trigger BIP 68 rules.
if (static_cast<uint32_t>(txTo->nVersion) < 2)
return false;
// Sequence numbers with their most significant bit set are not
// defined by BIP68. Testing that the transaction's sequence
// number do not have this bit set prevents using this property
// to get around a CHECKSEQUENCEVERIFY check.
if (txToSequence & CTxIn::SEQUENCE_LOCKTIME_DISABLE_FLAG)
return false;
// Mask off any bits that do not have BIP68 consensus-enforced meaning
// before doing the integer comparisons of ::VerifySequence.
const uint32_t nLockTimeMask = CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG
| CTxIn::SEQUENCE_LOCKTIME_MASK;
if (!::VerifySequence(txToSequence & nLockTimeMask,
CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG,
nSequence & nLockTimeMask))
return false;
return true;
}
static bool VerifySequence(int64_t txToSequence, int64_t nThreshold, const CScriptNum& nSequence)
{
// There are two kinds of nLockTime: lock-by-blockheight
// and lock-by-blocktime, distinguished by whether
// nSequence < nThreshold (CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG).
//
// We want to compare apples to apples, so fail the script
// unless the type of nSequence being tested is the same as
// the nSequence in the transaction.
if (!(
(txToSequence < nThreshold && nSequence < nThreshold) ||
(txToSequence >= nThreshold && nSequence >= nThreshold)
))
return false;
// Now that we know we're comparing apples-to-apples, the
// comparison is a simple numeric one.
if (nSequence > txToSequence)
return false;
return true;
}
if (stack.size() < 1)
return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
// Note that elsewhere numeric opcodes are limited to
// operands in the range -2**31+1 to 2**31-1, however it is
// legal for opcodes to produce results exceeding that
// range. This limitation is implemented by CScriptNum's
// default 4-byte limit.
//
// Thus as a special case we tell CScriptNum to accept up
// to 5-byte bignums, which are good until 2**39-1, well
// beyond the 2**32-1 limit of the nSequence field itself.
const CScriptNum nSequence(stacktop(-1), fRequireMinimal, 5);
// In the rare event that the argument may be < 0 due to
// some arithmetic being done first, you can always use
// 0 MAX CHECKSEQUENCEVERIFY.
if (nSequence < 0)
return set_error(serror, SCRIPT_ERR_NEGATIVE_LOCKTIME);
// To provide for future soft-fork extensibility, if the
// operand has the disabled lock-time flag set,
// CHECKSEQUENCEVERIFY behaves as a NOP.
if ((nSequence & CTxIn::SEQUENCE_LOCKTIME_DISABLE_FLAG) != 0)
break;
// Compare the specified sequence number with the input.
if (!checker.CheckSequence(nSequence))
return set_error(serror, SCRIPT_ERR_UNSATISFIED_LOCKTIME);
break;
}
bool TransactionSignatureChecker::CheckSequence(const CScriptNum& nSequence) const
{
// Relative lock times are supported by comparing the passed
// in operand to the sequence number of the input.
const int64_t txToSequence = (int64_t)txTo->vin[nIn].nSequence;
// Fail if the transaction's version number is not set high
// enough to trigger BIP 68 rules.
if (static_cast<uint32_t>(txTo->nVersion) < 2)
return false;
// Sequence numbers with their most significant bit set are not
// consensus constrained. Testing that the transaction's sequence
// number do not have this bit set prevents using this property
// to get around a CHECKSEQUENCEVERIFY check.
if (txToSequence & CTxIn::SEQUENCE_LOCKTIME_DISABLE_FLAG)
return false;
// Mask off any bits that do not have consensus-enforced meaning
// before doing the integer comparisons
const uint32_t nLockTimeMask = CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG | CTxIn::SEQUENCE_LOCKTIME_MASK;
const int64_t txToSequenceMasked = txToSequence & nLockTimeMask;
const CScriptNum nSequenceMasked = nSequence & nLockTimeMask;
// There are two kinds of nSequence: lock-by-blockheight
// and lock-by-blocktime, distinguished by whether
// nSequenceMasked < CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG.
//
// We want to compare apples to apples, so fail the script
// unless the type of nSequenceMasked being tested is the same as
// the nSequenceMasked in the transaction.
if (!(
(txToSequenceMasked < CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG && nSequenceMasked < CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG) ||
(txToSequenceMasked >= CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG && nSequenceMasked >= CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG)
))
return false;
// Now that we know we're comparing apples-to-apples, the
// comparison is a simple numeric one.
if (nSequenceMasked > txToSequenceMasked)
return false;
return true;
}
</pre>
==Reference Implementation==