aboutsummaryrefslogtreecommitdiff
path: root/src/script.cpp
diff options
context:
space:
mode:
authorPieter Wuille <pieter.wuille@gmail.com>2012-06-15 18:52:19 +0200
committerPieter Wuille <pieter.wuille@gmail.com>2012-10-20 23:08:56 +0200
commit69fc8047a9a96bcf5360f810c796049c27e16fcd (patch)
treeb800ff10cf08779f8e7e7e6f9aa0588452bb6885 /src/script.cpp
parent4d6144f97faf9d2a6c89f41d7d2360f21f0b71e2 (diff)
Compact serialization for scripts
Special serializers for script which detect common cases and encode them much more efficiently. 3 special cases are defined: * Pay to pubkey hash (encoded as 21 bytes) * Pay to script hash (encoded as 21 bytes) * Pay to pubkey starting with 0x02, 0x03 or 0x04 (encoded as 33 bytes) Other scripts up to 121 bytes require 1 byte + script length. Above that, scripts up to 16505 bytes require 2 bytes + script length.
Diffstat (limited to 'src/script.cpp')
-rw-r--r--src/script.cpp125
1 files changed, 125 insertions, 0 deletions
diff --git a/src/script.cpp b/src/script.cpp
index 89bc5632bc..a840bb1c0d 100644
--- a/src/script.cpp
+++ b/src/script.cpp
@@ -1951,3 +1951,128 @@ void CScript::SetMultisig(int nRequired, const std::vector<CKey>& keys)
*this << key.GetPubKey();
*this << EncodeOP_N(keys.size()) << OP_CHECKMULTISIG;
}
+
+bool CScriptCompressor::IsToKeyID(CKeyID &hash) const
+{
+ if (script.size() == 25 && script[0] == OP_DUP && script[1] == OP_HASH160
+ && script[2] == 20 && script[23] == OP_EQUALVERIFY
+ && script[24] == OP_CHECKSIG) {
+ memcpy(&hash, &script[3], 20);
+ return true;
+ }
+ return false;
+}
+
+bool CScriptCompressor::IsToScriptID(CScriptID &hash) const
+{
+ if (script.size() == 23 && script[0] == OP_HASH160 && script[1] == 20
+ && script[22] == OP_EQUAL) {
+ memcpy(&hash, &script[2], 20);
+ return true;
+ }
+ return false;
+}
+
+bool CScriptCompressor::IsToPubKey(std::vector<unsigned char> &pubkey) const
+{
+ if (script.size() == 35 && script[0] == 33 && script[34] == OP_CHECKSIG
+ && (script[1] == 0x02 || script[1] == 0x03)) {
+ pubkey.resize(33);
+ memcpy(&pubkey[0], &script[1], 33);
+ return true;
+ }
+ if (script.size() == 67 && script[0] == 65 && script[66] == OP_CHECKSIG
+ && script[1] == 0x04) {
+ pubkey.resize(65);
+ memcpy(&pubkey[0], &script[1], 65);
+ CKey key;
+ return (key.SetPubKey(CPubKey(pubkey))); // SetPubKey fails if this is not a valid public key, a case that would not be compressible
+ }
+ return false;
+}
+
+bool CScriptCompressor::Compress(std::vector<unsigned char> &out) const
+{
+ CKeyID keyID;
+ if (IsToKeyID(keyID)) {
+ out.resize(21);
+ out[0] = 0x00;
+ memcpy(&out[1], &keyID, 20);
+ return true;
+ }
+ CScriptID scriptID;
+ if (IsToScriptID(scriptID)) {
+ out.resize(21);
+ out[0] = 0x01;
+ memcpy(&out[1], &scriptID, 20);
+ return true;
+ }
+ std::vector<unsigned char> pubkey;
+ if (IsToPubKey(pubkey)) {
+ out.resize(33);
+ memcpy(&out[1], &pubkey[1], 32);
+ if (pubkey[0] == 0x02 || pubkey[0] == 0x03) {
+ out[0] = pubkey[0];
+ return true;
+ } else if (pubkey[0] == 0x04) {
+ out[0] = 0x04 | (pubkey[64] & 0x01);
+ return true;
+ }
+ }
+ return false;
+}
+
+unsigned int CScriptCompressor::GetSpecialSize(unsigned int nSize) const
+{
+ if (nSize == 0 || nSize == 1)
+ return 20;
+ if (nSize == 2 || nSize == 3 || nSize == 4 || nSize == 5)
+ return 32;
+ return 0;
+}
+
+bool CScriptCompressor::Decompress(unsigned int nSize, const std::vector<unsigned char> &in)
+{
+ switch(nSize) {
+ case 0x00:
+ script.resize(25);
+ script[0] = OP_DUP;
+ script[1] = OP_HASH160;
+ script[2] = 20;
+ memcpy(&script[3], &in[0], 20);
+ script[23] = OP_EQUALVERIFY;
+ script[24] = OP_CHECKSIG;
+ return true;
+ case 0x01:
+ script.resize(23);
+ script[0] = OP_HASH160;
+ script[1] = 20;
+ memcpy(&script[2], &in[0], 20);
+ script[22] = OP_EQUAL;
+ return true;
+ case 0x02:
+ case 0x03:
+ script.resize(35);
+ script[0] = 33;
+ script[1] = nSize;
+ memcpy(&script[2], &in[0], 32);
+ script[34] = OP_CHECKSIG;
+ return true;
+ case 0x04:
+ case 0x05:
+ std::vector<unsigned char> vch(33, 0x00);
+ vch[0] = nSize - 2;
+ memcpy(&vch[1], &in[0], 32);
+ CKey key;
+ if (!key.SetPubKey(CPubKey(vch)))
+ return false;
+ key.SetCompressedPubKey(false); // Decompress public key
+ CPubKey pubkey = key.GetPubKey();
+ script.resize(67);
+ script[0] = 65;
+ memcpy(&script[1], &pubkey.Raw()[0], 65);
+ script[66] = OP_CHECKSIG;
+ return true;
+ }
+ return false;
+}