Move compressor utility functions out of class

PIVX-Project · Jul 3, 2021 · 3e38199 · 3e38199
1 parent 7376a95
commit 3e38199
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Showing 3 changed files with 35 additions and 40 deletions.
diff --git a/src/compressor.cpp b/src/compressor.cpp
@@ -10,7 +10,15 @@
 #include "pubkey.h"
 #include "script/standard.h"
 
-bool CScriptCompressor::IsToKeyID(CKeyID& hash) const
+/*
+ * These check for scripts for which a special case with a shorter encoding is defined.
+ * They are implemented separately from the CScript test, as these test for exact byte
+ * sequence correspondences, and are more strict. For example, IsToPubKey also verifies
+ * whether the public key is valid (as invalid ones cannot be represented in compressed
+ * form).
+ */
+
+static bool IsToKeyID(const CScript& script, CKeyID &hash)
 {
     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);
@@ -19,7 +27,7 @@ bool CScriptCompressor::IsToKeyID(CKeyID& hash) const
     return false;
 }
 
-bool CScriptCompressor::IsToScriptID(CScriptID& hash) const
+static bool IsToScriptID(const CScript& script, CScriptID &hash)
 {
     if (script.size() == 23 && script[0] == OP_HASH160 && script[1] == 20 && script[22] == OP_EQUAL) {
         memcpy(&hash, &script[2], 20);
@@ -28,7 +36,7 @@ bool CScriptCompressor::IsToScriptID(CScriptID& hash) const
     return false;
 }
 
-bool CScriptCompressor::IsToPubKey(CPubKey& pubkey) const
+static bool IsToPubKey(const CScript& script, CPubKey &pubkey)
 {
     if (script.size() == 35 && script[0] == 33 && script[34] == OP_CHECKSIG && (script[1] == 0x02 || script[1] == 0x03)) {
         pubkey.Set(&script[1], &script[34]);
@@ -41,24 +49,24 @@ bool CScriptCompressor::IsToPubKey(CPubKey& pubkey) const
     return false;
 }
 
-bool CScriptCompressor::Compress(std::vector<unsigned char>& out) const
+bool CompressScript(const CScript& script, std::vector<unsigned char> &out)
 {
     CKeyID keyID;
-    if (IsToKeyID(keyID)) {
+    if (IsToKeyID(script, keyID)) {
         out.resize(21);
         out[0] = 0x00;
         memcpy(&out[1], &keyID, 20);
         return true;
     }
     CScriptID scriptID;
-    if (IsToScriptID(scriptID)) {
+    if (IsToScriptID(script, scriptID)) {
         out.resize(21);
         out[0] = 0x01;
         memcpy(&out[1], &scriptID, 20);
         return true;
     }
     CPubKey pubkey;
-    if (IsToPubKey(pubkey)) {
+    if (IsToPubKey(script, pubkey)) {
         out.resize(33);
         memcpy(&out[1], &pubkey[1], 32);
         if (pubkey[0] == 0x02 || pubkey[0] == 0x03) {
@@ -72,7 +80,7 @@ bool CScriptCompressor::Compress(std::vector<unsigned char>& out) const
     return false;
 }
 
-unsigned int CScriptCompressor::GetSpecialSize(unsigned int nSize) const
+unsigned int GetSpecialScriptSize(unsigned int nSize)
 {
     if (nSize == 0 || nSize == 1)
         return 20;
@@ -81,7 +89,7 @@ unsigned int CScriptCompressor::GetSpecialSize(unsigned int nSize) const
     return 0;
 }
 
-bool CScriptCompressor::Decompress(unsigned int nSize, const std::vector<unsigned char>& in)
+bool DecompressScript(CScript& script, unsigned int nSize, const std::vector<unsigned char> &in)
 {
     switch (nSize) {
     case 0x00:
@@ -135,7 +143,7 @@ bool CScriptCompressor::Decompress(unsigned int nSize, const std::vector<unsigne
 // * if e==9, we only know the resulting number is not zero, so output 1 + 10*(n - 1) + 9
 // (this is decodable, as d is in [1-9] and e is in [0-9])
 
-uint64_t CTxOutCompressor::CompressAmount(uint64_t n)
+uint64_t CompressAmount(uint64_t n)
 {
     if (n == 0)
         return 0;
@@ -154,7 +162,7 @@ uint64_t CTxOutCompressor::CompressAmount(uint64_t n)
     }
 }
 
-uint64_t CTxOutCompressor::DecompressAmount(uint64_t x)
+uint64_t DecompressAmount(uint64_t x)
 {
     // x = 0  OR  x = 1+10*(9*n + d - 1) + e  OR  x = 1+10*(n - 1) + 9
     if (x == 0)

diff --git a/src/compressor.h b/src/compressor.h
@@ -16,6 +16,13 @@ class CKeyID;
 class CPubKey;
 class CScriptID;
 
+bool CompressScript(const CScript& script, std::vector<unsigned char> &out);
+unsigned int GetSpecialScriptSize(unsigned int nSize);
+bool DecompressScript(CScript& script, unsigned int nSize, const std::vector<unsigned char> &out);
+
+uint64_t CompressAmount(uint64_t nAmount);
+uint64_t DecompressAmount(uint64_t nAmount);
+
 /** Compact serializer for scripts.
  *
  *  It detects common cases and encodes them much more efficiently.
@@ -38,32 +45,15 @@ class CScriptCompressor
      */
     static const unsigned int nSpecialScripts = 6;
 
-    CScript& script;
-
-protected:
-    /**
-     * These check for scripts for which a special case with a shorter encoding is defined.
-     * They are implemented separately from the CScript test, as these test for exact byte
-     * sequence correspondences, and are more strict. For example, IsToPubKey also verifies
-     * whether the public key is valid (as invalid ones cannot be represented in compressed
-     * form).
-     */
-    bool IsToKeyID(CKeyID& hash) const;
-    bool IsToScriptID(CScriptID& hash) const;
-    bool IsToPubKey(CPubKey& pubkey) const;
-
-    bool Compress(std::vector<unsigned char>& out) const;
-    unsigned int GetSpecialSize(unsigned int nSize) const;
-    bool Decompress(unsigned int nSize, const std::vector<unsigned char>& out);
-
+    CScript &script;
 public:
     CScriptCompressor(CScript& scriptIn) : script(scriptIn) {}
 
     template <typename Stream>
     void Serialize(Stream& s) const
     {
         std::vector<unsigned char> compr;
-        if (Compress(compr)) {
+        if (CompressScript(script, compr)) {
             s << MakeSpan(compr);
             return;
         }
@@ -78,9 +68,9 @@ class CScriptCompressor
         unsigned int nSize = 0;
         s >> VARINT(nSize);
         if (nSize < nSpecialScripts) {
-            std::vector<unsigned char> vch(GetSpecialSize(nSize), 0x00);
+            std::vector<unsigned char> vch(GetSpecialScriptSize(nSize), 0x00);
             s >> MakeSpan(vch);
-            Decompress(nSize, vch);
+            DecompressScript(script, nSize, vch);
             return;
         }
         nSize -= nSpecialScripts;
@@ -102,10 +92,7 @@ class CTxOutCompressor
     CTxOut& txout;
 
 public:
-    static uint64_t CompressAmount(uint64_t nAmount);
-    static uint64_t DecompressAmount(uint64_t nAmount);
-
-    CTxOutCompressor(CTxOut& txoutIn) : txout(txoutIn) {}
+    explicit CTxOutCompressor(CTxOut &txoutIn) : txout(txoutIn) { }
 
     ADD_SERIALIZE_METHODS;
 

diff --git a/src/test/compress_tests.cpp b/src/test/compress_tests.cpp
@@ -25,16 +25,16 @@
 BOOST_FIXTURE_TEST_SUITE(compress_tests, BasicTestingSetup)
 
 bool static TestEncode(uint64_t in) {
-    return in == CTxOutCompressor::DecompressAmount(CTxOutCompressor::CompressAmount(in));
+    return in == DecompressAmount(CompressAmount(in));
 }
 
 bool static TestDecode(uint64_t in) {
-    return in == CTxOutCompressor::CompressAmount(CTxOutCompressor::DecompressAmount(in));
+    return in == CompressAmount(DecompressAmount(in));
 }
 
 bool static TestPair(uint64_t dec, uint64_t enc) {
-    return CTxOutCompressor::CompressAmount(dec) == enc &&
-           CTxOutCompressor::DecompressAmount(enc) == dec;
+    return CompressAmount(dec) == enc &&
+           DecompressAmount(enc) == dec;
 }
 
 BOOST_AUTO_TEST_CASE(compress_amounts)