From 76a9aacd3fb75d5e0854e53bb3376f2ab603a561 Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Sat, 8 Jul 2017 16:43:34 -0700
Subject: Move compressor utility functions out of class

---
 src/compressor.cpp | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

(limited to 'src/compressor.cpp')

diff --git a/src/compressor.cpp b/src/compressor.cpp
index 86de2900e..da639a01a 100644
--- a/src/compressor.cpp
+++ b/src/compressor.cpp
@@ -9,7 +9,15 @@
 #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
@@ -20,7 +28,7 @@ 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) {
@@ -30,7 +38,7 @@ 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)) {
@@ -45,24 +53,24 @@ 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) {
@@ -76,7 +84,7 @@ 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;
@@ -85,7 +93,7 @@ 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:
@@ -139,7 +147,7 @@ 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;
@@ -158,7 +166,7 @@ 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)
-- 
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