Merge pull request #3839

fd704c7 move pow constants to chainparams (jtimon)
df852d2 Refactor proof of work related functions out of main (jtimon)

1 files changed, 1 insertions, 112 deletions

diff --git a/src/main.cpp b/src/main.cpp
index d3f04b95fa..ea47601081 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -12,6 +12,7 @@
 #include "checkqueue.h"
 #include "init.h"
 #include "net.h"
+#include "pow.h"
 #include "txdb.h"
 #include "txmempool.h"
 #include "ui_interface.h"
@@ -1194,118 +1195,6 @@ int64_t GetBlockValue(int nHeight, int64_t nFees)
     return nSubsidy + nFees;
 }
 
-static const int64_t nTargetTimespan = 14 * 24 * 60 * 60; // two weeks
-static const int64_t nTargetSpacing = 10 * 60;
-static const int64_t nInterval = nTargetTimespan / nTargetSpacing;
-
-//
-// minimum amount of work that could possibly be required nTime after
-// minimum work required was nBase
-//
-unsigned int ComputeMinWork(unsigned int nBase, int64_t nTime)
-{
-    const uint256 &bnLimit = Params().ProofOfWorkLimit();
-    // Testnet has min-difficulty blocks
-    // after nTargetSpacing*2 time between blocks:
-    if (Params().AllowMinDifficultyBlocks() && nTime > nTargetSpacing*2)
-        return bnLimit.GetCompact();
-
-    uint256 bnResult;
-    bnResult.SetCompact(nBase);
-    while (nTime > 0 && bnResult < bnLimit)
-    {
-        // Maximum 400% adjustment...
-        bnResult *= 4;
-        // ... in best-case exactly 4-times-normal target time
-        nTime -= nTargetTimespan*4;
-    }
-    if (bnResult > bnLimit)
-        bnResult = bnLimit;
-    return bnResult.GetCompact();
-}
-
-unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHeader *pblock)
-{
-    unsigned int nProofOfWorkLimit = Params().ProofOfWorkLimit().GetCompact();
-
-    // Genesis block
-    if (pindexLast == NULL)
-        return nProofOfWorkLimit;
-
-    // Only change once per interval
-    if ((pindexLast->nHeight+1) % nInterval != 0)
-    {
-        if (Params().AllowMinDifficultyBlocks())
-        {
-            // Special difficulty rule for testnet:
-            // If the new block's timestamp is more than 2* 10 minutes
-            // then allow mining of a min-difficulty block.
-            if (pblock->nTime > pindexLast->nTime + nTargetSpacing*2)
-                return nProofOfWorkLimit;
-            else
-            {
-                // Return the last non-special-min-difficulty-rules-block
-                const CBlockIndex* pindex = pindexLast;
-                while (pindex->pprev && pindex->nHeight % nInterval != 0 && pindex->nBits == nProofOfWorkLimit)
-                    pindex = pindex->pprev;
-                return pindex->nBits;
-            }
-        }
-        return pindexLast->nBits;
-    }
-
-    // Go back by what we want to be 14 days worth of blocks
-    const CBlockIndex* pindexFirst = pindexLast;
-    for (int i = 0; pindexFirst && i < nInterval-1; i++)
-        pindexFirst = pindexFirst->pprev;
-    assert(pindexFirst);
-
-    // Limit adjustment step
-    int64_t nActualTimespan = pindexLast->GetBlockTime() - pindexFirst->GetBlockTime();
-    LogPrintf("  nActualTimespan = %d  before bounds\n", nActualTimespan);
-    if (nActualTimespan < nTargetTimespan/4)
-        nActualTimespan = nTargetTimespan/4;
-    if (nActualTimespan > nTargetTimespan*4)
-        nActualTimespan = nTargetTimespan*4;
-
-    // Retarget
-    uint256 bnNew;
-    uint256 bnOld;
-    bnNew.SetCompact(pindexLast->nBits);
-    bnOld = bnNew;
-    bnNew *= nActualTimespan;
-    bnNew /= nTargetTimespan;
-
-    if (bnNew > Params().ProofOfWorkLimit())
-        bnNew = Params().ProofOfWorkLimit();
-
-    /// debug print
-    LogPrintf("GetNextWorkRequired RETARGET\n");
-    LogPrintf("nTargetTimespan = %d    nActualTimespan = %d\n", nTargetTimespan, nActualTimespan);
-    LogPrintf("Before: %08x  %s\n", pindexLast->nBits, bnOld.ToString());
-    LogPrintf("After:  %08x  %s\n", bnNew.GetCompact(), bnNew.ToString());
-
-    return bnNew.GetCompact();
-}
-
-bool CheckProofOfWork(uint256 hash, unsigned int nBits)
-{
-    bool fNegative;
-    bool fOverflow;
-    uint256 bnTarget;
-    bnTarget.SetCompact(nBits, &fNegative, &fOverflow);
-
-    // Check range
-    if (fNegative || bnTarget == 0 || fOverflow || bnTarget > Params().ProofOfWorkLimit())
-        return error("CheckProofOfWork() : nBits below minimum work");
-
-    // Check proof of work matches claimed amount
-    if (hash > bnTarget)
-        return error("CheckProofOfWork() : hash doesn't match nBits");
-
-    return true;
-}
-
 bool IsInitialBlockDownload()
 {
     LOCK(cs_main);