New Zero struct implements "compare with zero."

* Zero lets classes efficiently compare with 0, so you can use constructors like x < zero or y != zero. * New BEAST_CONSTEXPR to handle Windows/C++11 differences regarding the constexpr specifier.
2025-12-06 01:07:57 +00:00 · 2014-04-10 19:14:52 -04:00
parent 524f41177c
commit 64ee0d07d0
26 changed files with 591 additions and 425 deletions
--- a/src/beast/beast/config/CompilerConfig.h
+++ b/src/beast/beast/config/CompilerConfig.h
@@ -24,13 +24,8 @@
 #ifndef BEAST_CONFIG_COMPILERCONFIG_H_INCLUDED
 #define BEAST_CONFIG_COMPILERCONFIG_H_INCLUDED

-// This file has to work when included in a C source file.
-
-#ifndef BEAST_CONFIG_PLATFORMCONFIG_H_INCLUDED
-#error "PlatformConfig.h must come first!"
-#endif
-
 #include <assert.h>
+#include "PlatformConfig.h"

 // This file defines miscellaneous macros for debugging, assertions, etc.

@@ -47,6 +42,15 @@
 # define BEAST_CDECL
 #endif

+/** This macro fixes C++'s constexpr for VS2012, which doesn't understand it.
+*/
+#if BEAST_MSVC
+# define BEAST_CONSTEXPR const
+#else
+# define BEAST_CONSTEXPR constexpr
+#endif
+
+
 // Debugging and assertion macros

 #if BEAST_LOG_ASSERTIONS || BEAST_DEBUG
--- a/src/beast/beast/container/tests/hardened_hash.test.cpp
+++ b/src/beast/beast/container/tests/hardened_hash.test.cpp
@@ -17,7 +17,7 @@
 */
 //==============================================================================

-// MODULES: ../../crypto/impl/Sha256.cpp
+// MODULES: ../../crypto/impl/Sha256.cpp ../../container/impl/spookyv2.cpp

 #if BEAST_INCLUDE_BEASTCONFIG
 #include "../../../BeastConfig.h"
--- a/src/beast/beast/utility/Utility.cpp
+++ b/src/beast/beast/utility/Utility.cpp
@@ -31,3 +31,4 @@

 #include "tests/bassert.test.cpp"
 #include "tests/empty_base_optimization.test.cpp"
+#include "tests/Zero.test.cpp"
--- a/src/beast/beast/utility/Zero.h
+++ b/src/beast/beast/utility/Zero.h
@@ -0,0 +1,140 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of Beast: https://github.com/vinniefalco/Beast
+    Copyright 2014, Tom Ritchford <tom@swirly.com>
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#ifndef BEAST_UTILITY_ZERO_H_INCLUDED
+#define BEAST_UTILITY_ZERO_H_INCLUDED
+
+#include "../config/CompilerConfig.h"
+
+namespace beast {
+
+/** Zero allows classes to offer efficient comparisons to zero.
+
+    Zero is a struct to allow classes to efficiently compare with zero without
+    requiring an rvalue construction.
+
+    It's often the case that we have classes which combine a number and a unit.
+    In such cases, comparisons like t > 0 or t != 0 make sense, but comparisons
+    like t > 1 or t != 1 do not.
+
+    The class Zero allows such comparisons to be easily made.
+
+    The comparing class T either needs to have a method called signum() which
+    returns a positive number, 0, or a negative; or there needs to be a signum
+    function which resolves in the namespace which takes an instance of T and
+    returns a positive, zero or negative number.
+ */
+
+struct Zero {};
+
+namespace {
+
+static BEAST_CONSTEXPR Zero zero{};
+
+}  // namespace
+
+/** The default implementation of signum calls the method on the class.
+
+    Calls to signum must be made from a namespace that does not include
+    overloads of the function.
+ */
+template <typename T>
+auto signum(T const& t) -> decltype(t.signum()) {
+    return t.signum();
+}
+
+namespace detail {
+namespace zero_helper {
+
+template <class T>
+auto call_signum (T const& t) -> decltype(signum(t)) {
+    return signum(t);
+}
+
+} // zero_helper
+} // detail
+
+/** Handle operators where T is on the left side using signum. */
+template <typename T>
+bool operator==(T const& t, Zero) {
+    return detail::zero_helper::call_signum(t) == 0;
+}
+
+template <typename T>
+bool operator!=(T const& t, Zero) {
+    return detail::zero_helper::call_signum(t) != 0;
+}
+
+template <typename T>
+bool operator>(T const& t, Zero) {
+    return detail::zero_helper::call_signum(t) > 0;
+}
+
+template <typename T>
+bool operator>=(T const& t, Zero) {
+    return detail::zero_helper::call_signum(t) >= 0;
+}
+
+template <typename T>
+bool operator<(T const& t, Zero) {
+    return detail::zero_helper::call_signum(t) < 0;
+}
+
+template <typename T>
+bool operator<=(T const& t, Zero) {
+    return detail::zero_helper::call_signum(t) <= 0;
+}
+
+
+/** Handle operators where T is on the right side by reversing the operation,
+    so that T is on the left side.
+ */
+template <typename T>
+bool operator==(Zero, T const& t) {
+    return t == zero;
+}
+
+template <typename T>
+bool operator!=(Zero, T const& t) {
+    return t != zero;
+}
+
+template <typename T>
+bool operator>(Zero, T const& t) {
+    return t < zero;
+}
+
+template <typename T>
+bool operator>=(Zero, T const& t) {
+    return t <= zero;
+}
+
+template <typename T>
+bool operator<(Zero, T const& t) {
+    return t > zero;
+}
+
+template <typename T>
+bool operator<=(Zero, T const& t) {
+    return t >= zero;
+}
+
+}  // beast
+
+#endif
--- a/src/beast/beast/utility/tests/Zero.test.cpp
+++ b/src/beast/beast/utility/tests/Zero.test.cpp
@@ -0,0 +1,136 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of Beast: https://github.com/vinniefalco/Beast
+    Copyright 2014, Nikolaos D. Bougalis <nikb@bougalis.net>
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include "../Zero.h"
+
+#include "../../unit_test/suite.h"
+
+namespace beast {
+
+struct adl_tester {};
+
+int signum (adl_tester) { return 0; }
+
+
+namespace detail {
+
+struct adl_tester2 {};
+
+int signum (adl_tester2) { return 0; }
+
+}  // detail
+
+class Zero_test : public beast::unit_test::suite
+{
+private:
+    struct IntegerWrapper
+    {
+        int value;
+
+        IntegerWrapper (int v)
+            : value (v)
+        {
+        }
+
+        int signum() const
+        {
+            return value;
+        }
+    };
+
+public:
+    void expect_same(bool result, bool correct, char const* message)
+    {
+        expect(result == correct, message);
+    }
+
+    void
+    test_lhs_zero (IntegerWrapper x)
+    {
+        expect_same (x >= zero, x.signum () >= 0,
+            "lhs greater-than-or-equal-to");
+        expect_same (x > zero, x.signum () > 0,
+            "lhs greater than");
+        expect_same (x == zero, x.signum () == 0,
+            "lhs equal to");
+        expect_same (x != zero, x.signum () != 0,
+            "lhs not equal to");
+        expect_same (x < zero, x.signum () < 0,
+            "lhs less than");
+        expect_same (x <= zero, x.signum () <= 0,
+            "lhs less-than-or-equal-to");
+    }
+
+    void
+    test_lhs_zero ()
+    {
+        testcase ("lhs zero");
+
+        test_lhs_zero(-7);
+        test_lhs_zero(0);
+        test_lhs_zero(32);
+    }
+
+    void
+    test_rhs_zero (IntegerWrapper x)
+    {
+        expect_same (zero >= x, 0 >= x.signum (),
+            "rhs greater-than-or-equal-to");
+        expect_same (zero > x, 0 > x.signum (),
+            "rhs greater than");
+        expect_same (zero == x, 0 == x.signum (),
+            "rhs equal to");
+        expect_same (zero != x, 0 != x.signum (),
+            "rhs not equal to");
+        expect_same (zero < x, 0 < x.signum (),
+            "rhs less than");
+        expect_same (zero <= x, 0 <= x.signum (),
+            "rhs less-than-or-equal-to");
+    }
+
+    void
+    test_rhs_zero ()
+    {
+        testcase ("rhs zero");
+
+        test_rhs_zero(-4);
+        test_rhs_zero(0);
+        test_rhs_zero(64);
+    }
+
+    void
+    test_adl ()
+    {
+      expect (adl_tester{} == zero, "ADL failure!");
+      expect (detail::adl_tester2{} == zero, "ADL failure!");
+    }
+
+    void
+    run()
+    {
+        test_lhs_zero ();
+        test_rhs_zero ();
+        test_adl ();
+    }
+
+};
+
+BEAST_DEFINE_TESTSUITE(Zero, types, beast);
+
+}
--- a/src/beast/tests.sh
+++ b/src/beast/tests.sh
--- a/src/ripple_app/book/Amount.h
+++ b/src/ripple_app/book/Amount.h
@@ -25,119 +25,6 @@
 #include "../../beast/beast/utility/noexcept.h"
 #include "../../beast/beast/cxx14/type_traits.h" // <type_traits>

-//------------------------------------------------------------------------------
-
-struct Zero
-{
-    Zero()
-    {
-    }
-};
-
-namespace {
-static Zero const zero;
-}
-
-namespace detail {
-namespace Zero_helpers {
-template <class T>
-int
-get_signum (T const& t) noexcept
-{
-    return signum(t);
-}
-}
-}
-
-/** Handle operators where T is on the left side using signum. */
-template <class T>
-
-bool operator==(T const& t, Zero)
-{
-    return detail::Zero_helpers::get_signum(t) == 0;
-}
-
-template <class T>
-bool operator!=(T const& t, Zero)
-{
-    return detail::Zero_helpers::get_signum(t) != 0;
-}
-
-template <class T>
-bool operator>(T const& t, Zero)
-{
-    return detail::Zero_helpers::get_signum(t) > 0;
-}
-
-template <class T>
-bool operator>=(T const& t, Zero)
-{
-    return detail::Zero_helpers::get_signum(t) >= 0;
-}
-
-template <class T>
-bool operator<(T const& t, Zero)
-{
-    return detail::Zero_helpers::get_signum(t) < 0;
-}
-
-template <class T>
-bool operator<=(T const& t, Zero)
-{
-    return detail::Zero_helpers::get_signum(t) <= 0;
-}
-
-
-/** Handle operators where T is on the right side by reversing the operation,
-    so that T is on the left side.
- */
-template <class T>
-bool operator==(Zero, T const& t)
-{
-    return t == zero;
-}
-
-template <class T>
-bool operator!=(Zero, T const& t)
-{
-    return t != zero;
-}
-
-template <class T>
-bool operator>(Zero, T const& t)
-{
-    return t < zero;
-}
-
-template <class T>
-bool operator>=(Zero, T const& t)
-{
-    return t <= zero;
-}
-
-template <class T>
-bool operator<(Zero, T const& t)
-{
-    return t > zero;
-}
-
-template <class T>
-bool operator<=(Zero, T const& t)
-{
-    return t >= zero;
-}
-
-/** Default implementation calls the method on the class.
-    Alternatively, signum may be overloaded in the same namespace and found
-    via argument dependent lookup.
-*/
-template <class T>
-auto signum(T const& t) -> decltype(t.signum()) {
-    return t.signum();
-}
-
-//------------------------------------------------------------------------------
-
 namespace ripple {
 namespace core {

--- a/src/ripple_app/book/Amounts.h
+++ b/src/ripple_app/book/Amounts.h
@@ -39,7 +39,7 @@ struct Amounts
    bool
    empty() const noexcept
    {
-        return ! in.isPositive() || ! out.isPositive();
+        return in <= zero || out <= zero;
    }

    Amount in;
--- a/src/ripple_app/book/OfferStream.h
+++ b/src/ripple_app/book/OfferStream.h
@@ -212,7 +212,7 @@ dir() const noexcept
                m_offer.account(), m_offer.amount().out));

            // Check for unfunded offer
-            if (! owner_funds.isPositive())
+            if (owner_funds <= zero)
            {
                // If the owner's balance in the pristine view is the same,
                // we haven't modified the balance and therefore the
--- a/src/ripple_app/book/tests/Quality.test.cpp
+++ b/src/ripple_app/book/tests/Quality.test.cpp
@@ -230,7 +230,7 @@ public:
            Amount const limit (
                raw (4131113916555555, -16));       // .4131113916555555
            Amounts const result (q.ceil_out (value, limit));
-            expect (! result.in.isZero());
+            expect (result.in != zero);
        }
    }

--- a/src/ripple_app/ledger/LedgerEntrySet.cpp
+++ b/src/ripple_app/ledger/LedgerEntrySet.cpp
@@ -1116,7 +1116,7 @@ STAmount LedgerEntrySet::rippleOwed (const uint160& uToAccountID, const uint160&
    }
    else
    {
-        saBalance.zero (uCurrencyID, uToAccountID);
+        saBalance.clear (uCurrencyID, uToAccountID);

        WriteLog (lsDEBUG, LedgerEntrySet) << "rippleOwed: No credit line between "
                                           << RippleAddress::createHumanAccountID (uFromAccountID)
@@ -1149,7 +1149,7 @@ STAmount LedgerEntrySet::rippleLimit (const uint160& uToAccountID, const uint160
    }
    else
    {
-        saLimit.zero (uCurrencyID, uToAccountID);
+        saLimit.clear (uCurrencyID, uToAccountID);
 #if 0
        // We could cut off coming here if we test for no line sooner.
        assert (false);
@@ -1244,7 +1244,7 @@ STAmount LedgerEntrySet::rippleHolds (const uint160& uAccountID, const uint160&

    if (!sleRippleState)
    {
-        saBalance.zero (uCurrencyID, uIssuerID);
+        saBalance.clear (uCurrencyID, uIssuerID);
    }
    else if (uAccountID > uIssuerID)
    {
@@ -1279,7 +1279,7 @@ STAmount LedgerEntrySet::accountHolds (const uint160& uAccountID, const uint160&

        if (saBalance < uReserve)
        {
-            saAmount.zero ();
+            saAmount.clear ();
        }
        else
        {
@@ -1525,8 +1525,8 @@ TER LedgerEntrySet::rippleCredit (const uint160& uSenderID, const uint160& uRece
        std::uint32_t  uFlags;

        // YYY Could skip this if rippling in reverse.
-        if (saBefore.isPositive ()                                                                              // Sender balance was positive.
-                && !saBalance.isPositive ()                                                                         // Sender is zero or negative.
+        if (saBefore > zero                                                                              // Sender balance was positive.
+                && saBalance <= zero                                                                         // Sender is zero or negative.
                && isSetBit ((uFlags = sleRippleState->getFieldU32 (sfFlags)), !bSenderHigh ? lsfLowReserve : lsfHighReserve) // Sender reserve is set.
                && !isSetBit (uFlags, !bSenderHigh ? lsfLowNoRipple : lsfHighNoRipple)
                && !sleRippleState->getFieldAmount (!bSenderHigh ? sfLowLimit : sfHighLimit)                        // Sender trust limit is 0.
@@ -1617,7 +1617,7 @@ TER LedgerEntrySet::accountSend (const uint160& uSenderID, const uint160& uRecei
 {
    TER terResult   = tesSUCCESS;

-    assert (!saAmount.isNegative ());
+    assert (saAmount >= zero);

    if (!saAmount || (uSenderID == uReceiverID))
    {
--- a/src/ripple_app/misc/NetworkOPs.cpp
+++ b/src/ripple_app/misc/NetworkOPs.cpp
@@ -2927,11 +2927,11 @@ void NetworkOPsImp::getBookPage (Ledger::pointer lpLedger, const uint160& uTaker
                        saOwnerFunds    = lesActive.accountHolds (uOfferOwnerID, uTakerGetsCurrencyID, uTakerGetsIssuerID);

                        // m_journal.info << boost::str(boost::format("getBookPage: saOwnerFunds=%s (new)") % saOwnerFunds.getFullText());
-                        if (saOwnerFunds.isNegative ())
+                        if (saOwnerFunds < zero)
                        {
                            // Treat negative funds as zero.

-                            saOwnerFunds.zero ();
+                            saOwnerFunds.clear ();
                        }
                    }
                }
@@ -2985,7 +2985,7 @@ void NetworkOPsImp::getBookPage (Ledger::pointer lpLedger, const uint160& uTaker

                umBalance[uOfferOwnerID]    = saOwnerFunds - saOwnerPays;

-                if (!saOwnerFunds.isZero () || uOfferOwnerID == uTakerID)
+                if (saOwnerFunds != zero || uOfferOwnerID == uTakerID)
                {
                    // Only provide funded offers and offers of the taker.
                    Json::Value& jvOf   = jvOffers.append (jvOffer);
--- a/src/ripple_app/paths/PathRequest.cpp
+++ b/src/ripple_app/paths/PathRequest.cpp
@@ -114,7 +114,7 @@ bool PathRequest::needsUpdate (bool newOnly, LedgerIndex index)
 bool PathRequest::isValid (RippleLineCache::ref crCache)
 {
    ScopedLockType sl (mLock);
-    bValid = raSrcAccount.isSet () && raDstAccount.isSet () && saDstAmount.isPositive ();
+    bValid = raSrcAccount.isSet () && raDstAccount.isSet () && saDstAmount > zero;
    Ledger::pointer lrLedger = crCache->getLedger ();

    if (bValid)
@@ -246,7 +246,7 @@ int PathRequest::parseJson (const Json::Value& jvParams, bool complete)
        if (!saDstAmount.bSetJson (jvParams["destination_amount"]) ||
                (saDstAmount.getCurrency ().isZero () && saDstAmount.getIssuer ().isNonZero ()) ||
                (saDstAmount.getCurrency () == CURRENCY_BAD) ||
-                !saDstAmount.isPositive ())
+                saDstAmount <= zero)
        {
            jvStatus = rpcError (rpcDST_AMT_MALFORMED);
            return PFR_PJ_INVALID;
--- a/src/ripple_app/paths/PathState.cpp
+++ b/src/ripple_app/paths/PathState.cpp
@@ -307,7 +307,7 @@ TER PathState::pushNode (
                    }
                    else if ((isSetBit (sleBck->getFieldU32 (sfFlags), lsfRequireAuth)
                             && !isSetBit (sleRippleState->getFieldU32 (sfFlags), (bHigh ? lsfHighAuth : lsfLowAuth)))
-                             && sleRippleState->getFieldAmount(sfBalance).isZero()) // CHECKME
+                             && sleRippleState->getFieldAmount(sfBalance) == zero) // CHECKME
                    {
                        WriteLog (lsWARNING, RippleCalc) << "pushNode: delay: can't receive IOUs from issuer without auth.";

@@ -319,7 +319,7 @@ TER PathState::pushNode (
                        STAmount    saOwed  = lesEntries.rippleOwed (pnCur.uAccountID, pnBck.uAccountID, pnCur.uCurrencyID);
                        STAmount    saLimit;

-                        if (!saOwed.isPositive ()
+                        if (saOwed <= zero
                                && -saOwed >= (saLimit = lesEntries.rippleLimit (pnCur.uAccountID, pnBck.uAccountID, pnCur.uCurrencyID)))
                        {
                            WriteLog (lsWARNING, RippleCalc) << boost::str (boost::format ("pushNode: dry: saOwed=%s saLimit=%s")
--- a/src/ripple_app/paths/Pathfinder.cpp
+++ b/src/ripple_app/paths/Pathfinder.cpp
@@ -104,7 +104,7 @@ Pathfinder::Pathfinder (RippleLineCache::ref cache,
        mLedger (cache->getLedger ()), mRLCache (cache)
 {

-    if (((mSrcAccountID == mDstAccountID) && (mSrcCurrencyID == mDstAmount.getCurrency ())) || mDstAmount.isZero ())
+    if ((mSrcAccountID == mDstAccountID && mSrcCurrencyID == mDstAmount.getCurrency ()) || mDstAmount == zero)
    {
        // no need to send to same account with same currency, must send non-zero
        bValid = false;
@@ -373,7 +373,7 @@ STPathSet Pathfinder::filterPaths(int iMaxPaths, STPath& extraPath)
                WriteLog (lsDEBUG, Pathfinder) << "Skipping a non-filling path: " << mCompletePaths[lqt.get<3> ()].getJson (0);
        }

-        if (remaining.isPositive ())
+        if (remaining > zero)
        {
            WriteLog (lsINFO, Pathfinder) << "Paths could not send " << remaining << " of " << mDstAmount;
        }
@@ -409,7 +409,7 @@ boost::unordered_set<uint160> usAccountSourceCurrencies (
        const STAmount& saBalance   = rspEntry->getBalance ();

        // Filter out non
-        if (saBalance.isPositive ()                             // Have IOUs to send.
+        if (saBalance > zero                             // Have IOUs to send.
                || (rspEntry->getLimitPeer ()                       // Peer extends credit.
                    && ((-saBalance) < rspEntry->getLimitPeer ()))) // Credit left.
        {
@@ -489,7 +489,7 @@ int Pathfinder::getPathsOut (RippleCurrency const& currencyID, const uint160& ac

        if (currencyID != rspEntry->getLimit ().getCurrency ())
            nothing ();
-        else if (!rspEntry->getBalance ().isPositive () &&
+        else if (rspEntry->getBalance () <= zero &&
                 (!rspEntry->getLimitPeer ()
                  || -rspEntry->getBalance () >= rspEntry->getLimitPeer ()
                  ||  (bAuthRequired && !rspEntry->getAuth ())))
@@ -657,7 +657,7 @@ void Pathfinder::addLink(
                    if ((uEndCurrency == rspEntry.getLimit().getCurrency()) &&
                        !currentPath.hasSeen(acctID, uEndCurrency, acctID))
                    { // path is for correct currency and has not been seen
-                        if (!rspEntry.getBalance().isPositive()
+                        if (rspEntry.getBalance() <= zero
                            && (!rspEntry.getLimitPeer()
                                || -rspEntry.getBalance() >= rspEntry.getLimitPeer()
                                || (bRequireAuth && !rspEntry.getAuth())))
--- a/src/ripple_app/paths/RippleCalc.cpp
+++ b/src/ripple_app/paths/RippleCalc.cpp
@@ -226,7 +226,7 @@ TER RippleCalc::calcNodeAdvance (
                    musUnfundedFound.insert(uOfferIndex);
                    continue;
                }
-                else if (!saTakerPays.isPositive () || !saTakerGets.isPositive ())
+                else if (saTakerPays <= zero || saTakerGets <= zero)
                {
                    // Offer has bad amounts. Offers should never have a bad amounts.

@@ -301,7 +301,7 @@ TER RippleCalc::calcNodeAdvance (

                saOfferFunds    = lesActive.accountFunds (uOfrOwnerID, saTakerGets); // Funds held.

-                if (!saOfferFunds.isPositive ())
+                if (saOfferFunds <= zero)
                {
                    // Offer is unfunded.
                    WriteLog (lsTRACE, RippleCalc) << "calcNodeAdvance: unfunded offer";
@@ -388,7 +388,7 @@ TER RippleCalc::calcNodeDeliverRev (
        bDirectRestart  = true;                     // Restart at same quality.

    // YYY Note this gets zeroed on each increment, ideally only on first increment, then it could be a limit on the forward pass.
-    saOutAct.zero (saOutReq);
+    saOutAct.clear (saOutReq);

    WriteLog (lsTRACE, RippleCalc) << boost::str (boost::format ("calcNodeDeliverRev> saOutAct=%s saOutReq=%s saPrvDlvReq=%s")
                                  % saOutAct
@@ -421,7 +421,8 @@ TER RippleCalc::calcNodeDeliverRev (
        STAmount&       saTakerGets     = pnCur.saTakerGets;
        STAmount&       saRateMax       = pnCur.saRateMax;

-        terResult   = calcNodeAdvance (uNode, psCur, bMultiQuality || saOutAct.isZero(), true);      // If needed, advance to next funded offer.
+        terResult   = calcNodeAdvance (uNode, psCur, bMultiQuality || saOutAct == zero, true);
+        // If needed, advance to next funded offer.

        if (tesSUCCESS != terResult || !uOfferIndex)
        {
@@ -595,7 +596,7 @@ TER RippleCalc::calcNodeDeliverRev (
        STAmount    saTakerGetsNew  = saTakerGets - saOutPassAct;
        STAmount    saTakerPaysNew  = saTakerPays - saInPassAct;

-        if (saTakerPaysNew.isNegative () || saTakerGetsNew.isNegative ())
+        if (saTakerPaysNew < zero || saTakerGetsNew < zero)
        {
            WriteLog (lsWARNING, RippleCalc) << boost::str (boost::format ("calcNodeDeliverRev: NEGATIVE: saTakerPaysNew=%s saTakerGetsNew=%s")
                                             % saTakerPaysNew % saTakerGetsNew);
@@ -683,8 +684,8 @@ TER RippleCalc::calcNodeDeliverFwd (
    else
        bDirectRestart  = true;                     // Restart at same quality.

-    saInAct.zero (saInReq);
-    saInFees.zero (saInReq);
+    saInAct.clear (saInReq);
+    saInFees.clear (saInReq);

    int loopCount = 0;

@@ -700,7 +701,8 @@ TER RippleCalc::calcNodeDeliverFwd (
        }

        // Determine values for pass to adjust saInAct, saInFees, and saCurDeliverAct
-        terResult   = calcNodeAdvance (uNode, psCur, bMultiQuality || saInAct.isZero(), false);             // If needed, advance to next funded offer.
+        terResult   = calcNodeAdvance (uNode, psCur, bMultiQuality || saInAct == zero, false);
+        // If needed, advance to next funded offer.

        if (tesSUCCESS != terResult)
        {
@@ -738,8 +740,8 @@ TER RippleCalc::calcNodeDeliverFwd (
            STAmount    saInTotal       = STAmount::mulRound (saInFunded, saInFeeRate, true);               // Offer maximum in with fees.
            STAmount    saInRemaining   = saInReq - saInAct - saInFees;

-            if (saInRemaining.isNegative())
-                saInRemaining.zero();
+            if (saInRemaining < zero)
+                saInRemaining.clear();

            STAmount    saInSum         = std::min (saInTotal, saInRemaining);                              // In limited by remaining.
            STAmount    saInPassAct     = std::min (saTakerPays, STAmount::divRound (saInSum, saInFeeRate, true));     // In without fees.
@@ -766,7 +768,7 @@ TER RippleCalc::calcNodeDeliverFwd (
                                          % saInPassAct
                                          % saOutPassMax);

-            if (!saTakerPays || !saInSum.isPositive()) // FIXME: We remove an offer if WE didn't want anything out of it?
+            if (!saTakerPays || saInSum <= zero) // FIXME: We remove an offer if WE didn't want anything out of it?
            {
                WriteLog (lsDEBUG, RippleCalc) << "calcNodeDeliverFwd: Microscopic offer unfunded.";

@@ -883,7 +885,7 @@ TER RippleCalc::calcNodeDeliverFwd (
            STAmount    saTakerGetsNew  = saTakerGets - saOutPassAct;
            STAmount    saTakerPaysNew  = saTakerPays - saInPassAct;

-            if (saTakerPaysNew.isNegative () || saTakerGetsNew.isNegative ())
+            if (saTakerPaysNew < zero || saTakerGetsNew < zero)
            {
                WriteLog (lsWARNING, RippleCalc) << boost::str (boost::format ("calcNodeDeliverFwd: NEGATIVE: saTakerPaysNew=%s saTakerGetsNew=%s")
                                                 % saTakerPaysNew % saTakerGetsNew);
@@ -899,7 +901,7 @@ TER RippleCalc::calcNodeDeliverFwd (

            lesActive.entryModify (sleOffer);

-            if ((saOutPassAct == saOutFunded) || saTakerGetsNew.isZero())
+            if (saOutPassAct == saOutFunded || saTakerGetsNew == zero)
            {
                // Offer became unfunded.

@@ -1046,12 +1048,12 @@ void RippleCalc::calcNodeRipple (
                                   % saPrvAct
                                   % saCurAct);

-    assert (saCurReq.isPositive ()); // FIXME: saCurReq was zero
+    assert (saCurReq > zero); // FIXME: saCurReq was zero
    assert (saPrvReq.getCurrency () == saCurReq.getCurrency ());
    assert (saPrvReq.getCurrency () == saPrvAct.getCurrency ());
    assert (saPrvReq.getIssuer () == saPrvAct.getIssuer ());

-    const bool      bPrvUnlimited   = saPrvReq.isNegative ();
+    const bool      bPrvUnlimited   = saPrvReq < zero;
    const STAmount  saPrv           = bPrvUnlimited ? STAmount (saPrvReq) : saPrvReq - saPrvAct;
    const STAmount  saCur           = saCurReq - saCurAct;

@@ -1187,11 +1189,11 @@ TER RippleCalc::calcNodeAccountRev (const unsigned int uNode, PathState& psCur,
                                   % saPrvLimit);

    // Previous can redeem the owed IOUs it holds.
-    const STAmount  saPrvRedeemReq  = saPrvOwed.isPositive () ? saPrvOwed : STAmount (saPrvOwed.getCurrency (), saPrvOwed.getIssuer ());
+    const STAmount  saPrvRedeemReq  = (saPrvOwed > zero) ? saPrvOwed : STAmount (saPrvOwed.getCurrency (), saPrvOwed.getIssuer ());
    STAmount&       saPrvRedeemAct  = pnPrv.saRevRedeem;

    // Previous can issue up to limit minus whatever portion of limit already used (not including redeemable amount).
-    const STAmount  saPrvIssueReq   = saPrvOwed.isNegative () ? saPrvLimit + saPrvOwed : saPrvLimit;
+    const STAmount  saPrvIssueReq   = (saPrvOwed < zero) ? saPrvLimit + saPrvOwed : saPrvLimit;
    STAmount&       saPrvIssueAct   = pnPrv.saRevIssue;

    // For !bPrvAccount
@@ -1222,7 +1224,7 @@ TER RippleCalc::calcNodeAccountRev (const unsigned int uNode, PathState& psCur,

    assert (!saCurRedeemReq || (-saNxtOwed) >= saCurRedeemReq); // Current redeem req can't be more than IOUs on hand.
    assert (!saCurIssueReq                  // If not issuing, fine.
-            || !saNxtOwed.isNegative ()         // saNxtOwed >= 0: Sender not holding next IOUs, saNxtOwed < 0: Sender holding next IOUs.
+            || saNxtOwed >= zero         // saNxtOwed >= 0: Sender not holding next IOUs, saNxtOwed < 0: Sender holding next IOUs.
            || -saNxtOwed == saCurRedeemReq);   // If issue req, then redeem req must consume all owed.

    if (!uNode)
@@ -1262,11 +1264,11 @@ TER RippleCalc::calcNodeAccountRev (const unsigned int uNode, PathState& psCur,
            }
            else
            {
-                saPrvRedeemAct.zero (saPrvRedeemReq);
+                saPrvRedeemAct.clear (saPrvRedeemReq);
            }

            // Calculate issuing.
-            saPrvIssueAct.zero (saPrvIssueReq);
+            saPrvIssueAct.clear (saPrvIssueReq);

            if (saCurWantedReq != saCurWantedAct        // Need more.
                    && saPrvIssueReq)                       // Will accept IOUs from prevous.
@@ -1290,8 +1292,8 @@ TER RippleCalc::calcNodeAccountRev (const unsigned int uNode, PathState& psCur,
        else
        {
            // ^|account --> ACCOUNT --> account
-            saPrvRedeemAct.zero (saPrvRedeemReq);
-            saPrvIssueAct.zero (saPrvIssueReq);
+            saPrvRedeemAct.clear (saPrvRedeemReq);
+            saPrvIssueAct.clear (saPrvIssueReq);

            // redeem (part 1) -> redeem
            if (saCurRedeemReq                          // Next wants IOUs redeemed.
@@ -1364,12 +1366,12 @@ TER RippleCalc::calcNodeAccountRev (const unsigned int uNode, PathState& psCur,
        // Note: deliver is always issue as ACCOUNT is the issuer for the offer input.
        WriteLog (lsTRACE, RippleCalc) << boost::str (boost::format ("calcNodeAccountRev: account --> ACCOUNT --> offer"));

-        saPrvRedeemAct.zero (saPrvRedeemReq);
-        saPrvIssueAct.zero (saPrvIssueReq);
+        saPrvRedeemAct.clear (saPrvRedeemReq);
+        saPrvIssueAct.clear (saPrvIssueReq);

        // redeem -> deliver/issue.
-        if (saPrvOwed.isPositive ()                 // Previous has IOUs to redeem.
-                && saCurDeliverReq)                     // Need some issued.
+        if (saPrvOwed > zero                    // Previous has IOUs to redeem.
+            && saCurDeliverReq)                 // Need some issued.
        {
            // Rate : 1.0 : transfer_rate
            calcNodeRipple (QUALITY_ONE, lesActive.rippleTransferRate (uCurAccountID), saPrvRedeemReq, saCurDeliverReq, saPrvRedeemAct, saCurDeliverAct, uRateMax);
@@ -1407,14 +1409,15 @@ TER RippleCalc::calcNodeAccountRev (const unsigned int uNode, PathState& psCur,
                                           % psCur.saOutAct
                                           % psCur.saOutReq);

-            if (!saCurWantedReq.isPositive ())
+            if (saCurWantedReq <= zero)
            {
                // TEMPORARY emergency fix
                WriteLog (lsFATAL, RippleCalc) << "CurWantReq was not positive";
                return tefEXCEPTION;
            }

-            assert (saCurWantedReq.isPositive ()); // FIXME: We got one of these
+            assert (saCurWantedReq > zero); // FIXME: We got one of these
+            // TR notes: can only be a race condition if true!

            // Rate: quality in : 1.0
            calcNodeRipple (uQualityIn, QUALITY_ONE, saPrvDeliverReq, saCurWantedReq, saPrvDeliverAct, saCurWantedAct, uRateMax);
@@ -1576,7 +1579,7 @@ TER RippleCalc::calcNodeAccountFwd (

            saCurRedeemAct      = saCurRedeemReq;

-            if (!psCur.saInReq.isNegative ())
+            if (psCur.saInReq >= zero)
            {
                // Limit by send max.
                saCurRedeemAct      = std::min (saCurRedeemAct, psCur.saInReq - psCur.saInAct);
@@ -1588,7 +1591,7 @@ TER RippleCalc::calcNodeAccountFwd (
                                  ? saCurIssueReq
                                  : STAmount (saCurIssueReq);

-            if (!!saCurIssueAct && !psCur.saInReq.isNegative ())
+            if (!!saCurIssueAct && psCur.saInReq >= zero)
            {
                // Limit by send max.
                saCurIssueAct       = std::min (saCurIssueAct, psCur.saInReq - psCur.saInAct - saCurRedeemAct);
@@ -1640,8 +1643,8 @@ TER RippleCalc::calcNodeAccountFwd (
            // account --> ACCOUNT --> account
            WriteLog (lsTRACE, RippleCalc) << boost::str (boost::format ("calcNodeAccountFwd: account --> ACCOUNT --> account"));

-            saCurRedeemAct.zero (saCurRedeemReq);
-            saCurIssueAct.zero (saCurIssueReq);
+            saCurRedeemAct.clear (saCurRedeemReq);
+            saCurIssueAct.clear (saCurIssueReq);

            // Previous redeem part 1: redeem -> redeem
            if (saPrvRedeemReq && saCurRedeemReq)           // Previous wants to redeem.
@@ -1696,7 +1699,7 @@ TER RippleCalc::calcNodeAccountFwd (
            // Non-XRP, current node is the issuer.
            WriteLog (lsTRACE, RippleCalc) << boost::str (boost::format ("calcNodeAccountFwd: account --> ACCOUNT --> offer"));

-            saCurDeliverAct.zero (saCurDeliverReq);
+            saCurDeliverAct.clear (saCurDeliverReq);

            // redeem -> issue/deliver.
            // Previous wants to redeem.
@@ -1727,7 +1730,7 @@ TER RippleCalc::calcNodeAccountFwd (
            saCurDeliverAct     = saCurDeliverReq;

            // If limited, then limit by send max and available.
-            if (!psCur.saInReq.isNegative ())
+            if (psCur.saInReq >= zero)
            {
                // Limit by send max.
                saCurDeliverAct     = std::min (saCurDeliverAct, psCur.saInReq - psCur.saInAct);
@@ -1784,8 +1787,8 @@ TER RippleCalc::calcNodeAccountFwd (
            // offer --> ACCOUNT --> account
            WriteLog (lsTRACE, RippleCalc) << boost::str (boost::format ("calcNodeAccountFwd: offer --> ACCOUNT --> account"));

-            saCurRedeemAct.zero (saCurRedeemReq);
-            saCurIssueAct.zero (saCurIssueReq);
+            saCurRedeemAct.clear (saCurRedeemReq);
+            saCurIssueAct.clear (saCurIssueReq);

            // deliver -> redeem
            if (saPrvDeliverReq && saCurRedeemReq)          // Previous wants to deliver and can current redeem.
@@ -1817,7 +1820,7 @@ TER RippleCalc::calcNodeAccountFwd (
        // deliver/redeem -> deliver/issue.
        WriteLog (lsTRACE, RippleCalc) << boost::str (boost::format ("calcNodeAccountFwd: offer --> ACCOUNT --> offer"));

-        saCurDeliverAct.zero (saCurDeliverReq);
+        saCurDeliverAct.clear (saCurDeliverReq);

        if (saPrvDeliverReq                                 // Previous wants to deliver
                && saCurIssueReq)                               // Current wants issue.
@@ -1937,10 +1940,10 @@ void RippleCalc::pathNext (PathState::ref psrCur, const bool bMultiQuality, cons
    {
        PathState::Node& pnCur   = psrCur->vpnNodes[uIndex];

-        pnCur.saRevRedeem.zero ();
-        pnCur.saRevIssue.zero ();
-        pnCur.saRevDeliver.zero ();
-        pnCur.saFwdDeliver.zero ();
+        pnCur.saRevRedeem.clear ();
+        pnCur.saRevIssue.clear ();
+        pnCur.saRevDeliver.clear ();
+        pnCur.saFwdDeliver.clear ();
    }

    psrCur->terStatus   = calcNodeRev (uLast, *psrCur, bMultiQuality);
@@ -2139,12 +2142,12 @@ TER RippleCalc::rippleCalc (
                pspCur->saInAct     = saMaxAmountAct;                       // Update to current amount processed.
                pspCur->saOutAct    = saDstAmountAct;

-                CondLog (pspCur->saInReq.isPositive () && pspCur->saInAct >= pspCur->saInReq, lsWARNING, RippleCalc)
+                CondLog (pspCur->saInReq > zero && pspCur->saInAct >= pspCur->saInReq, lsWARNING, RippleCalc)
                        << boost::str (boost::format ("rippleCalc: DONE: saInAct=%s saInReq=%s")
                                       % pspCur->saInAct
                                       % pspCur->saInReq);

-                assert (pspCur->saInReq.isNegative () || pspCur->saInAct < pspCur->saInReq); // Error if done.
+                assert (pspCur->saInReq < zero || pspCur->saInAct < pspCur->saInReq); // Error if done.

                CondLog (pspCur->saOutAct >= pspCur->saOutReq, lsWARNING, RippleCalc)
                        << boost::str (boost::format ("rippleCalc: ALREADY DONE: saOutAct=%s saOutReq=%s")
--- a/src/ripple_app/rpc/RPCHandler.cpp
+++ b/src/ripple_app/rpc/RPCHandler.cpp
@@ -1674,7 +1674,7 @@ Json::Value RPCHandler::doRipplePathFind (Json::Value params, Resource::Charge&
        // Parse saDstAmount.
        !params.isMember ("destination_amount")
        || !saDstAmount.bSetJson (params["destination_amount"])
-        || !saDstAmount.isPositive()
+        || saDstAmount <= zero
        || (!!saDstAmount.getCurrency () && (!saDstAmount.getIssuer () || ACCOUNT_ONE == saDstAmount.getIssuer ())))
    {
        WriteLog (lsINFO, RPCHandler) << "Bad destination_amount.";
--- a/src/ripple_app/transactors/OfferCreateTransactor.cpp
+++ b/src/ripple_app/transactors/OfferCreateTransactor.cpp
@@ -53,7 +53,7 @@ bool OfferCreateTransactor::isValidOffer (
        return false;
    }

-    if (!saOfferGets.isPositive () || !saOfferPays.isPositive ())
+    if (saOfferGets <= zero || saOfferPays <= zero)
    {
        // Offer has bad amounts. Consider offer expired. Delete it.
        m_journal.warning << "isValidOffer: BAD OFFER:" <<
@@ -70,7 +70,7 @@ bool OfferCreateTransactor::isValidOffer (

    saOfferFunds = mEngine->view ().accountFunds (uOfferOwnerID, saOfferPays);

-    if (!saOfferFunds.isPositive ())
+    if (saOfferFunds <= zero)
    {
        // Offer is unfunded, possibly due to previous balance action.
        m_journal.debug << "isValidOffer: offer unfunded: delete";
@@ -107,7 +107,7 @@ bool OfferCreateTransactor::canCross (
    bool& isUnfunded,
    TER& terResult) const
 {
-    if (!saTakerFunds.isPositive ())
+    if (saTakerFunds <= zero)
    {
        // Taker is out of funds. Don't create the offer.
        isUnfunded = true;
@@ -115,7 +115,7 @@ bool OfferCreateTransactor::canCross (
        return false;
    }

-    if (!saSubTakerPays.isPositive() || !saSubTakerGets.isPositive())
+    if (saSubTakerPays <= zero || saSubTakerGets <= zero)
    {
        // Offer is completely consumed
        terResult = tesSUCCESS;
@@ -201,8 +201,8 @@ bool OfferCreateTransactor::applyOffer (
 {
    saOfferGets.throwComparable (saTakerFunds);

-    assert (saOfferFunds.isPositive () && saTakerFunds.isPositive ()); // Both must have funds.
-    assert (saOfferGets.isPositive () && saOfferPays.isPositive ()); // Must not be a null offer.
+    assert (saOfferFunds > zero && saTakerFunds > zero); // Both must have funds.
+    assert (saOfferGets > zero && saOfferPays > zero); // Must not be a null offer.

    // Available = limited by funds.
    // Limit offerer funds available, by transfer fees.
@@ -292,7 +292,7 @@ bool OfferCreateTransactor::applyOffer (
                              ? saTakerFunds - saTakerPaid // Not enough funds to cover fee, stiff issuer the rounding error.
                              : saTakerCost - saTakerPaid;
        WriteLog (lsINFO, STAmount) << "applyOffer: saTakerIssuerFee=" << saTakerIssuerFee.getFullText ();
-        assert (!saTakerIssuerFee.isNegative ());
+        assert (saTakerIssuerFee >= zero);
    }

    if (uOfferPaysRate == QUALITY_ONE)
@@ -600,7 +600,7 @@ TER OfferCreateTransactor::takeOffers (
                // TODO check the synthetic case here (to ensure there
                //      is no corruption)

-                if (!saOfferPays.isPositive () || !saOfferGets.isPositive ())
+                if (saOfferPays <= zero || saOfferGets <= zero)
                {
                    m_journal.warning <<
                        "takeOffers: ILLEGAL OFFER RESULT.";
@@ -811,7 +811,7 @@ TER OfferCreateTransactor::doApply ()

        terResult   = temBAD_OFFER;
    }
-    else if (!saTakerPays.isPositive () || !saTakerGets.isPositive ())
+    else if (saTakerPays <= zero || saTakerGets <= zero)
    {
        m_journal.warning <<
            "Malformed offer: bad amount";
@@ -840,7 +840,7 @@ TER OfferCreateTransactor::doApply ()

        terResult   = temBAD_ISSUER;
    }
-    else if (!lesActive.accountFunds (mTxnAccountID, saTakerGets).isPositive ())
+    else if (lesActive.accountFunds (mTxnAccountID, saTakerGets) <= zero)
    {
        m_journal.warning <<
            "delay: Offers must be at least partially funded.";
@@ -1019,7 +1019,7 @@ TER OfferCreateTransactor::doApply ()
        // nothing to do
        nothing ();
    }
-    else if (saTakerPays.isNegative () || saTakerGets.isNegative ())
+    else if (saTakerPays < zero || saTakerGets < zero)
    {
        // If ledger is not final, can vote no.
        // When we are processing an open ledger, failures are local and we charge no fee;
@@ -1033,11 +1033,11 @@ TER OfferCreateTransactor::doApply ()
        lesActive.swapWith (lesCheckpoint); // Restore with just fees paid.
    }
    else if (
-        !saTakerPays.isPositive()                                           // Wants nothing more.
-        || !saTakerGets.isPositive()                                        // Offering nothing more.
-        || bImmediateOrCancel                                               // Do not persist.
-        || !lesActive.accountFunds (mTxnAccountID, saTakerGets).isPositive () // Not funded.
-        || bUnfunded)                                                       // Consider unfunded.
+        saTakerPays <= zero                                             // Wants nothing more.
+        || saTakerGets <= zero                                          // Offering nothing more.
+        || bImmediateOrCancel                                           // Do not persist.
+        || lesActive.accountFunds (mTxnAccountID, saTakerGets) <= zero  // Not funded.
+        || bUnfunded)                                                   // Consider unfunded.
    {
        // Complete as is.
        nothing ();
--- a/src/ripple_app/transactors/PaymentTransactor.cpp
+++ b/src/ripple_app/transactors/PaymentTransactor.cpp
@@ -38,7 +38,7 @@ TER PaymentTransactor::doApply ()
                                        mTxnAccountID,
                                        saDstAmount.getMantissa (),
                                        saDstAmount.getExponent (),
-                                        saDstAmount.isNegative ());
+                                        saDstAmount < zero);
    uint160 const uSrcCurrency = saMaxAmount.getCurrency ();
    uint160 const uDstCurrency = saDstAmount.getCurrency ();
    bool const bXRPDirect = uSrcCurrency.isZero () && uDstCurrency.isZero ();
@@ -64,14 +64,14 @@ TER PaymentTransactor::doApply ()

        return temDST_NEEDED;
    }
-    else if (bMax && !saMaxAmount.isPositive ())
+    else if (bMax && saMaxAmount <= zero)
    {
        m_journal.trace <<
            "Malformed transaction: bad max amount: " << saMaxAmount.getFullText ();

        return temBAD_AMOUNT;
    }
-    else if (!saDstAmount.isPositive ())
+    else if (saDstAmount <= zero)
    {
        m_journal.trace <<
            "Malformed transaction: bad dst amount: " << saDstAmount.getFullText ();
--- a/src/ripple_app/transactors/RegularKeySetTransactor.cpp
+++ b/src/ripple_app/transactors/RegularKeySetTransactor.cpp
@@ -45,7 +45,7 @@ TER RegularKeySetTransactor::doApply ()
        return temINVALID_FLAG;
    }

-    if (mFeeDue.isZero ())
+    if (mFeeDue == zero)
    {
        mTxnAccount->setFlag (lsfPasswordSpent);
    }
--- a/src/ripple_app/transactors/Transactor.cpp
+++ b/src/ripple_app/transactors/Transactor.cpp
@@ -116,7 +116,7 @@ TER Transactor::payFee ()
        return telINSUF_FEE_P;
    }

-    if (saPaid.isNegative () || !saPaid.isNative ())
+    if (saPaid < zero || !saPaid.isNative ())
        return temBAD_FEE;

    if (!saPaid) return tesSUCCESS;
--- a/src/ripple_app/transactors/TrustSetTransactor.cpp
+++ b/src/ripple_app/transactors/TrustSetTransactor.cpp
@@ -73,7 +73,7 @@ TER TrustSetTransactor::doApply ()
        return temBAD_LIMIT;
    }

-    if (saLimitAmount.isNegative ())
+    if (saLimitAmount < zero)
    {
        m_journal.trace <<
            "Malformed transaction: Negative credit limit.";
@@ -233,7 +233,7 @@ TER TrustSetTransactor::doApply ()
        std::uint32_t const uFlagsIn (sleRippleState->getFieldU32 (sfFlags));
        std::uint32_t uFlagsOut (uFlagsIn);

-        if (bSetNoRipple && !bClearNoRipple && (bHigh ? saHighBalance : saLowBalance).isGEZero())
+        if (bSetNoRipple && !bClearNoRipple && (bHigh ? saHighBalance : saLowBalance) >= zero)
        {
            uFlagsOut           |= (bHigh ? lsfHighNoRipple : lsfLowNoRipple);
        }
@@ -249,12 +249,12 @@ TER TrustSetTransactor::doApply ()

        bool const  bLowReserveSet      = uLowQualityIn || uLowQualityOut ||
                                          isSetBit (uFlagsOut, lsfLowNoRipple) ||
-                                          !!saLowLimit || saLowBalance.isPositive ();
+                                          !!saLowLimit || saLowBalance > zero;
        bool const  bLowReserveClear    = !bLowReserveSet;

        bool const  bHighReserveSet     = uHighQualityIn || uHighQualityOut ||
                                          isSetBit (uFlagsOut, lsfHighNoRipple) ||
-                                          !!saHighLimit || saHighBalance.isPositive ();
+                                          !!saHighLimit || saHighBalance > zero;
        bool const  bHighReserveClear   = !bHighReserveSet;

        bool const  bDefault            = bLowReserveClear && bHighReserveClear;
--- a/src/ripple_basics/ripple_basics.h
+++ b/src/ripple_basics/ripple_basics.h
@@ -27,6 +27,10 @@

 #include <atomic>
 #include "../../beast/beast/cxx14/memory.h"
+#include "../../beast/beast/utility/Zero.h"
+
+using beast::zero;
+using beast::Zero;

 #ifndef  RIPPLE_TRACK_MUTEXES
 # define RIPPLE_TRACK_MUTEXES 0
--- a/src/ripple_data/protocol/STAmount.cpp
+++ b/src/ripple_data/protocol/STAmount.cpp
@@ -482,7 +482,7 @@ void STAmount::add (Serializer& s) const
    }
    else
    {
-        if (isZero ())
+        if (*this == zero)
            s.add64 (cNotNative);
        else if (mIsNegative) // 512 = not native
            s.add64 (mValue | (static_cast<std::uint64_t> (mOffset + 512 + 97) << (64 - 10)));
@@ -625,7 +625,8 @@ std::string STAmount::getRaw () const
 std::string STAmount::getText () const
 {
    // keep full internal accuracy, but make more human friendly if posible
-    if (isZero ()) return "0";
+    if (*this == zero)
+        return "0";

    if (mIsNative)
    {
@@ -821,9 +822,10 @@ STAmount operator+ (const STAmount& v1, const STAmount& v2)
 {
    v1.throwComparable (v2);

-    if (v2.isZero ()) return v1;
+    if (v2 == zero)
+        return v1;

-    if (v1.isZero ())
+    if (v1 == zero)
    {
        // Result must be in terms of v1 currency and issuer.
        return STAmount (v1.getFName (), v1.mCurrency, v1.mIssuer, v2.mValue, v2.mOffset, v2.mIsNegative);
@@ -867,7 +869,8 @@ STAmount operator- (const STAmount& v1, const STAmount& v2)
 {
    v1.throwComparable (v2);

-    if (v2.isZero ()) return v1;
+    if (v2 == zero)
+        return v1;

    if (v2.mIsNative)
    {
@@ -908,10 +911,10 @@ STAmount operator- (const STAmount& v1, const STAmount& v2)

 STAmount STAmount::divide (const STAmount& num, const STAmount& den, const uint160& uCurrencyID, const uint160& uIssuerID)
 {
-    if (den.isZero ())
+    if (den == zero)
        throw std::runtime_error ("division by zero");

-    if (num.isZero ())
+    if (num == zero)
        return STAmount (uCurrencyID, uIssuerID);

    std::uint64_t numVal = num.mValue, denVal = den.mValue;
@@ -951,7 +954,7 @@ STAmount STAmount::divide (const STAmount& num, const STAmount& den, const uint1

 STAmount STAmount::multiply (const STAmount& v1, const STAmount& v2, const uint160& uCurrencyID, const uint160& uIssuerID)
 {
-    if (v1.isZero () || v2.isZero ())
+    if (v1 == zero || v2 == zero)
        return STAmount (uCurrencyID, uIssuerID);

    if (v1.mIsNative && v2.mIsNative && uCurrencyID.isZero ())
@@ -1018,14 +1021,14 @@ STAmount STAmount::multiply (const STAmount& v1, const STAmount& v2, const uint1
 // Zero is returned if the offer is worthless.
 std::uint64_t STAmount::getRate (const STAmount& offerOut, const STAmount& offerIn)
 {
-    if (offerOut.isZero ())
+    if (offerOut == zero)
        return 0;

    try
    {
        STAmount r = divide (offerIn, offerOut, CURRENCY_ONE, ACCOUNT_ONE);

-        if (r.isZero ()) // offer is too good
+        if (r == zero) // offer is too good
            return 0;

        assert ((r.getExponent () >= -100) && (r.getExponent () <= 155));
@@ -1055,7 +1058,7 @@ STAmount STAmount::setRate (std::uint64_t rate)
 STAmount STAmount::getPay (const STAmount& offerOut, const STAmount& offerIn, const STAmount& needed)
 {
    // Someone wants to get (needed) out of the offer, how much should they pay in?
-    if (offerOut.isZero ())
+    if (offerOut == zero)
        return STAmount (offerIn.getCurrency (), offerIn.getIssuer ());

    if (needed >= offerOut)
@@ -1289,127 +1292,127 @@ public:
    {
        testcase ("native currency");

-        STAmount zero, one (1), hundred (100);
+        STAmount zeroSt, one (1), hundred (100);

-        unexpected (serializeAndDeserialize (zero) != zero, "STAmount fail");
+        unexpected (serializeAndDeserialize (zeroSt) != zeroSt, "STAmount fail");

        unexpected (serializeAndDeserialize (one) != one, "STAmount fail");

        unexpected (serializeAndDeserialize (hundred) != hundred, "STAmount fail");

-        unexpected (!zero.isNative (), "STAmount fail");
+        unexpected (!zeroSt.isNative (), "STAmount fail");

        unexpected (!hundred.isNative (), "STAmount fail");

-        unexpected (!zero.isZero (), "STAmount fail");
+        unexpected (zeroSt != zero, "STAmount fail");

-        unexpected (one.isZero (), "STAmount fail");
+        unexpected (one == zero, "STAmount fail");

-        unexpected (hundred.isZero (), "STAmount fail");
+        unexpected (hundred == zero, "STAmount fail");

-        unexpected ((zero < zero), "STAmount fail");
+        unexpected ((zeroSt < zeroSt), "STAmount fail");

-        unexpected (! (zero < one), "STAmount fail");
+        unexpected (! (zeroSt < one), "STAmount fail");

-        unexpected (! (zero < hundred), "STAmount fail");
+        unexpected (! (zeroSt < hundred), "STAmount fail");

-        unexpected ((one < zero), "STAmount fail");
+        unexpected ((one < zeroSt), "STAmount fail");

        unexpected ((one < one), "STAmount fail");

        unexpected (! (one < hundred), "STAmount fail");

-        unexpected ((hundred < zero), "STAmount fail");
+        unexpected ((hundred < zeroSt), "STAmount fail");

        unexpected ((hundred < one), "STAmount fail");

        unexpected ((hundred < hundred), "STAmount fail");

-        unexpected ((zero > zero), "STAmount fail");
+        unexpected ((zeroSt > zeroSt), "STAmount fail");

-        unexpected ((zero > one), "STAmount fail");
+        unexpected ((zeroSt > one), "STAmount fail");

-        unexpected ((zero > hundred), "STAmount fail");
+        unexpected ((zeroSt > hundred), "STAmount fail");

-        unexpected (! (one > zero), "STAmount fail");
+        unexpected (! (one > zeroSt), "STAmount fail");

        unexpected ((one > one), "STAmount fail");

        unexpected ((one > hundred), "STAmount fail");

-        unexpected (! (hundred > zero), "STAmount fail");
+        unexpected (! (hundred > zeroSt), "STAmount fail");

        unexpected (! (hundred > one), "STAmount fail");

        unexpected ((hundred > hundred), "STAmount fail");

-        unexpected (! (zero <= zero), "STAmount fail");
+        unexpected (! (zeroSt <= zeroSt), "STAmount fail");

-        unexpected (! (zero <= one), "STAmount fail");
+        unexpected (! (zeroSt <= one), "STAmount fail");

-        unexpected (! (zero <= hundred), "STAmount fail");
+        unexpected (! (zeroSt <= hundred), "STAmount fail");

-        unexpected ((one <= zero), "STAmount fail");
+        unexpected ((one <= zeroSt), "STAmount fail");

        unexpected (! (one <= one), "STAmount fail");

        unexpected (! (one <= hundred), "STAmount fail");

-        unexpected ((hundred <= zero), "STAmount fail");
+        unexpected ((hundred <= zeroSt), "STAmount fail");

        unexpected ((hundred <= one), "STAmount fail");

        unexpected (! (hundred <= hundred), "STAmount fail");

-        unexpected (! (zero >= zero), "STAmount fail");
+        unexpected (! (zeroSt >= zeroSt), "STAmount fail");

-        unexpected ((zero >= one), "STAmount fail");
+        unexpected ((zeroSt >= one), "STAmount fail");

-        unexpected ((zero >= hundred), "STAmount fail");
+        unexpected ((zeroSt >= hundred), "STAmount fail");

-        unexpected (! (one >= zero), "STAmount fail");
+        unexpected (! (one >= zeroSt), "STAmount fail");

        unexpected (! (one >= one), "STAmount fail");

        unexpected ((one >= hundred), "STAmount fail");

-        unexpected (! (hundred >= zero), "STAmount fail");
+        unexpected (! (hundred >= zeroSt), "STAmount fail");

        unexpected (! (hundred >= one), "STAmount fail");

        unexpected (! (hundred >= hundred), "STAmount fail");

-        unexpected (! (zero == zero), "STAmount fail");
+        unexpected (! (zeroSt == zeroSt), "STAmount fail");

-        unexpected ((zero == one), "STAmount fail");
+        unexpected ((zeroSt == one), "STAmount fail");

-        unexpected ((zero == hundred), "STAmount fail");
+        unexpected ((zeroSt == hundred), "STAmount fail");

-        unexpected ((one == zero), "STAmount fail");
+        unexpected ((one == zeroSt), "STAmount fail");

        unexpected (! (one == one), "STAmount fail");

        unexpected ((one == hundred), "STAmount fail");

-        unexpected ((hundred == zero), "STAmount fail");
+        unexpected ((hundred == zeroSt), "STAmount fail");

        unexpected ((hundred == one), "STAmount fail");

        unexpected (! (hundred == hundred), "STAmount fail");

-        unexpected ((zero != zero), "STAmount fail");
+        unexpected ((zeroSt != zeroSt), "STAmount fail");

-        unexpected (! (zero != one), "STAmount fail");
+        unexpected (! (zeroSt != one), "STAmount fail");

-        unexpected (! (zero != hundred), "STAmount fail");
+        unexpected (! (zeroSt != hundred), "STAmount fail");

-        unexpected (! (one != zero), "STAmount fail");
+        unexpected (! (one != zeroSt), "STAmount fail");

        unexpected ((one != one), "STAmount fail");

        unexpected (! (one != hundred), "STAmount fail");

-        unexpected (! (hundred != zero), "STAmount fail");
+        unexpected (! (hundred != zeroSt), "STAmount fail");

        unexpected (! (hundred != one), "STAmount fail");

@@ -1439,129 +1442,129 @@ public:
    {
        testcase ("custom currency");

-        STAmount zero (CURRENCY_ONE, ACCOUNT_ONE), one (CURRENCY_ONE, ACCOUNT_ONE, 1), hundred (CURRENCY_ONE, ACCOUNT_ONE, 100);
+        STAmount zeroSt (CURRENCY_ONE, ACCOUNT_ONE), one (CURRENCY_ONE, ACCOUNT_ONE, 1), hundred (CURRENCY_ONE, ACCOUNT_ONE, 100);

        serializeAndDeserialize (one).getRaw ();

-        unexpected (serializeAndDeserialize (zero) != zero, "STAmount fail");
+        unexpected (serializeAndDeserialize (zeroSt) != zeroSt, "STAmount fail");

        unexpected (serializeAndDeserialize (one) != one, "STAmount fail");

        unexpected (serializeAndDeserialize (hundred) != hundred, "STAmount fail");

-        unexpected (zero.isNative (), "STAmount fail");
+        unexpected (zeroSt.isNative (), "STAmount fail");

        unexpected (hundred.isNative (), "STAmount fail");

-        unexpected (!zero.isZero (), "STAmount fail");
+        unexpected (zeroSt != zero, "STAmount fail");

-        unexpected (one.isZero (), "STAmount fail");
+        unexpected (one == zero, "STAmount fail");

-        unexpected (hundred.isZero (), "STAmount fail");
+        unexpected (hundred == zero, "STAmount fail");

-        unexpected ((zero < zero), "STAmount fail");
+        unexpected ((zeroSt < zeroSt), "STAmount fail");

-        unexpected (! (zero < one), "STAmount fail");
+        unexpected (! (zeroSt < one), "STAmount fail");

-        unexpected (! (zero < hundred), "STAmount fail");
+        unexpected (! (zeroSt < hundred), "STAmount fail");

-        unexpected ((one < zero), "STAmount fail");
+        unexpected ((one < zeroSt), "STAmount fail");

        unexpected ((one < one), "STAmount fail");

        unexpected (! (one < hundred), "STAmount fail");

-        unexpected ((hundred < zero), "STAmount fail");
+        unexpected ((hundred < zeroSt), "STAmount fail");

        unexpected ((hundred < one), "STAmount fail");

        unexpected ((hundred < hundred), "STAmount fail");

-        unexpected ((zero > zero), "STAmount fail");
+        unexpected ((zeroSt > zeroSt), "STAmount fail");

-        unexpected ((zero > one), "STAmount fail");
+        unexpected ((zeroSt > one), "STAmount fail");

-        unexpected ((zero > hundred), "STAmount fail");
+        unexpected ((zeroSt > hundred), "STAmount fail");

-        unexpected (! (one > zero), "STAmount fail");
+        unexpected (! (one > zeroSt), "STAmount fail");

        unexpected ((one > one), "STAmount fail");

        unexpected ((one > hundred), "STAmount fail");

-        unexpected (! (hundred > zero), "STAmount fail");
+        unexpected (! (hundred > zeroSt), "STAmount fail");

        unexpected (! (hundred > one), "STAmount fail");

        unexpected ((hundred > hundred), "STAmount fail");

-        unexpected (! (zero <= zero), "STAmount fail");
+        unexpected (! (zeroSt <= zeroSt), "STAmount fail");

-        unexpected (! (zero <= one), "STAmount fail");
+        unexpected (! (zeroSt <= one), "STAmount fail");

-        unexpected (! (zero <= hundred), "STAmount fail");
+        unexpected (! (zeroSt <= hundred), "STAmount fail");

-        unexpected ((one <= zero), "STAmount fail");
+        unexpected ((one <= zeroSt), "STAmount fail");

        unexpected (! (one <= one), "STAmount fail");

        unexpected (! (one <= hundred), "STAmount fail");

-        unexpected ((hundred <= zero), "STAmount fail");
+        unexpected ((hundred <= zeroSt), "STAmount fail");

        unexpected ((hundred <= one), "STAmount fail");

        unexpected (! (hundred <= hundred), "STAmount fail");

-        unexpected (! (zero >= zero), "STAmount fail");
+        unexpected (! (zeroSt >= zeroSt), "STAmount fail");

-        unexpected ((zero >= one), "STAmount fail");
+        unexpected ((zeroSt >= one), "STAmount fail");

-        unexpected ((zero >= hundred), "STAmount fail");
+        unexpected ((zeroSt >= hundred), "STAmount fail");

-        unexpected (! (one >= zero), "STAmount fail");
+        unexpected (! (one >= zeroSt), "STAmount fail");

        unexpected (! (one >= one), "STAmount fail");

        unexpected ((one >= hundred), "STAmount fail");

-        unexpected (! (hundred >= zero), "STAmount fail");
+        unexpected (! (hundred >= zeroSt), "STAmount fail");

        unexpected (! (hundred >= one), "STAmount fail");

        unexpected (! (hundred >= hundred), "STAmount fail");

-        unexpected (! (zero == zero), "STAmount fail");
+        unexpected (! (zeroSt == zeroSt), "STAmount fail");

-        unexpected ((zero == one), "STAmount fail");
+        unexpected ((zeroSt == one), "STAmount fail");

-        unexpected ((zero == hundred), "STAmount fail");
+        unexpected ((zeroSt == hundred), "STAmount fail");

-        unexpected ((one == zero), "STAmount fail");
+        unexpected ((one == zeroSt), "STAmount fail");

        unexpected (! (one == one), "STAmount fail");

        unexpected ((one == hundred), "STAmount fail");

-        unexpected ((hundred == zero), "STAmount fail");
+        unexpected ((hundred == zeroSt), "STAmount fail");

        unexpected ((hundred == one), "STAmount fail");

        unexpected (! (hundred == hundred), "STAmount fail");

-        unexpected ((zero != zero), "STAmount fail");
+        unexpected ((zeroSt != zeroSt), "STAmount fail");

-        unexpected (! (zero != one), "STAmount fail");
+        unexpected (! (zeroSt != one), "STAmount fail");

-        unexpected (! (zero != hundred), "STAmount fail");
+        unexpected (! (zeroSt != hundred), "STAmount fail");

-        unexpected (! (one != zero), "STAmount fail");
+        unexpected (! (one != zeroSt), "STAmount fail");

        unexpected ((one != one), "STAmount fail");

        unexpected (! (one != hundred), "STAmount fail");

-        unexpected (! (hundred != zero), "STAmount fail");
+        unexpected (! (hundred != zeroSt), "STAmount fail");

        unexpected (! (hundred != one), "STAmount fail");

@@ -1708,27 +1711,27 @@ public:
                           (STAmount::cMinValue + STAmount::cMaxValue) / 2, STAmount::cMaxOffset - 1);
        STAmount smallValue (CURRENCY_ONE, ACCOUNT_ONE,
                             (STAmount::cMinValue + STAmount::cMaxValue) / 2, STAmount::cMinOffset + 1);
-        STAmount zero (CURRENCY_ONE, ACCOUNT_ONE, 0);
+        STAmount zeroSt (CURRENCY_ONE, ACCOUNT_ONE, 0);

        STAmount smallXsmall = STAmount::multiply (smallValue, smallValue, CURRENCY_ONE, ACCOUNT_ONE);

-        expect (smallXsmall.isZero (), "smallXsmall != 0");
+        expect (smallXsmall == zero, "smallXsmall != 0");

        STAmount bigDsmall = STAmount::divide (smallValue, bigValue, CURRENCY_ONE, ACCOUNT_ONE);

-        expect (bigDsmall.isZero (), beast::String ("small/big != 0: ") + bigDsmall.getText ());
+        expect (bigDsmall == zero, beast::String ("small/big != 0: ") + bigDsmall.getText ());

        bigDsmall = STAmount::divide (smallValue, bigNative, CURRENCY_ONE, uint160 ());

-        expect (bigDsmall.isZero (), beast::String ("small/bigNative != 0: ") + bigDsmall.getText ());
+        expect (bigDsmall == zero, beast::String ("small/bigNative != 0: ") + bigDsmall.getText ());

        bigDsmall = STAmount::divide (smallValue, bigValue, uint160 (), uint160 ());

-        expect (bigDsmall.isZero (), beast::String ("(small/big)->N != 0: ") + bigDsmall.getText ());
+        expect (bigDsmall == zero, beast::String ("(small/big)->N != 0: ") + bigDsmall.getText ());

        bigDsmall = STAmount::divide (smallValue, bigNative, uint160 (), uint160 ());

-        expect (bigDsmall.isZero (), beast::String ("(small/bigNative)->N != 0: ") + bigDsmall.getText ());
+        expect (bigDsmall == zero, beast::String ("(small/bigNative)->N != 0: ") + bigDsmall.getText ());

        // very bad offer
        std::uint64_t r = STAmount::getRate (smallValue, bigValue);
--- a/src/ripple_data/protocol/STAmountRound.cpp
+++ b/src/ripple_data/protocol/STAmountRound.cpp
@@ -203,7 +203,7 @@ STAmount STAmount::subRound (const STAmount& v1, const STAmount& v2, bool roundU
 STAmount STAmount::mulRound (const STAmount& v1, const STAmount& v2,
                             const uint160& uCurrencyID, const uint160& uIssuerID, bool roundUp)
 {
-    if (v1.isZero () || v2.isZero ())
+    if (v1 == zero || v2 == zero)
        return STAmount (uCurrencyID, uIssuerID);

    if (v1.mIsNative && v2.mIsNative && uCurrencyID.isZero ())
@@ -267,10 +267,10 @@ STAmount STAmount::mulRound (const STAmount& v1, const STAmount& v2,
 STAmount STAmount::divRound (const STAmount& num, const STAmount& den,
                             const uint160& uCurrencyID, const uint160& uIssuerID, bool roundUp)
 {
-    if (den.isZero ())
+    if (den == zero)
        throw std::runtime_error ("division by zero");

-    if (num.isZero ())
+    if (num == zero)
        return STAmount (uCurrencyID, uIssuerID);

    std::uint64_t numVal = num.mValue, denVal = den.mValue;
--- a/src/ripple_data/protocol/SerializedTypes.h
+++ b/src/ripple_data/protocol/SerializedTypes.h
@@ -574,6 +574,11 @@ public:
        return mValue;
    }

+    int signum () const
+    {
+        return mValue ? (mIsNegative ? -1 : 1) : 0;
+    }
+
    // When the currency is XRP, the value in raw units. S=signed
    std::uint64_t getNValue () const
    {
@@ -596,30 +601,6 @@ public:
    {
        return mIsNative;
    }
-    bool isZero () const
-    {
-        return mValue == 0;
-    }
-    bool isNonZero () const
-    {
-        return mValue != 0;
-    }
-    bool isNegative () const
-    {
-        return mIsNegative && !isZero ();
-    }
-    bool isPositive () const
-    {
-        return !mIsNegative && !isZero ();
-    }
-    bool isLEZero () const
-    {
-        return mIsNegative || isZero ();
-    }
-    bool isGEZero () const
-    {
-        return !mIsNegative;
-    }
    bool isLegalNet () const
    {
        return !mIsNative || (mValue <= cMaxNativeN);
@@ -628,15 +609,16 @@ public:
    explicit
    operator bool () const noexcept
    {
-        return !isZero ();
+        return *this != zero;
    }

    void negate ()
    {
-        if (!isZero ()) mIsNegative = !mIsNegative;
+        if (*this != zero)
+            mIsNegative = !mIsNegative;
    }

-    void zero ()
+    void clear ()
    {
        // VFALCO: Why -100?
        mOffset = mIsNative ? 0 : -100;
@@ -645,19 +627,25 @@ public:
    }

    // Zero while copying currency and issuer.
-    void zero (const STAmount& saTmpl)
+    void clear (const STAmount& saTmpl)
    {
        mCurrency = saTmpl.mCurrency;
        mIssuer = saTmpl.mIssuer;
        mIsNative = saTmpl.mIsNative;
-        zero ();
+        clear ();
    }
-    void zero (const uint160& uCurrencyID, const uint160& uIssuerID)
+    void clear (const uint160& uCurrencyID, const uint160& uIssuerID)
    {
        mCurrency = uCurrencyID;
        mIssuer = uIssuerID;
        mIsNative = !uCurrencyID;
-        zero ();
+        clear ();
+    }
+
+    STAmount& operator=(beast::Zero)
+    {
+        clear ();
+        return *this;
    }

    int compare (const STAmount&) const;