From c9c54c97994b3729604a42c5b96bcf6c25d8ba8d Mon Sep 17 00:00:00 2001
From: Howard Hinnant <howard.hinnant@gmail.com>
Date: Wed, 20 Apr 2022 17:10:04 -0400
Subject: [PATCH] Add implicit conversion from STAmount to Number

---
 src/ripple/basics/impl/Number.cpp           | 9 +++++----
 src/ripple/protocol/STAmount.h              | 9 +++++++++
 src/ripple/rpc/impl/ShardArchiveHandler.cpp | 9 +++++----
 src/test/basics/Number_test.cpp             | 5 +++++
 4 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/src/ripple/basics/impl/Number.cpp b/src/ripple/basics/impl/Number.cpp
index c9e9c51ce..e59ca5fb6 100644
--- a/src/ripple/basics/impl/Number.cpp
+++ b/src/ripple/basics/impl/Number.cpp
@@ -325,7 +325,7 @@ Number::operator*=(Number const& y)
             std::to_string(xe));
     mantissa_ = xm * zn;
     exponent_ = xe;
-    assert(isnormal());
+    assert(isnormal() || *this == Number{});
     return *this;
 }
 
@@ -362,8 +362,9 @@ Number::operator/=(Number const& y)
     static_assert(a2.isnormal());
     Number rm2{};
     Number rm1{};
-    Number r = a2;
-    r = (a2 * d + a1) * d + a0;
+    Number r = (a2 * d + a1) * d + a0;
+    //  Newton–Raphson iteration of 1/x - d with initial guess r
+    //  halt when r stops changing, checking for bouncing on the last iteration
     do
     {
         rm2 = rm1;
@@ -376,7 +377,7 @@ Number::operator/=(Number const& y)
 
 Number::operator rep() const
 {
-    std::int64_t drops = mantissa_;
+    rep drops = mantissa_;
     int offset = exponent_;
     guard g;
     if (drops != 0)
diff --git a/src/ripple/protocol/STAmount.h b/src/ripple/protocol/STAmount.h
index d0add30db..b6e0e3046 100644
--- a/src/ripple/protocol/STAmount.h
+++ b/src/ripple/protocol/STAmount.h
@@ -23,6 +23,7 @@
 #include <ripple/basics/CountedObject.h>
 #include <ripple/basics/IOUAmount.h>
 #include <ripple/basics/LocalValue.h>
+#include <ripple/basics/Number.h>
 #include <ripple/basics/XRPAmount.h>
 #include <ripple/protocol/Issue.h>
 #include <ripple/protocol/SField.h>
@@ -144,6 +145,7 @@ public:
     // Legacy support for new-style amounts
     STAmount(IOUAmount const& amount, Issue const& issue);
     STAmount(XRPAmount const& amount);
+    operator Number() const;
 
     //--------------------------------------------------------------------------
     //
@@ -370,6 +372,13 @@ inline STAmount::operator bool() const noexcept
     return *this != beast::zero;
 }
 
+inline STAmount::operator Number() const
+{
+    if (mIsNative)
+        return xrp();
+    return iou();
+}
+
 inline STAmount& STAmount::operator=(beast::Zero)
 {
     clear();
diff --git a/src/ripple/rpc/impl/ShardArchiveHandler.cpp b/src/ripple/rpc/impl/ShardArchiveHandler.cpp
index 2284780c2..d05744f48 100644
--- a/src/ripple/rpc/impl/ShardArchiveHandler.cpp
+++ b/src/ripple/rpc/impl/ShardArchiveHandler.cpp
@@ -37,11 +37,12 @@ using namespace std::chrono_literals;
 boost::filesystem::path
 ShardArchiveHandler::getDownloadDirectory(Config const& config)
 {
-    return get(config.section(ConfigSection::shardDatabase()),
-               "download_path",
+    return boost::filesystem::path{
                get(config.section(ConfigSection::shardDatabase()),
-                   "path",
-                   "")) /
+                   "download_path",
+                   get(config.section(ConfigSection::shardDatabase()),
+                       "path",
+                       ""))} /
         "download";
 }
 
diff --git a/src/test/basics/Number_test.cpp b/src/test/basics/Number_test.cpp
index 43a8884c5..b605ed434 100644
--- a/src/test/basics/Number_test.cpp
+++ b/src/test/basics/Number_test.cpp
@@ -20,6 +20,7 @@
 #include <ripple/basics/IOUAmount.h>
 #include <ripple/basics/Number.h>
 #include <ripple/beast/unit_test.h>
+#include <ripple/protocol/STAmount.h>
 
 namespace ripple {
 
@@ -124,6 +125,10 @@ public:
         BEAST_EXPECT((y == Number{5, 6}));
         IOUAmount z{y};
         BEAST_EXPECT(x == z);
+        XRPAmount xrp{500};
+        STAmount st = xrp;
+        Number n = st;
+        BEAST_EXPECT(XRPAmount{n} == xrp);
     }
 
     void