From aaa44dd400fe04e0d1b3ed165e9dc6630634c5de Mon Sep 17 00:00:00 2001
From: Adam Heinermann <aheinerm@gmail.com>
Date: Sun, 17 Nov 2024 04:02:44 -0800
Subject: [PATCH] feat(big): add SBigToUnsigned

---
 storm/Big.cpp     |  4 ++++
 storm/Big.hpp     |  2 ++
 storm/big/Ops.cpp |  5 +++++
 storm/big/Ops.hpp |  2 ++
 test/Big.cpp      | 24 ++++++++++++++++++++++++
 test/big/Ops.cpp  |  1 -
 6 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/storm/Big.cpp b/storm/Big.cpp
index 298a924..1741df5 100644
--- a/storm/Big.cpp
+++ b/storm/Big.cpp
@@ -143,6 +143,10 @@ void SBigToBinaryBuffer(BigData* num, uint8_t* data, uint32_t maxBytes, uint32_t
     }
 }
 
+void SBigToUnsigned(BigData* num, uint32_t* val) {
+    ToUnsigned(val, num->Primary());
+}
+
 void SBigXor(BigData* a, BigData* b, BigData* c) {
     Xor(a->Primary(), b->Primary(), c->Primary());
 }
diff --git a/storm/Big.hpp b/storm/Big.hpp
index f39a90e..dae161c 100644
--- a/storm/Big.hpp
+++ b/storm/Big.hpp
@@ -60,4 +60,6 @@ void SBigToBinaryBuffer(BigData* num, uint8_t* data, uint32_t maxBytes, uint32_t
 
 void SBigXor(BigData* a, BigData* b, BigData* c);
 
+void SBigToUnsigned(BigData* num, uint32_t* val);
+
 #endif
diff --git a/storm/big/Ops.cpp b/storm/big/Ops.cpp
index b40623f..a78cb1a 100644
--- a/storm/big/Ops.cpp
+++ b/storm/big/Ops.cpp
@@ -483,6 +483,11 @@ void ToStream(TSGrowableArray<uint8_t>& output, const BigBuffer& buffer) {
     ToBinaryAppend(output, buffer);
 }
 
+void ToUnsigned(uint32_t* a, const BigBuffer& b) {
+    *a = 0;
+    *a = b[0];
+}
+
 void Xor(BigBuffer& a, const BigBuffer& b, const BigBuffer& c) {
     uint32_t i = 0;
     for (; b.IsUsed(i) || c.IsUsed(i); i++) {
diff --git a/storm/big/Ops.hpp b/storm/big/Ops.hpp
index 3f38596..c8b20dc 100644
--- a/storm/big/Ops.hpp
+++ b/storm/big/Ops.hpp
@@ -75,6 +75,8 @@ void ToBinary(TSGrowableArray<uint8_t>& output, const BigBuffer& buffer);
 
 void ToStream(TSGrowableArray<uint8_t>& output, const BigBuffer& buffer);
 
+void ToUnsigned(uint32_t* a, const BigBuffer& b);
+
 void Xor(BigBuffer& a, const BigBuffer& b, const BigBuffer& c);
 
 #endif
diff --git a/test/Big.cpp b/test/Big.cpp
index cd924e4..82b9e1d 100644
--- a/test/Big.cpp
+++ b/test/Big.cpp
@@ -746,6 +746,30 @@ TEST_CASE("SBigToBinaryBuffer", "[big]") {
     }
 }
 
+TEST_CASE("SBigToUnsigned", "[big]") {
+    BigDataTest num;
+
+    SECTION("converts bignum values to uint") {
+        auto v = GENERATE(0UL, 1UL, 1000UL, UINT32_MAX);
+
+        SBigFromUnsigned(num, v);
+
+        uint32_t result;
+        SBigToUnsigned(num, &result);
+
+        CHECK(result == v);
+    }
+
+    SECTION("truncates large values") {
+        SBigFromStr(num, std::to_string(0x123456789ABCDEFULL).c_str());
+
+        uint32_t result;
+        SBigToUnsigned(num, &result);
+
+        CHECK(result == 0x89ABCDEF);
+    }
+}
+
 TEST_CASE("SBigXor", "[big]") {
     BigDataTest a, b, c;
 
diff --git a/test/big/Ops.cpp b/test/big/Ops.cpp
index 935c060..e2e7501 100644
--- a/test/big/Ops.cpp
+++ b/test/big/Ops.cpp
@@ -1070,7 +1070,6 @@ TEST_CASE("Sub", "[big]") {
     }
 }
 
-
 TEST_CASE("ToStream", "[big]") {
     BigDataTest a;