Partial #19326: Simplify hash.h interface using Spans

src/bench/chacha_poly_aead.cpp

@@ -94,7 +94,7 @@ static void HASH(benchmark::State& state, size_t buffersize)
     uint8_t hash[CHash256::OUTPUT_SIZE];
     std::vector<uint8_t> in(buffersize,0);
     while (state.KeepRunning())
-        CHash256().Write(in.data(), in.size()).Finalize(hash);
+        CHash256().Write(in).Finalize(hash);
 }
 
 static void HASH_64BYTES(benchmark::State& state)

src/bench/crypto_hash.cpp

@@ -58,14 +58,14 @@ static void HASH_DSHA256(benchmark::State& state)
     uint8_t hash[CSHA256::OUTPUT_SIZE];
     std::vector<uint8_t> in(BUFFER_SIZE,0);
     while (state.KeepRunning())
-        CHash256().Write(in.data(), in.size()).Finalize(hash);
+        CHash256().Write(in).Finalize(hash);
 }
 
 static void HASH_DSHA256_0032b(benchmark::State& state)
 {
     std::vector<uint8_t> in(32,0);
     while (state.KeepRunning()) {
-        CHash256().Write(in.data(), in.size()).Finalize(in.data());
+        CHash256().Write(in).Finalize(in);
     }
 }
 
@@ -116,42 +116,42 @@ static void HASH_DSHA256_0032b_single(benchmark::State& state)
 {
     std::vector<uint8_t> in(32,0);
     while (state.KeepRunning())
-        CHash256().Write(in.data(), in.size()).Finalize(in.data());
+        CHash256().Write(in).Finalize(in);
 }
 
 static void HASH_DSHA256_0080b_single(benchmark::State& state)
 {
     std::vector<uint8_t> in(80,0);
     while (state.KeepRunning())
-        CHash256().Write(in.data(), in.size()).Finalize(in.data());
+        CHash256().Write(in).Finalize(in);
 }
 
 static void HASH_DSHA256_0128b_single(benchmark::State& state)
 {
     std::vector<uint8_t> in(128,0);
     while (state.KeepRunning())
-        CHash256().Write(in.data(), in.size()).Finalize(in.data());
+        CHash256().Write(in).Finalize(in);
 }
 
 static void HASH_DSHA256_0512b_single(benchmark::State& state)
 {
     std::vector<uint8_t> in(512,0);
     while (state.KeepRunning())
-        CHash256().Write(in.data(), in.size()).Finalize(in.data());
+        CHash256().Write(in).Finalize(in);
 }
 
 static void HASH_DSHA256_1024b_single(benchmark::State& state)
 {
     std::vector<uint8_t> in(1024,0);
     while (state.KeepRunning())
-        CHash256().Write(in.data(), in.size()).Finalize(in.data());
+        CHash256().Write(in).Finalize(in);
 }
 
 static void HASH_DSHA256_2048b_single(benchmark::State& state)
 {
     std::vector<uint8_t> in(2048,0);
     while (state.KeepRunning())
-        CHash256().Write(in.data(), in.size()).Finalize(in.data());
+        CHash256().Write(in).Finalize(in);
 }
 
 static void HASH_X11(benchmark::State& state)

src/blockfilter.cpp

@@ -244,7 +244,7 @@ uint256 BlockFilter::GetHash() const
     const std::vector<unsigned char>& data = GetEncodedFilter();
 
     uint256 result;
-    CHash256().Write(data.data(), data.size()).Finalize(result.begin());
+    CHash256().Write(data).Finalize(result);
     return result;
 }
 
@@ -254,8 +254,8 @@ uint256 BlockFilter::ComputeHeader(const uint256& prev_header) const
 
     uint256 result;
     CHash256()
-        .Write(filter_hash.begin(), filter_hash.size())
+        .Write(filter_hash)
-        .Write(prev_header.begin(), prev_header.size())
+        .Write(prev_header)
-        .Finalize(result.begin());
+        .Finalize(result);
     return result;
 }

src/hash.cpp

@@ -12,7 +12,7 @@ inline uint32_t ROTL32(uint32_t x, int8_t r)
     return (x << r) | (x >> (32 - r));
 }
 
-unsigned int MurmurHash3(unsigned int nHashSeed, const std::vector<unsigned char>& vDataToHash)
+unsigned int MurmurHash3(unsigned int nHashSeed, Span<const unsigned char> vDataToHash)
 {
     // The following is MurmurHash3 (x86_32), see http://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp
     uint32_t h1 = nHashSeed;

src/hash.h

@@ -38,14 +38,15 @@ private:
 public:
     static const size_t OUTPUT_SIZE = CSHA256::OUTPUT_SIZE;
 
-    void Finalize(unsigned char hash[OUTPUT_SIZE]) {
+    void Finalize(Span<unsigned char> output) {
+        assert(output.size() == OUTPUT_SIZE);
         unsigned char buf[CSHA256::OUTPUT_SIZE];
         sha.Finalize(buf);
-        sha.Reset().Write(buf, CSHA256::OUTPUT_SIZE).Finalize(hash);
+        sha.Reset().Write(buf, CSHA256::OUTPUT_SIZE).Finalize(output.data());
     }
 
-    CHash256& Write(const unsigned char *data, size_t len) {
+    CHash256& Write(Span<const unsigned char> input) {
-        sha.Write(data, len);
+        sha.Write(input.data(), input.size());
         return *this;
     }
 
@@ -62,14 +63,15 @@ private:
 public:
     static const size_t OUTPUT_SIZE = CRIPEMD160::OUTPUT_SIZE;
 
-    void Finalize(unsigned char hash[OUTPUT_SIZE]) {
+    void Finalize(Span<unsigned char> output) {
+        assert(output.size() == OUTPUT_SIZE);
         unsigned char buf[CSHA256::OUTPUT_SIZE];
         sha.Finalize(buf);
-        CRIPEMD160().Write(buf, CSHA256::OUTPUT_SIZE).Finalize(hash);
+        CRIPEMD160().Write(buf, CSHA256::OUTPUT_SIZE).Finalize(output.data());
     }
 
-    CHash160& Write(const unsigned char *data, size_t len) {
+    CHash160& Write(Span<const unsigned char> input) {
-        sha.Write(data, len);
+        sha.Write(input.data(), input.size());
         return *this;
     }
 
@@ -85,8 +87,8 @@ inline uint256 Hash(const T1 pbegin, const T1 pend)
 {
     static const unsigned char pblank[1] = {};
     uint256 result;
-    CHash256().Write(pbegin == pend ? pblank : (const unsigned char*)&pbegin[0], (pend - pbegin) * sizeof(pbegin[0]))
+    CHash256().Write({pbegin == pend ? pblank : (const unsigned char*)&pbegin[0], (pend - pbegin) * sizeof(pbegin[0])})
-              .Finalize((unsigned char*)&result);
+              .Finalize(result);
     return result;
 }
 
@@ -96,9 +98,9 @@ inline uint256 Hash(const T1 p1begin, const T1 p1end,
                     const T2 p2begin, const T2 p2end) {
     static const unsigned char pblank[1] = {};
     uint256 result;
-    CHash256().Write(p1begin == p1end ? pblank : (const unsigned char*)&p1begin[0], (p1end - p1begin) * sizeof(p1begin[0]))
+    CHash256().Write({p1begin == p1end ? pblank : (const unsigned char*)&p1begin[0], (p1end - p1begin) * sizeof(p1begin[0])})
-              .Write(p2begin == p2end ? pblank : (const unsigned char*)&p2begin[0], (p2end - p2begin) * sizeof(p2begin[0]))
+              .Write({p2begin == p2end ? pblank : (const unsigned char*)&p2begin[0], (p2end - p2begin) * sizeof(p2begin[0])})
-              .Finalize((unsigned char*)&result);
+              .Finalize(result);
     return result;
 }
 
@@ -162,8 +164,8 @@ inline uint160 Hash160(const T1 pbegin, const T1 pend)
 {
     static unsigned char pblank[1] = {};
     uint160 result;
-    CHash160().Write(pbegin == pend ? pblank : (const unsigned char*)&pbegin[0], (pend - pbegin) * sizeof(pbegin[0]))
+    CHash160().Write({pbegin == pend ? pblank : (const unsigned char*)&pbegin[0], (pend - pbegin) * sizeof(pbegin[0])})
-              .Finalize((unsigned char*)&result);
+              .Finalize(result);
     return result;
 }
 
@@ -196,13 +198,13 @@ public:
     int GetVersion() const { return nVersion; }
 
     void write(const char *pch, size_t size) {
-        ctx.Write((const unsigned char*)pch, size);
+        ctx.Write({(const unsigned char*)pch, size});
     }
 
     // invalidates the object
     uint256 GetHash() {
         uint256 result;
-        ctx.Finalize((unsigned char*)&result);
+        ctx.Finalize(result);
         return result;
     }
 
@@ -258,7 +260,7 @@ uint256 SerializeHash(const T& obj, int nType=SER_GETHASH, int nVersion=PROTOCOL
     return ss.GetHash();
 }
 
-unsigned int MurmurHash3(unsigned int nHashSeed, const std::vector<unsigned char>& vDataToHash);
+unsigned int MurmurHash3(unsigned int nHashSeed, Span<const unsigned char> vDataToHash);
 
 void BIP32Hash(const ChainCode &chainCode, unsigned int nChild, unsigned char header, const unsigned char data[32], unsigned char output[64]);
 

src/key.cpp

@@ -212,7 +212,7 @@ bool CKey::VerifyPubKey(const CPubKey& pubkey) const {
     std::string str = "Bitcoin key verification\n";
     GetRandBytes(rnd, sizeof(rnd));
     uint256 hash;
-    CHash256().Write((unsigned char*)str.data(), str.size()).Write(rnd, sizeof(rnd)).Finalize(hash.begin());
+    CHash256().Write(MakeUCharSpan(str)).Write(rnd).Finalize(hash);
     std::vector<unsigned char> vchSig;
     Sign(hash, vchSig);
     return pubkey.Verify(hash, vchSig);

src/net.cpp

@@ -948,7 +948,7 @@ int CNetMessage::readData(const char *pch, unsigned int nBytes)
         vRecv.resize(std::min(hdr.nMessageSize, nDataPos + nCopy + 256 * 1024));
     }
 
-    hasher.Write((const unsigned char*)pch, nCopy);
+    hasher.Write({(const unsigned char*)pch, nCopy});
     memcpy(&vRecv[nDataPos], pch, nCopy);
     nDataPos += nCopy;
 
@@ -959,7 +959,7 @@ const uint256& CNetMessage::GetMessageHash() const
 {
     assert(complete());
     if (data_hash.IsNull())
-        hasher.Finalize(data_hash.begin());
+        hasher.Finalize(data_hash);
     return data_hash;
 }
 

src/script/interpreter.cpp

@@ -934,9 +934,9 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript&
                     else if (opcode == OP_SHA256)
                         CSHA256().Write(vch.data(), vch.size()).Finalize(vchHash.data());
                     else if (opcode == OP_HASH160)
-                        CHash160().Write(vch.data(), vch.size()).Finalize(vchHash.data());
+                        CHash160().Write(vch).Finalize(vchHash);
                     else if (opcode == OP_HASH256)
-                        CHash256().Write(vch.data(), vch.size()).Finalize(vchHash.data());
+                        CHash256().Write(vch).Finalize(vchHash);
                     popstack(stack);
                     stack.push_back(vchHash);
                 }

src/span.h

@@ -179,4 +179,16 @@ T& SpanPopBack(Span<T>& span)
     return back;
 }
 
+// Helper functions to safely cast to unsigned char pointers.
+inline unsigned char* UCharCast(char* c) { return (unsigned char*)c; }
+inline unsigned char* UCharCast(unsigned char* c) { return c; }
+inline const unsigned char* UCharCast(const char* c) { return (unsigned char*)c; }
+inline const unsigned char* UCharCast(const unsigned char* c) { return c; }
+
+// Helper function to safely convert a Span to a Span<[const] unsigned char>.
+template <typename T> constexpr auto UCharSpanCast(Span<T> s) -> Span<typename std::remove_pointer<decltype(UCharCast(s.data()))>::type> { return {UCharCast(s.data()), s.size()}; }
+
+/** Like MakeSpan, but for (const) unsigned char member types only. Only works for (un)signed char containers. */
+template <typename V> constexpr auto MakeUCharSpan(V&& v) -> decltype(UCharSpanCast(MakeSpan(std::forward<V>(v)))) { return UCharSpanCast(MakeSpan(std::forward<V>(v))); }
+
 #endif

src/test/crypto_tests.cpp

@@ -817,7 +817,7 @@ BOOST_AUTO_TEST_CASE(sha256d64)
             in[j] = InsecureRandBits(8);
         }
         for (int j = 0; j < i; ++j) {
-            CHash256().Write(in + 64 * j, 64).Finalize(out1 + 32 * j);
+            CHash256().Write({in + 64 * j, 64}).Finalize({out1 + 32 * j, 32});
         }
         SHA256D64(out2, in, i);
         BOOST_CHECK(memcmp(out1, out2, 32 * i) == 0);

src/test/merkle_tests.cpp

@@ -60,7 +60,7 @@ static void MerkleComputation(const std::vector<uint256>& leaves, uint256* proot
                 }
             }
             mutated |= (inner[level] == h);
-            CHash256().Write(inner[level].begin(), 32).Write(h.begin(), 32).Finalize(h.begin());
+            CHash256().Write(inner[level]).Write(h).Finalize(h);
         }
         // Store the resulting hash at inner position level.
         inner[level] = h;
@@ -86,7 +86,7 @@ static void MerkleComputation(const std::vector<uint256>& leaves, uint256* proot
         if (pbranch && matchh) {
             pbranch->push_back(h);
         }
-        CHash256().Write(h.begin(), 32).Write(h.begin(), 32).Finalize(h.begin());
+        CHash256().Write(h).Write(h).Finalize(h);
         // Increment count to the value it would have if two entries at this
         // level had existed.
         count += (((uint32_t)1) << level);
@@ -101,7 +101,7 @@ static void MerkleComputation(const std::vector<uint256>& leaves, uint256* proot
                     matchh = true;
                 }
             }
-            CHash256().Write(inner[level].begin(), 32).Write(h.begin(), 32).Finalize(h.begin());
+            CHash256().Write(inner[level]).Write(h).Finalize(h);
             level++;
         }
     }

src/uint256.cpp

@@ -13,8 +13,8 @@
 template <unsigned int BITS>
 base_blob<BITS>::base_blob(const std::vector<unsigned char>& vch)
 {
-    assert(vch.size() == sizeof(data));
+    assert(vch.size() == sizeof(m_data));
-    memcpy(data, vch.data(), sizeof(data));
+    memcpy(m_data, vch.data(), sizeof(m_data));
 }
 
 template <unsigned int BITS>
@@ -22,7 +22,7 @@ std::string base_blob<BITS>::GetHex() const
 {
     uint8_t m_data_rev[WIDTH];
     for (int i = 0; i < WIDTH; ++i) {
-        m_data_rev[i] = data[WIDTH - 1 - i];
+        m_data_rev[i] = m_data[WIDTH - 1 - i];
     }
     return HexStr(m_data_rev);
 }
@@ -30,7 +30,7 @@ std::string base_blob<BITS>::GetHex() const
 template <unsigned int BITS>
 void base_blob<BITS>::SetHex(const char* psz)
 {
-    memset(data, 0, sizeof(data));
+    memset(m_data, 0, sizeof(m_data));
 
     // skip leading spaces
     while (isspace(*psz))
@@ -45,7 +45,7 @@ void base_blob<BITS>::SetHex(const char* psz)
     while (::HexDigit(*psz) != -1)
         psz++;
     psz--;
-    unsigned char* p1 = (unsigned char*)data;
+    unsigned char* p1 = (unsigned char*)m_data;
     unsigned char* pend = p1 + WIDTH;
     while (psz >= pbegin && p1 < pend) {
         *p1 = ::HexDigit(*psz--);

src/uint256.h

@@ -21,11 +21,11 @@ class base_blob
 {
 protected:
     static constexpr int WIDTH = BITS / 8;
-    uint8_t data[WIDTH];
+    uint8_t m_data[WIDTH];
 public:
     base_blob()
     {
-        memset(data, 0, sizeof(data));
+        memset(m_data, 0, sizeof(m_data));
     }
 
     explicit base_blob(const std::vector<unsigned char>& vch);
@@ -33,17 +33,17 @@ public:
     bool IsNull() const
     {
         for (int i = 0; i < WIDTH; i++)
-            if (data[i] != 0)
+            if (m_data[i] != 0)
                 return false;
         return true;
     }
 
     void SetNull()
     {
-        memset(data, 0, sizeof(data));
+        memset(m_data, 0, sizeof(m_data));
     }
 
-    inline int Compare(const base_blob& other) const { return memcmp(data, other.data, sizeof(data)); }
+    inline int Compare(const base_blob& other) const { return memcmp(m_data, other.m_data, sizeof(m_data)); }
 
     friend inline bool operator==(const base_blob& a, const base_blob& b) { return a.Compare(b) == 0; }
     friend inline bool operator!=(const base_blob& a, const base_blob& b) { return a.Compare(b) != 0; }
@@ -54,34 +54,37 @@ public:
     void SetHex(const std::string& str);
     std::string ToString() const;
 
+    const unsigned char* data() const { return m_data; }
+    unsigned char* data() { return m_data; }
+
     unsigned char* begin()
     {
-        return &data[0];
+        return &m_data[0];
     }
 
     unsigned char* end()
     {
-        return &data[WIDTH];
+        return &m_data[WIDTH];
     }
 
     const unsigned char* begin() const
     {
-        return &data[0];
+        return &m_data[0];
     }
 
     const unsigned char* end() const
     {
-        return &data[WIDTH];
+        return &m_data[WIDTH];
     }
 
     unsigned int size() const
     {
-        return sizeof(data);
+        return sizeof(m_data);
     }
 
     uint64_t GetUint64(int pos) const
     {
-        const uint8_t* ptr = data + pos * 8;
+        const uint8_t* ptr = m_data + pos * 8;
         return ((uint64_t)ptr[0]) | \
                ((uint64_t)ptr[1]) << 8 | \
                ((uint64_t)ptr[2]) << 16 | \
@@ -95,13 +98,13 @@ public:
     template<typename Stream>
     void Serialize(Stream& s) const
     {
-        s.write((char*)data, sizeof(data));
+        s.write((char*)m_data, sizeof(m_data));
     }
 
     template<typename Stream>
     void Unserialize(Stream& s)
     {
-        s.read((char*)data, sizeof(data));
+        s.read((char*)m_data, sizeof(m_data));
     }
 };
 
@@ -132,7 +135,7 @@ public:
      */
     uint64_t GetCheapHash() const
     {
-        return ReadLE64(data);
+        return ReadLE64(m_data);
     }
 };
 
@@ -167,7 +170,7 @@ public:
     uint256 trim256() const
     {
         uint256 result;
-        memcpy((void*)&result, (void*)data, 32);
+        memcpy((void*)&result, (void*)m_data, 32);
         return result;
     }
 };