New supporting functions for eth-sn-contracts

include/ethyl/provider.hpp

@@ -2,6 +2,7 @@
 #pragma once
 
 #include <string>
+#include <string_view>
 #include <optional>
 #include <chrono>
 
@@ -38,9 +39,10 @@ class Provider {
     void connectToNetwork();
     void disconnectFromNetwork();
 
-    uint64_t getTransactionCount(const std::string& address, const std::string& blockTag);
-    std::string callReadFunction(const ReadCallData& callData, uint64_t blockNumberInt);
-    std::string callReadFunction(const ReadCallData& callData, const std::string& blockNumber = "latest");
+    uint64_t       getTransactionCount(const std::string& address, const std::string& blockTag);
+    nlohmann::json callReadFunctionJSON(const ReadCallData& callData, std::string_view blockNumber = "latest");
+    std::string    callReadFunction(const ReadCallData& callData, std::string_view blockNumber = "latest");
+    std::string    callReadFunction(const ReadCallData& callData, uint64_t blockNumberInt);
 
     uint32_t getNetworkChainId();
     std::string evm_snapshot();

include/ethyl/signer.hpp

@@ -24,7 +24,8 @@ class Signer {
 
     // Returns <Pubkey, Seckey>
     std::pair<std::vector<unsigned char>, std::vector<unsigned char>> generate_key_pair();
-    std::string addressFromPrivateKey(const std::vector<unsigned char>& seckey);
+    std::array<unsigned char, 20>                                     secretKeyToAddress(const std::vector<unsigned char>& seckey);
+    std::string                                                       secretKeyToAddressString(const std::vector<unsigned char>& seckey);
 
     std::vector<unsigned char> sign(const std::array<unsigned char, 32>& hash, const std::vector<unsigned char>& seckey);
     std::vector<unsigned char> sign(const std::string& hash, const std::vector<unsigned char>& seckey);

include/ethyl/utils.hpp

@@ -34,18 +34,19 @@ namespace utils
         return oss.str();
     }
 
-    std::string decimalToHex(uint64_t decimal);
+    std::string      decimalToHex(uint64_t decimal);
+    std::string_view trimPrefix(std::string_view src, std::string_view prefix);
+    std::string_view trimLeadingZeros(std::string_view src);
 
-    std::vector<unsigned char> fromHexString(std::string hex_str);
-    uint64_t fromHexStringToUint64(std::string hex_str);
-
-    std::array<unsigned char, 32> fromHexString32Byte(std::string hex_str);
+    std::vector<unsigned char>    fromHexString(std::string_view hexStr);
+    uint64_t                      fromHexStringToUint64(std::string_view hexStr);
+    std::array<unsigned char, 32> fromHexString32Byte(std::string_view hexStr);
 
     std::array<unsigned char, 32> hash(std::string in);
 
     std::string getFunctionSignature(const std::string& function);
 
-    std::string padToNBytes(const std::string& input, size_t byte_count, PaddingDirection direction = PaddingDirection::LEFT);
+    std::string padToNBytes(const std::string& input, size_t byteCount, PaddingDirection direction = PaddingDirection::LEFT);
     std::string padTo8Bytes(const std::string& input, PaddingDirection direction = PaddingDirection::LEFT);
     std::string padTo32Bytes(const std::string& input, PaddingDirection direction = PaddingDirection::LEFT);
 

src/provider.cpp

@@ -48,30 +48,44 @@ cpr::Response Provider::makeJsonRpcRequest(const std::string& method, const nloh
     return session.Post();
 }
 
-std::string Provider::callReadFunction(const ReadCallData& callData, uint64_t blockNumberInt) {
-    std::stringstream stream;
-    stream << "0x" << std::hex << blockNumberInt;  // Convert uint64_t to hex string
-    std::string blockNumberHex = stream.str();
-
-    return callReadFunction(callData, blockNumberHex);  // Call the original function
-}
+nlohmann::json Provider::callReadFunctionJSON(const ReadCallData& callData, std::string_view blockNumber) {
+    nlohmann::json result = {};
 
-std::string Provider::callReadFunction(const ReadCallData& callData, const std::string& blockNumber) {
     // Prepare the params for the eth_call request
-    nlohmann::json params = nlohmann::json::array();
-    params[0]["to"] = callData.contractAddress;
-    params[0]["data"] = callData.data;
-    params[1] = blockNumber; // use the provided block number or default to "latest"
+    nlohmann::json params  = nlohmann::json::array();
+    params[0]["to"]        = callData.contractAddress;
+    params[0]["data"]      = callData.data;
+    params[1]              = blockNumber; // use the provided block number or default to "latest"
     cpr::Response response = makeJsonRpcRequest("eth_call", params);
 
     if (response.status_code == 200) {
         nlohmann::json responseJson = nlohmann::json::parse(response.text);
         if (!responseJson["result"].is_null()) {
-            return responseJson["result"];
+            result = responseJson["result"];
+            return result;
         }
     }
 
-    throw std::runtime_error("Unable to get the result of the function call");
+    std::stringstream stream;
+    stream << "'eth_call' invoked on node for block '" << blockNumber
+           << "' to '" << callData.contractAddress
+           << "' with data payload '" << callData.data
+           << "' however it returned a response that does not have a result: "
+           << response.text;
+    throw std::runtime_error(stream.str());
+}
+
+std::string Provider::callReadFunction(const ReadCallData& callData, std::string_view blockNumber) {
+    std::string result = callReadFunctionJSON(callData, blockNumber);
+    return result;
+}
+
+std::string Provider::callReadFunction(const ReadCallData& callData, uint64_t blockNumberInt) {
+    std::stringstream stream;
+    stream << "0x" << std::hex << blockNumberInt; // Convert uint64_t to hex string
+    std::string blockNumberHex = stream.str();
+    std::string result         = callReadFunctionJSON(callData, blockNumberHex);
+    return result;
 }
 
 uint32_t Provider::getNetworkChainId() {

src/signer.cpp

@@ -60,7 +60,7 @@ std::pair<std::vector<unsigned char>, std::vector<unsigned char>> Signer::genera
             std::vector<unsigned char>(compressed_pubkey, compressed_pubkey + sizeof(compressed_pubkey))};
 }
 
-std::string Signer::addressFromPrivateKey(const std::vector<unsigned char>& seckey) {
+std::array<unsigned char, 20> Signer::secretKeyToAddress(const std::vector<unsigned char>& seckey) {
     std::string address;
 
     // Verify the private key.
@@ -84,10 +84,18 @@ std::string Signer::addressFromPrivateKey(const std::vector<unsigned char>& seck
     auto hashed_pub = utils::hash(pub_string);
 
     // The last 20 bytes of the Keccak-256 hash of the public key in hex is the address.
-    address = utils::toHexString(hashed_pub);
-    address = address.substr(address.size() - 40);
+    std::array<unsigned char, 20> result = {};
+    std::memcpy(result.data(), hashed_pub.data() + hashed_pub.size() - result.size(), result.size());
+    return result;
+}
 
-    return "0x" + address;
+std::string Signer::secretKeyToAddressString(const std::vector<unsigned char>& seckey) {
+    std::array<unsigned char, 20> address = secretKeyToAddress(seckey);
+    std::string                   result  = {};
+    result.reserve(2 + (address.max_size() * 2));
+    result += "0x";
+    result += utils::toHexString(address);
+    return result;
 }
 
 
@@ -173,7 +181,7 @@ std::string Signer::signTransaction(Transaction& txn, const std::vector<unsigned
 
 // Populates the txn, signs and sends
 std::string Signer::sendTransaction(Transaction& txn, const std::vector<unsigned char>& seckey) {
-    const auto senders_address = addressFromPrivateKey(seckey);
+    const auto senders_address = secretKeyToAddressString(seckey);
 
     populateTransaction(txn, senders_address);
     const auto signature_hex = utils::toHexString(sign(txn.hash(), seckey));

src/utils.cpp

@@ -4,6 +4,7 @@
 #include <string>
 #include <cstdlib>
 #include <ctime>
+#include <cassert>
 
 extern "C" {
 #include "crypto/keccak.h"
@@ -15,37 +16,86 @@ std::string utils::decimalToHex(uint64_t decimal) {
     return ss.str();
 }
 
-std::vector<unsigned char> utils::fromHexString(std::string hex_str) {
-    std::vector<unsigned char> bytes;
-
-    // Check for "0x" prefix and remove it
-    if(hex_str.size() >= 2 && hex_str[0] == '0' && hex_str[1] == 'x') {
-        hex_str = hex_str.substr(2);
+std::string_view utils::trimPrefix(std::string_view src, std::string_view prefix)
+{
+    std::string_view result = src;
+    if (result.size() >= prefix.size()) {
+        if (result.substr(0, prefix.size()) == prefix) {
+            result = result.substr(prefix.size(), result.size() - prefix.size());
+        }
     }
+    return result;
+}
 
-    for (unsigned int i = 0; i < hex_str.length(); i += 2) {
-        std::string byteString = hex_str.substr(i, 2);
-        //if (byteString[0] == 0) byteString[0] = '0';
-        //if (byteString[1] == 0) byteString[1] = '0';
-        unsigned char byte = static_cast<unsigned char>(strtol(byteString.c_str(), nullptr, 16));
-        bytes.push_back(byte);
+std::string_view utils::trimLeadingZeros(std::string_view src)
+{
+    std::string_view result = src;
+    while (result.size() && result[0] == '0') {
+        result = result.substr(1, result.size() - 1);
     }
+    return result;
+}
+
+struct HexToU8Result {
+    bool    success;
+    uint8_t u8;
+};
+
+static HexToU8Result hexToU8(char ch) {
+    HexToU8Result result = {};
+    result.success       = true;
+
+    if (ch >= 'a' && ch <= 'f')
+        result.u8 = static_cast<uint8_t>(ch - 'a' + 10);
+    else if (ch >= 'A' && ch <= 'F')
+        result.u8 = static_cast<uint8_t>(ch - 'A' + 10);
+    else if (ch >= '0' && ch <= '9')
+        result.u8 = static_cast<uint8_t>(ch - '0');
+    else
+        result.success = false;
 
-    return bytes;
+    return result;
 }
 
-uint64_t utils::fromHexStringToUint64(std::string hex_str) {
-    // Check for "0x" prefix and remove it
-    if(hex_str.size() >= 2 && hex_str[0] == '0' && hex_str[1] == 'x') {
-        hex_str = hex_str.substr(2);
+std::vector<unsigned char> utils::fromHexString(std::string_view hexStr) {
+    hexStr = trimPrefix(hexStr, "0x");
+    assert(hexStr.size() % 2 == 0);
+
+    std::vector<unsigned char> result;
+    for (size_t i = 0; i < hexStr.length(); i += 2) {
+        std::string_view byteString = hexStr.substr(i, 2);
+        HexToU8Result    hi         = hexToU8(byteString[0]);
+        HexToU8Result    lo         = hexToU8(byteString[1]);
+        unsigned char    byte       = static_cast<unsigned char>(hi.u8 << 4 | lo.u8 << 0);
+        result.push_back(byte);
     }
+    return result;
+}
 
-    uint64_t value = std::stoull(hex_str, nullptr, 16);
-    return value;
+uint64_t utils::fromHexStringToUint64(std::string_view hexStr) {
+    std::string_view realHex = trimPrefix(hexStr, "0x");
+
+    // NOTE: Trim leading '0's
+    while (realHex.size() && realHex[0] == '0') {
+        realHex = realHex.substr(1, realHex.size() - 1);
+    }
+
+    size_t maxHexSize = sizeof(uint64_t) * 2 /*hex chars per byte*/;
+    assert(realHex.size() <= maxHexSize);
+
+    size_t   size   = std::min(maxHexSize, realHex.size());
+    uint64_t result = 0;
+    for (size_t index = 0; index < size; index++) {
+        char          ch        = realHex[index];
+        HexToU8Result hexResult = hexToU8(ch);
+        assert(hexResult.success);
+        result = (result << 4) | hexResult.u8;
+    }
+    return result;
 }
 
-std::array<unsigned char, 32> utils::fromHexString32Byte(std::string hex_str) {
-    std::vector<unsigned char> bytesVec = fromHexString(hex_str);
+std::array<unsigned char, 32> utils::fromHexString32Byte(std::string_view hexStr) {
+    std::vector<unsigned char> bytesVec = fromHexString(hexStr);
 
     if(bytesVec.size() != 32) {
         throw std::invalid_argument("Input string length should be 64 characters for 32 bytes");
@@ -81,7 +131,7 @@ std::string utils::getFunctionSignature(const std::string& function) {
     return "0x" + hashHex.substr(0, 8);
 }
 
-std::string utils::padToNBytes(const std::string& input, size_t byte_count, utils::PaddingDirection direction) {
+std::string utils::padToNBytes(const std::string& input, size_t byteCount, utils::PaddingDirection direction) {
     std::string output = input;
     bool has0xPrefix = false;
 
@@ -92,20 +142,21 @@ std::string utils::padToNBytes(const std::string& input, size_t byte_count, util
     }
 
     // Calculate padding size based on byteCount * 2 (since each byte is represented by 2 hex characters)
-    size_t targetHexStringSize = byte_count * 2;
-    size_t nextMultiple = (output.size() + targetHexStringSize - 1) / targetHexStringSize * targetHexStringSize;
-    size_t paddingSize = nextMultiple - output.size();
-    std::string padding(paddingSize, '0');
+    const size_t targetHexStringSize   = byteCount * 2;
+    const size_t startingSize          = std::max(output.size(), static_cast<size_t>(1)); // Size is atleast 1 element such that we handle when output.size == 0
+    const size_t startingSizeRoundedUp = startingSize + (targetHexStringSize - 1);
+    const size_t nextMultiple          = /*floor*/ (startingSizeRoundedUp / targetHexStringSize) * targetHexStringSize;
+    const size_t paddingSize           = nextMultiple - output.size();
 
     if (direction == PaddingDirection::LEFT) {
-        output = padding + output;
+        output.insert(0, paddingSize, '0');
     } else {
-        output += padding;
+        output.append(paddingSize, '0');
     }
 
     // If input started with "0x", add it back
     if (has0xPrefix) {
-        output = "0x" + output;
+        output.insert(0, "0x");
     }
 
     return output;

test/src/ethereum_client.cpp

@@ -38,7 +38,7 @@ TEST_CASE( "SigningTest", "[signer]" ) {
 TEST_CASE( "Get address from private key", "[signer]" ) {
     std::vector<unsigned char> seckey = utils::fromHexString(std::string(PRIVATE_KEY));
     Signer signer;
-    std::string created_address = signer.addressFromPrivateKey(seckey);
+    std::string created_address = signer.secretKeyToAddressString(seckey);
     REQUIRE( created_address == ADDRESS );
 }