add ethereum conversion function

Signed-off-by: Mislav Novakovic <[email protected]>

Author: mislavn

eth/web3.c

@@ -235,3 +235,68 @@ int eth_getTransactionReceipt(web3_ctx_t *web3, const tx_hash_t *tx_hash)
     WEB3_TERMINATOR();
     return 0;
 }
+
+int eth_convert(const uint256_t *amount, enum ETH_UNIT from, enum ETH_UNIT to, char *buf, size_t buf_size)
+{
+    assert(amount != NULL);
+    size_t shift = from > to ? from - to : to - from;
+
+    if(tostring256(amount, 10, buf, buf_size) == false) {
+        return -1;
+    }
+
+    // special case '0'
+    if(buf[0] == '0') return 0;
+
+    // finish if the unit doesn't change
+    if (shift == 0) {
+        return 0;
+    // conversion to smaller unit, add '0'
+    } else if (from > to) {
+        size_t i;
+        size_t len = strlen(buf);
+        // check buffer size
+        if (len + shift > buf_size) {
+            return -1;
+        }
+        // add zeros
+        for (i = len; i < len + shift; ++i) {
+            buf[i] = '0';
+        }
+        buf[len + shift] = '\0';
+    // conversion to bigger unit add '.'
+    } else {
+        size_t i;
+        size_t len = strlen(buf);
+        size_t skip = LEADING_ZERO + DECIMAL_POINT;
+        if (len  > shift) {
+            // check buffer size
+            if (len + DECIMAL_POINT > buf_size) {
+                return -1;
+            }
+            // move numbers
+            for (i = len + skip; i > len - shift; --i) {
+                buf[i] = buf[i - 1];
+            }
+            buf[len - shift] = '.';
+        } else {
+            // check buffer size
+            if (shift + skip > buf_size) {
+                return -1;
+            }
+            // move numbers
+            for (i = len; (int) i >= 0; --i) {
+                buf[i + shift + skip - len] = buf[i];
+            }
+            // add '0.' at the beggining
+            buf[0] = '0';
+            buf[1] = '.';
+            // fill the rest with zeros
+            for (i = skip; i < shift - len + skip; ++i) {
+                buf[i] = '0';
+            }
+        }
+    }
+
+    return 0;
+}

eth/web3.h

@@ -35,6 +35,24 @@ int eth_call(web3_ctx_t *web3, const address_t *from, const transaction_t *tx, u
 int eth_estimateGas(web3_ctx_t *web3, const address_t *from, const transaction_t *tx);
 int eth_getTransactionReceipt(web3_ctx_t *web3, const tx_hash_t *tx_hash);
 
+#define DECIMAL_POINT 1
+#define LEADING_ZERO  1
+
+enum ETH_UNIT {
+    ETH_UNIT_WEI    = 0,
+    ETH_UNIT_KWEI   = 3,
+    ETH_UNIT_MWEI   = 6,
+    ETH_UNIT_GWEI   = 9,
+    ETH_UNIT_SZABO  = 12,
+    ETH_UNIT_FINNEY = 15,
+    ETH_UNIT_ETHER  = 18,
+    ETH_UNIT_KETHER = 21,
+    ETH_UNIT_METHER = 24,
+    ETH_UNIT_GETHER = 27,
+    ETH_UNIT_TETHER = 30
+};
+int eth_convert(const uint256_t *amount, enum ETH_UNIT from, enum ETH_UNIT to, char *buf, size_t buf_size);
+
 #ifdef __cplusplus
 }
 #endif

examples/tests/src/test_web3.cpp

@@ -105,3 +105,75 @@ TEST(TEST_WEB3, test_decode_txreceipt)
     ASSERT_EQ(receipt.blockNumber, 0x8d1447);
 }
 
+void helper_eth_convert(uint64_t value, const char *compare, enum ETH_UNIT from, enum ETH_UNIT to)
+{
+    int rc;
+    uint256_t amount;
+    const size_t buf_len = 50;
+    char buf[buf_len] = {0};
+    set256_uint64(&amount, value);
+    rc = eth_convert(&amount, from, to, buf, buf_len);
+    ASSERT_EQ(rc, 0);
+    ASSERT_EQ(strcmp(buf, compare), 0);
+    ASSERT_EQ(strlen(buf), strlen(compare));
+}
+
+TEST(TEST_ETH_CONVERT, test_eth_convert)
+{
+    int rc;
+    uint256_t amount;
+    const size_t buf_len = 50;
+    char buf[buf_len] = {0};
+
+    set256_uint64(&amount, 1234);
+
+    rc = eth_convert(&amount, ETH_UNIT_ETHER, ETH_UNIT_FINNEY, buf, 3);
+    ASSERT_EQ(rc, -1);
+
+    rc = eth_convert(&amount, ETH_UNIT_ETHER, ETH_UNIT_ETHER, buf, 4);
+    ASSERT_EQ(rc, 0);
+    ASSERT_EQ(strcmp(buf, "1234"), 0);
+
+    rc = eth_convert(&amount, ETH_UNIT_ETHER, ETH_UNIT_FINNEY, buf, 6);
+    ASSERT_EQ(rc, -1);
+
+    rc = eth_convert(&amount, ETH_UNIT_ETHER, ETH_UNIT_FINNEY, buf, 7);
+    ASSERT_EQ(rc, 0);
+    ASSERT_EQ(strcmp(buf, "1234000"), 0);
+
+    rc = eth_convert(&amount, ETH_UNIT_ETHER, ETH_UNIT_KETHER, buf, 4);
+    ASSERT_EQ(rc, -1);
+
+    rc = eth_convert(&amount, ETH_UNIT_ETHER, ETH_UNIT_KETHER, buf, 5);
+    ASSERT_EQ(rc, 0);
+    ASSERT_EQ(strcmp(buf, "1.234"), 0);
+
+    rc = eth_convert(&amount, ETH_UNIT_ETHER, ETH_UNIT_METHER, buf, 7);
+    ASSERT_EQ(rc, -1);
+
+    rc = eth_convert(&amount, ETH_UNIT_ETHER, ETH_UNIT_METHER, buf, 8);
+    ASSERT_EQ(rc, 0);
+    ASSERT_EQ(strcmp(buf, "0.001234"), 0);
+
+    helper_eth_convert(1,"1000000000000000000", ETH_UNIT_ETHER, ETH_UNIT_WEI);
+    helper_eth_convert(1,"1000000000000000", ETH_UNIT_ETHER, ETH_UNIT_KWEI);
+    helper_eth_convert(1,"1000000000000", ETH_UNIT_ETHER, ETH_UNIT_MWEI);
+    helper_eth_convert(1,"1000000000", ETH_UNIT_ETHER, ETH_UNIT_GWEI);
+    helper_eth_convert(1,"1000000", ETH_UNIT_ETHER, ETH_UNIT_SZABO);
+    helper_eth_convert(1,"1000", ETH_UNIT_ETHER, ETH_UNIT_FINNEY);
+    helper_eth_convert(1,"1", ETH_UNIT_ETHER, ETH_UNIT_ETHER);
+    helper_eth_convert(1,"0.001", ETH_UNIT_ETHER, ETH_UNIT_KETHER);
+    helper_eth_convert(1,"0.000001", ETH_UNIT_ETHER, ETH_UNIT_METHER);
+    helper_eth_convert(1,"0.000000001", ETH_UNIT_ETHER, ETH_UNIT_GETHER);
+    helper_eth_convert(1,"0.000000000001", ETH_UNIT_ETHER, ETH_UNIT_TETHER);
+
+    set256_uint64(&amount, 0);
+    rc = eth_convert(&amount, ETH_UNIT_ETHER, ETH_UNIT_WEI, buf, buf_len);
+    ASSERT_EQ(rc, 0);
+    ASSERT_EQ(strcmp(buf, "0"), 0);
+
+    helper_eth_convert(123,"0.123", ETH_UNIT_ETHER, ETH_UNIT_KETHER);
+    helper_eth_convert(1234,"1.234", ETH_UNIT_ETHER, ETH_UNIT_KETHER);
+    helper_eth_convert(12345,"12.345", ETH_UNIT_ETHER, ETH_UNIT_KETHER);
+    helper_eth_convert(123456,"123.456", ETH_UNIT_ETHER, ETH_UNIT_KETHER);
+}