add zcash_script_transparent_output_address() to get address from output

src/script/zcash_script.cpp

@@ -232,6 +232,94 @@ unsigned int zcash_script_legacy_sigop_count(
     }
 }
 
+zcash_script_uint160 zcash_script_transparent_output_address_precomputed(
+    const void* pre_preTx,
+    unsigned int nOut,
+    zcash_script_type* type,
+    zcash_script_error* err)
+{
+    const PrecomputedTransaction* preTx = static_cast<const PrecomputedTransaction*>(pre_preTx);
+
+    zcash_script_uint160 r;
+    memset(&r, 0, sizeof(r));
+
+    if (nOut >= preTx->tx.vout.size()) {
+        set_error(err, zcash_script_ERR_TX_INDEX);
+        return r;
+    }
+
+    const CTxOut& out = preTx->tx.vout[nOut];
+    CScript::ScriptType scriptType = out.scriptPubKey.GetType();
+    switch (scriptType) {
+        case CScript::ScriptType::P2PKH:
+            if (type) {
+                *type = zcash_script_TYPE_P2PKH;
+            }
+            break;
+        case CScript::ScriptType::P2SH:
+            if (type) {
+                *type = zcash_script_TYPE_P2SH;
+            }
+            break;
+        default:
+            set_error(err, zcash_script_ERR_TX_INVALID_SCRIPT);
+            return r;
+    }
+    const uint160 addr = out.scriptPubKey.AddressHash();
+
+    assert(sizeof(r.value) == addr.size());
+    memcpy(r.value, addr.begin(), addr.size());
+    set_error(err, zcash_script_ERR_OK);
+    return r;
+}
+
+zcash_script_uint160 zcash_script_transparent_output_address(
+    const unsigned char *txTo,
+    unsigned int txToLen,
+    unsigned int nOut,
+    zcash_script_type* type,
+    zcash_script_error* err)
+{
+    TxInputStream stream(SER_NETWORK, PROTOCOL_VERSION, txTo, txToLen);
+    CTransaction tx;
+    zcash_script_uint160 r;
+    memset(&r, 0, sizeof(r));
+
+    stream >> tx;
+    if (nOut >= tx.vout.size()) {
+        set_error(err, zcash_script_ERR_TX_INDEX);
+        return r;
+    }
+    if (GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION) != txToLen) {
+        set_error(err, zcash_script_ERR_TX_SIZE_MISMATCH);
+        return r;
+    }
+
+    const CTxOut& out = tx.vout[nOut];
+    CScript::ScriptType scriptType = out.scriptPubKey.GetType();
+    switch (scriptType) {
+        case CScript::ScriptType::P2PKH:
+            if (type) {
+                *type = zcash_script_TYPE_P2PKH;
+            }
+            break;
+        case CScript::ScriptType::P2SH:
+            if (type) {
+                *type = zcash_script_TYPE_P2SH;
+            }
+            break;
+        default:
+            set_error(err, zcash_script_ERR_TX_INVALID_SCRIPT);
+            return r;
+    }
+    const uint160 addr = out.scriptPubKey.AddressHash();
+
+    assert(sizeof(r.value) == addr.size());
+    memcpy(r.value, addr.begin(), addr.size());
+    set_error(err, zcash_script_ERR_OK);
+    return r;
+}
+
 unsigned int zcash_script_version()
 {
     // Just use the API version for now

src/script/zcash_script.h

@@ -33,7 +33,7 @@
 extern "C" {
 #endif
 
-#define ZCASH_SCRIPT_API_VER 2
+#define ZCASH_SCRIPT_API_VER 3
 
 typedef enum zcash_script_error_t
 {
@@ -43,6 +43,7 @@ typedef enum zcash_script_error_t
     zcash_script_ERR_TX_DESERIALIZE,
     // Defined since API version 3.
     zcash_script_ERR_TX_VERSION,
+    zcash_script_ERR_TX_INVALID_SCRIPT,
 } zcash_script_error;
 
 /** Script verification flags */
@@ -53,6 +54,19 @@ enum
     zcash_script_SCRIPT_FLAGS_VERIFY_CHECKLOCKTIMEVERIFY = (1U << 9), // enable CHECKLOCKTIMEVERIFY (BIP65)
 };
 
+/** Address type enumeration */
+typedef enum zcash_script_type_t
+{
+    zcash_script_TYPE_P2PKH = 1,
+    zcash_script_TYPE_P2SH  = 2,
+} zcash_script_type;
+
+/// A Zcash transparent address encoded as 20 bytes.
+typedef struct zcash_script_uint160_t
+{
+    unsigned char value[20];
+} zcash_script_uint160;
+
 /// Deserializes the given transaction and precomputes values to improve
 /// script verification performance.
 ///
@@ -129,6 +143,26 @@ EXPORT_SYMBOL unsigned int zcash_script_legacy_sigop_count(
     unsigned int txToLen,
     zcash_script_error* err);
 
+/// Return the destination address for transparent output nOut of the precomputed transaction
+/// pointed to by preTx.
+/// If not NULL, type will contain the address type.
+/// If not NULL, err will contain an error/success code for the operation.
+EXPORT_SYMBOL zcash_script_uint160 zcash_script_transparent_output_address_precomputed(
+    const void* pre_preTx,
+    unsigned int nOut,
+    zcash_script_type* type,
+    zcash_script_error* err);
+
+/// Return the destination address for transparent output nOut of the transaction txTo.
+/// If not NULL, type will contain the address type.
+/// If not NULL, err will contain an error/success code for the operation.
+EXPORT_SYMBOL zcash_script_uint160 zcash_script_transparent_output_address(
+    const unsigned char *txTo,
+    unsigned int txToLen,
+    unsigned int nOut,
+    zcash_script_type* type,
+    zcash_script_error* err);
+
 /// Returns the current version of the zcash_script library.
 EXPORT_SYMBOL unsigned int zcash_script_version();