tx: add and use constants for explicit and empty confidential commitments

Author: jgriffiths

include/wally_transaction.h

@@ -44,12 +44,14 @@ extern "C" {
 
 #define WALLY_SIGHASH_MASK         0x1f /* Mask for determining ALL/NONE/SINGLE */
 
-#define WALLY_TX_ASSET_CT_VALUE_PREFIX_A 8
-#define WALLY_TX_ASSET_CT_VALUE_PREFIX_B 9
-#define WALLY_TX_ASSET_CT_ASSET_PREFIX_A 10
-#define WALLY_TX_ASSET_CT_ASSET_PREFIX_B 11
-#define WALLY_TX_ASSET_CT_NONCE_PREFIX_A 2
-#define WALLY_TX_ASSET_CT_NONCE_PREFIX_B 3
+#define WALLY_TX_ASSET_CT_EMPTY_PREFIX    0x00
+#define WALLY_TX_ASSET_CT_EXPLICIT_PREFIX 0x01
+#define WALLY_TX_ASSET_CT_VALUE_PREFIX_A  0x08
+#define WALLY_TX_ASSET_CT_VALUE_PREFIX_B  0x09
+#define WALLY_TX_ASSET_CT_ASSET_PREFIX_A  0x0a
+#define WALLY_TX_ASSET_CT_ASSET_PREFIX_B  0x0b
+#define WALLY_TX_ASSET_CT_NONCE_PREFIX_A  0x02
+#define WALLY_TX_ASSET_CT_NONCE_PREFIX_B  0x03
 
 #define WALLY_TX_ASSET_TAG_LEN 32
 #define WALLY_TX_ASSET_CT_VALUE_LEN 33 /* version byte + 32 bytes */

src/script.c

@@ -193,7 +193,7 @@ static size_t get_commitment_len(const unsigned char *bytes,
 {
     if (!bytes || !*bytes)
         return sizeof(uint8_t); /* Null commitment */
-    if (*bytes == 1) {
+    if (*bytes == WALLY_TX_ASSET_CT_EXPLICIT_PREFIX) {
         /* Explicit value (unblinded) */
         if (prefixA == WALLY_TX_ASSET_CT_VALUE_PREFIX_A)
             return WALLY_TX_ASSET_CT_VALUE_UNBLIND_LEN; /* uint64 value */
@@ -209,7 +209,7 @@ static size_t confidential_commitment_varint_from_bytes(const unsigned char *byt
                                                         bool ct_value)
 {
     switch (*bytes) {
-    case 1:
+    case WALLY_TX_ASSET_CT_EXPLICIT_PREFIX:
         *v = ct_value ? WALLY_TX_ASSET_CT_VALUE_UNBLIND_LEN : WALLY_TX_ASSET_CT_LEN;
         return *v;
     case WALLY_TX_ASSET_CT_VALUE_PREFIX_A:

src/transaction.c

@@ -2414,11 +2414,11 @@ static int analyze_tx(const unsigned char *bytes, size_t bytes_len,
 
 #define ensure_commitment(dst, explicit_siz, prefix_a, prefix_b) \
     switch (*dst) { \
-    case 0: \
+    case WALLY_TX_ASSET_CT_EMPTY_PREFIX: \
         ensure_n(sizeof(uint8_t)); \
         p++; \
         break; \
-    case 1: \
+    case WALLY_TX_ASSET_CT_EXPLICIT_PREFIX: \
         ensure_n(explicit_siz); \
         p += explicit_siz; \
         break; \

src/wasm_package/const.js

@@ -164,15 +164,17 @@ export const WALLY_SIGHASH_NONE = 0x02;
 export const WALLY_SIGHASH_RANGEPROOF = 0x40 ; /* Liquid/Elements only */
 export const WALLY_SIGHASH_SINGLE = 0x03;
 export const WALLY_TX_ASSET_CT_ASSET_LEN = 33; /* version byte + 32 bytes */
-export const WALLY_TX_ASSET_CT_ASSET_PREFIX_A = 10;
-export const WALLY_TX_ASSET_CT_ASSET_PREFIX_B = 11;
+export const WALLY_TX_ASSET_CT_ASSET_PREFIX_A = 0x0a;
+export const WALLY_TX_ASSET_CT_ASSET_PREFIX_B = 0x0b;
+export const WALLY_TX_ASSET_CT_EMPTY_PREFIX = 0x00;
+export const WALLY_TX_ASSET_CT_EXPLICIT_PREFIX = 0x01;
 export const WALLY_TX_ASSET_CT_LEN = 33      ; /* version byte + 32 bytes */
 export const WALLY_TX_ASSET_CT_NONCE_LEN = 33; /* version byte + 32 bytes */
-export const WALLY_TX_ASSET_CT_NONCE_PREFIX_A = 2;
-export const WALLY_TX_ASSET_CT_NONCE_PREFIX_B = 3;
+export const WALLY_TX_ASSET_CT_NONCE_PREFIX_A = 0x02;
+export const WALLY_TX_ASSET_CT_NONCE_PREFIX_B = 0x03;
 export const WALLY_TX_ASSET_CT_VALUE_LEN = 33; /* version byte + 32 bytes */
-export const WALLY_TX_ASSET_CT_VALUE_PREFIX_A = 8;
-export const WALLY_TX_ASSET_CT_VALUE_PREFIX_B = 9;
+export const WALLY_TX_ASSET_CT_VALUE_PREFIX_A = 0x08;
+export const WALLY_TX_ASSET_CT_VALUE_PREFIX_B = 0x09;
 export const WALLY_TX_ASSET_CT_VALUE_UNBLIND_LEN = 9; /* version byte + 8 bytes */
 export const WALLY_TX_ASSET_TAG_LEN = 32;
 export const WALLY_TX_DUMMY_NULL = 0x1; /* An empty witness item */