bip32: add calls to compute the length of a path string

Author: jgriffiths

include/wally.hpp

@@ -202,17 +202,29 @@ inline int bip32_key_unserialize_alloc(const BYTES& bytes, struct ext_key** outp
 }
 
 template <class PATH_STR>
-inline int bip32_path_from_str(const PATH_STR& path_str, uint32_t child_num, uint32_t multi_index, uint32_t flags, uint32_t* child_path_out, uint32_t child_path_out_len, size_t* written) {
+inline int bip32_path_from_str(const PATH_STR& path_str, uint32_t child_num, uint32_t multi_index, uint32_t flags, uint32_t* child_path_out, size_t child_path_out_len, size_t* written) {
     int ret = ::bip32_path_from_str(detail::get_p(path_str), child_num, multi_index, flags, child_path_out, child_path_out_len, written);
     return detail::check_ret(__FUNCTION__, ret);
 }
 
 template <class PATH_STR>
-inline int bip32_path_from_str_n(const PATH_STR& path_str, size_t path_str_len, uint32_t child_num, uint32_t multi_index, uint32_t flags, uint32_t* child_path_out, uint32_t child_path_out_len, size_t* written) {
+inline int bip32_path_from_str_len(const PATH_STR& path_str, uint32_t child_num, uint32_t multi_index, uint32_t flags, size_t* written) {
+    int ret = ::bip32_path_from_str_len(detail::get_p(path_str), child_num, multi_index, flags, written);
+    return detail::check_ret(__FUNCTION__, ret);
+}
+
+template <class PATH_STR>
+inline int bip32_path_from_str_n(const PATH_STR& path_str, size_t path_str_len, uint32_t child_num, uint32_t multi_index, uint32_t flags, uint32_t* child_path_out, size_t child_path_out_len, size_t* written) {
     int ret = ::bip32_path_from_str_n(detail::get_p(path_str), path_str_len, child_num, multi_index, flags, child_path_out, child_path_out_len, written);
     return detail::check_ret(__FUNCTION__, ret);
 }
 
+template <class PATH_STR>
+inline int bip32_path_from_str_n_len(const PATH_STR& path_str, size_t path_str_len, uint32_t child_num, uint32_t multi_index, uint32_t flags, size_t* written) {
+    int ret = ::bip32_path_from_str_n_len(detail::get_p(path_str), path_str_len, child_num, multi_index, flags, written);
+    return detail::check_ret(__FUNCTION__, ret);
+}
+
 template <class PATH_STR>
 inline int bip32_path_str_get_features(const PATH_STR& path_str, uint32_t* value_out) {
     int ret = ::bip32_path_str_get_features(detail::get_p(path_str), value_out);

include/wally_bip32.h

@@ -465,6 +465,22 @@ WALLY_CORE_API int bip32_key_get_fingerprint(
     unsigned char *bytes_out,
     size_t len);
 
+/**
+ * Get the number of child path elements in a BIP32 path string.
+ *
+ * :param path_str: The BIP32 path string of child numbers to convert from.
+ * :param child_num: The child number to use if ``path_str`` contains a ``*`` wildcard.
+ * :param multi_index: The multi-path item to use if ``path_str`` contains a ``<>`` multi-path.
+ * :param flags: :ref:`bip32-flags` controlling path parsing behaviour.
+ * :param written: Destination for the number of path elements in the path string.
+ */
+WALLY_CORE_API int bip32_path_from_str_len(
+    const char *path_str,
+    uint32_t child_num,
+    uint32_t multi_index,
+    uint32_t flags,
+    size_t *written);
+
 /**
  * Convert a BIP32 path string to a path.
  *
@@ -482,7 +498,20 @@ WALLY_CORE_API int bip32_path_from_str(
     uint32_t multi_index,
     uint32_t flags,
     uint32_t *child_path_out,
-    uint32_t child_path_out_len,
+    size_t child_path_out_len,
+    size_t *written);
+
+/**
+ * Get the number of child path elements in a known-length BIP32 path string.
+ *
+ * See `bip32_path_from_str_len`.
+ */
+WALLY_CORE_API int bip32_path_from_str_n_len(
+    const char *path_str,
+    size_t path_str_len,
+    uint32_t child_num,
+    uint32_t multi_index,
+    uint32_t flags,
     size_t *written);
 
 /**
@@ -497,7 +526,7 @@ WALLY_CORE_API int bip32_path_from_str_n(
     uint32_t multi_index,
     uint32_t flags,
     uint32_t *child_path_out,
-    uint32_t child_path_out_len,
+    size_t child_path_out_len,
     size_t *written);
 
 /**

src/bip32.c

@@ -89,7 +89,7 @@ static bool is_hardened_indicator(char c, bool allow_upper, uint32_t *features)
 static int path_from_str_n(const char *str, size_t str_len,
                            uint32_t child_num, uint32_t multi_index,
                            uint32_t *features, uint32_t flags,
-                           uint32_t *child_path, uint32_t child_path_len,
+                           uint32_t *child_path, size_t child_path_len,
                            size_t *written)
 {
     const bool allow_upper = flags & BIP32_FLAG_ALLOW_UPPER;
@@ -242,17 +242,27 @@ static int path_from_str_n(const char *str, size_t str_len,
 int bip32_path_from_str_n(const char *str, size_t str_len,
                           uint32_t child_num, uint32_t multi_index,
                           uint32_t flags,
-                          uint32_t *child_path, uint32_t child_path_len,
+                          uint32_t *child_path, size_t child_path_len,
                           size_t *written)
 {
     uint32_t features;
     return path_from_str_n(str, str_len, child_num, multi_index, &features,
                            flags, child_path, child_path_len, written);
 }
 
+int bip32_path_from_str_n_len(const char *str, size_t str_len,
+                              uint32_t child_num, uint32_t multi_index,
+                              uint32_t flags,
+                              size_t *written)
+{
+    uint32_t child_path;
+    return bip32_path_from_str_n(str, str_len, child_num, multi_index,
+                                 flags, &child_path, 1, written);
+}
+
 int bip32_path_from_str(const char *str, uint32_t child_num,
                         uint32_t multi_index, uint32_t flags,
-                        uint32_t *child_path, uint32_t child_path_len,
+                        uint32_t *child_path, size_t child_path_len,
                         size_t *written)
 {
     uint32_t features;
@@ -261,6 +271,14 @@ int bip32_path_from_str(const char *str, uint32_t child_num,
                            child_path, child_path_len, written);
 }
 
+int bip32_path_from_str_len(const char *str, uint32_t child_num,
+                            uint32_t multi_index, uint32_t flags,
+                            size_t *written)
+{
+    return bip32_path_from_str_n_len(str, str ? strlen(str) : 0, child_num,
+                           multi_index, flags, written);
+}
+
 int bip32_path_str_n_get_features(const char *str, size_t str_len,
                                   uint32_t *value_out)
 {

src/swig_java/swig.i

@@ -499,6 +499,8 @@ static jobjectArray create_jstringArray(JNIEnv *jenv, char **p, size_t len) {
 %rename("bip32_key_unserialize") bip32_key_unserialize_alloc;
 %returns_struct(bip32_key_with_tweak_from_parent_path_alloc, ext_key);
 %rename("bip32_key_with_tweak_from_parent_path") bip32_key_with_tweak_from_parent_path_alloc;
+%returns_size_t(bip32_path_from_str_len);
+%returns_size_t(bip32_path_from_str_n_len);
 %returns_array_(bip38_raw_from_private_key, 6, 7, BIP38_SERIALIZED_LEN);
 %returns_string(bip38_from_private_key);
 %returns_array_(bip38_raw_to_private_key, 6, 7, 32);

src/swig_python/python_extra.py_in

@@ -138,6 +138,8 @@ bip32_key_get_pub_key = _wrap_bin(bip32_key_get_pub_key, EC_PUBLIC_KEY_LEN)
 bip32_key_init = bip32_key_init_alloc
 bip32_key_serialize = _wrap_bin(bip32_key_serialize, BIP32_SERIALIZED_LEN)
 bip32_key_unserialize = bip32_key_unserialize_alloc
+bip32_path_from_str = _wrap_int_array(bip32_path_from_str, bip32_path_from_str_len)
+bip32_path_from_str_n = _wrap_int_array(bip32_path_from_str_n, bip32_path_from_str_n_len)
 bip340_tagged_hash = _wrap_bin(bip340_tagged_hash, SHA256_LEN)
 bip38_raw_from_private_key = _wrap_bin(bip38_raw_from_private_key, BIP38_SERIALIZED_LEN)
 bip38_raw_to_private_key = _wrap_bin(bip38_raw_to_private_key, EC_PRIVATE_KEY_LEN)

src/test/util.py

@@ -235,8 +235,10 @@ class wally_psbt(Structure):
     ('bip32_key_unserialize_alloc', c_int, [c_void_p, c_size_t, POINTER(POINTER(ext_key))]),
     ('bip32_key_with_tweak_from_parent_path', c_int, [POINTER(ext_key), POINTER(c_uint32), c_size_t, c_uint32, POINTER(ext_key)]),
     ('bip32_key_with_tweak_from_parent_path_alloc', c_int, [POINTER(ext_key), POINTER(c_uint32), c_size_t, c_uint32, POINTER(POINTER(ext_key))]),
-    ('bip32_path_from_str', c_int, [c_char_p, c_uint32, c_uint32, c_uint32, POINTER(c_uint32), c_uint32, c_size_t_p]),
-    ('bip32_path_from_str_n', c_int, [c_char_p, c_size_t, c_uint32, c_uint32, c_uint32, POINTER(c_uint32), c_uint32, c_size_t_p]),
+    ('bip32_path_from_str', c_int, [c_char_p, c_uint32, c_uint32, c_uint32, POINTER(c_uint32), c_size_t, c_size_t_p]),
+    ('bip32_path_from_str_len', c_int, [c_char_p, c_uint32, c_uint32, c_uint32, c_size_t_p]),
+    ('bip32_path_from_str_n', c_int, [c_char_p, c_size_t, c_uint32, c_uint32, c_uint32, POINTER(c_uint32), c_size_t, c_size_t_p]),
+    ('bip32_path_from_str_n_len', c_int, [c_char_p, c_size_t, c_uint32, c_uint32, c_uint32, c_size_t_p]),
     ('bip32_path_str_get_features', c_int, [c_char_p, c_uint32_p]),
     ('bip32_path_str_n_get_features', c_int, [c_char_p, c_size_t, c_uint32_p]),
     ('bip38_from_private_key', c_int, [c_void_p, c_size_t, c_void_p, c_size_t, c_uint32, c_char_p_p]),

src/wasm_package/src/functions.js

@@ -95,8 +95,8 @@ export function bip32_key_unserialize(bytes: Buffer|Uint8Array): Ref_ext_key;
 export function bip32_key_unserialize_noalloc(bytes: Buffer|Uint8Array, output: Ref_ext_key): void;
 export function bip32_key_with_tweak_from_parent_path(hdkey: Ref_ext_key, child_path: Uint32Array|number[], flags: number): Ref_ext_key;
 export function bip32_key_with_tweak_from_parent_path_noalloc(hdkey: Ref_ext_key, child_path: Uint32Array|number[], flags: number, output: Ref_ext_key): void;
-export function bip32_path_from_str(path_str: string, child_num: number, multi_index: number, flags: number, child_path_out_len: number): [child_path_out: number, written: number];
-export function bip32_path_from_str_n(path_str: string, path_str_len: number, child_num: number, multi_index: number, flags: number, child_path_out_len: number): [child_path_out: number, written: number];
+export function bip32_path_from_str_len(path_str: string, child_num: number, multi_index: number, flags: number): number;
+export function bip32_path_from_str_n_len(path_str: string, path_str_len: number, child_num: number, multi_index: number, flags: number): number;
 export function bip32_path_str_get_features(path_str: string): number;
 export function bip32_path_str_n_get_features(path_str: string, path_str_len: number): number;
 export function bip340_tagged_hash(bytes: Buffer|Uint8Array, tag: string): Buffer;
@@ -753,6 +753,8 @@ export function base58_n_to_bytes(str_in: string, str_len: number, flags: number
 export function base58_to_bytes(str_in: string, flags: number): Buffer;
 export function base64_n_to_bytes(str_in: string, str_len: number, flags: number): Buffer;
 export function base64_to_bytes(str_in: string, flags: number): Buffer;
+export function bip32_path_from_str(path_str: string, child_num: number, multi_index: number, flags: number): Uint32Array;
+export function bip32_path_from_str_n(path_str: string, path_str_len: number, child_num: number, multi_index: number, flags: number): Uint32Array;
 export function descriptor_get_key_child_path_str(descriptor: Ref_wally_descriptor, index: number): string;
 export function descriptor_get_key_origin_path_str(descriptor: Ref_wally_descriptor, index: number): string;
 export function descriptor_to_script(descriptor: Ref_wally_descriptor, depth: number, index: number, variant: number, multi_index: number, child_num: number, flags: number): Buffer;

src/wasm_package/src/index.d.ts

@@ -37,7 +37,9 @@ EXPORTED_FUNCTIONS="['_malloc','_free','_bip32_key_free' \
 ,'_bip32_key_unserialize' \
 ,'_bip32_key_unserialize_alloc' \
 ,'_bip32_path_from_str' \
+,'_bip32_path_from_str_len' \
 ,'_bip32_path_from_str_n' \
+,'_bip32_path_from_str_n_len' \
 ,'_bip32_path_str_get_features' \
 ,'_bip32_path_str_n_get_features' \
 ,'_bip38_get_flags' \