add

ccxt/static_dependencies/ethereum/utils/hexadecimal.py

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+# String encodings and numeric representations
+
+import binascii
+import re
+from typing import (
+    Any,
+    AnyStr,
+)
+
+from ..typing import (
+    HexStr,
+)
+
+from .types import (
+    is_string,
+    is_text,
+)
+
+_HEX_REGEXP = re.compile("(0[xX])?[0-9a-fA-F]*")
+
+
+def decode_hex(value: str) -> bytes:
+    if not is_text(value):
+        raise TypeError("Value must be an instance of str")
+    non_prefixed = remove_0x_prefix(HexStr(value))
+    # unhexlify will only accept bytes type someday
+    ascii_hex = non_prefixed.encode("ascii")
+    return binascii.unhexlify(ascii_hex)
+
+
+def encode_hex(value: AnyStr) -> HexStr:
+    if not is_string(value):
+        raise TypeError("Value must be an instance of str or unicode")
+    elif isinstance(value, (bytes, bytearray)):
+        ascii_bytes = value
+    else:
+        ascii_bytes = value.encode("ascii")
+
+    binary_hex = binascii.hexlify(ascii_bytes)
+    return add_0x_prefix(HexStr(binary_hex.decode("ascii")))
+
+
+def is_0x_prefixed(value: str) -> bool:
+    if not is_text(value):
+        raise TypeError(
+            f"is_0x_prefixed requires text typed arguments. Got: {repr(value)}"
+        )
+    return value.startswith(("0x", "0X"))
+
+
+def remove_0x_prefix(value: HexStr) -> HexStr:
+    if is_0x_prefixed(value):
+        return HexStr(value[2:])
+    return value
+
+
+def add_0x_prefix(value: HexStr) -> HexStr:
+    if is_0x_prefixed(value):
+        return value
+    return HexStr("0x" + value)
+
+
+def is_hexstr(value: Any) -> bool:
+    if not is_text(value) or not value:
+        return False
+    return _HEX_REGEXP.fullmatch(value) is not None
+
+
+def is_hex(value: Any) -> bool:
+    if not is_text(value):
+        raise TypeError(f"is_hex requires text typed arguments. Got: {repr(value)}")
+    if not value:
+        return False
+    return _HEX_REGEXP.fullmatch(value) is not None