second commit

env/lib/python3.11/site-packages/mdurl/_decode.py

@@ -0,0 +1,104 @@
+from __future__ import annotations
+
+from collections.abc import Sequence
+import functools
+import re
+
+DECODE_DEFAULT_CHARS = ";/?:@&=+$,#"
+DECODE_COMPONENT_CHARS = ""
+
+decode_cache: dict[str, list[str]] = {}
+
+
+def get_decode_cache(exclude: str) -> Sequence[str]:
+    if exclude in decode_cache:
+        return decode_cache[exclude]
+
+    cache: list[str] = []
+    decode_cache[exclude] = cache
+
+    for i in range(128):
+        ch = chr(i)
+        cache.append(ch)
+
+    for i in range(len(exclude)):
+        ch_code = ord(exclude[i])
+        cache[ch_code] = "%" + ("0" + hex(ch_code)[2:].upper())[-2:]
+
+    return cache
+
+
+# Decode percent-encoded string.
+#
+def decode(string: str, exclude: str = DECODE_DEFAULT_CHARS) -> str:
+    cache = get_decode_cache(exclude)
+    repl_func = functools.partial(repl_func_with_cache, cache=cache)
+    return re.sub(r"(%[a-f0-9]{2})+", repl_func, string, flags=re.IGNORECASE)
+
+
+def repl_func_with_cache(match: re.Match, cache: Sequence[str]) -> str:
+    seq = match.group()
+    result = ""
+
+    i = 0
+    l = len(seq)  # noqa: E741
+    while i < l:
+        b1 = int(seq[i + 1 : i + 3], 16)
+
+        if b1 < 0x80:
+            result += cache[b1]
+            i += 3  # emulate JS for loop statement3
+            continue
+
+        if (b1 & 0xE0) == 0xC0 and (i + 3 < l):
+            # 110xxxxx 10xxxxxx
+            b2 = int(seq[i + 4 : i + 6], 16)
+
+            if (b2 & 0xC0) == 0x80:
+                all_bytes = bytes((b1, b2))
+                try:
+                    result += all_bytes.decode()
+                except UnicodeDecodeError:
+                    result += "\ufffd" * 2
+
+                i += 3
+                i += 3  # emulate JS for loop statement3
+                continue
+
+        if (b1 & 0xF0) == 0xE0 and (i + 6 < l):
+            # 1110xxxx 10xxxxxx 10xxxxxx
+            b2 = int(seq[i + 4 : i + 6], 16)
+            b3 = int(seq[i + 7 : i + 9], 16)
+
+            if (b2 & 0xC0) == 0x80 and (b3 & 0xC0) == 0x80:
+                all_bytes = bytes((b1, b2, b3))
+                try:
+                    result += all_bytes.decode()
+                except UnicodeDecodeError:
+                    result += "\ufffd" * 3
+
+                i += 6
+                i += 3  # emulate JS for loop statement3
+                continue
+
+        if (b1 & 0xF8) == 0xF0 and (i + 9 < l):
+            # 111110xx 10xxxxxx 10xxxxxx 10xxxxxx
+            b2 = int(seq[i + 4 : i + 6], 16)
+            b3 = int(seq[i + 7 : i + 9], 16)
+            b4 = int(seq[i + 10 : i + 12], 16)
+
+            if (b2 & 0xC0) == 0x80 and (b3 & 0xC0) == 0x80 and (b4 & 0xC0) == 0x80:
+                all_bytes = bytes((b1, b2, b3, b4))
+                try:
+                    result += all_bytes.decode()
+                except UnicodeDecodeError:
+                    result += "\ufffd" * 4
+
+                i += 9
+                i += 3  # emulate JS for loop statement3
+                continue
+
+        result += "\ufffd"
+        i += 3  # emulate JS for loop statement3
+
+    return result