Reject bases>36 for compatibility with int

Author: skirpichev

main.c

@@ -150,11 +150,8 @@ MPZ_abs(MPZ_Object *u)
     return res;
 }
 
-/* Maps 1-byte integer to digit character for bases up to 36 and
-   from 37 up to 62, respectively. */
-static const char *num_to_text36 = "0123456789abcdefghijklmnopqrstuvwxyz";
-static const char *num_to_text62 = ("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-                                    "abcdefghijklmnopqrstuvwxyz");
+/* Maps 1-byte integer to digit character for bases up to 36. */
+static const char *num_to_text = "0123456789abcdefghijklmnopqrstuvwxyz";
 
 static const char *mpz_tag = "mpz(";
 static int OPT_TAG = 0x1;
@@ -163,9 +160,9 @@ static int OPT_PREFIX = 0x2;
 static PyObject *
 MPZ_to_str(MPZ_Object *u, int base, int options)
 {
-    if (base < 2 || base > 62) {
+    if (base < 2 || base > 36) {
         PyErr_SetString(PyExc_ValueError,
-                        "base must be in the interval [2, 62]");
+                        "mpz base must be >= 2 and <= 36");
         return NULL;
     }
 
@@ -209,9 +206,6 @@ MPZ_to_str(MPZ_Object *u, int base, int options)
         return PyErr_NoMemory();
         /* LCOV_EXCL_STOP */
     }
-
-    const char *num_to_text = base > 36 ? num_to_text62 : num_to_text36;
-
     for (size_t i = 0; i < len; i++) {
         *p = num_to_text[*p];
         p++;
@@ -266,9 +260,9 @@ const unsigned char gmp_digit_value_tab[] =
 static MPZ_Object *
 MPZ_from_str(PyObject *obj, int base)
 {
-    if (base != 0 && (base < 2 || base > 62)) {
+    if (base != 0 && (base < 2 || base > 36)) {
         PyErr_SetString(PyExc_ValueError,
-                        "base must be 0 or in the interval [2, 62]");
+                        "mpz base must be >= 2 and <= 36, or 0");
         return NULL;
     }
 
@@ -339,11 +333,6 @@ MPZ_from_str(PyObject *obj, int base)
     }
 
     const unsigned char *digit_value = gmp_digit_value_tab;
-
-    if (base > 36) {
-        digit_value += 208;
-    }
-
     Py_ssize_t new_len = len;
 
     for (Py_ssize_t i = 0; i < len; i++) {

tests/test_mpz.py

@@ -685,11 +685,9 @@ def test___sizeof__():
 def to_digits(n, base):
     if n == 0:
         return "0"
-    if base < 2 or base > 62:
-        raise ValueError("base must be in the interval [2, 62]")
+    if base < 2 or base > 36:
+        raise ValueError("mpz base must be >= 2 and <= 36")
     num_to_text = string.digits + string.ascii_lowercase
-    if base > 36:
-        num_to_text = num_to_text.upper() + string.ascii_lowercase
     digits = []
     if n < 0:
         sign = "-"
@@ -704,37 +702,7 @@ def to_digits(n, base):
     return sign + "".join(digits[::-1])
 
 
-def from_digits(s, base):
-    if s == "0":
-        return 0
-    if base < 2 or base > 62:
-        raise ValueError("base must be in the interval [2, 62]")
-    if base <= 36:
-        return int(s, base)
-    if s[0] == "-":
-        negative = True
-        s = s[1:]
-    else:
-        negative = False
-    n = 0
-    b = 1
-    for c in reversed(s):
-        v = ord(c)
-        if ord("0") <= v <= ord("9"):
-            v -= ord("0")
-        elif ord("A") <= v <= ord("Z"):
-            v -= ord("A") - 10
-        else:
-            if base <= 36:
-                v -= ord("a") - 10
-            else:
-                v -= ord("a") - 36
-        n += v*b
-        b *= base
-    return -n if negative else n
-
-
-@given(integers(), integers(min_value=2, max_value=62))
+@given(integers(), integers(min_value=2, max_value=36))
 def test_digits(x, base):
     mx = mpz(x)
     res = to_digits(x, base)
@@ -761,7 +729,7 @@ def test_digits_interface():
 
 
 @given(integers(), integers(min_value=2, max_value=36))
-def test_digits_frombase_low(x, base):
+def test_digits_frombase(x, base):
     mx = mpz(x)
     smx = mx.digits(base)
     assert mpz(smx, base) == mx
@@ -777,22 +745,6 @@ def test_digits_frombase_low(x, base):
         assert mpz(smx, smaller_base) == i
 
 
-@given(integers(), integers(min_value=37, max_value=62))
-def test_digits_frombase_high(x, base):
-    mx = mpz(x)
-    smx = mx.digits(base)
-    assert mpz(smx, base) == mx
-    assert from_digits(smx, base) == mx
-    smaller_base = (base + 2)//2 + 1
-    try:
-        g = from_digits(smx, smaller_base)
-    except ValueError:
-        with pytest.raises(ValueError):
-            mpz(smx, smaller_base)
-    else:
-        assert mpz(smx, smaller_base) == g
-
-
 @given(integers())
 def test_frombase_auto(x):
     mx = mpz(x)