Merge pull request #1936 from bettio/support-unnormalized-intn

Support unnormalized intn

Fix documentation about functions accepting big integers in not-normalized form,
and extend intn_to_double to accept them.

These changes are made under both the "Apache 2.0" and the "GNU Lesser General
Public License 2.1 or later" license terms (dual license).

SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later

Author: bettio

src/libAtomVM/intn.c

@@ -899,8 +899,10 @@ size_t intn_count_digits(const intn_digit_t *num, size_t num_len)
     return count;
 }
 
-double intn_to_double(const intn_digit_t *num, size_t len, intn_integer_sign_t sign)
+double intn_to_double(const intn_digit_t *num, size_t num_len, intn_integer_sign_t sign)
 {
+    size_t len = intn_count_digits(num, num_len);
+
     double acc = 0.0;
     double base = ((double) (UINT32_MAX)) + 1;
 

src/libAtomVM/intn.h

@@ -79,12 +79,8 @@
  * ## Functions Requiring Normalized Input
  *
  * The following functions MUST receive normalized input for correct operation:
- * - \c intn_to_string() - for correct output
- * - \c intn_to_double() - for correct conversion
  * - \c intn_to_int64() - for correct conversion
  * - \c intn_fits_int64() - for accurate check
- * - \c intn_to_integer_bytes() - for correct size calculation
- * - \c intn_required_unsigned_integer_bytes() - for accurate size
  *
  * All other functions accept both normalized and non-normalized inputs.
  *
@@ -719,9 +715,9 @@ size_t intn_count_digits(const intn_digit_t *num, size_t num_len);
  * @return Newly allocated null-terminated string (caller must free)
  *
  * @pre base >= 2 && base <= 36
- * @pre Input must be normalized for correct output
  * @post Returned string must be freed by caller
  * @note Output format: uppercase letters, no base prefix
+ * @note Accepts both normalized and non-normalized inputs
  */
 char *intn_to_string(const intn_digit_t *num, size_t len, intn_integer_sign_t num_sign, int base,
     size_t *string_len);
@@ -763,9 +759,9 @@ int intn_parse(
  * @param sign Sign of integer
  * @return Double representation
  *
- * @pre Input must be normalized
  * @note Precision loss expected for integers > 53 bits
  * @note With current 256-bit limit, result always fits in double range
+ * @note Accepts both normalized and non-normalized inputs
  */
 double intn_to_double(const intn_digit_t *num, size_t len, intn_integer_sign_t sign);