From 96ca2263af6d12d875d1ac729c6c268d00fad8dc Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Tue, 14 Jun 2022 22:32:05 -0400
Subject: [PATCH] Working version of str2bignum

---
 include/cyclone/types.h |  2 +-
 runtime.c               | 25 +++++++++++++++----------
 test-bn.scm             |  6 ++++--
 3 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/include/cyclone/types.h b/include/cyclone/types.h
index f1c3e9fc..99a7f981 100644
--- a/include/cyclone/types.h
+++ b/include/cyclone/types.h
@@ -1608,7 +1608,7 @@ void Cyc_int2bignum(int n, mp_int *bn);
 object Cyc_int2bignum2(gc_thread_data *data, int n);
 // TODO: debug only, remove this function from here!
 string_type *bignum2string(void *data, bignum2_type *bn, int base);
-void _str_to_bignum(void *data, char *str, *char *str_end, int radix);
+object _str_to_bignum(void *data, char *str, char *str_end, int radix);
 object bignum2_plus_unsigned(void *data, bignum2_type *x, bignum2_type *y, int negp);
 
 /* Remaining GC prototypes that require objects to be defined */
diff --git a/runtime.c b/runtime.c
index 28e16625..7daaa815 100644
--- a/runtime.c
+++ b/runtime.c
@@ -2948,16 +2948,6 @@ inline static int hex_char_to_digit(int ch)
   else return ch - (int)'0'; /* decimal (OR INVALID; handled elsewhere) */
 }
 
-void _str_to_bignum(void *data, char *str, *char *str_end, int radix) 
-{
-  TODO:
-   need to figure out sign, size (using nlz), what else??
-  bignum2_type *bn = gc_alloc_bignum2(data, 2);
-  bn->num_digits = 2;
-  bn->sign = 0;
-  str_to_bignum(data, bn, str, str_end, radix);
-}
-
 /* Write from digit character stream to bignum.  Bignum does not need
  * to be initialised.  Returns the bignum, or a fixnum.  Assumes the
  * string contains only digits that fit within radix (checked by
@@ -3022,6 +3012,21 @@ static object str_to_bignum(void *data, object bignum, char *str, char *str_end,
   return C_bignum_simplify(bignum);
 }
 
+object _str_to_bignum(void *data, char *str, char *str_end, int radix) 
+{
+  int negp = 0;
+  size_t nbits;
+  uint32_t size;
+  if (*str == '+' || *str == '-') {
+    negp = ((*str++) == '-') ? 1 : 0;
+  }
+  nbits = (str_end - str) * nlz(radix - 1);
+  size = C_BIGNUM_BITS_TO_DIGITS(nbits);
+  bignum2_type *bn = gc_alloc_bignum2(data, size);
+  bn->sign = negp;
+  return str_to_bignum(data, bn, str, str_end, radix);
+}
+
 // TODO: static
 //object bignum_plus_unsigned(C_word **ptr, C_word x, C_word y, C_word negp)
 object bignum2_plus_unsigned(void *data, bignum2_type *x, bignum2_type *y, int negp)
diff --git a/test-bn.scm b/test-bn.scm
index 53828522..9ad45cc1 100644
--- a/test-bn.scm
+++ b/test-bn.scm
@@ -17,8 +17,7 @@
    "(void *data, int argc, closure _, object k, object str, object radix)"
    " int len = string_len(str);
      char *s = string_str(str);
-     bignum2_type *bn = gc_alloc_bignum2(data, len);
-     bn = str_to_bignum(data, bn, s, s + len, obj_obj2int(radix));
+     object bn = _str_to_bignum(data, s, s + len, obj_obj2int(radix));
      return_closcall1(data, k, bn); ")
 
  (define-c test-plus
@@ -55,6 +54,9 @@ if(is_value_type(result)) {
 (write (test-str2bn "123454354534523454243999" 10))
 (newline)
 
+(write (test-str2bn "-123454354534523454243999" 10))
+(newline)
+
 (write (test-str2bn "123454354534523454243999" 16))
 (newline)