py: Implement bit-shift and not operations for mpz.

Implement not, shl and shr in mpz library.  Add function to create mpzs
on the stack, used for memory efficiency when rhs is a small int.
Factor out code to parse base-prefix of number into a dedicated function.

1 files changed, 40 insertions, 0 deletions

diff --git a/py/parsenumbase.c b/py/parsenumbase.c
new file mode 100644
index 0000000000..ad24cc678b
--- /dev/null
+++ b/py/parsenumbase.c
@@ -0,0 +1,40 @@
+#include "misc.h"
+#include "mpconfig.h"
+#include "parsenumbase.h"
+
+// find real radix base, and strip preceding '0x', '0o' and '0b'
+// puts base in *base, and returns number of bytes to skip the prefix
+int mp_parse_num_base(const char *str, uint len, int *base) {
+    const char *p = str;
+    int c = *(p++);
+    if ((*base == 0 || *base == 16) && c == '0') {
+        c = *(p++);
+        if ((c | 32) == 'x') {
+            *base = 16;
+        } else if (*base == 0 && (c | 32) == 'o') {
+            *base = 8;
+        } else if (*base == 0 && (c | 32) == 'b') {
+            *base = 2;
+        } else {
+            *base = 10;
+            p -= 2;
+        }
+    } else if (*base == 8 && c == '0') {
+        c = *(p++);
+        if ((c | 32) != 'o') {
+            p -= 2;
+        }
+    } else if (*base == 2 && c == '0') {
+        c = *(p++);
+        if ((c | 32) != 'b') {
+            p -= 2;
+        }
+    } else {
+        if (*base == 0) {
+            *base = 10;
+        }
+        p--;
+    }
+    return p - str;
+}
+