From 715ee9d925871f2c44632442ff42cb58c99ee9c7 Mon Sep 17 00:00:00 2001
From: Damien George <damien.p.george@gmail.com>
Date: Sat, 28 May 2016 23:27:38 +0100
Subject: [PATCH] py/modstruct: Allow to have "0s" in struct format.
---
py/modstruct.c | 24 +++++++++---------------
tests/basics/struct2.py | 28 ++++++++++++++++++++++++++++
2 files changed, 37 insertions(+), 15 deletions(-)
create mode 100644 tests/basics/struct2.py
diff --git a/py/modstruct.c b/py/modstruct.c
index eabc951ae..2016add17 100644
--- a/py/modstruct.c
+++ b/py/modstruct.c
@@ -103,30 +103,24 @@ STATIC mp_obj_t struct_calcsize(mp_obj_t fmt_in) {
char fmt_type = get_fmt_type(&fmt);
mp_uint_t size;
for (size = 0; *fmt; fmt++) {
- mp_uint_t align = 1;
mp_uint_t cnt = 1;
if (unichar_isdigit(*fmt)) {
cnt = get_fmt_num(&fmt);
}
- mp_uint_t sz = 0;
if (*fmt == 's') {
- sz = cnt;
- cnt = 1;
- }
-
- while (cnt--) {
- // If we already have size for 's' case, don't set it again
- if (sz == 0) {
- sz = (mp_uint_t)mp_binary_get_size(fmt_type, *fmt, &align);
- }
+ size += cnt;
+ } else {
+ mp_uint_t align;
+ size_t sz = mp_binary_get_size(fmt_type, *fmt, &align);
if (sz == 0) {
nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "unsupported format"));
}
- // Apply alignment
- size = (size + align - 1) & ~(align - 1);
- size += sz;
- sz = 0;
+ while (cnt--) {
+ // Apply alignment
+ size = (size + align - 1) & ~(align - 1);
+ size += sz;
+ }
}
}
return MP_OBJ_NEW_SMALL_INT(size);
diff --git a/tests/basics/struct2.py b/tests/basics/struct2.py
new file mode 100644
index 000000000..f438bb55d
--- /dev/null
+++ b/tests/basics/struct2.py
@@ -0,0 +1,28 @@
+# test ustruct with a count specified before the type
+
+try:
+ import ustruct as struct
+except:
+ import struct
+
+print(struct.calcsize('0s'))
+print(struct.unpack('0s', b''))
+print(struct.pack('0s', b'123'))
+
+print(struct.calcsize('2s'))
+print(struct.unpack('2s', b'12'))
+print(struct.pack('2s', b'123'))
+
+print(struct.calcsize('2H'))
+print(struct.unpack('<2H', b'1234'))
+print(struct.pack('<2H', 258, 515))
+
+print(struct.calcsize('0s1s0H2H'))
+print(struct.unpack('<0s1s0H2H', b'01234'))
+print(struct.pack('<0s1s0H2H', b'abc', b'abc', 258, 515))
+
+# check that zero of an unknown type raises an exception
+try:
+ struct.calcsize('0z')
+except:
+ print('Exception')
--
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