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libfreefare/0001-libfreefare-resolve-compiler-warning-on-breakage-of-.patch

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From 3dd547d851cca5906edc674e127ecaa2b49591b6 Mon Sep 17 00:00:00 2001
From: Jan Engelhardt <jengelh@inai.de>
Date: Wed, 5 Jun 2013 18:22:26 +0200
X-Upstream-Status: submitted, awaiting merge
Subject: [PATCH] libfreefare: resolve compiler warning on breakage of strict
aliasing
gcc warns:
mifare_classic.c:353:45: warning: dereferencing type-punned pointer
will break strict-aliasing rules [-Wstrict-aliasing]
There is another problem with this code: "data", being a 16-byte
array, may not be suitably aligned for the other types in the union.
This patch resolves this.
---
libfreefare/mifare_classic.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/libfreefare/mifare_classic.c b/libfreefare/mifare_classic.c
index aaf2d64..1502fe8 100644
--- a/libfreefare/mifare_classic.c
+++ b/libfreefare/mifare_classic.c
@@ -346,12 +346,10 @@ mifare_classic_init_value (MifareTag tag, const MifareClassicBlockNumber block,
int
mifare_classic_read_value (MifareTag tag, const MifareClassicBlockNumber block, int32_t *value, MifareClassicBlockNumber *adr)
{
- MifareClassicBlock data;
- if (mifare_classic_read (tag, block, &data) < 0)
- return -1;
-
- union mifare_classic_block b = *((union mifare_classic_block *)(&data));
+ union mifare_classic_block b;
+ if (mifare_classic_read (tag, block, b.data) < 0)
+ return -1;
if ((b.value.value ^ (uint32_t)~b.value.value_) || (b.value.value != b.value.value__)) {
errno = EIO;
--
1.8.2