diff options
| author | Guy Harris <guy@alum.mit.edu> | 2015-04-30 13:39:39 -0700 |
|---|---|---|
| committer | Guy Harris <guy@alum.mit.edu> | 2015-04-30 20:40:17 +0000 |
| commit | d2b02eaf591145f40eaa65d6b50908e47d7c4484 (patch) | |
| tree | 43b7a0df4e0b7a7212bc084cd401aac1c26cfce7 /wsutil/sign_ext.h | |
| parent | fac11078c3b5ace9b84c1058fb44714339f91190 (diff) | |
Don't shift signed values left.
That's not valid in C99, at least, if the value is negative or if the
shift count is the number of bits in the value - 1, and we might get
compile-time or run-time complaints about that.
Also, make bit masks unsigned; to quote a run-time error reported in
https://www.wireshark.org/lists/wireshark-dev/201504/msg00084.html
"left shift of 1 by 31 places cannot be represented in type 'int'", so
use type "unsigned int" instead, by shifting 1U rather than 1 left.
Change-Id: I62220808058cb93f83329c1916b888a2067d524c
Reviewed-on: https://code.wireshark.org/review/8254
Reviewed-by: Guy Harris <guy@alum.mit.edu>
Diffstat (limited to 'wsutil/sign_ext.h')
| -rw-r--r-- | wsutil/sign_ext.h | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/wsutil/sign_ext.h b/wsutil/sign_ext.h index 4371cacde6..e680361401 100644 --- a/wsutil/sign_ext.h +++ b/wsutil/sign_ext.h @@ -35,8 +35,14 @@ ws_sign_ext32(guint32 val, int no_of_bits) if (no_of_bits == 0) return val; - if (val & (1 << (no_of_bits-1))) - val |= (-1 << no_of_bits); + /* + * Don't shift signed values left; that's not valid in C99, at + * least, if the value is negative or if the shift count is + * the number of bits in the value - 1, and we might get + * compile-time or run-time complaints about that. + */ + if (val & (1U << (no_of_bits-1))) + val |= (0xFFFFFFFFU << no_of_bits); return val; } @@ -49,8 +55,14 @@ ws_sign_ext64(guint64 val, int no_of_bits) if (no_of_bits == 0) return val; - if (val & (G_GINT64_CONSTANT(1) << (no_of_bits-1))) - val |= (G_GINT64_CONSTANT(-1) << no_of_bits); + /* + * Don't shift signed values left; that's not valid in C99, at + * least, if the value is negative or if the shift count is + * the number of bits in the value - 1, and we might get + * compile-time or run-time complaints about that. + */ + if (val & (G_GUINT64_CONSTANT(1) << (no_of_bits-1))) + val |= (G_GUINT64_CONSTANT(0xFFFFFFFFFFFFFFFF) << no_of_bits); return val; } |