From 230b1c070baa3b6d4bd590426a365b843d60ff50 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Martin=20Storsj=C3=B6?= Date: Mon, 1 Aug 2016 09:07:48 +0300 Subject: [PATCH] intreadwrite: Add intermediate variables in the byteswise AV_W*() macros MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This avoids issues with expanding the argument multiple times, and makes sure that it is of the right type for the following shifts. Even if the caller of a macro could be expected not to pass parameters that have side effects if expanded multiple times, these fallback codepaths are rarely, if ever, tested, so it is expected that such issues can arise. Thefore, for safety, make sure the fallback codepaths only expand the arguments once. Signed-off-by: Martin Storsjö --- libavutil/intreadwrite.h | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/libavutil/intreadwrite.h b/libavutil/intreadwrite.h index cdf1ef47ec..5f65957ce5 100644 --- a/libavutil/intreadwrite.h +++ b/libavutil/intreadwrite.h @@ -210,7 +210,8 @@ union unaligned_16 { uint16_t l; } __attribute__((packed)) av_alias; ((const uint8_t*)(x))[1]) #endif #ifndef AV_WB16 -# define AV_WB16(p, d) do { \ +# define AV_WB16(p, val) do { \ + uint16_t d = val; \ ((uint8_t*)(p))[1] = (d); \ ((uint8_t*)(p))[0] = (d)>>8; \ } while(0) @@ -222,7 +223,8 @@ union unaligned_16 { uint16_t l; } __attribute__((packed)) av_alias; ((const uint8_t*)(x))[0]) #endif #ifndef AV_WL16 -# define AV_WL16(p, d) do { \ +# define AV_WL16(p, val) do { \ + uint16_t d = val; \ ((uint8_t*)(p))[0] = (d); \ ((uint8_t*)(p))[1] = (d)>>8; \ } while(0) @@ -236,7 +238,8 @@ union unaligned_16 { uint16_t l; } __attribute__((packed)) av_alias; ((const uint8_t*)(x))[3]) #endif #ifndef AV_WB32 -# define AV_WB32(p, d) do { \ +# define AV_WB32(p, val) do { \ + uint32_t d = val; \ ((uint8_t*)(p))[3] = (d); \ ((uint8_t*)(p))[2] = (d)>>8; \ ((uint8_t*)(p))[1] = (d)>>16; \ @@ -252,7 +255,8 @@ union unaligned_16 { uint16_t l; } __attribute__((packed)) av_alias; ((const uint8_t*)(x))[0]) #endif #ifndef AV_WL32 -# define AV_WL32(p, d) do { \ +# define AV_WL32(p, val) do { \ + uint32_t d = val; \ ((uint8_t*)(p))[0] = (d); \ ((uint8_t*)(p))[1] = (d)>>8; \ ((uint8_t*)(p))[2] = (d)>>16; \ @@ -272,7 +276,8 @@ union unaligned_16 { uint16_t l; } __attribute__((packed)) av_alias; (uint64_t)((const uint8_t*)(x))[7]) #endif #ifndef AV_WB64 -# define AV_WB64(p, d) do { \ +# define AV_WB64(p, val) do { \ + uint64_t d = val; \ ((uint8_t*)(p))[7] = (d); \ ((uint8_t*)(p))[6] = (d)>>8; \ ((uint8_t*)(p))[5] = (d)>>16; \ @@ -296,7 +301,8 @@ union unaligned_16 { uint16_t l; } __attribute__((packed)) av_alias; (uint64_t)((const uint8_t*)(x))[0]) #endif #ifndef AV_WL64 -# define AV_WL64(p, d) do { \ +# define AV_WL64(p, val) do { \ + uint64_t d = val; \ ((uint8_t*)(p))[0] = (d); \ ((uint8_t*)(p))[1] = (d)>>8; \ ((uint8_t*)(p))[2] = (d)>>16; \