[Gnash-commit] [SCM] Gnash branch, master, updated. 8a15dbc96e1786dae6b0e527e80c07a5b1724f9b

[Benjamin Wolsey]

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- Log -----------------------------------------------------------------
http://git.savannah.gnu.org/cgit//commit/?id=8a15dbc96e1786dae6b0e527e80c07a5b1724f9b


commit 8a15dbc96e1786dae6b0e527e80c07a5b1724f9b
Author: Benjamin Wolsey <address@hidden>
Date:   Thu Nov 25 10:30:14 2010 +0100

    Restore undefined behaviour because Lenny doesn't have boost 1.35

diff --git a/libbase/GnashNumeric.h b/libbase/GnashNumeric.h
index 567811d..5518ae6 100644
--- a/libbase/GnashNumeric.h
+++ b/libbase/GnashNumeric.h
@@ -34,8 +34,6 @@
 #include <algorithm>
 #include <boost/cstdint.hpp>
 #include <limits>
-#include <boost/type_traits/make_signed.hpp>
-#include <boost/type_traits/make_unsigned.hpp>
 #include <boost/utility/enable_if.hpp>
 
 namespace gnash {
@@ -58,66 +56,6 @@ isFinite(double d)
 #endif
 }
 
-/// Convert an unsigned type to a signed type of the same width.
-//
-/// This mimics the conversion from a two's complement signed type
-/// to a corresponding unsigned type. This is the de facto default
-/// conversion on most i686 machines, but the behaviour is undefined
-/// *in all cases* in C++, and produces incorrect results on
-/// some platforms.
-//
-/// @tparam unsigned_type   The type to convert from
-/// @param t                The value to convert
-/// @return                 An unsigned type of the same width
-template<typename unsigned_type>
-typename boost::make_signed<unsigned_type>::type
-to_signed(unsigned_type t,
-    typename boost::enable_if<
-        typename boost::is_unsigned<unsigned_type> >::type* dummy = 0)
-{
-    (void)dummy;
-    typedef typename boost::make_signed<unsigned_type>::type signed_type;
-
-    // The max of the corresponding signed type can be represented in the
-    // unsigned type.
-    const unsigned_type max = std::numeric_limits<signed_type>::max();
-
-    if (t <= max) return t;
-
-    const signed_type x = t & max;
-
-    const signed_type min = std::numeric_limits<signed_type>::min();
-
-    return min + x;
-}
-
-/// Convert a signed type to an unsigned type of the same width.
-//
-/// This mimics the conversion from an unsigned type to a two's
-/// complement signed type. This is the de facto default
-/// conversion on most i686 machines, but the behaviour is undefined
-/// *in all cases* in C++, and produces incorrect results on
-/// some platforms.
-//
-/// @tparam signed_type     The type to convert from
-/// @param t                The value to convert
-/// @return                 A signed type of the same width
-template<typename signed_type>
-typename boost::make_unsigned<signed_type>::type
-to_unsigned(signed_type t,
-    typename boost::enable_if<
-        typename boost::is_signed<signed_type> >::type* dummy = 0)
-{
-    (void)dummy;
-
-    typedef typename boost::make_unsigned<signed_type>::type unsigned_type;
-
-    // Anything positive can be represented.
-    if (t >= 0) return t;
-
-    return std::numeric_limits<unsigned_type>::max() + t + 1;
-}
-
 inline double
 infinite_to_zero(double x)
 {
@@ -173,7 +111,7 @@ truncateWithFactor(double a)
                 std::numeric_limits<boost::int32_t>::min() / factor;
 
     if (a >= lowerSignedLimit && a <= upperSignedLimit) {
-        return to_signed<boost::uint32_t>(a * factor);
+        return static_cast<boost::int32_t>(a * factor);
     }
 
     // This slow truncation happens only in very unlikely cases.
diff --git a/libcore/SWFMatrix.cpp b/libcore/SWFMatrix.cpp
index 5d8cf94..682c00f 100644
--- a/libcore/SWFMatrix.cpp
+++ b/libcore/SWFMatrix.cpp
@@ -69,13 +69,9 @@ toFixed16(double a)
 inline boost::int32_t
 multiplyFixed16(boost::int32_t a, boost::int32_t b)
 {
-    // Overflows are permitted only in unsigned types, so
-    // convert using two's complement first.
-    const boost::uint32_t mult = 
-        (to_unsigned<boost::int64_t>(a) * to_unsigned<boost::int64_t>(b) + 
0x8000) >> 16;
+    return (static_cast<boost::int64_t>(a) *
+            static_cast<boost::int64_t>(b) + 0x8000) >> 16;
 
-    // Convert back.
-    return to_signed<boost::uint32_t>(mult);
 }
 
 } // anonymous namepace
diff --git a/libcore/vm/ASHandlers.cpp b/libcore/vm/ASHandlers.cpp
index a683b64..c68eb08 100644
--- a/libcore/vm/ASHandlers.cpp
+++ b/libcore/vm/ASHandlers.cpp
@@ -1517,10 +1517,8 @@ ActionChr(ActionExec& thread)
 {
     as_environment& env = thread.env;
     
-    // The conversion to unsigned happens before truncation;
-    // this is important.
-    const boost::uint16_t c = to_unsigned<boost::int32_t>(
-        toInt(env.top(0), getVM(env)));
+    // This is UB:
+    const boost::uint16_t c = toInt(env.top(0), getVM(env));
 
     // If the argument to chr() is '0', we return
     // nothing, not NULL
@@ -1665,10 +1663,8 @@ ActionMbChr(ActionExec& thread)
         // No need to return.
     }
 
-    // The conversion to unsigned happens before truncation;
-    // this is important.
-    const boost::uint16_t i = to_unsigned<boost::int32_t>(
-        toInt(env.top(0), getVM(env)));
+    // This is UB
+    const boost::uint16_t i = toInt(env.top(0), getVM(env));
     
     std::string out = utf8::encodeUnicodeCharacter(i);
     
@@ -3031,7 +3027,8 @@ ActionShiftRight(ActionExec& thread)
 {
     as_environment& env = thread.env;
 
-    boost::uint32_t amount = to_unsigned(toInt(env.top(0), getVM(env)));
+    // This is UB.
+    boost::uint32_t amount = toInt(env.top(0), getVM(env));
     boost::int32_t value = toInt(env.top(1), getVM(env));
 
     value = value >> amount;
@@ -3045,7 +3042,8 @@ ActionShiftRight2(ActionExec& thread)
 {
     as_environment& env = thread.env;
 
-    boost::uint32_t amount = to_unsigned(toInt(env.top(0), getVM(env))); 
+    // This is UB
+    boost::uint32_t amount = toInt(env.top(0), getVM(env)); 
     boost::int32_t value = toInt(env.top(1), getVM(env));
 
     value = boost::uint32_t(value) >> amount;

-----------------------------------------------------------------------

Summary of changes:
 libbase/GnashNumeric.h    |   64 +--------------------------------------------
 libcore/SWFMatrix.cpp     |    8 +----
 libcore/vm/ASHandlers.cpp |   18 +++++-------
 3 files changed, 11 insertions(+), 79 deletions(-)


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