fix overflows in rational comparisons. part of #2960

JuliaLang · Jul 2, 2013 · d4c4d2a · d4c4d2a
1 parent cf01a16
commit d4c4d2a
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Showing 5 changed files with 19 additions and 5 deletions.
diff --git a/base/gmp.jl b/base/gmp.jl
@@ -316,7 +316,9 @@ end
 ndigits(x::BigInt) = ccall((:__gmpz_sizeinbase,:libgmp), Culong, (Ptr{BigInt}, Int32), &x, 10)
 isprime(x::BigInt, reps=25) = ccall((:__gmpz_probab_prime_p,:libgmp), Cint, (Ptr{BigInt}, Cint), &x, reps) > 0
 
-widemul(x::BigInt, y::BigInt) = x*y
-widemul(x::Union(Int128,Uint128), y::Union(Int128,Uint128)) = BigInt(x)*BigInt(y)
+widemul(x::BigInt, y::BigInt)   = x*y
+widemul(x::Int128, y::Uint128)  = BigInt(x)*BigInt(y)
+widemul(x::Uint128, y::Int128)  = BigInt(x)*BigInt(y)
+widemul{T<:Integer}(x::T, y::T) = BigInt(x)*BigInt(y)
 
 end # module
diff --git a/base/int.jl b/base/int.jl
@@ -484,6 +484,8 @@ widemul(x::Uint16, y::Uint16) = uint32(x)*uint32(y)
 widemul(x::Int32, y::Int32) = int64(x)*int64(y)
 widemul(x::Uint32, y::Uint32) = uint64(x)*uint64(y)
 
+widemul(x::Integer, y::Integer) = widemul(promote(x,y)...)
+
 if WORD_SIZE==32
     function widemul(u::Int64, v::Int64)
         local u0::Uint64, v0::Uint64, w0::Uint64

diff --git a/base/rational.jl b/base/rational.jl
@@ -144,12 +144,18 @@ end
 ==(q::Rational, x::FloatingPoint) = ispow2(q.den) & (x == q.num/q.den) & (x*q.den == q.num)
 
 # TODO: fix inequalities to be in line with equality check
-< (x::Rational, y::Rational) = x.den == y.den ? x.num < y.num : x.num*y.den < x.den*y.num
+< (x::Rational, y::Rational) = x.den == y.den ? x.num < y.num :
+                               widemul(x.num,y.den) < widemul(x.den,y.num)
+< (x::Rational, y::Integer ) = x.num < widemul(x.den,y)
 < (x::Rational, y::Real    ) = x.num < x.den*y
+< (x::Integer , y::Rational) = widemul(x,y.den) < y.num
 < (x::Real    , y::Rational) = x*y.den < y.num
 
-<=(x::Rational, y::Rational) = x.den == y.den ? x.num <= y.num : x.num*y.den <= x.den*y.num
+<=(x::Rational, y::Rational) = x.den == y.den ? x.num <= y.num :
+                               widemul(x.num,y.den) <= widemul(x.den,y.num)
+<=(x::Rational, y::Integer ) = x.num <= widemul(x.den,y)
 <=(x::Rational, y::Real    ) = x.num <= x.den*y
+<=(x::Integer , y::Rational) = widemul(x,y.den) <= y.num
 <=(x::Real    , y::Rational) = x*y.den <= y.num
 
 div(x::Rational, y::Rational) = div(x.num*y.den, x.den*y.num)

diff --git a/src/ccall.cpp b/src/ccall.cpp
@@ -54,7 +54,7 @@ static std::map<std::string, void*> libMap;
 
 extern "C" int add_library_mapping(char *lib, void *hnd)
 {
-    JL_PUTS((char*)"WARNING: add_library_mapping is deprecated, use push!(DL_LOAD_PATH,\"/path/to/search\") instead.\n", JL_STDERR);
+    JL_PUTS(const_cast<char*>("WARNING: add_library_mapping is deprecated, use push!(DL_LOAD_PATH,\"/path/to/search\") instead.\n"), JL_STDERR);
     if (libMap[lib] == NULL && hnd != NULL) {
         libMap[lib] = hnd;
         return 0;

diff --git a/test/numbers.jl b/test/numbers.jl
@@ -1479,3 +1479,7 @@ end
 
 # issue #3520 - certain int literals on 32-bit systems
 @test -536870913 === -536870912-1
+
+# overflow in rational comparison
+@test 3//2 < typemax(Int)
+@test 3//2 <= typemax(Int)