Generalize findn and findnz for non-1 indices

Author: timholy

base/array.jl

@@ -794,7 +794,7 @@ function findn(A::AbstractMatrix)
     I = similar(A, Int, nnzA)
     J = similar(A, Int, nnzA)
     count = 1
-    for j=1:size(A,2), i=1:size(A,1)
+    for j=indices(A,2), i=indices(A,1)
         if A[i,j] != 0
             I[count] = i
             J[count] = j
@@ -811,7 +811,7 @@ function findnz{T}(A::AbstractMatrix{T})
     NZs = Array{T,1}(nnzA)
     count = 1
     if nnzA > 0
-        for j=1:size(A,2), i=1:size(A,1)
+        for j=indices(A,2), i=indices(A,1)
             Aij = A[i,j]
             if Aij != 0
                 I[count] = i

test/offsetarray.jl

@@ -369,6 +369,14 @@ pmax, ipmax = findmax(parent(A))
 @test amax == pmax
 @test A[iamax] == amax
 @test amax == parent(A)[ipmax]
+z = OffsetArray([0 0; 2 0; 0 0; 0 0], (-3,-1))
+I,J = findn(z)
+@test I == [-1]
+@test J == [0]
+I,J,N = findnz(z)
+@test I == [-1]
+@test J == [0]
+@test N == [2]
 
 v  = OffsetArray([1,1e100,1,-1e100], (-3,))*1000
 v2 = OffsetArray([1,-1e100,1,1e100], (5,))*1000