add getindex for Buffer

Author: bicycle1885

src/buffer.jl

@@ -32,6 +32,21 @@ function Base.length(buf::Buffer)
     return length(buf.data)
 end
 
+function Base.endof(buf::Buffer)
+    return buffersize(buf)
+end
+
+function Base.getindex(buf::Buffer, i::Integer)
+    @boundscheck checkbounds(buf, i)
+    @inbounds return buf.data[i+buf.bufferpos-1]
+end
+
+function Base.checkbounds(buf::Buffer, i::Integer)
+    if !(1 ≤ i ≤ endof(buf))
+        throw(BoundsError(buf, i))
+    end
+end
+
 function bufferptr(buf::Buffer)
     return pointer(buf.data, buf.bufferpos)
 end

test/runtests.jl

@@ -57,6 +57,15 @@ using Base.Test
     @test read(stream, UInt8) == data[3]
     skip(stream, 5)
     @test read(stream, UInt8) == data[9]
+
+    s = TranscodingStream(Identity(), IOBuffer(b"baz"))
+    @test endof(s.state.buffer1) == 0
+    read(s, UInt8)
+    @test endof(s.state.buffer1) == 2
+    @test s.state.buffer1[1] === UInt8('a')
+    @test s.state.buffer1[2] === UInt8('z')
+    @test_throws BoundsError s.state.buffer1[0]
+    @test_throws BoundsError s.state.buffer1[3]
 end
 
 Pkg.test("CodecZlib")