add indexing methods for Memory

Author: bicycle1885

docs/src/index.md

@@ -255,3 +255,7 @@ TranscodingStreams.finalize
 TranscodingStreams.startproc
 TranscodingStreams.process
 ```
+
+```@docs
+TranscodingStreams.Memory
+```

src/memory.jl

@@ -1,6 +1,11 @@
 # Memory
 # ======
 
+"""
+A contiguous memory.
+
+This type works like a `Vector` method.
+"""
 struct Memory
     ptr::Ptr{UInt8}
     size::UInt
@@ -9,3 +14,23 @@ end
 function Base.length(mem::Memory)
     return mem.size
 end
+
+function Base.endof(mem::Memory)
+    return Int(mem.size)
+end
+
+function Base.checkbounds(mem::Memory, i::Integer)
+    if !(1 ≤ i ≤ endof(mem))
+        throw(BoundsError(mem, i))
+    end
+end
+
+function Base.getindex(mem::Memory, i::Integer)
+    @boundscheck checkbounds(mem, i)
+    return unsafe_load(mem.ptr, i)
+end
+
+function Base.setindex!(mem::Memory, val::UInt8, i::Integer)
+    @boundscheck checkbounds(mem, i)
+    return unsafe_store!(mem.ptr, val, i)
+end

test/runtests.jl

@@ -2,6 +2,29 @@ using TranscodingStreams
 using TranscodingStreams.CodecIdentity
 using Base.Test
 
+@testset "Memory" begin
+    data = b"foobar"
+    mem = TranscodingStreams.Memory(pointer(data), sizeof(data))
+    @test mem isa TranscodingStreams.Memory
+    @test mem.ptr === pointer(data)
+    @test mem.size === length(mem) === UInt(sizeof(data))
+    @test endof(mem) === 6
+    @test mem[1] === UInt8('f')
+    @test mem[2] === UInt8('o')
+    @test mem[3] === UInt8('o')
+    @test mem[4] === UInt8('b')
+    @test mem[5] === UInt8('a')
+    @test mem[6] === UInt8('r')
+    @test_throws BoundsError mem[7]
+    @test_throws BoundsError mem[0]
+    mem[1] = UInt8('z')
+    @test mem[1] === UInt8('z')
+    mem[3] = UInt8('!')
+    @test mem[3] === UInt8('!')
+    @test_throws BoundsError mem[7] = 0x00
+    @test_throws BoundsError mem[0] = 0x00
+end
+
 @testset "Identity Codec" begin
     source = IOBuffer("")
     stream = TranscodingStream(Identity(), source)