From ba64ff777080225a128796c1423ded4d76c11df5 Mon Sep 17 00:00:00 2001
From: Ben Baumgold <4933671+baumgold@users.noreply.github.com>
Date: Tue, 11 Apr 2023 21:25:30 -0400
Subject: [PATCH 1/6] assert that input and output buffers passed to transcode!
 are independent

---
 src/transcode.jl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/transcode.jl b/src/transcode.jl
index b1b03876..fb8ccdb3 100644
--- a/src/transcode.jl
+++ b/src/transcode.jl
@@ -117,6 +117,7 @@ function transcode!(
     codec::Codec,
     input::Buffer,
 )
+    @assert input.data !== output.data "input and outbut buffers must be independent"
     error = Error()
     code = startproc(codec, :write, error)
     if code === :error

From 65e5f4d33072c4324fabcc0a7a6a82aba169e857 Mon Sep 17 00:00:00 2001
From: Ben Baumgold <4933671+baumgold@users.noreply.github.com>
Date: Thu, 13 Apr 2023 18:12:46 -0400
Subject: [PATCH 2/6] Use Base.dataids

Co-authored-by: Mark Kittisopikul <mkitti@users.noreply.github.com>
---
 src/transcode.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/transcode.jl b/src/transcode.jl
index fb8ccdb3..e91845e8 100644
--- a/src/transcode.jl
+++ b/src/transcode.jl
@@ -117,7 +117,7 @@ function transcode!(
     codec::Codec,
     input::Buffer,
 )
-    @assert input.data !== output.data "input and outbut buffers must be independent"
+    @assert Base.dataids(input.data) !== Base.dataids(output.data) "input and outbut buffers must be independent"
     error = Error()
     code = startproc(codec, :write, error)
     if code === :error

From 2d5e125c343450cf2731abeb83d9035016d4dd75 Mon Sep 17 00:00:00 2001
From: Ben Baumgold <4933671+baumgold@users.noreply.github.com>
Date: Fri, 14 Apr 2023 15:02:07 -0400
Subject: [PATCH 3/6] use Base.mightalias and add test

---
 src/noop.jl       | 7 +++----
 src/transcode.jl  | 2 +-
 test/codecnoop.jl | 2 ++
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/noop.jl b/src/noop.jl
index 2ebc44c2..a75b0f00 100644
--- a/src/noop.jl
+++ b/src/noop.jl
@@ -116,11 +116,10 @@ function Base.unsafe_write(stream::NoopStream, input::Ptr{UInt8}, nbytes::UInt)
     end
 end
 
-function Base.transcode(::Type{Noop}, data::ByteData)
-    return transcode(Noop(), data)
-end
+initial_output_size(codec::Noop, input::Memory) = length(input)
 
-function Base.transcode(codec::Noop, input::Buffer, output::Buffer = Buffer())
+function transcode!(output::Buffer, codec::Noop, input::Buffer)
+    @assert !Base.mightalias(input.data, output.data) "input and outbut buffers must be independent"
     copydata!(output, input)
     return output.data
 end
diff --git a/src/transcode.jl b/src/transcode.jl
index e91845e8..df6ca86d 100644
--- a/src/transcode.jl
+++ b/src/transcode.jl
@@ -117,7 +117,7 @@ function transcode!(
     codec::Codec,
     input::Buffer,
 )
-    @assert Base.dataids(input.data) !== Base.dataids(output.data) "input and outbut buffers must be independent"
+    @assert !Base.mightalias(input.data, output.data) "input and outbut buffers must be independent"
     error = Error()
     code = startproc(codec, :write, error)
     if code === :error
diff --git a/test/codecnoop.jl b/test/codecnoop.jl
index 22e6e93c..a303bcad 100644
--- a/test/codecnoop.jl
+++ b/test/codecnoop.jl
@@ -189,6 +189,8 @@
     @test transcode(Noop, data)  == data
     @test transcode(Noop, data) !== data
 
+    data = Vector{UInt8}()
+    @test_throws AssertionError transcode(Noop(), data, data)
     data = b""
     @test transcode(Noop(), data)  == data
     @test transcode(Noop(), data) !== data

From cecee5690d21ba66589133408b32fac6fa5e6a4b Mon Sep 17 00:00:00 2001
From: Ben Baumgold <4933671+baumgold@users.noreply.github.com>
Date: Fri, 14 Apr 2023 15:24:23 -0400
Subject: [PATCH 4/6] fix noop codec implementation

---
 src/noop.jl | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/noop.jl b/src/noop.jl
index a75b0f00..30258dfc 100644
--- a/src/noop.jl
+++ b/src/noop.jl
@@ -118,13 +118,13 @@ end
 
 initial_output_size(codec::Noop, input::Memory) = length(input)
 
-function transcode!(output::Buffer, codec::Noop, input::Buffer)
-    @assert !Base.mightalias(input.data, output.data) "input and outbut buffers must be independent"
-    copydata!(output, input)
-    return output.data
+function process(codec::Noop, input::Memory, output::Memory, error::Error)
+    iszero(length(input)) && return (0, 0, :end)
+    n = min(length(input), length(output))
+    unsafe_copyto!(output.ptr, input.ptr, n)
+    (n, n, :ok)
 end
 
-
 # Stats
 # -----
 

From 2eec7700136d18e3bf7378ba49f7c2a7c54a07ca Mon Sep 17 00:00:00 2001
From: Ben Baumgold <4933671+baumgold@users.noreply.github.com>
Date: Tue, 18 Apr 2023 07:46:25 -0400
Subject: [PATCH 5/6] add unsafe_transcode

---
 src/transcode.jl | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/src/transcode.jl b/src/transcode.jl
index df6ca86d..c9e65664 100644
--- a/src/transcode.jl
+++ b/src/transcode.jl
@@ -106,10 +106,10 @@ end
 """
     transcode!(output::Buffer, codec::Codec, input::Buffer)
 
-Transcode `input` by applying `codec` and storing the results in `output`.
-Note that this method does not initialize or finalize `codec`. This is
-efficient when you transcode a number of pieces of data, but you need to call
-[`TranscodingStreams.initialize`](@ref) and
+Transcode `input` by applying `codec` and storing the results in `output`
+with validation of input and output.  Note that this method does not initialize
+or finalize `codec`. This is efficient when you transcode a number of
+pieces of data, but you need to call [`TranscodingStreams.initialize`](@ref) and
 [`TranscodingStreams.finalize`](@ref) explicitly.
 """
 function transcode!(
@@ -118,6 +118,23 @@ function transcode!(
     input::Buffer,
 )
     @assert !Base.mightalias(input.data, output.data) "input and outbut buffers must be independent"
+    unsafe_transcode!(output, codec, input)
+end
+
+"""
+    unsafe_transcode!(output::Buffer, codec::Codec, input::Buffer)
+
+Transcode `input` by applying `codec` and storing the results in `output`
+without validation of input or output.  Note that this method does not initialize
+or finalize `codec`. This is efficient when you transcode a number of
+pieces of data, but you need to call [`TranscodingStreams.initialize`](@ref) and
+[`TranscodingStreams.finalize`](@ref) explicitly.
+"""
+function unsafe_transcode!(
+    output::Buffer,
+    codec::Codec,
+    input::Buffer,
+)
     error = Error()
     code = startproc(codec, :write, error)
     if code === :error

From bd5fe77f3f30d0a40ae07ad3f4caaf80212958a4 Mon Sep 17 00:00:00 2001
From: Ben Baumgold <4933671+baumgold@users.noreply.github.com>
Date: Tue, 18 Apr 2023 08:48:40 -0400
Subject: [PATCH 6/6] add test

---
 src/transcode.jl  | 6 ++++++
 test/codecnoop.jl | 1 +
 2 files changed, 7 insertions(+)

diff --git a/src/transcode.jl b/src/transcode.jl
index c9e65664..461f95b9 100644
--- a/src/transcode.jl
+++ b/src/transcode.jl
@@ -183,6 +183,12 @@ Base.transcode(codec::Codec, data::Buffer, output::ByteData) =
 Base.transcode(codec::Codec, data::ByteData, args...) =
     transcode(codec, Buffer(data), args...)
 
+unsafe_transcode!(codec::Codec, data::Buffer, output::ByteData) =
+    unsafe_transcode!(Buffer(output), codec, data)
+
+unsafe_transcode!(codec::Codec, data::ByteData, args...) =
+    unsafe_transcode!(codec, Buffer(data), args...)
+
 # Return the initial output buffer size.
 function initial_output_size(codec::Codec, input::Memory)
     return max(
diff --git a/test/codecnoop.jl b/test/codecnoop.jl
index a303bcad..d288f3c3 100644
--- a/test/codecnoop.jl
+++ b/test/codecnoop.jl
@@ -190,6 +190,7 @@
     @test transcode(Noop, data) !== data
 
     data = Vector{UInt8}()
+    @test TranscodingStreams.unsafe_transcode!(Noop(), data, data) == data
     @test_throws AssertionError transcode(Noop(), data, data)
     data = b""
     @test transcode(Noop(), data)  == data