Code review by LLM

CLAUDE.md

@@ -0,0 +1,41 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+MemoryViews.jl provides `MemoryView`, a low-level view into `Memory{T}` for Julia ≥ 1.11. It's a `DenseVector{T}` subtype representing a `MemoryRef{T}` + length, with static mutability tracking via type parameter (`Mutable`/`Immutable`). The package also defines the `MemoryKind` trait for dispatch on memory-backed types.
+
+## Commands
+
+```bash
+# Run tests
+JULIA_TEST_FAILFAST=true julia --project -e 'using Pkg; Pkg.test()'
+
+# Format code
+runic -i .
+```
+
+## Architecture
+
+**Core types** (defined in `src/MemoryViews.jl`):
+- `MemoryView{T, M}` where `M ∈ {Mutable, Immutable}` — the main type
+- `MemoryKind` trait: `IsMemory{T}` / `NotMemory` for dispatch
+
+**Source files**:
+- `construction.jl` — constructors from Array, Memory, String, SubArray, CodeUnits
+- `basic.jl` — indexing, slicing (returns views, not copies), copying, find operations with memchr/memrchr C calls, comparison via memcmp
+- `experimental.jl` — `split_first`, `split_last`, `split_at`, `split_unaligned`
+- `delimited.jl` — `split_each` delimiter iterator
+- `base_arrays.jl` — Vector/Memory conversion, append
+- `io.jl` — `readbytes!`
+
+**Extensions** (`ext/`): StringViews, FixedSizeArrays, LibDeflate integration.
+
+## Key Patterns
+
+- Slicing creates views into the same memory (no allocation)
+- Performance-critical paths use `@ccall` to libc (`memset`, `memcmp`, `memchr`, `memrchr`) with `GC.@preserve`
+- Version-conditional code for Julia 1.12+ vs 1.13+ (e.g., `Base.memoryindex` for `parentindices`)
+- Trait-based dispatch pattern: define `foo(x)` → `foo(MemoryKind(typeof(x)), x)` → specialized on `IsMemory`/`NotMemory`
+- `@boundscheck`/`@inbounds` used throughout for safe-by-default with opt-in elision

Project.toml

@@ -1,6 +1,6 @@
 name = "MemoryViews"
 uuid = "a791c907-b98b-4e44-8f4d-e4c2362c6b2f"
-version = "0.3.6"
+version = "0.3.7"
 authors = ["Jakob Nybo Nissen <jakobnybonissen@gmail.com>"]
 
 [weakdeps]

src/basic.jl

@@ -332,10 +332,11 @@ function Base.:(==)(a::Mem, b::Mem) where {Mem <: BitMemory}
     length(a) == length(b) || return false
     (eltype(a) === Union{} || Base.issingletontype(eltype(a))) && return true
     a.ref === b.ref && return true
+    nbytes = length(a) * sizeof(eltype(a))
     GC.@preserve a b begin
         aptr = Ptr{Nothing}(pointer(a))
         bptr = Ptr{Nothing}(pointer(b))
-        y = @ccall memcmp(aptr::Ptr{Nothing}, bptr::Ptr{Nothing}, length(a)::Int)::Cint
+        y = @ccall memcmp(aptr::Ptr{Nothing}, bptr::Ptr{Nothing}, nbytes::Csize_t)::Cint
     end
     return iszero(y)
 end

src/io.jl

@@ -14,5 +14,5 @@ function Base.readbytes!(io::IO, v::MutableMemoryView{UInt8}, nb::Integer = leng
         GC.@preserve v unsafe_read(io, Base.unsafe_convert(Ptr{UInt8}, remaining), ba % UInt)
         remaining = remaining[(ba + 1):end]
     end
-    return length(v) - length(remaining)
+    return min(nb, length(v) - length(remaining))
 end

test/runtests.jl

@@ -659,7 +659,7 @@ end
     data = b"Hello, world!"
     buf = IOBuffer(data)
     v = fill(0xaa, 25)
-    readbytes!(buf, MemoryView(v), 7)
+    @test readbytes!(buf, MemoryView(v), 7) == 7
     @test v[1:8] == b"Hello, \xaa"
 
     # With nb being higher than the vector length