WASM sanitizer for acropalypse

gistfile1.txt

(module
  (import "js" "mem" (memory 1))
  (import "console" "log" (func $log (param i32)))

  (func $getbyte (param $pos i32) (result i32)
    local.get $pos
    i32.const 255
    i32.and
  )
  
  (func (export "memtest") (param $size i32) (result i32)
    (local $hdr i32) (local $ftr i32) (local $hdridx i32) 
    (local $ftridx i32) (local $idx i32)

    i32.const 0
    local.set $hdr
    i32.const 0
    local.set $ftr
    i32.const 4 
    local.set $idx

    local.get $idx
    i32.load
    i32.const 0x474E5089
    i32.eq
    if
        local.get $idx
        i32.const 4
        i32.add
        local.set $idx
    else
        i32.const 1
        return
    end

    (loop $locate_iend
        local.get $idx
        i32.load
        i32.const 0x444E4549
        i32.eq
        if
            local.get $idx
            local.set $ftr
            local.get $idx
            i32.const 8
            i32.add
            local.set $idx
        else
            local.get $idx
            i32.const 1
            i32.add
            local.set $idx
            br $locate_iend
        end
    )

    local.get $ftr
    i32.const 0
    i32.gt_s
    if
        local.get $idx
        local.get $size
        i32.lt_s
        if
            (loop $null_bytes
                local.get $idx
                i32.const 0
                i32.store

                local.get $idx
                i32.const 1
                i32.add
                local.set $idx

                local.get $idx
                local.get $size
                i32.lt_s
                if
                    br $null_bytes
                end
            )
        end
    end

    i32.const 1
    return)
)