[tarantool-patches] Re: [PATCH] lua: Add string.decodehex method

[Vladislav Shpilevoy]

Hello. Thanks for contributing! See my 1 comment below.

On 07/05/2018 17:17, (Redacted sender gleb-skiba for DMARC) wrote:
> From: Gleb <gleb-skiba at mail.ru>
> 
> Add string.fromhex method.
> Add test for string.fromhex().
> 
> Fixes #2562
> ---
> Issue from https://github.com/tarantool/tarantool/issues/2562.
> Source from https://github.com/tarantool/tarantool/compare/gh-2562-string-bin?expand=1.
>   src/lua/string.lua           | 30 ++++++++++++++++++++++++++++++
>   test/app-tap/string.test.lua | 12 +++++++++++-
>   2 files changed, 41 insertions(+), 1 deletion(-)
> 
> diff --git a/src/lua/string.lua b/src/lua/string.lua
> index 5ff64c9..9be9a2a 100644
> --- a/src/lua/string.lua
> +++ b/src/lua/string.lua
> @@ -292,6 +292,35 @@ local function string_hex(inp)
>       return ffi.string(res, len)
>   end
>   
> +local tonum = {[48] = 0, [49] = 1, [50] = 2, [51] = 3, [52] = 4, [53] = 5,
> +[54] = 6, [55] = 7, [56] = 8, [57] = 9, [97] = 10, [98] = 11,
> +[99] = 12, [100] = 13, [101] = 14, [102] = 15, [65] = 10, [66] = 11,
> +[67] = 12, [68] = 13, [69] = 14, [70] = 15 }
> +
> +local function string_fromhex(inp)
> +    if type(inp) ~= 'string' then
> +        error(err_string_arg:format(1, 'string.fromhex', 'string', type(inp)), 2)
> +    end
> +
> +    if inp:len() % 2 ~= 0 then
> +        error(err_string_arg:format(1, 'string.fromhex', 'even string', 'odd string'), 2)
> +    end
> +
> +    local len = inp:len() / 2
> +    local uinp = ffi.cast('const char *', inp)
> +    local ans = ffi.new('char[?]', len)
> +
> +    for i = 0, len - 1 do
> +        local first = tonum[uinp[i * 2]]
> +        local second = tonum[uinp[i * 2 + 1]]
> +        if ((first == nil) or (second == nil)) then
> +            error(err_string_arg:format(1, 'string.fromhex', 'hex string', 'not hex string'), 2)
> +        end
> +        ans[i] = first * 16 + second
> +    end
> +    return ffi.string(ans, len)
> +end
> +
>   local function string_strip(inp)
>       if type(inp) ~= 'string' then
>           error(err_string_arg:format(1, "string.strip", 'string', type(inp)), 2)
> @@ -323,6 +352,7 @@ string.center     = string_center
>   string.startswith = string_startswith
>   string.endswith   = string_endswith
>   string.hex        = string_hex
> +string.fromhex    =string_fromhex

Put white spaces around '=', please.