Re: [PATCH] MdePkg/BaseLib: Base64Decode(): don't declare variables in nested blocks

["Liming Gao" <liming.gao@intel.com>]

Reviewed-by: Liming Gao <liming.gao@intel.com>

> -----Original Message-----
> From: Laszlo Ersek [mailto:lersek@redhat.com]
> Sent: Wednesday, July 17, 2019 6:59 AM
> To: edk2-devel-groups-io <devel@edk2.groups.io>
> Cc: Gao, Liming <liming.gao@intel.com>; Kinney, Michael D <michael.d.kinney@intel.com>; Philippe Mathieu-Daudé
> <philmd@redhat.com>; Gao, Zhichao <zhichao.gao@intel.com>
> Subject: [PATCH] MdePkg/BaseLib: Base64Decode(): don't declare variables in nested blocks
> 
> The EDK II C Coding Standards Specification (v2.20) strongly discourages
> variable declarations in nested block scope:
> 
> 5       Source Files
> 5.4     Code File Structure
> 5.4.1   Scoping Rules
> 5.4.1.1 Scope
> 
> > Block (local) Scope
> >
> > [...]
> >
> > Data declarations may follow the opening brace of a compound statement,
> > regardless of nesting depth, and before any code generating statements
> > have been entered. Other than at the outermost block of a function body,
> > this type of declaration is strongly discouraged.
> 
> Hoist such variable declarations in Base64Decode() to the outermost
> function scope.
> 
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
> Cc: Zhichao Gao <zhichao.gao@intel.com>
> Fixes: 35e242b698cdc6205e99a6d6a188bf27fecf9fb4
> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1980
> Reported-by: Zhichao Gao <zhichao.gao@intel.com>
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> ---
> 
> Notes:
>     Repo:   https://github.com/lersek/edk2.git
>     Branch: b64_decode_no_nested_bz1980
> 
>  MdePkg/Library/BaseLib/String.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/MdePkg/Library/BaseLib/String.c b/MdePkg/Library/BaseLib/String.c
> index 6198ccbc9672..45198373f25c 100644
> --- a/MdePkg/Library/BaseLib/String.c
> +++ b/MdePkg/Library/BaseLib/String.c
> @@ -1978,6 +1978,9 @@ Base64Decode (
>    UINT32  Accumulator;
>    UINTN   OriginalDestinationSize;
>    UINTN   SourceIndex;
> +  CHAR8   SourceChar;
> +  UINT32  Base64Value;
> +  UINT8   DestinationOctet;
> 
>    if (DestinationSize == NULL) {
>      return RETURN_INVALID_PARAMETER;
> @@ -2054,10 +2057,6 @@ Base64Decode (
>    // Decoding loop.
>    //
>    for (SourceIndex = 0; SourceIndex < SourceSize; SourceIndex++) {
> -    CHAR8  SourceChar;
> -    UINT32 Base64Value;
> -    UINT8  DestinationOctet;
> -
>      SourceChar = Source[SourceIndex];
> 
>      //
> --
> 2.19.1.3.g30247aa5d201