[PATCH v2] media: staging/intel-ipu3: css: simplify expression

[PATCH v2] media: staging/intel-ipu3: css: simplify expression

[Deepak R Varma]

An array index computed inside square brackets leading to complexity
and code line exceeding 80 character. Add new variable to compute
array index separately and use it as an index during assignment.

Signed-off-by: Deepak R Varma <mh12gx2825@gmail.com>
---
Changes since v1:
  - Added feedback from Helen
	1. Updated variable type to "unsigned int" from earlier "int"
	2. Implemented the change in another area in same scope
	3. Left newly added variable unintialised.
  

 drivers/staging/media/ipu3/ipu3-css-params.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/media/ipu3/ipu3-css-params.c b/drivers/staging/media/ipu3/ipu3-css-params.c
index 4533dacad4be..5622319b69ff 100644
--- a/drivers/staging/media/ipu3/ipu3-css-params.c
+++ b/drivers/staging/media/ipu3/ipu3-css-params.c
@@ -49,13 +49,13 @@ imgu_css_scaler_setup_lut(unsigned int taps, unsigned int input_width,
 	int tap, phase, phase_sum_left, phase_sum_right;
 	int exponent = imgu_css_scaler_get_exp(output_width, input_width);
 	int mantissa = (1 << exponent) * output_width;
-	unsigned int phase_step;
+	unsigned int phase_step, phase_taps;
 
 	if (input_width == output_width) {
 		for (phase = 0; phase < IMGU_SCALER_PHASES; phase++) {
+			phase_taps = phase * IMGU_SCALER_FILTER_TAPS;
 			for (tap = 0; tap < taps; tap++) {
-				coeff_lut[phase * IMGU_SCALER_FILTER_TAPS + tap]
-					= 0;
+				coeff_lut[phase_taps + tap] = 0;
 			}
 		}
 
@@ -82,8 +82,8 @@ imgu_css_scaler_setup_lut(unsigned int taps, unsigned int input_width,
 			coeff += 1 << (IMGU_SCALER_COEFF_BITS - 1);
 			coeff >>= IMGU_SCALER_COEFF_BITS;
 
-			coeff_lut[phase * IMGU_SCALER_FILTER_TAPS + tap] =
-				coeff;
+			phase_taps = phase * IMGU_SCALER_FILTER_TAPS + tap;
+			coeff_lut[phase_taps] = coeff;
 		}
 	}
 
-- 
2.17.1

Re: [Outreachy kernel] [PATCH v2] media: staging/intel-ipu3: css: simplify expression

[Julia Lawall]

On Sat, 14 Mar 2020, Deepak R Varma wrote:

> An array index computed inside square brackets leading to complexity
> and code line exceeding 80 character.

This needs a verb.  "leading to complexity" is not precise enough to be
useful.

julia

> Add new variable to compute
> array index separately and use it as an index during assignment.
>
> Signed-off-by: Deepak R Varma <mh12gx2825@gmail.com>
> ---
> Changes since v1:
>   - Added feedback from Helen
> 	1. Updated variable type to "unsigned int" from earlier "int"
> 	2. Implemented the change in another area in same scope
> 	3. Left newly added variable unintialised.
>
>
>  drivers/staging/media/ipu3/ipu3-css-params.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/staging/media/ipu3/ipu3-css-params.c b/drivers/staging/media/ipu3/ipu3-css-params.c
> index 4533dacad4be..5622319b69ff 100644
> --- a/drivers/staging/media/ipu3/ipu3-css-params.c
> +++ b/drivers/staging/media/ipu3/ipu3-css-params.c
> @@ -49,13 +49,13 @@ imgu_css_scaler_setup_lut(unsigned int taps, unsigned int input_width,
>  	int tap, phase, phase_sum_left, phase_sum_right;
>  	int exponent = imgu_css_scaler_get_exp(output_width, input_width);
>  	int mantissa = (1 << exponent) * output_width;
> -	unsigned int phase_step;
> +	unsigned int phase_step, phase_taps;
>
>  	if (input_width == output_width) {
>  		for (phase = 0; phase < IMGU_SCALER_PHASES; phase++) {
> +			phase_taps = phase * IMGU_SCALER_FILTER_TAPS;
>  			for (tap = 0; tap < taps; tap++) {
> -				coeff_lut[phase * IMGU_SCALER_FILTER_TAPS + tap]
> -					= 0;
> +				coeff_lut[phase_taps + tap] = 0;
>  			}
>  		}
>
> @@ -82,8 +82,8 @@ imgu_css_scaler_setup_lut(unsigned int taps, unsigned int input_width,
>  			coeff += 1 << (IMGU_SCALER_COEFF_BITS - 1);
>  			coeff >>= IMGU_SCALER_COEFF_BITS;
>
> -			coeff_lut[phase * IMGU_SCALER_FILTER_TAPS + tap] =
> -				coeff;
> +			phase_taps = phase * IMGU_SCALER_FILTER_TAPS + tap;
> +			coeff_lut[phase_taps] = coeff;
>  		}
>  	}
>
> --
> 2.17.1
>
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