Re: [FFmpeg-devel] [PATCH] lavu/eval: remove pow and exp2 for postfixes

2015-12-16 Thread Ganesh Ajjanagadde 
On Wed, Dec 16, 2015 at 6:17 AM, Michael Niedermayer  wrote:
> On Tue, Dec 15, 2015 at 10:56:16PM -0500, Ganesh Ajjanagadde wrote:
>> These postfixes can be computed statically, and there is no need to
>> waste runtime resources.
>>
>> Tested with FATE.
>>
>> Signed-off-by: Ganesh Ajjanagadde 
>> ---
>>  libavutil/eval.c | 52 
>>  1 file changed, 28 insertions(+), 24 deletions(-)
>
> LGTM
>
> thx

pushed, thanks

>
> [...]
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> Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
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Re: [FFmpeg-devel] [PATCH] lavu/eval: remove pow and exp2 for postfixes

2015-12-16 Thread Michael Niedermayer 
On Tue, Dec 15, 2015 at 10:56:16PM -0500, Ganesh Ajjanagadde wrote:
> These postfixes can be computed statically, and there is no need to
> waste runtime resources.
> 
> Tested with FATE.
> 
> Signed-off-by: Ganesh Ajjanagadde 
> ---
>  libavutil/eval.c | 52 
>  1 file changed, 28 insertions(+), 24 deletions(-)

LGTM

thx

[...]
-- 
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I do not agree with what you have to say, but I'll defend to the death your
right to say it. -- Voltaire


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[FFmpeg-devel] [PATCH] lavu/eval: remove pow and exp2 for postfixes

2015-12-15 Thread Ganesh Ajjanagadde 
These postfixes can be computed statically, and there is no need to
waste runtime resources.

Tested with FATE.

Signed-off-by: Ganesh Ajjanagadde 
---
 libavutil/eval.c | 52 
 1 file changed, 28 insertions(+), 24 deletions(-)

diff --git a/libavutil/eval.c b/libavutil/eval.c
index 44129d6..dcb8c56 100644
--- a/libavutil/eval.c
+++ b/libavutil/eval.c
@@ -57,27 +57,31 @@ typedef struct Parser {
 
 static const AVClass eval_class = { "Eval", av_default_item_name, NULL, 
LIBAVUTIL_VERSION_INT, offsetof(Parser,log_offset), offsetof(Parser,log_ctx) };
 
-static const int8_t si_prefixes['z' - 'E' + 1] = {
-['y'-'E']= -24,
-['z'-'E']= -21,
-['a'-'E']= -18,
-['f'-'E']= -15,
-['p'-'E']= -12,
-['n'-'E']= - 9,
-['u'-'E']= - 6,
-['m'-'E']= - 3,
-['c'-'E']= - 2,
-['d'-'E']= - 1,
-['h'-'E']=   2,
-['k'-'E']=   3,
-['K'-'E']=   3,
-['M'-'E']=   6,
-['G'-'E']=   9,
-['T'-'E']=  12,
-['P'-'E']=  15,
-['E'-'E']=  18,
-['Z'-'E']=  21,
-['Y'-'E']=  24,
+static const struct {
+double bin_val;
+double dec_val;
+int8_t exp;
+} si_prefixes['z' - 'E' + 1] = {
+['y'-'E']= { 8.271806125530276749e-25, 1e-24, -24 },
+['z'-'E']= { 8.4703294725430034e-22, 1e-21, -21 },
+['a'-'E']= { 8.6736173798840355e-19, 1e-18, -18 },
+['f'-'E']= { 8.8817841970012523e-16, 1e-15, -15 },
+['p'-'E']= { 9.0949470177292824e-13, 1e-12, -12 },
+['n'-'E']= { 9.3132257461547852e-10, 1e-9,  -9 },
+['u'-'E']= { 9.5367431640625e-7, 1e-6, -6 },
+['m'-'E']= { 9.765625e-4, 1e-3, -3 },
+['c'-'E']= { 9.8431332023036951e-3, 1e-2, -2 },
+['d'-'E']= { 9.921256574801246e-2, 1e-1, -1 },
+['h'-'E']= { 1.0159366732596479e2, 1e2, 2 },
+['k'-'E']= { 1.024e3, 1e3, 3 },
+['K'-'E']= { 1.024e3, 1e3, 3 },
+['M'-'E']= { 1.048576e6, 1e6, 6 },
+['G'-'E']= { 1.073741824e9, 1e9, 9 },
+['T'-'E']= { 1.099511627776e12, 1e12, 12 },
+['P'-'E']= { 1.125899906842624e15, 1e15, 15 },
+['E'-'E']= { 1.152921504606847e18, 1e18, 18 },
+['Z'-'E']= { 1.1805916207174113e21, 1e21, 21 },
+['Y'-'E']= { 1.2089258196146292e24, 1e24, 24 },
 };
 
 static const struct {
@@ -105,13 +109,13 @@ double av_strtod(const char *numstr, char **tail)
 d = pow(10, d / 20);
 next += 2;
 } else if (*next >= 'E' && *next <= 'z') {
-int e= si_prefixes[*next - 'E'];
+int e= si_prefixes[*next - 'E'].exp;
 if (e) {
 if (next[1] == 'i') {
-d*= pow( 2, e/0.3);
+d*= si_prefixes[*next - 'E'].bin_val;
 next+=2;
 } else {
-d*= pow(10, e);
+d*= si_prefixes[*next - 'E'].dec_val;
 next++;
 }
 }
-- 
2.6.4

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