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lavu/eval: remove pow and exp2 for postfixes 

These postfixes can be computed statically, and there is no need to
waste runtime resources.

Tested with FATE.

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
This commit is contained in:
Ganesh Ajjanagadde 2015-12-15 22:42:05 -05:00
parent 10b16aee1b
commit 4fa6f09c2c
1 changed files with 28 additions and 24 deletions
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52
libavutil/eval.c
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@ -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++;
}
}