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top: nested function allows us to reuse some code

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(not everyone likes them - but code does get smaller).

display_generic                                        -     761    +761
static.fmt_100percent_8                                -     111    +111
fmt_100percent_8                                     101       -    -101
display_status                                      1489     581    -908
------------------------------------------------------------------------------
(add/remove: 2/1 grow/shrink: 0/1 up/down: 872/-1009)        Total: -137 bytes
   text    data     bss     dec     hex filename
 677020    3344   13936  694300   a981c busybox_old
 676876    3344   13936  694156   a978c busybox_unstripped
This commit is contained in:
Denis Vlasenko 2007-07-15 19:27:48 +00:00
parent 24c5fbaf42
commit 110967a6f7
2 changed files with 57 additions and 53 deletions
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2
procps/Config.in
View File

@ -122,7 +122,7 @@ config FEATURE_TOP_CPU_GLOBAL_PERCENTS
Makes top display "CPU: NN% usr NN% sys..." line.
config FEATURE_TOP_DECIMALS
bool "Show 1/10th of a percent in CPU/mem statistics (adds 0.5k bytes)"
bool "Show 1/10th of a percent in CPU/mem statistics (adds 0.3k bytes)"
default n
depends on FEATURE_TOP_CPU_USAGE_PERCENTAGE
help

76
procps/top.c
View File

@ -212,30 +212,6 @@ static void do_stats(void)
}
#endif /* FEATURE_TOP_CPU_USAGE_PERCENTAGE */
#if ENABLE_FEATURE_TOP_DECIMALS
/* formats 7 char string (8 with terminating NUL) */
static char *fmt_100percent_8(char buf[8], unsigned value_10)
{
unsigned t;
if (value_10 >= 1000) {
strcpy(buf, " 100% ");
return buf;
}
/* else generate " [N/space]N.N% " string */
t = value_10 / 100;
value_10 = value_10 % 100;
buf[0] = ' ';
buf[1] = t ? t + '0' : ' ';
buf[2] = '0' + (value_10 / 10);
buf[3] = '.';
buf[4] = '0' + (value_10 % 10);
buf[5] = '%';
buf[6] = ' ';
buf[7] = '\0';
return buf;
}
#endif
/* display generic info (meminfo / loadavg) */
static unsigned long display_generic(int scr_width)
{
@ -243,6 +219,34 @@ static unsigned long display_generic(int scr_width)
char buf[80];
char scrbuf[80];
unsigned long total, used, mfree, shared, buffers, cached;
unsigned total_diff;
#if ENABLE_FEATURE_TOP_DECIMALS
/* formats 7 char string (8 with terminating NUL) */
/* using GCCism (nested function) - we need to access total_diff */
/* This produces more than 100 bytes smaller code */
char *fmt_100percent_8(char pbuf[8], unsigned value)
{
unsigned t;
if (value >= total_diff) { /* 100% ? */
strcpy(pbuf, " 100% ");
return pbuf;
}
/* else generate " [N/space]N.N% " string */
value = 1000 * value / total_diff;
t = value / 100;
value = value % 100;
pbuf[0] = ' ';
pbuf[1] = t ? t + '0' : ' ';
pbuf[2] = '0' + (value / 10);
pbuf[3] = '.';
pbuf[4] = '0' + (value % 10);
pbuf[5] = '%';
pbuf[6] = ' ';
pbuf[7] = '\0';
return pbuf;
}
#endif
/* read memory info */
fp = xfopen("meminfo", "r");
@ -292,37 +296,32 @@ static unsigned long display_generic(int scr_width)
}
fclose(fp);
/* read load average as a string */
buf[0] = '\0';
open_read_close("loadavg", buf, sizeof("N.NN N.NN N.NN")-1);
buf[sizeof("N.NN N.NN N.NN")-1] = '\0';
/* output memory info and load average */
/* clear screen & go to top */
/* output memory info */
if (scr_width > sizeof(scrbuf))
scr_width = sizeof(scrbuf);
snprintf(scrbuf, scr_width,
"Mem: %luK used, %luK free, %luK shrd, %luK buff, %luK cached",
used, mfree, shared, buffers, cached);
/* clear screen & go to top */
printf(OPT_BATCH_MODE ? "%s\n" : "\e[H\e[J%s\n", scrbuf);
if (ENABLE_FEATURE_TOP_CPU_GLOBAL_PERCENTS) {
/*
* xxx% = (jif.xxx - prev_jif.xxx) / (jif.total - prev_jif.total) * 100%
*/
/* using (unsigned) casts to make operations cheaper cheaper */
unsigned total_diff = ((unsigned)(jif.total - prev_jif.total) ? : 1);
/* using (unsigned) casts to make operations cheaper */
total_diff = ((unsigned)(jif.total - prev_jif.total) ? : 1);
#if ENABLE_FEATURE_TOP_DECIMALS
/* Generated code is approx +0.5k */
/* Generated code is approx +0.3k */
#define CALC_STAT(xxx) char xxx[8]
#define SHOW_STAT(xxx) fmt_100percent_8(xxx, 1000 * (unsigned)(jif.xxx - prev_jif.xxx) / total_diff)
#define SHOW_STAT(xxx) fmt_100percent_8(xxx, (unsigned)(jif.xxx - prev_jif.xxx))
#define FMT "%s"
#else
#define CALC_STAT(xxx) unsigned xxx = 100 * (unsigned)(jif.xxx - prev_jif.xxx) / total_diff
#define SHOW_STAT(xxx) xxx
#define FMT "%4u%% "
#endif
{ /* need block: CALC_STAT are declarations */
CALC_STAT(usr);
CALC_STAT(sys);
CALC_STAT(nic);
@ -340,12 +339,17 @@ static unsigned long display_generic(int scr_width)
//, SHOW_STAT(steal) - what is this 'steal' thing?
// I doubt anyone wants to know it
);
}
puts(scrbuf);
#undef SHOW_STAT
#undef CALC_STAT
#undef FMT
}
/* read load average as a string */
buf[0] = '\0';
open_read_close("loadavg", buf, sizeof("N.NN N.NN N.NN")-1);
buf[sizeof("N.NN N.NN N.NN")-1] = '\0';
snprintf(scrbuf, scr_width, "Load average: %s", buf);
puts(scrbuf);