Implement format_bytes(), which pretty prints a given u_int64_t into a

given buffer, and if necessary, reducing the display width of the
number to fit in the buffer by increasing the units (from kilobytes
(2^10) through to exabytes (2^60)).
This commit is contained in:
lukem 1999-05-09 13:48:44 +00:00
parent 5ac207165b
commit 719cd63d24

View File

@ -1,12 +1,12 @@
/* $NetBSD: kern_subr.c,v 1.47 1999/04/21 02:37:07 mrg Exp $ */
/* $NetBSD: kern_subr.c,v 1.48 1999/05/09 13:48:44 lukem Exp $ */
/*-
* Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
* Copyright (c) 1997, 1998, 1999 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center.
* NASA Ames Research Center, and by Luke Mewburn.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@ -950,3 +950,44 @@ getstr(cp, size)
}
}
}
/*
* snprintf() `bytes' into `buf', reformatting it so that the number
* (plus a possible `xB' extension) fits into len bytes (including the
* terminating NUL). Returns the number of bytes stored in buf, or -1
* if there was a problem. E.g, given a len of 9:
* bytes result
* ----- ------
* 99999 `99999'
* 100000 `97 KB'
* 66715648 `65152 KB'
* 252215296 `240 MB'
*/
int
format_bytes(buf, len, bytes)
char *buf;
size_t len;
u_int64_t bytes;
{
/* prefixes are: Kilo, Mega, Giga, Tera, Peta, Exa */
static const char prefixes[] = " KMGTPE";
int i, r;
u_int64_t max;
if (len > 0)
buf[0] = '\0';
if (len < 6)
return (-1); /* not enough room for `xx yB\0' */
for (max = 1, i = 0; i < len - 4; i++)
max *= 10;
for (i = 0; bytes >= max && i < sizeof(prefixes); i++)
bytes /= 1024;
r = snprintf(buf, len, "%qd", (long long)bytes);
if (i > 0)
r += snprintf(buf + r, len - r, " %cB", prefixes[i]);
return (r);
}