util.c

   1 /* See LICENSE file for copyright and license details. */
   2 #include <errno.h>
   3 #include <stdarg.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7
   8 #include "util.h"
   9
  10 char *argv0;
  11
  12 static void
  13 verr(const char *fmt, va_list ap)
  14 {
  15         if (argv0 && strncmp(fmt, "usage", sizeof("usage") - 1)) {
  16                 fprintf(stderr, "%s: ", argv0);
  17         }
  18
  19         vfprintf(stderr, fmt, ap);
  20
  21         if (fmt[0] && fmt[strlen(fmt) - 1] == ':') {
  22                 fputc(' ', stderr);
  23                 perror(NULL);
  24         } else {
  25                 fputc('\n', stderr);
  26         }
  27 }
  28
  29 void
  30 warn(const char *fmt, ...)
  31 {
  32         va_list ap;
  33
  34         va_start(ap, fmt);
  35         verr(fmt, ap);
  36         va_end(ap);
  37 }
  38
  39 void
  40 die(const char *fmt, ...)
  41 {
  42         va_list ap;
  43
  44         va_start(ap, fmt);
  45         verr(fmt, ap);
  46         va_end(ap);
  47
  48         exit(1);
  49 }
  50
  51 const char *
  52 bprintf(const char *fmt, ...)
  53 {
  54         va_list ap;
  55         int ret;
  56
  57         va_start(ap, fmt);
  58         if ((ret = vsnprintf(buf, sizeof(buf), fmt, ap)) < 0) {
  59                 warn("vsnprintf:");
  60         } else if ((size_t)ret >= sizeof(buf)) {
  61                 warn("vsnprintf: Output truncated");
  62         }
  63         va_end(ap);
  64
  65         return buf;
  66 }
  67
  68 const char *
  69 fmt_scaled(size_t bytes)
  70 {
  71         unsigned int i;
  72         float scaled;
  73         const char *units[] = { "B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB",
  74                                 "ZiB", "YiB" };
  75
  76         scaled = bytes;
  77         for (i = 0; i < LEN(units) && scaled >= 1024; i++) {
  78                 scaled /= 1024.0;
  79         }
  80
  81         return bprintf("%.1f%s", scaled, units[i]);
  82 }
  83
  84 int
  85 pscanf(const char *path, const char *fmt, ...)
  86 {
  87         FILE *fp;
  88         va_list ap;
  89         int n;
  90
  91         if (!(fp = fopen(path, "r"))) {
  92                 warn("fopen '%s':", path);
  93                 return -1;
  94         }
  95         va_start(ap, fmt);
  96         n = vfscanf(fp, fmt, ap);
  97         va_end(ap);
  98         fclose(fp);
  99
 100         return (n == EOF) ? -1 : n;
 101 }