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 int
  52 esnprintf(char *str, size_t size, const char *fmt, ...)
  53 {
  54         va_list ap;
  55         int ret;
  56
  57         va_start(ap, fmt);
  58         ret = vsnprintf(str, size, fmt, ap);
  59         va_end(ap);
  60
  61         if (ret < 0) {
  62                 warn("snprintf:");
  63                 return -1;
  64         } else if ((size_t)ret >= size) {
  65                 warn("snprintf: Output truncated");
  66                 return -1;
  67         }
  68
  69         return ret;
  70 }
  71
  72 const char *
  73 bprintf(const char *fmt, ...)
  74 {
  75         va_list ap;
  76         int ret;
  77
  78         va_start(ap, fmt);
  79         if ((ret = vsnprintf(buf, sizeof(buf), fmt, ap)) < 0) {
  80                 warn("vsnprintf:");
  81         } else if ((size_t)ret >= sizeof(buf)) {
  82                 warn("vsnprintf: Output truncated");
  83         }
  84         va_end(ap);
  85
  86         return buf;
  87 }
  88
  89 const char *
  90 fmt_human(size_t num, int base)
  91 {
  92         double scaled;
  93         size_t i, prefixlen;
  94         const char **prefix;
  95         const char *prefix_1000[] = { "", "k", "M", "G", "T", "P", "E", "Z", "Y" };
  96         const char *prefix_1024[] = { "", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei",
  97                                       "Zi", "Yi" };
  98
  99         switch (base) {
 100         case 1000:
 101                 prefix = prefix_1000;
 102                 prefixlen = LEN(prefix_1000);
 103                 break;
 104         case 1024:
 105                 prefix = prefix_1024;
 106                 prefixlen = LEN(prefix_1024);
 107                 break;
 108         default:
 109                 warn("fmt_human: Invalid base");
 110                 return NULL;
 111         }
 112
 113         scaled = num;
 114         for (i = 0; i < prefixlen && scaled >= base; i++) {
 115                 scaled /= base;
 116         }
 117
 118         return bprintf("%.1f%s", scaled, prefix[i]);
 119 }
 120
 121 int
 122 pscanf(const char *path, const char *fmt, ...)
 123 {
 124         FILE *fp;
 125         va_list ap;
 126         int n;
 127
 128         if (!(fp = fopen(path, "r"))) {
 129                 warn("fopen '%s':", path);
 130                 return -1;
 131         }
 132         va_start(ap, fmt);
 133         n = vfscanf(fp, fmt, ap);
 134         va_end(ap);
 135         fclose(fp);
 136
 137         return (n == EOF) ? -1 : n;
 138 }