util.c

   1 /* See LICENSE file for copyright and license details. */
   2 #include <errno.h>
   3 #include <stdarg.h>
   4 #include <stdint.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8
   9 #include "util.h"
  10
  11 char *argv0;
  12
  13 static void
  14 verr(const char *fmt, va_list ap)
  15 {
  16         if (argv0 && strncmp(fmt, "usage", sizeof("usage") - 1)) {
  17                 fprintf(stderr, "%s: ", argv0);
  18         }
  19
  20         vfprintf(stderr, fmt, ap);
  21
  22         if (fmt[0] && fmt[strlen(fmt) - 1] == ':') {
  23                 fputc(' ', stderr);
  24                 perror(NULL);
  25         } else {
  26                 fputc('\n', stderr);
  27         }
  28 }
  29
  30 void
  31 warn(const char *fmt, ...)
  32 {
  33         va_list ap;
  34
  35         va_start(ap, fmt);
  36         verr(fmt, ap);
  37         va_end(ap);
  38 }
  39
  40 void
  41 die(const char *fmt, ...)
  42 {
  43         va_list ap;
  44
  45         va_start(ap, fmt);
  46         verr(fmt, ap);
  47         va_end(ap);
  48
  49         exit(1);
  50 }
  51
  52 static int
  53 evsnprintf(char *str, size_t size, const char *fmt, va_list ap)
  54 {
  55         int ret;
  56
  57         ret = vsnprintf(str, size, fmt, ap);
  58
  59         if (ret < 0) {
  60                 warn("vsnprintf:");
  61                 return -1;
  62         } else if ((size_t)ret >= size) {
  63                 warn("vsnprintf: Output truncated");
  64                 return -1;
  65         }
  66
  67         return ret;
  68 }
  69
  70 int
  71 esnprintf(char *str, size_t size, const char *fmt, ...)
  72 {
  73         va_list ap;
  74         int ret;
  75
  76         va_start(ap, fmt);
  77         ret = evsnprintf(str, size, fmt, ap);
  78         va_end(ap);
  79
  80         return ret;
  81 }
  82
  83 const char *
  84 bprintf(const char *fmt, ...)
  85 {
  86         va_list ap;
  87         int ret;
  88
  89         va_start(ap, fmt);
  90         ret = evsnprintf(buf, sizeof(buf), fmt, ap);
  91         va_end(ap);
  92
  93         return (ret < 0) ? NULL : buf;
  94 }
  95
  96 const char *
  97 fmt_human(uint64_t num, int base)
  98 {
  99         double scaled;
 100         size_t i, prefixlen;
 101         const char **prefix;
 102         const char *prefix_1000[] = { "", "k", "M", "G", "T", "P", "E", "Z", "Y" };
 103         const char *prefix_1024[] = { "", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei",
 104                                       "Zi", "Yi" };
 105
 106         switch (base) {
 107         case 1000:
 108                 prefix = prefix_1000;
 109                 prefixlen = LEN(prefix_1000);
 110                 break;
 111         case 1024:
 112                 prefix = prefix_1024;
 113                 prefixlen = LEN(prefix_1024);
 114                 break;
 115         default:
 116                 warn("fmt_human: Invalid base");
 117                 return NULL;
 118         }
 119
 120         scaled = num;
 121         for (i = 0; i < prefixlen && scaled >= base; i++) {
 122                 scaled /= base;
 123         }
 124
 125         return bprintf("%.1f%s", scaled, prefix[i]);
 126 }
 127
 128 int
 129 pscanf(const char *path, const char *fmt, ...)
 130 {
 131         FILE *fp;
 132         va_list ap;
 133         int n;
 134
 135         if (!(fp = fopen(path, "r"))) {
 136                 warn("fopen '%s':", path);
 137                 return -1;
 138         }
 139         va_start(ap, fmt);
 140         n = vfscanf(fp, fmt, ap);
 141         va_end(ap);
 142         fclose(fp);
 143
 144         return (n == EOF) ? -1 : n;
 145 }