bin/mandoc/dba_write.c

   1 /*      $Id: dba_write.c,v 1.3 2016/08/05 23:15:08 schwarze Exp $ */
   2 /*
   3  * Copyright (c) 2016 Ingo Schwarze <schwarze@openbsd.org>
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  *
  17  * Low-level functions for serializing allocation-based data to disk.
  18  * The interface is defined in "dba_write.h".
  19  */
  20 #include "config.h"
  21
  22 #include <assert.h>
  23 #if HAVE_ENDIAN
  24 #include <endian.h>
  25 #elif HAVE_SYS_ENDIAN
  26 #include <sys/endian.h>
  27 #elif HAVE_NTOHL
  28 #include <arpa/inet.h>
  29 #endif
  30 #if HAVE_ERR
  31 #include <err.h>
  32 #endif
  33 #include <errno.h>
  34 #include <fcntl.h>
  35 #include <stdint.h>
  36 #include <stdio.h>
  37
  38 #include "dba_write.h"
  39
  40 static FILE     *ofp;
  41
  42
  43 int
  44 dba_open(const char *fname)
  45 {
  46         ofp = fopen(fname, "w");
  47         return ofp == NULL ? -1 : 0;
  48 }
  49
  50 int
  51 dba_close(void)
  52 {
  53         return fclose(ofp) == EOF ? -1 : 0;
  54 }
  55
  56 int32_t
  57 dba_tell(void)
  58 {
  59         long             pos;
  60
  61         if ((pos = ftell(ofp)) == -1)
  62                 err(1, "ftell");
  63         if (pos >= INT32_MAX) {
  64                 errno = EOVERFLOW;
  65                 err(1, "ftell = %ld", pos);
  66         }
  67         return pos;
  68 }
  69
  70 void
  71 dba_seek(int32_t pos)
  72 {
  73         if (fseek(ofp, pos, SEEK_SET) == -1)
  74                 err(1, "fseek(%d)", pos);
  75 }
  76
  77 int32_t
  78 dba_align(void)
  79 {
  80         int32_t          pos;
  81
  82         pos = dba_tell();
  83         while (pos & 3) {
  84                 dba_char_write('\0');
  85                 pos++;
  86         }
  87         return pos;
  88 }
  89
  90 int32_t
  91 dba_skip(int32_t nmemb, int32_t sz)
  92 {
  93         const int32_t    out[5] = {0, 0, 0, 0, 0};
  94         int32_t          i, pos;
  95
  96         assert(sz >= 0);
  97         assert(nmemb > 0);
  98         assert(nmemb <= 5);
  99         pos = dba_tell();
 100         for (i = 0; i < sz; i++)
 101                 if (nmemb - fwrite(&out, sizeof(out[0]), nmemb, ofp))
 102                         err(1, "fwrite");
 103         return pos;
 104 }
 105
 106 void
 107 dba_char_write(int c)
 108 {
 109         if (putc(c, ofp) == EOF)
 110                 err(1, "fputc");
 111 }
 112
 113 void
 114 dba_str_write(const char *str)
 115 {
 116         if (fputs(str, ofp) == EOF)
 117                 err(1, "fputs");
 118         dba_char_write('\0');
 119 }
 120
 121 void
 122 dba_int_write(int32_t i)
 123 {
 124         i = htobe32(i);
 125         if (fwrite(&i, sizeof(i), 1, ofp) != 1)
 126                 err(1, "fwrite");
 127 }