file.c

   1 /* hexedit -- Hexadecimal Editor for Binary Files
   2    Copyright (C) 1998 Pixel (Pascal Rigaux)
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software
  16    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.*/
  17 #include "hexedit.h"
  18 #include <libgen.h>
  19
  20 void openFile(void)
  21 {
  22   struct stat st;
  23
  24   if (!is_file(fileName)) {
  25     fprintf(stderr, "%s: %s: Not a file.\n", progName, fileName);
  26     exit(1);
  27   }
  28
  29   /* edited should be cleaned here (assert(edited == NULL)) */
  30   if ((fd = open(fileName, O_RDWR)) == -1) {
  31     isReadOnly = TRUE;
  32     if ((fd = open(fileName, O_RDONLY)) == -1) {
  33       if (page) exitCurses();
  34       if (fileName[0] == '-') DIE(usage);
  35       fprintf(stderr, "%s: ", progName);
  36       perror(fileName);
  37       exit(1);
  38     }
  39   } else isReadOnly = FALSE;
  40   baseName = basename(fileName);
  41   mark_set = FALSE;
  42   lastEditedLoc = base = cursor = cursorOffset = 0;
  43
  44   /* check file size- doesn't work on devices.  I considered implementing a conquer-and-divide algorithm, but it would unpleasant on tape drives and such. */
  45   if (fstat(fd, &st) != -1 && st.st_size > 0)
  46     fileSize = st.st_size;
  47   else {
  48 #ifdef BLKGETSIZE
  49     unsigned long i;
  50     if (ioctl(fd, BLKGETSIZE, &i) == 0)
  51       fileSize = (off_t) i * 512;
  52     else
  53 #endif
  54       fileSize = 0;
  55   }
  56   biggestLoc = fileSize;
  57 }
  58
  59 void readFile(void)
  60 {
  61   typePage *p;
  62   off_t i;
  63
  64   memset(buffer, 0, page * sizeof(*buffer));
  65
  66   LSEEK(fd, base);
  67   nbBytes = read(fd, buffer, page);
  68   if (nbBytes < 0)
  69     nbBytes = 0;
  70   else if (nbBytes && base + nbBytes > biggestLoc)
  71     biggestLoc = base + nbBytes;
  72   memset(bufferAttr, A_NORMAL, page * sizeof(*bufferAttr));
  73   for (p = edited; p; p = p->next) {
  74     for (i = MAX(base, p->base); i < MIN(p->base + p->size, base + page); i++) {
  75       if (buffer[i - base] != p->vals[i - p->base]) {
  76         buffer[i - base] = p->vals[i - p->base];
  77         bufferAttr[i - base] |= MODIFIED;
  78       }
  79     }
  80     if (p->base + p->size > base + nbBytes) {   /* Check for modifications past EOF */
  81       for(; p->base + p->size > base + nbBytes && nbBytes < page; nbBytes++)
  82         bufferAttr[nbBytes] |= MODIFIED;
  83     }
  84   }
  85   if (mark_set) markSelectedRegion();
  86
  87 }
  88
  89 int findFile(void)
  90 {
  91   char *p, tmp[BLOCK_SEARCH_SIZE];
  92   p = lastFindFile ? strdup(lastFindFile) : NULL;
  93   if (!displayMessageAndGetString("File name: ", &p, tmp, sizeof(tmp))) return FALSE;
  94   if (!is_file(tmp)) return FALSE;
  95   FREE(lastFindFile); lastFindFile = fileName;
  96   fileName = p;
  97   return TRUE;
  98 }
  99
 100
 101 off_t getfilesize(void)
 102 {
 103   return MAX(lastEditedLoc, biggestLoc);
 104 }
 105
 106
 107 /* tryloc:
 108  *   returns TRUE if loc is an apropriate location to place the cursor
 109  *   assumes the file won't shrink.
 110  *   returns TRUE if the cursor is one past EOF to allow appending
 111  */
 112
 113 int tryloc(off_t loc)
 114 {
 115   char c;
 116   if (loc < 0)
 117     return FALSE;
 118   if (loc <= lastEditedLoc)
 119     return TRUE;
 120
 121   if (loc <= biggestLoc)
 122     return TRUE;
 123
 124   if (LSEEK_(fd, loc - 1) != -1 && /* don't have to worry about loc - 1 < 0 */
 125       read(fd, &c, 1) == 1) {
 126     biggestLoc = loc;
 127     return TRUE;
 128   }
 129   return FALSE;
 130 }
 131
 132 int is_file(char *name)
 133 {
 134   struct stat st;
 135   return stat(name, &st) != -1 && !S_ISDIR(st.st_mode);
 136 }
 137
 138