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  1. /*
  2.  * Copyright (c) 2008 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup fs
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file    fat_dentry.c
  35.  * @brief   Functions that work with FAT directory entries.
  36.  */
  37.  
  38. #include "fat_dentry.h"
  39. #include <ctype.h>
  40. #include <string.h>
  41.  
  42. #define FAT_PAD         ' '
  43.  
  44. #define FAT_DENTRY_UNUSED   0x00
  45. #define FAT_DENTRY_E5_ESC   0x05
  46. #define FAT_DENTRY_DOT      0x2e
  47. #define FAT_DENTRY_ERASED   0xe5
  48.  
  49. static bool is_d_char(const char ch)
  50. {
  51.     if (isalnum(ch) || ch == '_')
  52.         return true;
  53.     else
  54.         return false;
  55. }
  56.  
  57. /** Compare path component with the name read from the dentry.
  58.  *
  59.  * This function compares the path component with the name read from the dentry.
  60.  * The comparison is case insensitive and tolerates a mismatch on the trailing
  61.  * dot character at the end of the name (i.e. when there is a dot, but no
  62.  * extension).
  63.  *
  64.  * @param name      Node name read from the dentry.
  65.  * @param component Path component.
  66.  *
  67.  * @return      Zero on match, non-zero otherwise.
  68.  */
  69. int fat_dentry_namecmp(char *name, const char *component)
  70. {
  71.     int rc;
  72.     if (!(rc = stricmp(name, component)))
  73.         return rc;
  74.     if (!strchr(name, '.')) {
  75.         /*
  76.          * There is no '.' in the name, so we know that there is enough
  77.          * space for appending an extra '.' to name.
  78.          */
  79.         name[strlen(name)] = '.';
  80.         name[strlen(name) + 1] = '\0';
  81.         rc = stricmp(name, component);
  82.     }
  83.     return rc;
  84. }
  85.  
  86. bool fat_dentry_name_verify(const char *name)
  87. {
  88.     unsigned i, dot;
  89.     bool dot_found = false;
  90.    
  91.  
  92.     for (i = 0; name[i]; i++) {
  93.         if (name[i] == '.') {
  94.             if (dot_found) {
  95.                 return false;
  96.             } else {
  97.                 dot_found = true;
  98.                 dot = i;
  99.             }
  100.         } else {
  101.             if (!is_d_char(name[i]))
  102.                 return false;
  103.         }
  104.     }
  105.  
  106.     if (dot_found) {
  107.         if (dot > FAT_NAME_LEN)
  108.             return false;
  109.         if (i - dot > FAT_EXT_LEN + 1)
  110.             return false;
  111.     } else {
  112.         if (i > FAT_NAME_LEN)
  113.             return false;
  114.     }
  115.  
  116.     return true;
  117. }
  118.  
  119. void fat_dentry_name_get(const fat_dentry_t *d, char *buf)
  120. {
  121.     int i;
  122.  
  123.     for (i = 0; i < FAT_NAME_LEN; i++) {
  124.         if (d->name[i] == FAT_PAD)
  125.             break;
  126.         if (d->name[i] == FAT_DENTRY_E5_ESC)
  127.             *buf++ = 0xe5;
  128.         else
  129.             *buf++ = d->name[i];
  130.     }
  131.     if (d->ext[0] != FAT_PAD)
  132.         *buf++ = '.';
  133.     for (i = 0; i < FAT_EXT_LEN; i++) {
  134.         if (d->ext[i] == FAT_PAD) {
  135.             *buf = '\0';
  136.             return;
  137.         }
  138.         if (d->ext[i] == FAT_DENTRY_E5_ESC)
  139.             *buf++ = 0xe5;
  140.         else
  141.             *buf++ = d->ext[i];
  142.     }
  143.     *buf = '\0';
  144. }
  145.  
  146. void fat_dentry_name_set(fat_dentry_t *d, const char *name)
  147. {
  148.     int i;
  149.     const char fake_ext[] = "   ";
  150.  
  151.  
  152.     for (i = 0; i < FAT_NAME_LEN; i++) {
  153.         switch ((uint8_t) *name) {
  154.         case 0xe5:
  155.             d->name[i] = FAT_DENTRY_E5_ESC;
  156.             name++;
  157.             break;
  158.         case '\0':
  159.         case '.':
  160.             d->name[i] = FAT_PAD;
  161.             break;
  162.         default:
  163.             d->name[i] = toupper(*name++);
  164.             break;
  165.         }
  166.     }
  167.     if (*name++ != '.')
  168.         name = fake_ext;
  169.     for (i = 0; i < FAT_EXT_LEN; i++) {
  170.         switch ((uint8_t) *name) {
  171.         case 0xe5:
  172.             d->ext[i] = FAT_DENTRY_E5_ESC;
  173.             name++;
  174.             break;
  175.         case '\0':
  176.             d->ext[i] = FAT_PAD;
  177.             break;
  178.         default:
  179.             d->ext[i] = toupper(*name++);
  180.             break;
  181.         }
  182.     }
  183. }
  184.  
  185. fat_dentry_clsf_t fat_classify_dentry(const fat_dentry_t *d)
  186. {
  187.     if (d->attr & FAT_ATTR_VOLLABEL) {
  188.         /* volume label entry */
  189.         return FAT_DENTRY_SKIP;
  190.     }
  191.     if (d->name[0] == FAT_DENTRY_ERASED) {
  192.         /* not-currently-used entry */
  193.         return FAT_DENTRY_FREE;
  194.     }
  195.     if (d->name[0] == FAT_DENTRY_UNUSED) {
  196.         /* never used entry */
  197.         return FAT_DENTRY_LAST;
  198.     }
  199.     if (d->name[0] == FAT_DENTRY_DOT) {
  200.         /*
  201.          * Most likely '.' or '..'.
  202.          * It cannot occur in a regular file name.
  203.          */
  204.         return FAT_DENTRY_SKIP;
  205.     }
  206.     return FAT_DENTRY_VALID;
  207. }
  208.  
  209. /**
  210.  * @}
  211.  */
  212.