Changeset 9119d25 in mainline for uspace/srv/fs/fat/fat_ops.c

Timestamp:

2007-12-05T22:45:41Z (17 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

5832e9b

Parents:

6364d3c

Message:

FAT work.
Foundation for FAT dentry comparison function.
Beware of looking at the diff or risk loosing sanity.

File:

• uspace/srv/fs/fat/fat_ops.c (modified) (1 diff)

uspace/srv/fs/fat/fat_ops.c

@@ -54 +54 @@
 #define FAT_DENTRY_ERASED       0xe5
 
-static int match_path_component(fat_dentry_t *dentry, unsigned index,
-    size_t len)
+/** Compare one component of path to a directory entry.
+ *
+ * @param dentry        Directory entry to compare the path component with.
+ * @param start         Index into PLB where the path component starts.
+ * @param last          Index of the last character of the path in PLB.
+ *
+ * @return              Zero on failure or delta such that (index + delta) %
+ *                      PLB_SIZE points to a new path component in PLB.
+ */
+static unsigned match_path_component(fat_dentry_t *dentry, unsigned start,
+    unsigned last)
 {
+        unsigned cur;   /* current position in PLB */
+        int pos;        /* current position in dentry->name or dentry->ext */
+        bool name_processed = false;
+        bool dot_processed = false;
+        bool ext_processed = false;
+
+        if (last < start)
+                last += PLB_SIZE;
+        for (pos = 0, cur = start; (cur <= last) && (PLB_GET_CHAR(cur) != '/');
+            pos++, cur++) {
+                if (!name_processed) {
+                        if ((pos == FAT_NAME_LEN - 1) ||
+                            (dentry->name[pos + 1] == FAT_PAD)) {
+                                /* this is the last character in name */
+                                name_processed = true;
+                        }
+                        if (dentry->name[0] == FAT_PAD) {
+                                /* name is empty */
+                                name_processed = true;
+                        } else if ((pos == 0) && (dentry->name[pos] ==
+                            FAT_DENTRY_E5_ESC)) {
+                                if (PLB_GET_CHAR(cur) == 0xe5)
+                                        continue;
+                                else
+                                        return 0;       /* character mismatch */
+                        } else {
+                                if (PLB_GET_CHAR(cur) == dentry->name[pos])
+                                        continue;
+                                else
+                                        return 0;       /* character mismatch */
+                        }
+                }
+                if (!dot_processed) {
+                        dot_processed = true;
+                        pos = -1;
+                        if (PLB_GET_CHAR(cur) != '.')
+                                return 0;
+                        continue;
+                }
+                if (!ext_processed) {
+                        if ((pos == FAT_EXT_LEN - 1) ||
+                            (dentry->ext[pos + 1] == FAT_PAD)) {
+                                /* this is the last character in ext */
+                                ext_processed = true;
+                        }
+                        if (dentry->ext[0] == FAT_PAD) {
+                                /* ext is empty; the match will fail */
+                                ext_processed = true;
+                        } else if (PLB_GET_CHAR(cur) == dentry->ext[pos]) {
+                                continue;
+                        } else {
+                                /* character mismatch */
+                                return 0;
+                        }
+                }
+                return 0;       /* extra characters in the component */
+        }
+        if (ext_processed || (name_processed && dentry->ext[0] == FAT_PAD))
+                return cur - start;
+        else
+                return 0;
 }