Changeset ed19497 in mainline

Timestamp:

2011-06-05T14:26:58Z (13 years ago)

Author:

Oleg Romanenko <romanenko.oleg@…>

Branches:

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

Children:

34fdb75

Parents:

2df7fdd4

Message:

Function for compute cheksum for Node name

Location:

uspace/srv/fs/fat

Files:

• fat_dentry.c (modified) (1 diff)
• fat_dentry.h (modified) (1 diff)

uspace/srv/fs/fat/fat_dentry.c

@@ -240 +240 @@
 }
 
+/** Compute checksum of Node name.
+ *
+ * Returns an unsigned byte checksum computed on an unsigned byte
+ * array. The array must be 11 bytes long and is assumed to contain
+ * a name stored in the format of a MS-DOS directory entry.
+ *
+ * @param name          Node name read from the dentry.
+ *
+ * @return              An 8-bit unsigned checksum of the name.
+ */
+uint8_t fat_dentry_chksum(uint8_t *name)
+{
+        uint8_t i, sum=0;
+        for (i=0; i<(FAT_NAME_LEN+FAT_EXT_LEN); i++) {
+                sum = ((sum & 1) ? 0x80 : 0) + (sum >> 1) + name[i];
+        }
+        return sum;
+}
+
+
 /**
  * @}

uspace/srv/fs/fat/fat_dentry.h

@@ -112 +112 @@
 extern void fat_dentry_name_set(fat_dentry_t *, const char *);
 extern fat_dentry_clsf_t fat_classify_dentry(const fat_dentry_t *);
+extern uint8_t fat_dentry_chksum(uint8_t *);
 
 #endif