Changeset 7751ff1 in mainline for tools/mkfat.py

Timestamp:

2012-04-13T14:50:33Z (12 years ago)

Author:

Martin Decky <martin@…>

Branches:

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

Children:

3e72e41

Parents:

4f4cae1

Message:

improve FAT16 LFN creation support

• add proper support for non-ASCII characters (by removing them from the legacy 8+3 names and by proper UTF-16 encoding in LFN names)
• do not use the ugly global 8+3 disambiguation list, but create the legacy 8+3 names on directory basis
• improve cstyle and code readability

File:

• tools/mkfat.py (modified) (6 diffs)

tools/mkfat.py

@@ -168 +168 @@
 """
 
-LFN_ENTRY = """little:
-        uint8_t pos
-        uint16_t name1[5]
-        uint8_t attr
-        uint8_t type
-        uint8_t csum
-        uint16_t name2[6]
-        uint16_t fc
-        uint16_t name3[2]
-"""
-
-# Global variable to hold the file names in 8.3 format. Needed to 
-# keep track of "number" when creating a short fname from a LFN.
-name83_list = []
-
-def name83(fname):
-        "Create a 8.3 name for the given fname"
-
-        # FIXME: filter illegal characters
-        parts = fname.split('.')
-        
-        name = ''
-        ext = ''
+LFN_DIR_ENTRY = """little:
+        uint8_t seq                /* sequence number */
+        char name1[10]             /* first part of the name */
+        uint8_t attr               /* attributes */
+        uint8_t rec_type           /* LFN record type */
+        uint8_t checksum           /* LFN checksum */
+        char name2[12]             /* second part of the name */
+        uint16_t cluster           /* cluster */
+        char name3[4]              /* third part of the name */
+"""
+
+lchars = set(['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
+              'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
+              'U', 'V', 'W', 'X', 'Y', 'Z',
+              '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+              '!', '#', '$', '%', '&', '\'', '(', ')', '-', '@',
+              '^', '_', '`', '{', '}', '~', '.'])
+
+def fat_lchars(name):
+        "Filter FAT legal characters"
+        
+        filtered_name = ''
+        
+        for char in name.encode('ascii', 'ignore').upper():
+                if not char in lchars:
+                        continue
+                
+                filtered_name += char
+        
+        return filtered_name
+
+def fat_name83(name, name83_list):
+        "Create a 8.3 name for the given name"
+        
+        ascii_name = fat_lchars(name)
+        ascii_parts = ascii_name.split('.')
+        
+        short_name = ''
+        short_ext = ''
         lfn = False
-
-        if len(fname) > 11 :
+        
+        if len(ascii_name) > 11:
                 lfn = True
-
-        if len(parts) > 0:
-                name = parts[0]
-                if len(name) > 8 :
+        
+        if len(ascii_parts) > 0:
+                short_name = ascii_parts[0]
+                if len(short_name) > 8:
                         lfn = True
-
-        if len(parts) > 1 :
-                ext = parts[-1]
-                if len(ext) > 3 :
+        
+        if len(ascii_parts) > 1:
+                short_ext = ascii_parts[-1]
+                if len(short_ext) > 3:
                         lfn = True
-
-        if len(parts) > 2 :
+        
+        if len(ascii_parts) > 2:
                 lfn = True
-
-        if (lfn == False) :
-                return (name.ljust(8)[0:8], ext.ljust(3)[0:3], False)
-
+        
+        if lfn == False:
+                name83_list.append(short_name + '.' + short_ext)
+                return (short_name.ljust(8)[0:8], short_ext.ljust(3)[0:3], False)
+        
         # For filenames with multiple extensions, we treat the last one
         # as the actual extension. The rest of the filename is stripped
         # of dots and concatenated to form the short name
-        for _name in parts[1:-1]:
-                name = name + _name             
-
-        global name83_list
-        for number in range(1, 10000) :
-                number_str = '~' + str(number)
-
-                if len(name) + len(number_str) > 8 :
-                        name = name[0:8 - len(number_str)]
-
-                name = name + number_str;
-
-                if (name + ext) not in name83_list :
+        for part in ascii_parts[1:-1]:
+                short_name += part
+        
+        for number in range(1, 999999):
+                number_str = ('~' + str(number)).upper()
+                
+                if len(short_name) + len(number_str) > 8:
+                        short_name = short_name[0:8 - len(number_str)]
+                
+                short_name += number_str;
+                
+                if not (short_name + '.' + short_ext) in name83_list:
                         break
-                        
-        name83_list.append(name + ext)  
-
-        return (name.ljust(8)[0:8], ext.ljust(3)[0:3], True)
-
-def get_utf16(name, l) :
-        "Create a int array out of a string which we can store in uint16_t arrays"
-
-        bs = [0xFFFF for i in range(l)]
-
-        for i in range(len(name)) :
-                bs[i] = ord(name[i])
-        
-        if (len(name) < l) :
-                bs[len(name)] = 0;
-        
-        return bs
-
-def create_lfn_entry((name, index)) :
-        entry = xstruct.create(LFN_ENTRY)
-
-        entry.name1 = get_utf16(name[0:5], 5)
-        entry.name2 = get_utf16(name[5:11], 6)
-        entry.name3 = get_utf16(name[11:13], 2)
-        entry.pos = index
-
-        entry.attr = 0xF
-        entry.fc = 0
-        entry.type = 0
-
-        return entry
-
-def create_dirent(name, directory, cluster, size):
+        
+        name83_list.append(short_name + '.' + short_ext)
+        return (short_name.ljust(8)[0:8], short_ext.ljust(3)[0:3], True)
+
+def create_lfn_dirent(name, seq, checksum):
+        "Create LFN directory entry"
+        
+        entry = xstruct.create(LFN_DIR_ENTRY)
+        name_rest = name[26:]
+        
+        if len(name_rest) > 0:
+                entry.seq = seq
+        else:
+                entry.seq = seq | 0x40
+        
+        entry.name1 = name[0:10]
+        entry.name2 = name[10:22]
+        entry.name3 = name[22:26]
+        
+        entry.attr = 0x0F
+        entry.rec_type = 0
+        entry.checksum = checksum
+        entry.cluster = 0
+        
+        return (entry, name_rest)
+
+def lfn_checksum(name):
+        "Calculate LFN checksum"
+        
+        checksum = 0
+        for i in range(0, 11):
+                checksum = (((checksum & 1) << 7) + (checksum >> 1) + ord(name[i])) & 0xFF
+        
+        return checksum
+
+def create_dirent(name, name83_list, directory, cluster, size):
+        short_name, short_ext, lfn = fat_name83(name, name83_list)
         
         dir_entry = xstruct.create(DIR_ENTRY)
         
-        dir_entry.name, dir_entry.ext, lfn = name83(name)
-
-        dir_entry.name = dir_entry.name.upper().encode('ascii')
-        dir_entry.ext = dir_entry.ext.upper().encode('ascii')
-
+        dir_entry.name = short_name
+        dir_entry.ext = short_ext
+        
         if (directory):
                 dir_entry.attr = 0x30
@@ -289 +307 @@
                 dir_entry.size = size
         
-
         if not lfn:
                 return [dir_entry]
-
-        n = len(name) / 13 + 1
-        names = [(name[i * 13: (i + 1) * 13 + 1], i + 1) for i in range(n)]
-
-        entries = sorted(map (create_lfn_entry, names), reverse = True, key = lambda e : e.pos)
-        entries[0].pos |= 0x40
-
-        fname11 = dir_entry.name + dir_entry.ext
-
-        csum = 0
-        for i in range(0, 11) :
-                csum = ((csum & 1) << 7) + (csum  >> 1) + ord(fname11[i])
-                csum = csum & 0xFF
-        
-        for e in entries :
-                e.csum = csum;
-        
-        entries.append(dir_entry)
-
+        
+        long_name = name.encode('utf_16_le')
+        entries = [dir_entry]
+        
+        seq = 1
+        checksum = lfn_checksum(dir_entry.name + dir_entry.ext)
+        
+        while len(long_name) > 0:
+                long_entry, long_name = create_lfn_dirent(long_name, seq, checksum)
+                entries.append(long_entry)
+                seq += 1
+        
+        entries.reverse()
         return entries
 
@@ -355 +366 @@
         
         directory = []
-        
-        if (not head):
+        name83_list = []
+        
+        if not head:
                 # Directory cluster preallocation
                 empty_cluster = fat.index(0)
-                fat[empty_cluster] = 0xffff
+                fat[empty_cluster] = 0xFFFF
                 
                 directory.append(create_dot_dirent(empty_cluster))
@@ -366 +378 @@
                 empty_cluster = 0
         
-        for item in listdir_items(root):                
+        for item in listdir_items(root):
                 if item.is_file:
                         rv = write_file(item, outf, cluster_size, data_start, fat, reserved_clusters)
-                        directory.extend(create_dirent(item.name, False, rv[0], rv[1]))
+                        directory.extend(create_dirent(item.name, name83_list, False, rv[0], rv[1]))
                 elif item.is_dir:
                         rv = recursion(False, item.path, outf, cluster_size, root_start, data_start, fat, reserved_clusters, dirent_size, empty_cluster)
-                        directory.extend(create_dirent(item.name, True, rv[0], rv[1]))
-        
-        if (head):
+                        directory.extend(create_dirent(item.name, name83_list, True, rv[0], rv[1]))
+        
+        if head:
                 outf.seek(root_start)
                 for dir_entry in directory:
@@ -431 +443 @@
         extra_bytes = int(sys.argv[1])
         
-        path = os.path.abspath(sys.argv[2])
+        path = os.path.abspath(sys.argv[2].decode())
         if (not os.path.isdir(path)):
                 print("<PATH> must be a directory")
@@ -529 +541 @@
         
         outf.close()
-        
+
 if __name__ == '__main__':
         main()