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4.2.2 File Identifier Descriptor struct FileIdentifierDescriptor { /* ECMA 167 4/14.4 */ struct tag DescriptorTag; Uint16 FileVersionNumber; Uint8 FileCharacteristics; Uint8 LengthofFileIdentifier; struct long_ad ICB; Uint16 LengthofImplementationUse; byte ImplementationUse[]; char FileIdentifier[]; byte Padding[]; } 4.2.2.1 char FileIdentifier[] Since most operating systems have their own specifications as to characteristics of a legal FileIdentifier, this becomes a problem with interchange. Therefore since all implementations must perform some form of FileIdentifier translation it would be to the users advantage if all implementations used the same algorithm. The problems with FileIdentifier translations fall within one or more of the following categories: • Name Length –Most operating systems have some fixed limit for the length of a file identifier. • Invalid Characters – Most operating systems have certain characters considered as being illegal within a file identifier name. • Displayable Characters – Since UDF supports the Unicode character set standard characters within a file identifier may be encountered which are not displayable on the receiving system. • Case Insensitive – Some operating systems are case insensitive in regards to file identifiers. For example OS/2 preserves the original case of the file identifier when the file is created, but uses a case insensitive operations when accessing the file identifier. In OS/2 “Abc” and “ABC” would be the same file name. • Reserved Names – Some operating systems have certain names that cannot be used for a file identifier name. The following sections outline the FileIdentifier translation algorithm for each specific operating system covered by this document. This algorithm shall be used UDF 2.01 99 March50 April
y all OSTA UDF compliant implementations. The algorithm only applies when reading an illegal FileIdentifier. The original FileIdentifier name on the media should not be modified. This algorithm shall be applied by any implementation that performs some form of FileIdentifier translation to meet operating system file identifier restrictions. All OSTA UDF compliant implementations shall support the UDF translation algorithms, but may support additional algorithms. If multiple algorithms are supported the user of the implementation shall be provided with a method to select the UDF translation algorithms. It is recommended that the default displayable algorithm be the UDF defined algorithm. The primary goal of these algorithms is to produce a unique file name that meets the specific operating system restrictions without having to scan the entire directory in which the file resides. C source code for the following algorithms may be found in the appendices of this document. NOTE: In the definition of the following algorithms anytime a d-character is specified in quotes, the Unicode hexadecimal value will also be specified. The following algorithms reference “CS0 Hex representation”, which corresponds to using the Unicode values #0030 - #0039, and #0041 - #0046 to represent a value in hex. In addition, the following algorithms reference “CS0 Base41 representation”, which corresponds to augmenting the CS0 Hex representation to use #0047 - #005A, #0023, #005F, #007E, #002D and #0040 to represent digits 16-40. The following algorithms could still result in name-collisions being reported to the user of an implementation. However, the rationale includes the need for efficient access to the contents of a directory and consistent name translations across logical volume mounts and file system driver implementations, while allowing the user to obtain access to any file within the directory (through possibly renaming a file). Some name transformations in section 4.2.2.1 result in two namespaces being visible at once in a given directory – the space of primary names, those which are physically recorded in a directory; and the space of generated names, those which are derived from the primary names. This is distinct from transformations that take an otherwise illegal name and render it into a legal form, the illegal name not being considered part of the namespace of the directory on that system. For UDF implementations using such transforms, the implementation should search a directory in two passes: pass one should match against the primary namespace and pass two should match against the generated namespace. A match in the primary namespace should be preferred to a match against the generated namespace. UDF 2.01 100 March50 April
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Universal Disk Format ® Specificat
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REVISION HISTORY 1.00 October 24, 1
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CONTENTS 1. INTRODUCTION ..........
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6.4 OSTA Compressed Unicode Algorit
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1. Introduction The OSTA Universal
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1.2 Compliance This document requir
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Media Block Address NOTE 1: This is
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1.3.3 Terms May Optional Shall Shou
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non-overlapping Partitions with 2 p
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2.1 Part 1 - General 2.1.1 Characte
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length of the field. The characters
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2.1.5.2 char Identifier[23] Unless
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The Suffix Type column in the above
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For an Application Entity Identifie
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2.2 Part 3 - Volume Structure 2.2.1
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NOTE: This field is used to determi
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2.2.4 Logical Volume Descriptor str
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2.2.5 Unallocated Space Descriptor
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EntityID. The scope of this EntityI
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2.2.7.2.2 dstring LogicalVolumeIden
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Layout of Type 2 partition map for
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• Bits 1-7: Reserved. Shall be se
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Virtual Allocation Table structure
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the offset and length of a partitio
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The Metadata Partition Map (see2.2.
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2.2.13.1 Metadata File (and Metadat
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2.2.13.4 Procedure for de-allocatin
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} struct EntityID byte byte Impleme
Page 58 and 59: 2.3.2 File Set Descriptor struct Fi
Page 60 and 61: 2.3.2.7 struct EntityID DomainIdent
Page 62 and 63: In order to assist a UDF implementa
Page 64 and 65: 2.3.5.1 Uint16 StrategyType The co
Page 66 and 67: 2.3.6 File Entry struct FileEntry {
Page 68 and 69: 2.3.6.8 FileLinkCount Hard links to
Page 70 and 71: Descriptors should be used. For exa
Page 72 and 73: 2.3.11.2 Uint32 PreviousAllocationE
Page 74 and 75: 3.2 Part 3 - Volume Structure 3.2.1
Page 76 and 77: 3.3 Part 4 - File System 3.3.1 File
Page 78 and 79: 3.3.2.1.2 Macintosh Bits 6 & 7 (Set
Page 80 and 81: 3.3.3 File Entry struct FileEntry {
Page 82 and 83: would be considered writable if the
Page 84 and 85: 3.3.3.5 byte Extended Attributes Se
Page 86 and 87: ignored and the file creation time
Page 88 and 89: 3.3.4.5.1.1 FreeEASpace This extend
Page 90 and 91: MacVolumeInfo format RBP Length Nam
Page 92 and 93: UDFFXInfo format (Volume IV, page 1
Page 94 and 95: The ApplicationUse area for this ex
Page 96 and 97: stream directory. If present, there
Page 98 and 99: Since the streams listed above have
Page 100 and 101: Object Logical Block Number is the
Page 102 and 103: mechanism for the host software to
Page 104 and 105: Vendor ID - The Vendor ID reported
Page 106 and 107: The OS2EA Stream contains a table o
Page 110 and 111: Definitions: A FileIdentifier shall
Page 112 and 113: 3. Invalid Characters: A FileIdenti
Page 114 and 115: 4. Trailing Periods and Spaces: All
Page 116 and 117: If there is a file extension then t
Page 118 and 119: defined as space that is not direct
Page 120 and 121: UDF 2.01 111 March50 April
Page 122 and 123: 6.2 UDF Entity Identifier Values En
Page 124 and 125: 8 0 BeOS - generic 9 0 Windows CE -
Page 126 and 127: } } returnValue = unicodeIndex; } r
Page 128 and 129: } return crc; #ifdef MAIN unsigned
Page 130 and 131: 6.6 Algorithm for Strategy Type 409
Page 132 and 133: nameLen = udfNameLen; } else { /* A
Page 134 and 135: } needsCRC = TRUE; /* Append the CR
Page 136 and 137: if (index < udfLabelLen || index ==
Page 138 and 139: UDF 2.01 129 March50 April
Page 140 and 141: unicode_t *udfName, /* (Input) Name
Page 142 and 143: } #ifdef (OS2 | WIN_95 | WIN_NT) /*
Page 144 and 145: 6.8 Extended Attribute Checksum Alg
Page 146 and 147: • The data of each file shall be
Page 148 and 149: Read the File Identifier Descriptor
Page 150 and 151: • An intermediate state is allowe
Page 152 and 153: • The host shall perform read/mod
Page 154 and 155: 6.10.2.6.3 Level 3 No restrictions
Page 156 and 157: ISO 9660 converted to UDF 1 st sess
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For File Structure: 5. Unallocated
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6.13 Recommendations for DVD+R and
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6.13.1.4.2 Anchor Volume Descriptor
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6.13.2.1 Requirements • The packe
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6.126.15 UDF Media Format Revision
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Description DCN Updated in UDF Revi
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Registration Form Disk Format Speci
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L Logical Block Size, 8, 9, 2425 Lo
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