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author | Mike Buland <eichlan@xagasoft.com> | 2012-11-05 22:41:51 +0000 |
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committer | Mike Buland <eichlan@xagasoft.com> | 2012-11-05 22:41:51 +0000 |
commit | ec05778d5718a7912e506764d443a78d6a6179e3 (patch) | |
tree | 78a9a01532180030c095acefc45763f07c14edb8 /src/stable/myriad.h | |
parent | b20414ac1fe80a71a90601f4cd1767fa7014a9ba (diff) | |
download | libbu++-ec05778d5718a7912e506764d443a78d6a6179e3.tar.gz libbu++-ec05778d5718a7912e506764d443a78d6a6179e3.tar.bz2 libbu++-ec05778d5718a7912e506764d443a78d6a6179e3.tar.xz libbu++-ec05778d5718a7912e506764d443a78d6a6179e3.zip |
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Diffstat (limited to '')
-rw-r--r-- | src/stable/myriad.h | 426 |
1 files changed, 213 insertions, 213 deletions
diff --git a/src/stable/myriad.h b/src/stable/myriad.h index 6b1db41..4bfd88e 100644 --- a/src/stable/myriad.h +++ b/src/stable/myriad.h | |||
@@ -18,219 +18,219 @@ | |||
18 | 18 | ||
19 | namespace Bu | 19 | namespace Bu |
20 | { | 20 | { |
21 | class Stream; | 21 | class Stream; |
22 | class MyriadStream; | 22 | class MyriadStream; |
23 | 23 | ||
24 | subExceptionDeclBegin( MyriadException ) | 24 | subExceptionDeclBegin( MyriadException ) |
25 | enum | 25 | enum |
26 | { | 26 | { |
27 | emptyStream, | 27 | emptyStream, |
28 | invalidFormat, | 28 | invalidFormat, |
29 | badVersion, | 29 | badVersion, |
30 | invalidWordSize, | 30 | invalidWordSize, |
31 | noSuchStream, | 31 | noSuchStream, |
32 | streamExists, | 32 | streamExists, |
33 | invalidStreamId, | 33 | invalidStreamId, |
34 | protectedStream | 34 | protectedStream |
35 | }; | 35 | }; |
36 | subExceptionDeclEnd(); | 36 | subExceptionDeclEnd(); |
37 | 37 | ||
38 | /** | 38 | /** |
39 | * Myriad block-allocated stream multiplexing system. This is a system for | 39 | * Myriad block-allocated stream multiplexing system. This is a system for |
40 | * creating streams that contain other streams in a flexible and lightweight | 40 | * creating streams that contain other streams in a flexible and lightweight |
41 | * manner. Basically, you can create a file (or any other stream) that can | 41 | * manner. Basically, you can create a file (or any other stream) that can |
42 | * store any number of flexible, growing streams. The streams within the | 42 | * store any number of flexible, growing streams. The streams within the |
43 | * Myriad stream are automatically numbered, not named. This works more | 43 | * Myriad stream are automatically numbered, not named. This works more |
44 | * or less like a filesystem, but without the extra layer for managing | 44 | * or less like a filesystem, but without the extra layer for managing |
45 | * file and directory links. This would actually be very easy to add | 45 | * file and directory links. This would actually be very easy to add |
46 | * on top of Myriad, but is not required. | 46 | * on top of Myriad, but is not required. |
47 | * | 47 | * |
48 | * Header format is as follows: | 48 | * Header format is as follows: |
49 | * | 49 | * |
50 | * MMMMvBssssSSSS* | 50 | * MMMMvBssssSSSS* |
51 | * M = Magic number (0AD3FA84) | 51 | * M = Magic number (0AD3FA84) |
52 | * v = version number | 52 | * v = version number |
53 | * B = Bits per int | 53 | * B = Bits per int |
54 | * s = Blocksize in bytes | 54 | * s = Blocksize in bytes |
55 | * S = Number of Streams | 55 | * S = Number of Streams |
56 | * | 56 | * |
57 | * The * represents the Stream headers, one per stream, as follows: | 57 | * The * represents the Stream headers, one per stream, as follows: |
58 | * IIIIssss$ | 58 | * IIIIssss$ |
59 | * I = Id number of the stream | 59 | * I = Id number of the stream |
60 | * s = size of stream in bytes | 60 | * s = size of stream in bytes |
61 | * | 61 | * |
62 | * The $ represents the Block headers, one per used block, as follows: | 62 | * The $ represents the Block headers, one per used block, as follows: |
63 | * IIII | 63 | * IIII |
64 | * I = Index of the block | 64 | * I = Index of the block |
65 | * | 65 | * |
66 | * The stream/block data is interleaved in the header, so all blocks stored | 66 | * The stream/block data is interleaved in the header, so all blocks stored |
67 | * with one stream are together. The block headers are in order, and the | 67 | * with one stream are together. The block headers are in order, and the |
68 | * data in them is required to be "solid" you cannot fill partial blocks | 68 | * data in them is required to be "solid" you cannot fill partial blocks |
69 | * mid-way through a stream. | 69 | * mid-way through a stream. |
70 | * | 70 | * |
71 | * The initial block starts with the nids header, and is both the zero block | 71 | * The initial block starts with the nids header, and is both the zero block |
72 | * and the zero stream. For now, the minimum block size is the size needed | 72 | * and the zero stream. For now, the minimum block size is the size needed |
73 | * to store the base header, the zero stream header, and the first two | 73 | * to store the base header, the zero stream header, and the first two |
74 | * blocks of the zero stream, so 30 bytes. Since it's reccomended to use | 74 | * blocks of the zero stream, so 30 bytes. Since it's reccomended to use |
75 | * a size that will fit evenly into filesystem blocks, then a size of 32 is | 75 | * a size that will fit evenly into filesystem blocks, then a size of 32 is |
76 | * probably the smallest reccomended size because all powers of two equal | 76 | * probably the smallest reccomended size because all powers of two equal |
77 | * to or greater than 32 are evenly divisible by 32. | 77 | * to or greater than 32 are evenly divisible by 32. |
78 | * | 78 | * |
79 | * I have had a thought that if the block size were smaller than 42 bytes | 79 | * I have had a thought that if the block size were smaller than 42 bytes |
80 | * the header would consume the first N blocks where N * block size is | 80 | * the header would consume the first N blocks where N * block size is |
81 | * enough space to house the initial header, the first stream header, and | 81 | * enough space to house the initial header, the first stream header, and |
82 | * the first N block headers. This, of course, causes you to hit an | 82 | * the first N block headers. This, of course, causes you to hit an |
83 | * infinite header if the block size is small enough. | 83 | * infinite header if the block size is small enough. |
84 | */ | 84 | */ |
85 | class Myriad | 85 | class Myriad |
86 | { | 86 | { |
87 | friend class MyriadStream; | 87 | friend class MyriadStream; |
88 | public: | 88 | public: |
89 | /** | 89 | /** |
90 | * Create a Myriad object that uses the given stream to store data. | 90 | * Create a Myriad object that uses the given stream to store data. |
91 | * This stream must be random access. The block size and preallocate | 91 | * This stream must be random access. The block size and preallocate |
92 | * values passed in are values that will be used if the given stream | 92 | * values passed in are values that will be used if the given stream |
93 | * is empty. In that case the stream will be "formatted" for myriad | 93 | * is empty. In that case the stream will be "formatted" for myriad |
94 | * with the specified block size. If there is already a viable Myriad | 94 | * with the specified block size. If there is already a viable Myriad |
95 | * format present in the stream, then the blocksize and preallocate | 95 | * format present in the stream, then the blocksize and preallocate |
96 | * values will be ignored and the values from the stream will be used | 96 | * values will be ignored and the values from the stream will be used |
97 | * instead. If the stream doesn't appear to be Myriad formatted an | 97 | * instead. If the stream doesn't appear to be Myriad formatted an |
98 | * exception will be thrown. | 98 | * exception will be thrown. |
99 | */ | 99 | */ |
100 | Myriad( Bu::Stream &sStore, int iBlockSize=512, int iPreallocate=8 ); | 100 | Myriad( Bu::Stream &sStore, int iBlockSize=512, int iPreallocate=8 ); |
101 | virtual ~Myriad(); | 101 | virtual ~Myriad(); |
102 | 102 | ||
103 | /** | 103 | /** |
104 | * Destroy whatever data may be in the base stream and create a new | 104 | * Destroy whatever data may be in the base stream and create a new |
105 | * Myriad system there with the given blocksize. Use this with care, | 105 | * Myriad system there with the given blocksize. Use this with care, |
106 | * it will destroy anything that was already in the stream, and | 106 | * it will destroy anything that was already in the stream, and |
107 | * generally, should not ever have to be used. | 107 | * generally, should not ever have to be used. |
108 | */ | 108 | */ |
109 | void initialize( int iBlockSize, int iPreAllocate=1 ); | 109 | void initialize( int iBlockSize, int iPreAllocate=1 ); |
110 | 110 | ||
111 | /** | 111 | /** |
112 | * Create a new stream within the Myriad system. The ID of the new | 112 | * Create a new stream within the Myriad system. The ID of the new |
113 | * stream is returned. | 113 | * stream is returned. |
114 | */ | 114 | */ |
115 | int createStream( int iPreAllocate=1 ); | 115 | int createStream( int iPreAllocate=1 ); |
116 | 116 | ||
117 | /** | 117 | /** |
118 | * Create a new stream within the Myriad system with a given id. The | 118 | * Create a new stream within the Myriad system with a given id. The |
119 | * id that you provide will be the new id of the stream unless it's | 119 | * id that you provide will be the new id of the stream unless it's |
120 | * already used, in which case an error is thrown. This is primarilly | 120 | * already used, in which case an error is thrown. This is primarilly |
121 | * useful when copying an old Myriad file into a new one. | 121 | * useful when copying an old Myriad file into a new one. |
122 | */ | 122 | */ |
123 | int createStreamWithId( int iId, int iPreAllocate=1 ); | 123 | int createStreamWithId( int iId, int iPreAllocate=1 ); |
124 | 124 | ||
125 | /** | 125 | /** |
126 | * Delete a stream that's already within the Myriad. | 126 | * Delete a stream that's already within the Myriad. |
127 | */ | 127 | */ |
128 | void deleteStream( int iId ); | 128 | void deleteStream( int iId ); |
129 | 129 | ||
130 | /** | 130 | /** |
131 | * Return a new Stream object assosiated with the given stream ID. | 131 | * Return a new Stream object assosiated with the given stream ID. |
132 | */ | 132 | */ |
133 | MyriadStream openStream( int iId ); | 133 | MyriadStream openStream( int iId ); |
134 | 134 | ||
135 | Bu::Array<int> getStreamIds(); | 135 | Bu::Array<int> getStreamIds(); |
136 | int getStreamSize( int iId ); | 136 | int getStreamSize( int iId ); |
137 | bool hasStream( int iId ); | 137 | bool hasStream( int iId ); |
138 | 138 | ||
139 | int getNumStreams(); | 139 | int getNumStreams(); |
140 | int getBlockSize(); | 140 | int getBlockSize(); |
141 | int getNumBlocks(); | 141 | int getNumBlocks(); |
142 | int getNumUsedBlocks(); | 142 | int getNumUsedBlocks(); |
143 | Bu::size getTotalUsedBytes(); | 143 | Bu::size getTotalUsedBytes(); |
144 | Bu::size getTotalUnusedBytes(); | 144 | Bu::size getTotalUnusedBytes(); |
145 | Bu::size getTotalUnusedBytes( int iFakeBlockSize ); | 145 | Bu::size getTotalUnusedBytes( int iFakeBlockSize ); |
146 | 146 | ||
147 | /** | 147 | /** |
148 | * Syncronize the header data, etc. with the storage stream. It's not | 148 | * Syncronize the header data, etc. with the storage stream. It's not |
149 | * a bad idea to call this periodically. | 149 | * a bad idea to call this periodically. |
150 | */ | 150 | */ |
151 | void sync(); | 151 | void sync(); |
152 | 152 | ||
153 | /** | 153 | /** |
154 | * Read the first few bytes from the given stream and return true/false | 154 | * Read the first few bytes from the given stream and return true/false |
155 | * depending on weather or not it's a Myriad stream. This will throw | 155 | * depending on weather or not it's a Myriad stream. This will throw |
156 | * an exception if the stream is empty, or is not random access. | 156 | * an exception if the stream is empty, or is not random access. |
157 | */ | 157 | */ |
158 | static bool isMyriad( Bu::Stream &sStore, uint8_t &uVer ); | 158 | static bool isMyriad( Bu::Stream &sStore, uint8_t &uVer ); |
159 | 159 | ||
160 | /** | 160 | /** |
161 | * Read the first few bytes from the given stream and return true/false | 161 | * Read the first few bytes from the given stream and return true/false |
162 | * depending on weather or not it's a Myriad stream. This will throw | 162 | * depending on weather or not it's a Myriad stream. This will throw |
163 | * an exception if the stream is empty, or is not random access. | 163 | * an exception if the stream is empty, or is not random access. |
164 | */ | 164 | */ |
165 | static bool isMyriad( Bu::Stream &sStore ); | 165 | static bool isMyriad( Bu::Stream &sStore ); |
166 | 166 | ||
167 | const Bu::BitString getBlocksUsed() const; | 167 | const Bu::BitString getBlocksUsed() const; |
168 | 168 | ||
169 | private: | 169 | private: |
170 | /** | 170 | /** |
171 | * Initialize this object based on the data already in the assosiated | 171 | * Initialize this object based on the data already in the assosiated |
172 | * stream. This will be called automatically for you if you forget, | 172 | * stream. This will be called automatically for you if you forget, |
173 | * but if you want to pre-initialize for some reason, just call this | 173 | * but if you want to pre-initialize for some reason, just call this |
174 | * once before you actually start doing anything with your Myriad. | 174 | * once before you actually start doing anything with your Myriad. |
175 | */ | 175 | */ |
176 | void initialize(); | 176 | void initialize(); |
177 | 177 | ||
178 | enum | 178 | enum |
179 | { | 179 | { |
180 | blockUnused = 0xFFFFFFFFUL | 180 | blockUnused = 0xFFFFFFFFUL |
181 | }; | 181 | }; |
182 | 182 | ||
183 | typedef Bu::Array<int> BlockArray; | 183 | typedef Bu::Array<int> BlockArray; |
184 | class Stream | 184 | class Stream |
185 | { | 185 | { |
186 | public: | 186 | public: |
187 | int iId; | 187 | int iId; |
188 | int iSize; | 188 | int iSize; |
189 | BlockArray aBlocks; | 189 | BlockArray aBlocks; |
190 | }; | 190 | }; |
191 | typedef Bu::Array<Stream *> StreamArray; | 191 | typedef Bu::Array<Stream *> StreamArray; |
192 | 192 | ||
193 | class Block | 193 | class Block |
194 | { | 194 | { |
195 | public: | 195 | public: |
196 | char *pData; | 196 | char *pData; |
197 | bool bChanged; | 197 | bool bChanged; |
198 | int iBlockIndex; | 198 | int iBlockIndex; |
199 | }; | 199 | }; |
200 | 200 | ||
201 | void updateHeader(); | 201 | void updateHeader(); |
202 | int findEmptyBlock(); | 202 | int findEmptyBlock(); |
203 | 203 | ||
204 | /** | 204 | /** |
205 | *@todo Change this to use a binary search, it's nicer. | 205 | *@todo Change this to use a binary search, it's nicer. |
206 | */ | 206 | */ |
207 | Stream *findStream( int iId ); | 207 | Stream *findStream( int iId ); |
208 | 208 | ||
209 | Block *getBlock( int iBlock ); | 209 | Block *getBlock( int iBlock ); |
210 | void releaseBlock( Block *pBlock ); | 210 | void releaseBlock( Block *pBlock ); |
211 | void syncBlock( Block *pBlock ); | 211 | void syncBlock( Block *pBlock ); |
212 | 212 | ||
213 | int streamAddBlock( Stream *pStream ); | 213 | int streamAddBlock( Stream *pStream ); |
214 | void setStreamSize( Stream *pStream, long iSize ); | 214 | void setStreamSize( Stream *pStream, long iSize ); |
215 | 215 | ||
216 | void headerChanged(); | 216 | void headerChanged(); |
217 | 217 | ||
218 | private: | 218 | private: |
219 | Bu::Stream &sStore; | 219 | Bu::Stream &sStore; |
220 | int iBlockSize; | 220 | int iBlockSize; |
221 | int iBlocks; | 221 | int iBlocks; |
222 | int iUsed; | 222 | int iUsed; |
223 | typedef Bu::List<int> IndexList; | 223 | typedef Bu::List<int> IndexList; |
224 | IndexList lFreeBlocks; | 224 | IndexList lFreeBlocks; |
225 | // Bu::BitString bsBlockUsed; | 225 | // Bu::BitString bsBlockUsed; |
226 | StreamArray aStreams; | 226 | StreamArray aStreams; |
227 | typedef Bu::Hash<int, Block *> BlockHash; | 227 | typedef Bu::Hash<int, Block *> BlockHash; |
228 | BlockHash hActiveBlocks; | 228 | BlockHash hActiveBlocks; |
229 | bool bHeaderChanged; | 229 | bool bHeaderChanged; |
230 | 230 | ||
231 | Bu::Mutex mHeader; | 231 | Bu::Mutex mHeader; |
232 | Bu::Mutex mActiveBlocks; | 232 | Bu::Mutex mActiveBlocks; |
233 | }; | 233 | }; |
234 | }; | 234 | }; |
235 | 235 | ||
236 | #endif | 236 | #endif |