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Sparse Virtual File System
0.4.0
A Sparse Virtual File System.
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Go to the source code of this file.
Classes | |
| struct | cp_SparseVirtualFile |
| Python wrapper around a C++ SparseVirtualFile. More... | |
| class | AcquireLockSVF |
| A RAII wrapper around the PyThread_type_lock for the CPython SVF. More... | |
Macros | |
| #define | SVFS_SVF_METHOD_SIZE_T_WRAPPER(method_name, docstring) |
| #define | SVFS_SVF_METHOD_SIZE_T_REGISTER(method_name) |
| #define | ASSERT_FUNCTION_ENTRY_SVF(member) |
Functions | |
| static PyObject * | cp_SparseVirtualFile_new (PyTypeObject *type, PyObject *Py_UNUSED(args), PyObject *Py_UNUSED(kwds)) |
| static int | cp_SparseVirtualFile_init (cp_SparseVirtualFile *self, PyObject *args, PyObject *kwargs) |
| static void | cp_SparseVirtualFile_dealloc (cp_SparseVirtualFile *self) |
| PyDoc_STRVAR (cp_SparseVirtualFile_id_docstring, "id(self) -> str\n\n" "Returns the ID of the Sparse Virtual File.") | |
| static PyObject * | cp_SparseVirtualFile_id (cp_SparseVirtualFile *self) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER (size_of, "Returns the estimate of total memory usage of the Sparse Virtual File.") | |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER (num_bytes, "Returns the total number of file bytes held by the Sparse Virtual File.") | |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER (num_blocks, "Returns the total number of blocks of data held by the Sparse Virtual File System.") | |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER (last_file_position, "Returns the file position immediately past the last block.") | |
| PyDoc_STRVAR (cp_SparseVirtualFile_has_data_docstring, "has_data(self, file_position: int, length: int) -> bool\n\n" "Checks if the Sparse Virtual File of the ID has data at the given ``file_position`` and ``length``.\n\n" "Parameters\n\n" "file_position: int\n" " The absolute file position of the start of the data.\n\n" "length: int\n" " The length of the required data in bytes.\n\n" "Returns\n\n" "bool: True if the SVF contains the data, False otherwise.") | |
| static PyObject * | cp_SparseVirtualFile_has_data (cp_SparseVirtualFile *self, PyObject *args, PyObject *kwargs) |
| PyDoc_STRVAR (cp_SparseVirtualFile_write_docstring, "write(self, file_position: int, data: bytes) -> None\n\n" "Writes the data to the Sparse Virtual File of the given ID at ``file_position`` and ``data`` as a ``bytes`` object." " This will raise an ``IOError`` if ``self.compare_for_diff`` is True and given data is different than" " that seen before and only new data up to this point will be written." " If the ``byte`` data is empty nothing will be done." " This will raise a RuntimeError if the data can not be written for any other reason") | |
| static PyObject * | cp_SparseVirtualFile_write (cp_SparseVirtualFile *self, PyObject *args, PyObject *kwargs) |
| PyDoc_STRVAR (cp_SparseVirtualFile_read_docstring, "read(self, file_position: int, length: int) -> bytes\n\n" "Read the data from the Sparse Virtual File at ``file_position`` and ``length`` returning a ``bytes`` object." " This takes a file position and a length." " This will raise an ``IOError`` if any data is not present" " This will raise a ``RuntimeError`` if the data can not be read for any other reason") | |
| static PyObject * | private_SparseVirtualFile_svf_read_as_py_bytes (cp_SparseVirtualFile *self, unsigned long long fpos, unsigned long long len) |
| static PyObject * | cp_SparseVirtualFile_read (cp_SparseVirtualFile *self, PyObject *args, PyObject *kwargs) |
| PyDoc_STRVAR (cp_SparseVirtualFile_erase_docstring, "erase(self, file_position: int) -> None\n\n" "Erase the data from the Sparse Virtual File at the given ``file_position``" " which must be the beginning of a block.\n" "This will raise an ``IOError`` if a block is not present at that file position.") | |
| static PyObject * | cp_SparseVirtualFile_erase (cp_SparseVirtualFile *self, PyObject *args, PyObject *kwargs) |
| PyDoc_STRVAR (cp_SparseVirtualFile_need_docstring, "need(self, file_position: int, length: int, greedy_length: int = 0) -> typing.Tuple[typing.Tuple[int, int], ...]\n\n" "Given a file_position and length this returns a ordered list ``[(file_position, length), ...]`` of seek/read" " instructions of data that is required to be written to the Sparse Virtual File so that a subsequent read will" " succeed.\n" " If greedy_length is > 0 then, if possible, blocks will be coalesced to reduce the size of the return value." "\n\n" ".. note::\n" " If a greedy_length is given this will be the *minimum* size of the length of the required block." " If the length of the required block is so large (because of existing blocks likely to be coalesced)" " then the user might want to split the length, for example, into multiple (smaller) GET requests which" " will then be coalesced on ``write()``" "\n\n" ".. warning::\n" " The SVF has no knowledge of the the actual file size so when using a greedy length the need list might" " include positions beyond EOF.\n\n" " For example a file 1024 bytes long and a greedy length of 256 then ``need(1000, 24, 256)`` will create" " a need list of ``[(1000, 256),]``." " This should generate a ``write(1000, 24)`` not a ``write(1000, 256)``.\n\n" " It is up to the caller to handle this, however, ``reads()`` in C/C++/Python will ignore read lengths past" " EOF so the caller does not have to do anything.\n\n" "\n\nUsage::\n\n" " if not svf.has_data(position, length):\n" " for read_fpos, read_length in svf.need(position, length):\n" " # Somehow get data as a bytes object at read_fpos, read_length...\n" " svf.write(read_fpos, data)\n" " return svf.read(position, length):\n") | |
| static PyObject * | cp_SparseVirtualFile_need_internal (const SVFS::SparseVirtualFile *pSvf, unsigned long long fpos, unsigned long long len, unsigned long long greedy_len) |
| static PyObject * | cp_SparseVirtualFile_need (cp_SparseVirtualFile *self, PyObject *args, PyObject *kwargs) |
| PyDoc_STRVAR (cp_SparseVirtualFile_need_many_docstring, "need_many(self, seek_reads: typing.List[typing.Tuple[int, int]], greedy_length: int = 0) -> typing.Tuple[typing.Tuple[int, int], ...]\n\n" "Given a list of (file_position, length) this returns a ordered list ``[(file_position, length), ...]`` of seek/read" " instructions of data that is required to be written to the Sparse Virtual File so that a subsequent read will" " succeed.\n\n" "If greedy_length is > 0 then, if possible, blocks will be coalesced to reduce the size of the return value." "\n\n" "See also :py:meth:`svfsc.cSVF.need`") | |
| static PyObject * | cp_SparseVirtualFile_need_many_internal (PyObject *py_seek_reads, const SVFS::SparseVirtualFile *pSvf, unsigned long long greedy_len) |
| static PyObject * | cp_SparseVirtualFile_need_many (cp_SparseVirtualFile *self, PyObject *args, PyObject *kwargs) |
| PyDoc_STRVAR (cp_SparseVirtualFile_blocks_docstring, "blocks(self) -> typing.Tuple[typing.Tuple[int, int], ...]\n\n" "This returns a ordered tuple ``((file_position, length), ...)``" " of the shape of the blocks held by the SVF in file position order.") | |
| static PyObject * | cp_SparseVirtualFile_blocks (cp_SparseVirtualFile *self) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER (block_touch, "Return the latest value of the monotonically increasing block_touch value.") | |
| PyDoc_STRVAR (cp_SparseVirtualFile_block_touches_docstring, "block_touches(self) -> typing.Dict[int, int]\n\n" "This returns a dict ``{touch_int: file_position, ...}``" " of the touch integer of each block mapped to the file position.\n" "The caller can decide what older blocks can be used the erase(file_position).") | |
| static PyObject * | cp_SparseVirtualFile_block_touches (cp_SparseVirtualFile *self) |
| PyDoc_STRVAR (cp_SparseVirtualFile_lru_punt_docstring, "lru_punt(self, cache_size_upper_bound: int) -> int\n\n" "Reduces the size of the cache to < the given size by removing older blocks, at least one block will be left.\n" "There are limitations to this tactic, see the documentation in Technical Notes -> Cache Punting.") | |
| static PyObject * | cp_SparseVirtualFile_lru_punt (cp_SparseVirtualFile *self, PyObject *args, PyObject *kwargs) |
| PyDoc_STRVAR (cp_SparseVirtualFile_file_mod_time_matches_docstring, "file_mod_time_matches(self, file_mod_time: float) -> bool\n\n" "Returns True if the file modification time of the Sparse Virtual File matches the given time as a float.") | |
| static PyObject * | cp_SparseVirtualFile_file_mod_time_matches (cp_SparseVirtualFile *self, PyObject *args, PyObject *kwargs) |
| PyDoc_STRVAR (cp_SparseVirtualFile_file_mod_time_docstring, "file_mod_time(self) -> float\n\n" "Returns the file modification time as a float in UNIX time of the Sparse Virtual File.") | |
| static PyObject * | cp_SparseVirtualFile_file_mod_time (cp_SparseVirtualFile *self) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER (count_write, "Returns the count of write operations on the Sparse Virtual File.") | |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER (count_read, "Returns the count of read operations on the Sparse Virtual File.") | |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER (bytes_write, "Returns the count of the number of bytes writen to the Sparse Virtual File.") | |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER (bytes_read, "Returns the count of the number of bytes read from the Sparse Virtual File.") | |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER (blocks_erased, "Returns the The total count of blocks that have been erased either directly or by punting.") | |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER (bytes_erased, "Returns the The total count of bytes that have been erased either directly or by punting.") | |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER (blocks_punted, "Returns the The total count of blocks that have been erased by punting.") | |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER (bytes_punted, "Returns the The total count of bytes that have been erased by punting.") | |
| PyDoc_STRVAR (cp_SparseVirtualFile_time_write_docstring, "time_write(self) -> typing.Optional[datetime.datetime]\n\n" "Returns the timestamp of the last write to the Sparse Virtual File as a ``datetime.datetime``" " or ``None`` if no write has taken place.") | |
| static PyObject * | cp_SparseVirtualFile_time_write (cp_SparseVirtualFile *self) |
| PyDoc_STRVAR (cp_SparseVirtualFile_time_read_docstring, "time_read(self) -> typing.Optional[datetime.datetime]\n\n" "Returns the timestamp of the last read from the Sparse Virtual File as a ``datetime.datetime``" " or ``None`` if no read has taken place.") | |
| static PyObject * | cp_SparseVirtualFile_time_read (cp_SparseVirtualFile *self) |
| PyDoc_STRVAR (cp_SparseVirtualFile_config_docstring, "config(self) -> typing.Dict[str, bool]\n\n" "Returns the SVF configuration as a dict.") | |
| static PyObject * | cp_SparseVirtualFile_config (cp_SparseVirtualFile *self) |
| static PyObject * | cp_SparseVirtualFile___getstate__ (cp_SparseVirtualFile *self, PyObject *Py_UNUSED(ignored)) |
| static PyObject * | cp_SparseVirtualFile___setstate__ (cp_SparseVirtualFile *self, PyObject *state) |
| PyDoc_STRVAR (svfs_cSVF_doc, "This class implements a Sparse Virtual File (SVF)." " This is an in-memory file that has fragments of a real file." " It has read/write operations and can describe what file fragments are needed, if any, before any read operation." "\n\n" "The constructor takes a string as an ID and optionally:\n" " - A file modification time as a float (default 0.0)." " This can be used for checking if the actual file might been changed which might invalidate the SVF.\n" " - ``overwrite_on_exit``, a boolean that will overwrite the memory on destruction (default ``False``)." " If ``True`` then ``clear()`` on a 1Mb SVF typically takes 35 µs, if ``False`` 1.5 µs.\n" " - ``compare_for_diff``, a boolean that will check that overlapping writes match (default ``True``)." " If ``True`` this adds about 25% time to an overlapping write but gives better chance of catching changes to the" " original file.\n" "\n\n" "For example::" "\n\n" " import svfsc\n" " \n" " svf = svfsc.cSVF('some ID')\n" " svf.write(12, b'ABCD')\n" " svf.read(13, 2) # Returns b'BC'\n" " svf.need(10, 12) # Returns ((10, 2), 16, 6)), the file positions and lengths the the SVF needs\n" " svf.read(1024, 18) # SVF raises an error as it has no data here.\n" "\n" "Signature:\n\n``svfsc.cSVF(id: str, mod_time: float = 0.0, overwrite_on_exit: bool = False, compare_for_diff: bool = True)``") | |
Variables | |
| static const char * | PICKLE_ID_KEY = "id" |
| static const char * | PICKLE_FILE_MOD_TIME_KEY = "file_mod_time" |
| static const char * | PICKLE_BLOCKS_KEY = "blocks" |
| static const char * | PICKLE_VERSION_KEY = "pickle_version" |
| static int | PICKLE_VERSION = 1 |
| static PyMemberDef | cp_SparseVirtualFile_members [] |
| static PyMethodDef | cp_SparseVirtualFile_methods [] |
| static PyTypeObject | svfsc_cSVF |
Python wrapper around a C++ SparseVirtualFile.
Naming convention:
SVF functions are named cp_SparseVirtualFile_...
MIT License Copyright (c) 2020-2024 Paul Ross Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Definition in file _cSVF.cpp.
| #define ASSERT_FUNCTION_ENTRY_SVF | ( | member | ) |
Function entry point test macro. After construction, we expect this invariant at the entry to each function. The cast is necessary when used with functions that take a SVFS as a PyObject* such as cp_SparseVirtualFile_mapping_length
| #define SVFS_SVF_METHOD_SIZE_T_REGISTER | ( | method_name | ) |
Complimentary to SVFS_SVF_METHOD_SIZE_T_WRAPPER this is for adding methods into the methods table cp_SparseVirtualFile_methods
| #define SVFS_SVF_METHOD_SIZE_T_WRAPPER | ( | method_name, | |
| docstring | |||
| ) |
TODO: Implement the Buffer Protocol rather than returning a copy of the bytes? Look for PyBytes_FromStringAndSize(). This macro is for functions that return a size_t type such as count_write, count_read, bytes_write, bytes_read.
Usage:
PyDoc_STRVAR( cp_SparseVirtualFile_count_write_docstring, "count_write(self) -> int\n\n" "Returns the count of write operations on the Sparse Virtual File." );
Perhaps ret = Py_BuildValue("K", self->pSvf->method_name());
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Initialise the cp_SparseVirtualFile.
See the defaults for SVFS::SparseVirtualFileConfig for how that works.
Arguments/keywords:
id Mandatory, str, ID.mod_time Optional, float, modification time, defaults to 0.0overwrite_on_exit Optional, bool, See the defaults for SVFS::SparseVirtualFileConfigcompare_for_diff Optional, bool, See the defaults for SVFS::SparseVirtualFileConfig| self | The cp_SparseVirtualFile. |
| args | Order: "id", "mod_time", "overwrite_on_exit", "compare_for_diff". |
| kwargs | Can be "id", "mod_time", "overwrite_on_exit", "compare_for_diff". |
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See cp_SparseVirtualFile_lru_punt_docstring
| self | The cp_SparseVirtualFile |
| args | The upper bound of the number of bytes held by the cache. |
| kwargs | "cache_size_upper_bound". |
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See cp_SparseVirtualFile_need_docstring
| self | The cp_SparseVirtualFile |
| args | The file_position and length. Optionally a greedy_length. |
| kwargs | "file_position", "length", "greedy_length". |
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See cp_SparseVirtualFile_need_many_docstring
| self | The cp_SparseVirtualFile |
| args | The list of (file_position, length). Optionally a greedy_length. |
| kwargs | "seek_reads", "greedy_length". |
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Python new() for a cp_SparseVirtualFile. Contents will be NULL.
| type | The cp_SparseVirtualFile type. |
| _unused_args | Unused. |
| _unused_kwds | Unused. |
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| PyDoc_STRVAR | ( | cp_SparseVirtualFile_block_touches_docstring | , |
| "block_touches(self) -> typing.Dict\n\n" "This returns a dict ``{touch_int: file_position, ...}``" " of the touch integer of each block mapped to the file position.\n" "The caller can decide what older blocks can be used the erase(file_position)." | [int, int] | ||
| ) |
| PyDoc_STRVAR | ( | cp_SparseVirtualFile_blocks_docstring | , |
| "blocks(self) -> typing. | Tuple[typing.Tuple[int, int], | ||
| ...]\n\n" "This returns a ordered tuple ``((file_position, length),...)``" " of the shape of the blocks held by the SVF in file position order." | |||
| ) |
-— Meta information about the SVF -— The existing blocks. t_seek_reads blocks() const noexcept;
Information about memory used: size_of() gives best guess of total memory usage. size_t size_of() const noexcept;
Gives exact number of data bytes held. size_t num_bytes() const noexcept { return m_bytes_total; };
Gives exact number of blocks used. size_t num_blocks() const noexcept { return m_svf.size(); } t_fpos last_file_position() const noexcept;
Check the clients file modification time has changed. Caller has to decide what to do... bool file_mod_time_matches(const double &file_mod_time) const noexcept { return file_mod_time == m_file_mod_time; }
| PyDoc_STRVAR | ( | cp_SparseVirtualFile_config_docstring | , |
| "config(self) -> typing.Dict\n\n" "Returns the SVF configuration as a dict." | [str, bool] | ||
| ) |
| PyDoc_STRVAR | ( | cp_SparseVirtualFile_erase_docstring | , |
| "erase(self, file_position: int) -> None\n\n" "Erase the data from the Sparse Virtual File at the given ``file_position``" " which must be the beginning of a block.\n" "This will raise an ``IOError`` if a block is not present at that file position." | |||
| ) |
| PyDoc_STRVAR | ( | cp_SparseVirtualFile_file_mod_time_docstring | , |
| "file_mod_time(self) -> float\n\n" "Returns the file modification time as a float in UNIX time of the Sparse Virtual File." | |||
| ) |
-— Attribute access -— const std::string id() const noexcept { return m_id; } double file_mod_time() const noexcept { return m_file_mod_time; }
size_t count_write() const noexcept { return m_count_write; } size_t count_read() const noexcept { return m_count_read; } size_t bytes_write() const noexcept { return m_bytes_write; } size_t bytes_read() const noexcept { return m_bytes_read; }
std::chrono::time_point<std::chrono::system_clock> time_write() const noexcept { return m_time_write; } std::chrono::time_point<std::chrono::system_clock> time_read() const noexcept { return m_time_read; }
| PyDoc_STRVAR | ( | cp_SparseVirtualFile_file_mod_time_matches_docstring | , |
| "file_mod_time_matches(self, file_mod_time: float) -> bool\n\n" "Returns True if the file modification time of the Sparse Virtual File matches the given time as a float." | |||
| ) |
| PyDoc_STRVAR | ( | cp_SparseVirtualFile_has_data_docstring | , |
| "has_data(self, file_position: int, length: int) -> bool\n\n" "Checks if the Sparse Virtual File of the ID has data at the given ``file_position`` and ``length``.\n\n" "Parameters\n\n" "file_position: int\n" " The absolute file position of the start of the data.\n\n" "length: int\n" " The length of the required data in bytes.\n\n" "Returns\n\n" "bool: True if the SVF contains the | data, | ||
| False otherwise." | |||
| ) |
| PyDoc_STRVAR | ( | cp_SparseVirtualFile_id_docstring | , |
| "id(self) -> str\n\n" "Returns the ID of the Sparse Virtual File." | |||
| ) |
| PyDoc_STRVAR | ( | cp_SparseVirtualFile_lru_punt_docstring | , |
| "lru_punt(self, cache_size_upper_bound: int) -> int\n\n" "Reduces the size of the cache to < the given size by removing older blocks, at least one block will be left.\n" "There are limitations to this tactic, see the documentation in Technical Notes -> Cache Punting." | |||
| ) |
| PyDoc_STRVAR | ( | cp_SparseVirtualFile_need_docstring | , |
| "need(self, file_position: int, length: int, greedy_length: int = 0) -> typing. | Tuple[typing.Tuple[int, int], | ||
| ...]\n\n" "Given a file_position and length this returns a ordered list ```` of seek/read" " instructions of data that is required to be written to the Sparse Virtual File so that a subsequent read will" " succeed.\n" " If greedy_length | is[(file_position, length),...], | ||
| 0 | then, | ||
| if | possible, | ||
| blocks will be coalesced to reduce the size of the return value." "\n\n" ".. note::\n" " If a greedy_length is given this will be the *minimum *size of the length of the required block." " If the length of the required block is so large(because of existing blocks likely to be coalesced)" " then the user might want to split the | length, | ||
| for | example, | ||
| into multiple(smaller) GET requests which" " will then be coalesced on ``write()``" "\n\n" ".. warning::\n" " The SVF has no knowledge of the the actual file size so when using a greedy length the need list might" " include positions beyond EOF.\n\n" " For example a file 1024 bytes long and a greedy length of 256 then ``need(1000, 24, 256)`` will create" " a need list of ````." " This should generate a ``write(1000, 24)`` not a ``write(1000, 256)``.\n\n" " It is up to the caller to handle | this[(1000, 256),], | ||
| however | , | ||
| ``reads()`` in C/C++/Python will ignore read lengths past" " EOF so the caller does not have to do anything.\n\n" "\n\nUsage::\n\n" " if not svf.has_data(position, length):\n" " for | read_fpos, | ||
| read_length in svf.need(position, length):\n" " # Somehow get data as a bytes object at | read_fpos, | ||
| read_length...\n" " svf.write(read_fpos, data)\n" " return svf.read(position, length):\n" | |||
| ) |
| PyDoc_STRVAR | ( | cp_SparseVirtualFile_need_many_docstring | , |
| "need_many(self, seek_reads: typing.List[typing.Tuple[int, int]], greedy_length: int = 0) -> typing. | Tuple[typing.Tuple[int, int], | ||
| ...]\n\n" "Given a list of(file_position, length) this returns a ordered list ```` of seek/read" " instructions of data that is required to be written to the Sparse Virtual File so that a subsequent read will" " succeed.\n\n" "If greedy_length | is[(file_position, length),...], | ||
| 0 | then, | ||
| if | possible, | ||
| blocks will be coalesced to reduce the size of the return value." "\n\n" "See also :py:meth:`svfsc.cSVF.need`" | |||
| ) |
| PyDoc_STRVAR | ( | cp_SparseVirtualFile_read_docstring | , |
| "read(self, file_position: int, length: int) -> bytes\n\n" "Read the data from the Sparse Virtual File at ``file_position`` and ``length`` returning a ``bytes`` object." " This takes a file position and a length." " This will raise an ``IOError`` if any data is not present" " This will raise a ``RuntimeError`` if the data can not be read for any other reason" | |||
| ) |
| PyDoc_STRVAR | ( | cp_SparseVirtualFile_time_read_docstring | , |
| "time_read(self) -> typing.Optional\n\n" "Returns the timestamp of the last read from the Sparse Virtual File as a ``datetime.datetime``" " or ``None`` if no read has taken place." | [datetime.datetime] | ||
| ) |
| PyDoc_STRVAR | ( | cp_SparseVirtualFile_time_write_docstring | , |
| "time_write(self) -> typing.Optional\n\n" "Returns the timestamp of the last write to the Sparse Virtual File as a ``datetime.datetime``" " or ``None`` if no write has taken place." | [datetime.datetime] | ||
| ) |
| PyDoc_STRVAR | ( | cp_SparseVirtualFile_write_docstring | , |
| "write(self, file_position: int, data: bytes) -> None\n\n" "Writes the data to the Sparse Virtual File of the given ID at ``file_position`` and ``data`` as a ``bytes`` object." " This will raise an ``IOError`` if ``self.compare_for_diff`` is True and given data is different than" " that seen before and only new data up to this point will be written." " If the ``byte`` data is empty nothing will be done." " This will raise a RuntimeError if the data can not be written for any other reason" | |||
| ) |
| PyDoc_STRVAR | ( | svfs_cSVF_doc | , |
| "This class implements a Sparse Virtual File (SVF)." " This is an in-memory file that has fragments of a real file." " It has read/write operations and can describe what file fragments are | needed, | ||
| if | any, | ||
| before any read operation." "\n\n" "The constructor takes a string as an ID and optionally:\n" " - A file modification time as a float(default 0.0)." " This can be used for checking if the actual file might been changed which might invalidate the SVF.\n" " - ``overwrite_on_exit`` | , | ||
| a boolean that will overwrite the memory on destruction(default ``False``)." " If ``True`` then ``clear()`` on a 1Mb SVF typically takes 35 | µs, | ||
| if ``False`` 1.5 µs.\n" " - ``compare_for_diff`` | , | ||
| a boolean that will check that overlapping writes match(default ``True``)." " If ``True`` this adds about 25% time to an overlapping write but gives better chance of catching changes to the" " original file.\n" "\n\n" "For example::" "\n\n" " import svfsc\n" " \n" " | svf = svfsc.cSVF('some ID')\n" " svf.write(12, b'ABCD')\n" " svf.read(13, 2) # Returns b'BC'\n" " svf.need(10, 12) # Returns ((10, 2), 16, 6) |
||
| ) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER | ( | block_touch | , |
| "Return the latest value of the monotonically increasing block_touch value." | |||
| ) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER | ( | blocks_erased | , |
| "Returns the The total count of blocks that have been erased either directly or by punting." | |||
| ) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER | ( | blocks_punted | , |
| "Returns the The total count of blocks that have been erased by punting." | |||
| ) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER | ( | bytes_erased | , |
| "Returns the The total count of bytes that have been erased either directly or by punting." | |||
| ) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER | ( | bytes_punted | , |
| "Returns the The total count of bytes that have been erased by punting." | |||
| ) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER | ( | bytes_read | , |
| "Returns the count of the number of bytes read from the Sparse Virtual File." | |||
| ) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER | ( | bytes_write | , |
| "Returns the count of the number of bytes writen to the Sparse Virtual File." | |||
| ) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER | ( | count_read | , |
| "Returns the count of read operations on the Sparse Virtual File." | |||
| ) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER | ( | count_write | , |
| "Returns the count of write operations on the Sparse Virtual File." | |||
| ) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER | ( | last_file_position | , |
| "Returns the file position immediately past the last block." | |||
| ) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER | ( | num_blocks | , |
| "Returns the total number of blocks of data held by the Sparse Virtual File System." | |||
| ) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER | ( | num_bytes | , |
| "Returns the total number of file bytes held by the Sparse Virtual File." | |||
| ) |
| SVFS_SVF_METHOD_SIZE_T_WRAPPER | ( | size_of | , |
| "Returns the estimate of total memory usage of the Sparse Virtual File." | |||
| ) |
|
static |
|
static |
|
static |
1.9.1