bdk-blender/tools/modules/blendfile.py
Campbell Barton e955c94ed3 License Headers: Set copyright to "Blender Authors", add AUTHORS
Listing the "Blender Foundation" as copyright holder implied the Blender
Foundation holds copyright to files which may include work from many
developers.

While keeping copyright on headers makes sense for isolated libraries,
Blender's own code may be refactored or moved between files in a way
that makes the per file copyright holders less meaningful.

Copyright references to the "Blender Foundation" have been replaced with
"Blender Authors", with the exception of `./extern/` since these this
contains libraries which are more isolated, any changed to license
headers there can be handled on a case-by-case basis.

Some directories in `./intern/` have also been excluded:

- `./intern/cycles/` it's own `AUTHORS` file is planned.
- `./intern/opensubdiv/`.

An "AUTHORS" file has been added, using the chromium projects authors
file as a template.

Design task: #110784

Ref !110783.
2023-08-16 00:20:26 +10:00

1025 lines
33 KiB
Python

# SPDX-FileCopyrightText: 2009 At Mind B.V. - Jeroen Bakker.
# SPDX-FileCopyrightText: 2014 Blender Authors
#
# SPDX-License-Identifier: GPL-2.0-or-later
# -----------------------------------------------------------------------------
# NOTICE: this module is expanded upon in Blender Asset Tracer.
#
# See https://projects.blender.org/blender/blender-asset-tracer
# and https://pypi.org/project/blender-asset-tracer/
# -----------------------------------------------------------------------------
import gzip
import logging
import os
import struct
import tempfile
log = logging.getLogger("blendfile")
FILE_BUFFER_SIZE = 1024 * 1024
class BlendFileError(Exception):
"""Raised when there was an error reading/parsing a blend file."""
# -----------------------------------------------------------------------------
# module global routines
#
# read routines
# open a filename
# determine if the file is compressed
# and returns a handle
def open_blend(filename, access="rb"):
"""Opens a blend file for reading or writing pending on the access
supports 2 kind of blend files. Uncompressed and compressed.
Known issue: does not support packaged blend files
"""
handle = open(filename, access)
magic_test = b"BLENDER"
magic = handle.read(len(magic_test))
if magic == magic_test:
log.debug("normal blendfile detected")
handle.seek(0, os.SEEK_SET)
bfile = BlendFile(handle)
bfile.is_compressed = False
bfile.filepath_orig = filename
return bfile
elif magic[:2] == b'\x1f\x8b':
log.debug("gzip blendfile detected")
handle.close()
log.debug("decompressing started")
fs = gzip.open(filename, "rb")
data = fs.read(FILE_BUFFER_SIZE)
magic = data[:len(magic_test)]
if magic == magic_test:
handle = tempfile.TemporaryFile()
while data:
handle.write(data)
data = fs.read(FILE_BUFFER_SIZE)
log.debug("decompressing finished")
fs.close()
log.debug("resetting decompressed file")
handle.seek(os.SEEK_SET, 0)
bfile = BlendFile(handle)
bfile.is_compressed = True
bfile.filepath_orig = filename
return bfile
else:
raise BlendFileError("filetype inside gzip not a blend")
else:
raise BlendFileError("filetype not a blend or a gzip blend")
def pad_up_4(offset):
return (offset + 3) & ~3
# -----------------------------------------------------------------------------
# module classes
class BlendFile:
"""
Blend file.
"""
__slots__ = (
# file (result of open())
"handle",
# str (original name of the file path)
"filepath_orig",
# BlendFileHeader
"header",
# struct.Struct
"block_header_struct",
# BlendFileBlock
"blocks",
# [DNAStruct, ...]
"structs",
# dict {b'StructName': sdna_index}
# (where the index is an index into 'structs')
"sdna_index_from_id",
# dict {addr_old: block}
"block_from_offset",
# int
"code_index",
# bool (did we make a change)
"is_modified",
# bool (is file gzipped)
"is_compressed",
)
def __init__(self, handle):
log.debug("initializing reading blend-file")
self.handle = handle
self.header = BlendFileHeader(handle)
self.block_header_struct = self.header.create_block_header_struct()
self.blocks = []
self.code_index = {}
self.structs = []
self.sdna_index_from_id = {}
block = BlendFileBlock(handle, self)
while block.code != b'ENDB':
if block.code == b'DNA1':
(self.structs,
self.sdna_index_from_id,
) = BlendFile.decode_structs(self.header, block, handle)
else:
handle.seek(block.size, os.SEEK_CUR)
self.blocks.append(block)
self.code_index.setdefault(block.code, []).append(block)
block = BlendFileBlock(handle, self)
self.is_modified = False
self.blocks.append(block)
if not self.structs:
raise BlendFileError("No DNA1 block in file, this is not a valid .blend file!")
# Cache (could lazy init, in case we never use?).
self.block_from_offset = {block.addr_old: block for block in self.blocks if block.code != b'ENDB'}
def __repr__(self):
return '<%s %r>' % (self.__class__.__qualname__, self.handle)
def __enter__(self):
return self
def __exit__(self, type, value, traceback):
self.close()
def find_blocks_from_code(self, code):
assert type(code) == bytes
if code not in self.code_index:
return []
return self.code_index[code]
def find_block_from_offset(self, offset):
# same as looking looping over all blocks,
# then checking `block.addr_old == offset`.
assert type(offset) is int
return self.block_from_offset.get(offset)
def close(self):
"""
Close the blend file
writes the blend file to disk if changes has happened
"""
handle = self.handle
if self.is_modified:
if self.is_compressed:
log.debug("close compressed blend file")
handle.seek(os.SEEK_SET, 0)
log.debug("compressing started")
fs = gzip.open(self.filepath_orig, "wb")
data = handle.read(FILE_BUFFER_SIZE)
while data:
fs.write(data)
data = handle.read(FILE_BUFFER_SIZE)
fs.close()
log.debug("compressing finished")
handle.close()
def ensure_subtype_smaller(self, sdna_index_curr, sdna_index_next):
# never refine to a smaller type
if (self.structs[sdna_index_curr].size >
self.structs[sdna_index_next].size):
raise RuntimeError("cant refine to smaller type (%s -> %s)" %
(self.structs[sdna_index_curr].dna_type_id.decode('ascii'),
self.structs[sdna_index_next].dna_type_id.decode('ascii')))
@staticmethod
def decode_structs(header, block, handle):
"""
DNACatalog is a catalog of all information in the DNA1 file-block
"""
log.debug("building DNA catalog")
shortstruct = DNA_IO.USHORT[header.endian_index]
shortstruct2 = struct.Struct(header.endian_str + b'HH')
intstruct = DNA_IO.UINT[header.endian_index]
data = handle.read(block.size)
types = []
names = []
structs = []
sdna_index_from_id = {}
offset = 8
names_len = intstruct.unpack_from(data, offset)[0]
offset += 4
log.debug("building #%d names" % names_len)
for i in range(names_len):
tName = DNA_IO.read_data0_offset(data, offset)
offset = offset + len(tName) + 1
names.append(DNAName(tName))
del names_len
offset = pad_up_4(offset)
offset += 4
types_len = intstruct.unpack_from(data, offset)[0]
offset += 4
log.debug("building #%d types" % types_len)
for i in range(types_len):
dna_type_id = DNA_IO.read_data0_offset(data, offset)
# None will be replaced by the DNAStruct, below
types.append(DNAStruct(dna_type_id))
offset += len(dna_type_id) + 1
offset = pad_up_4(offset)
offset += 4
log.debug("building #%d type-lengths" % types_len)
for i in range(types_len):
tLen = shortstruct.unpack_from(data, offset)[0]
offset = offset + 2
types[i].size = tLen
del types_len
offset = pad_up_4(offset)
offset += 4
structs_len = intstruct.unpack_from(data, offset)[0]
offset += 4
log.debug("building #%d structures" % structs_len)
for sdna_index in range(structs_len):
d = shortstruct2.unpack_from(data, offset)
struct_type_index = d[0]
offset += 4
dna_struct = types[struct_type_index]
sdna_index_from_id[dna_struct.dna_type_id] = sdna_index
structs.append(dna_struct)
fields_len = d[1]
dna_offset = 0
for field_index in range(fields_len):
d2 = shortstruct2.unpack_from(data, offset)
field_type_index = d2[0]
field_name_index = d2[1]
offset += 4
dna_type = types[field_type_index]
dna_name = names[field_name_index]
if dna_name.is_pointer or dna_name.is_method_pointer:
dna_size = header.pointer_size * dna_name.array_size
else:
dna_size = dna_type.size * dna_name.array_size
field = DNAField(dna_type, dna_name, dna_size, dna_offset)
dna_struct.fields.append(field)
dna_struct.field_from_name[dna_name.name_only] = field
dna_offset += dna_size
return structs, sdna_index_from_id
class BlendFileBlock:
"""
Instance of a struct.
"""
__slots__ = (
# BlendFile
"file",
"code",
"size",
"addr_old",
"sdna_index",
"count",
"file_offset",
"user_data",
)
def __str__(self):
return ("<%s.%s (%s), size=%d at %s>" %
# fields=[%s]
(self.__class__.__name__,
self.dna_type_name,
self.code.decode(),
self.size,
# b", ".join(f.dna_name.name_only for f in self.dna_type.fields).decode('ascii'),
hex(self.addr_old),
))
def __init__(self, handle, bfile):
OLDBLOCK = struct.Struct(b'4sI')
self.file = bfile
self.user_data = None
data = handle.read(bfile.block_header_struct.size)
if len(data) != bfile.block_header_struct.size:
print("WARNING! Blend file seems to be badly truncated!")
self.code = b'ENDB'
self.size = 0
self.addr_old = 0
self.sdna_index = 0
self.count = 0
self.file_offset = 0
return
# header size can be 8, 20, or 24 bytes long
# 8: old blend files ENDB block (exception)
# 20: normal headers 32 bit platform
# 24: normal headers 64 bit platform
if len(data) > 15:
blockheader = bfile.block_header_struct.unpack(data)
self.code = blockheader[0].partition(b'\0')[0]
if self.code != b'ENDB':
self.size = blockheader[1]
self.addr_old = blockheader[2]
self.sdna_index = blockheader[3]
self.count = blockheader[4]
self.file_offset = handle.tell()
else:
self.size = 0
self.addr_old = 0
self.sdna_index = 0
self.count = 0
self.file_offset = 0
else:
blockheader = OLDBLOCK.unpack(data)
self.code = blockheader[0].partition(b'\0')[0]
self.code = DNA_IO.read_data0(blockheader[0])
self.size = 0
self.addr_old = 0
self.sdna_index = 0
self.count = 0
self.file_offset = 0
@property
def dna_type(self):
return self.file.structs[self.sdna_index]
@property
def dna_type_name(self):
return self.dna_type.dna_type_id.decode('ascii')
def refine_type_from_index(self, sdna_index_next):
assert type(sdna_index_next) is int
sdna_index_curr = self.sdna_index
self.file.ensure_subtype_smaller(sdna_index_curr, sdna_index_next)
self.sdna_index = sdna_index_next
def refine_type(self, dna_type_id):
assert type(dna_type_id) is bytes
self.refine_type_from_index(self.file.sdna_index_from_id[dna_type_id])
def get_file_offset(
self, path,
default=...,
sdna_index_refine=None,
base_index=0,
):
"""
Return (offset, length)
"""
assert type(path) is bytes
ofs = self.file_offset
if base_index != 0:
assert base_index < self.count
ofs += (self.size // self.count) * base_index
self.file.handle.seek(ofs, os.SEEK_SET)
if sdna_index_refine is None:
sdna_index_refine = self.sdna_index
else:
self.file.ensure_subtype_smaller(self.sdna_index, sdna_index_refine)
dna_struct = self.file.structs[sdna_index_refine]
field = dna_struct.field_from_path(
self.file.header, self.file.handle, path)
return (self.file.handle.tell(), field.dna_name.array_size)
def get(
self, path,
default=...,
sdna_index_refine=None,
use_nil=True, use_str=True,
base_index=0,
):
ofs = self.file_offset
if base_index != 0:
assert base_index < self.count
ofs += (self.size // self.count) * base_index
self.file.handle.seek(ofs, os.SEEK_SET)
if sdna_index_refine is None:
sdna_index_refine = self.sdna_index
else:
self.file.ensure_subtype_smaller(self.sdna_index, sdna_index_refine)
dna_struct = self.file.structs[sdna_index_refine]
return dna_struct.field_get(
self.file.header, self.file.handle, path,
default=default,
use_nil=use_nil, use_str=use_str,
)
def get_raw_data(self, dna_type_id, base_index=0):
dna_types_to_size = {
b'char': 1, b'uchar': 1,
b'short': 2, b'ushort': 2,
b'int': 4, b'uint': 4,
b'int64_t': 8, b'uint64_t': 8,
b'float': 4,
b'double': 8,
}
if dna_type_id not in dna_types_to_size:
raise NotImplementedError("Cannot read raw data of type %r" % dna_type_id)
is_pointer = False
dna_size = dna_types_to_size[dna_type_id]
array_size = self.size // dna_size
ofs = self.file_offset
if base_index != 0:
assert base_index < array_size
ofs += dna_size * base_index
self.file.handle.seek(ofs, os.SEEK_SET)
print(dna_type_id, array_size, dna_size)
return DNA_IO.read_data(self.file.handle, self.file.header,
is_pointer,
dna_type_id,
dna_size,
array_size)
def get_recursive_iter(
self, path, path_root=b"",
default=...,
sdna_index_refine=None,
use_nil=True, use_str=True,
base_index=0,
):
if path_root:
path_full = (
(path_root if type(path_root) is tuple else (path_root, )) +
(path if type(path) is tuple else (path, )))
else:
path_full = path
try:
yield (path_full, self.get(path_full, default, sdna_index_refine, use_nil, use_str, base_index))
except NotImplementedError as ex:
msg, dna_name, dna_type = ex.args
struct_index = self.file.sdna_index_from_id.get(dna_type.dna_type_id, None)
if struct_index is None:
yield (path_full, "<%s>" % dna_type.dna_type_id.decode('ascii'))
else:
struct = self.file.structs[struct_index]
if dna_name.array_size > 1:
for index in range(dna_name.array_size):
for f in struct.fields:
yield from self.get_recursive_iter(
(index, f.dna_name.name_only), path_full,
default, None, use_nil, use_str, 0)
else:
for f in struct.fields:
yield from self.get_recursive_iter(
f.dna_name.name_only, path_full,
default, None, use_nil, use_str, 0)
def items_recursive_iter(self, use_nil=True):
for k in self.keys():
yield from self.get_recursive_iter(k, use_nil=use_nil, use_str=False)
def get_data_hash(self):
"""
Generates a 'hash' that can be used instead of addr_old as block id, and that should be 'stable' across .blend
file load & save (i.e. it does not changes due to pointer addresses variations).
"""
# TODO This implementation is most likely far from optimal... and CRC32 is not renown as the best hashing
# algorithm either. But for now does the job!
import zlib
def _is_pointer(self, k):
return self.file.structs[self.sdna_index].field_from_path(
self.file.header, self.file.handle, k).dna_name.is_pointer
hsh = 1
for k, v in self.items_recursive_iter():
if not _is_pointer(self, k):
hsh = zlib.adler32(str(v).encode(), hsh)
return hsh
def set(
self, path, value,
sdna_index_refine=None,
):
if sdna_index_refine is None:
sdna_index_refine = self.sdna_index
else:
self.file.ensure_subtype_smaller(self.sdna_index, sdna_index_refine)
dna_struct = self.file.structs[sdna_index_refine]
self.file.handle.seek(self.file_offset, os.SEEK_SET)
self.file.is_modified = True
return dna_struct.field_set(
self.file.header, self.file.handle, path, value)
# ---------------
# Utility get/set
#
# avoid inline pointer casting
def get_pointer(
self, path,
default=...,
sdna_index_refine=None,
base_index=0,
):
if sdna_index_refine is None:
sdna_index_refine = self.sdna_index
result = self.get(path, default, sdna_index_refine=sdna_index_refine, base_index=base_index)
# default
if type(result) is not int:
return result
assert self.file.structs[sdna_index_refine].field_from_path(
self.file.header, self.file.handle, path).dna_name.is_pointer
if result != 0:
# possible (but unlikely)
# that this fails and returns None
# maybe we want to raise some exception in this case
return self.file.find_block_from_offset(result)
else:
return None
# ----------------------
# Python convenience API
# dict like access
def __getitem__(self, item):
return self.get(item, use_str=False)
def __setitem__(self, item, value):
self.set(item, value)
def keys(self):
return (f.dna_name.name_only for f in self.dna_type.fields)
def values(self):
for k in self.keys():
try:
yield self[k]
except NotImplementedError as ex:
msg, dna_name, dna_type = ex.args
yield "<%s>" % dna_type.dna_type_id.decode('ascii')
def items(self):
for k in self.keys():
try:
yield (k, self[k])
except NotImplementedError as ex:
msg, dna_name, dna_type = ex.args
yield (k, "<%s>" % dna_type.dna_type_id.decode('ascii'))
# -----------------------------------------------------------------------------
# Read Magic
#
# magic = str
# pointer_size = int
# is_little_endian = bool
# version = int
class BlendFileHeader:
"""
BlendFileHeader allocates the first 12 bytes of a blend file
it contains information about the hardware architecture
"""
__slots__ = (
# str
"magic",
# int 4/8
"pointer_size",
# bool
"is_little_endian",
# int
"version",
# str, used to pass to 'struct'
"endian_str",
# int, used to index common types
"endian_index",
)
def __init__(self, handle):
FILEHEADER = struct.Struct(b'7s1s1s3s')
log.debug("reading blend-file-header")
values = FILEHEADER.unpack(handle.read(FILEHEADER.size))
self.magic = values[0]
pointer_size_id = values[1]
if pointer_size_id == b'-':
self.pointer_size = 8
elif pointer_size_id == b'_':
self.pointer_size = 4
else:
assert 0
endian_id = values[2]
if endian_id == b'v':
self.is_little_endian = True
self.endian_str = b'<'
self.endian_index = 0
elif endian_id == b'V':
self.is_little_endian = False
self.endian_index = 1
self.endian_str = b'>'
else:
assert 0
version_id = values[3]
self.version = int(version_id)
def create_block_header_struct(self):
return struct.Struct(b''.join((
self.endian_str,
b'4sI',
b'I' if self.pointer_size == 4 else b'Q',
b'II',
)))
class DNAName:
"""
DNAName is a C-type name stored in the DNA
"""
__slots__ = (
"name_full",
"name_only",
"is_pointer",
"is_method_pointer",
"array_size",
)
def __init__(self, name_full):
self.name_full = name_full
self.name_only = self.calc_name_only()
self.is_pointer = self.calc_is_pointer()
self.is_method_pointer = self.calc_is_method_pointer()
self.array_size = self.calc_array_size()
def __repr__(self):
return '%s(%r)' % (type(self).__qualname__, self.name_full)
def as_reference(self, parent):
if parent is None:
result = b''
else:
result = parent + b'.'
result = result + self.name_only
return result
def calc_name_only(self):
result = self.name_full.strip(b'*()')
index = result.find(b'[')
if index != -1:
result = result[:index]
return result
def calc_is_pointer(self):
return (b'*' in self.name_full)
def calc_is_method_pointer(self):
return (b'(*' in self.name_full)
def calc_array_size(self):
result = 1
temp = self.name_full
index = temp.find(b'[')
while index != -1:
index_2 = temp.find(b']')
result *= int(temp[index + 1:index_2])
temp = temp[index_2 + 1:]
index = temp.find(b'[')
return result
class DNAField:
"""
DNAField is a coupled DNAStruct and DNAName
and cache offset for reuse
"""
__slots__ = (
# DNAName
"dna_name",
# tuple of 3 items
# [bytes (struct name), int (struct size), DNAStruct]
"dna_type",
# size on-disk
"dna_size",
# cached info (avoid looping over fields each time)
"dna_offset",
)
def __init__(self, dna_type, dna_name, dna_size, dna_offset):
self.dna_type = dna_type
self.dna_name = dna_name
self.dna_size = dna_size
self.dna_offset = dna_offset
class DNAStruct:
"""
DNAStruct is a C-type structure stored in the DNA
"""
__slots__ = (
"dna_type_id",
"size",
"fields",
"field_from_name",
"user_data",
)
def __init__(self, dna_type_id):
self.dna_type_id = dna_type_id
self.fields = []
self.field_from_name = {}
self.user_data = None
def __repr__(self):
return '%s(%r)' % (type(self).__qualname__, self.dna_type_id)
def field_from_path(self, header, handle, path):
"""
Support lookups as bytes or a tuple of bytes and optional index.
C style 'id.name' --> (b'id', b'name')
C style 'array[4]' --> ('array', 4)
"""
if type(path) is tuple:
name = path[0]
if len(path) >= 2 and type(path[1]) is not bytes:
name_tail = path[2:]
index = path[1]
assert type(index) is int
else:
name_tail = path[1:]
index = 0
else:
name = path
name_tail = None
index = 0
assert type(name) is bytes
field = self.field_from_name.get(name)
if field is not None:
handle.seek(field.dna_offset, os.SEEK_CUR)
if index != 0:
if field.dna_name.is_pointer:
index_offset = header.pointer_size * index
else:
index_offset = field.dna_type.size * index
assert index_offset < field.dna_size
handle.seek(index_offset, os.SEEK_CUR)
if not name_tail: # None or ()
return field
else:
return field.dna_type.field_from_path(header, handle, name_tail)
def field_get(
self, header, handle, path,
default=...,
use_nil=True, use_str=True,
):
field = self.field_from_path(header, handle, path)
if field is None:
if default is not ...:
return default
else:
raise KeyError("%r not found in %r (%r)" %
(path, [f.dna_name.name_only for f in self.fields], self.dna_type_id))
dna_type = field.dna_type
dna_name = field.dna_name
dna_size = field.dna_size
try:
return DNA_IO.read_data(handle, header,
dna_name.is_pointer,
dna_type.dna_type_id,
dna_size,
dna_name.array_size,
use_str=use_str,
use_str_nil=use_nil,
)
except NotImplementedError as e:
raise NotImplementedError("%r exists, but can't resolve field %r" %
(path, dna_name.name_only), dna_name, dna_type)
def field_set(self, header, handle, path, value):
assert type(path) == bytes
field = self.field_from_path(header, handle, path)
if field is None:
raise KeyError("%r not found in %r" %
(path, [f.dna_name.name_only for f in self.fields]))
dna_type = field.dna_type
dna_name = field.dna_name
if dna_type.dna_type_id == b'char':
if type(value) is str:
return DNA_IO.write_string(handle, value, dna_name.array_size)
else:
return DNA_IO.write_bytes(handle, value, dna_name.array_size)
else:
raise NotImplementedError("Setting %r is not yet supported for %r" %
(dna_type, dna_name), dna_name, dna_type)
class DNA_IO:
"""
Module like class, for read-write utility functions.
Only stores static methods & constants.
"""
__slots__ = ()
def __new__(cls, *args, **kwargs):
raise RuntimeError("%s should not be instantiated" % cls)
@classmethod
def read_data(
cls,
handle, header,
is_pointer, dna_type_id, dna_size, array_size,
use_str=True, use_str_nil=True,
):
if is_pointer:
return cls.read_pointer(handle, header)
elif dna_type_id == b'int':
if array_size > 1:
return [cls.read_int(handle, header) for i in range(array_size)]
return cls.read_int(handle, header)
elif dna_type_id == b'short':
if array_size > 1:
return [cls.read_short(handle, header) for i in range(array_size)]
return cls.read_short(handle, header)
elif dna_type_id == b'ushort':
if array_size > 1:
return [cls.read_ushort(handle, header) for i in range(array_size)]
return cls.read_ushort(handle, header)
elif dna_type_id == b'uint64_t':
if array_size > 1:
return [cls.read_ulong(handle, header) for i in range(array_size)]
return cls.read_ulong(handle, header)
elif dna_type_id == b'float':
if array_size > 1:
return [cls.read_float(handle, header) for i in range(array_size)]
return cls.read_float(handle, header)
elif dna_type_id == b'char':
if dna_size == 1 and array_size <= 1:
# Single char, assume it's bit-flag or int value, and not a string/bytes data.
return cls.read_char(handle, header)
if use_str:
if use_str_nil:
return cls.read_string0(handle, array_size)
else:
return cls.read_string(handle, array_size)
else:
if use_str_nil:
return cls.read_bytes0(handle, array_size)
else:
return cls.read_bytes(handle, array_size)
elif dna_type_id == b'uchar':
if array_size > 1:
return [cls.read_uchar(handle, header) for i in range(array_size)]
return cls.read_uchar(handle, header)
else:
raise NotImplementedError("Reading %r type is not implemented" % dna_type_id)
@staticmethod
def write_string(handle, astring, fieldlen):
assert isinstance(astring, str)
if len(astring) >= fieldlen:
stringw = astring[0:fieldlen]
else:
stringw = astring + '\0'
handle.write(stringw.encode('utf-8'))
@staticmethod
def write_bytes(handle, astring, fieldlen):
assert isinstance(astring, (bytes, bytearray))
if len(astring) >= fieldlen:
stringw = astring[0:fieldlen]
else:
stringw = astring + b'\0'
handle.write(stringw)
@staticmethod
def read_bytes(handle, length):
data = handle.read(length)
return data
@staticmethod
def read_bytes0(handle, length):
data = handle.read(length)
return DNA_IO.read_data0(data)
@staticmethod
def read_string(handle, length):
return DNA_IO.read_bytes(handle, length).decode('utf-8')
@staticmethod
def read_string0(handle, length):
return DNA_IO.read_bytes0(handle, length).decode('utf-8')
@staticmethod
def read_data0_offset(data, offset):
add = data.find(b'\0', offset) - offset
return data[offset:offset + add]
@staticmethod
def read_data0(data):
add = data.find(b'\0')
return data[:add]
UCHAR = struct.Struct(b'<B'), struct.Struct(b'>B')
@staticmethod
def read_uchar(handle, fileheader):
st = DNA_IO.UCHAR[fileheader.endian_index]
return st.unpack(handle.read(st.size))[0]
SCHAR = struct.Struct(b'<b'), struct.Struct(b'>b')
@staticmethod
def read_char(handle, fileheader):
st = DNA_IO.SCHAR[fileheader.endian_index]
return st.unpack(handle.read(st.size))[0]
USHORT = struct.Struct(b'<H'), struct.Struct(b'>H')
@staticmethod
def read_ushort(handle, fileheader):
st = DNA_IO.USHORT[fileheader.endian_index]
return st.unpack(handle.read(st.size))[0]
SSHORT = struct.Struct(b'<h'), struct.Struct(b'>h')
@staticmethod
def read_short(handle, fileheader):
st = DNA_IO.SSHORT[fileheader.endian_index]
return st.unpack(handle.read(st.size))[0]
UINT = struct.Struct(b'<I'), struct.Struct(b'>I')
@staticmethod
def read_uint(handle, fileheader):
st = DNA_IO.UINT[fileheader.endian_index]
return st.unpack(handle.read(st.size))[0]
SINT = struct.Struct(b'<i'), struct.Struct(b'>i')
@staticmethod
def read_int(handle, fileheader):
st = DNA_IO.SINT[fileheader.endian_index]
return st.unpack(handle.read(st.size))[0]
FLOAT = struct.Struct(b'<f'), struct.Struct(b'>f')
@staticmethod
def read_float(handle, fileheader):
st = DNA_IO.FLOAT[fileheader.endian_index]
return st.unpack(handle.read(st.size))[0]
ULONG = struct.Struct(b'<Q'), struct.Struct(b'>Q')
@staticmethod
def read_ulong(handle, fileheader):
st = DNA_IO.ULONG[fileheader.endian_index]
return st.unpack(handle.read(st.size))[0]
@staticmethod
def read_pointer(handle, header):
"""
reads an pointer from a file handle
the pointer size is given by the header (BlendFileHeader)
"""
if header.pointer_size == 4:
st = DNA_IO.UINT[header.endian_index]
return st.unpack(handle.read(st.size))[0]
if header.pointer_size == 8:
st = DNA_IO.ULONG[header.endian_index]
return st.unpack(handle.read(st.size))[0]