45 lines
1.2 KiB
Cython
45 lines
1.2 KiB
Cython
"""
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Simple buffer data structure that provides a view on existing memory
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(e.g. from a bytes object). This memory must stay alive while the
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buffer is in use.
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"""
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from cpython.bytes cimport PyBytes_AS_STRING
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# char* PyBytes_AS_STRING(object string)
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# Macro form of PyBytes_AsString() but without error
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# checking. Only string objects are supported; no Unicode objects
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# should be passed.
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cdef struct Buffer:
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char *ptr
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Py_ssize_t size
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cdef inline bytes to_bytes(Buffer *buf):
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return buf.ptr[:buf.size]
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cdef inline char *buf_ptr(Buffer *buf):
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return buf.ptr
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cdef inline char *buf_read(Buffer *buf, Py_ssize_t size) except NULL:
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if size > buf.size:
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raise IndexError("Requested more than length of buffer")
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return buf.ptr
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cdef inline int slice_buffer(Buffer *buf, Buffer *out,
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Py_ssize_t start, Py_ssize_t size) except -1:
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if size < 0:
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raise ValueError("Length must be positive")
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if start + size > buf.size:
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raise IndexError("Buffer slice out of bounds")
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out.ptr = buf.ptr + start
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out.size = size
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return 0
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cdef inline void from_ptr_and_size(char *ptr, Py_ssize_t size, Buffer *out):
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out.ptr = ptr
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out.size = size
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