Overrides org.python.core.buffer.BaseArrayBuffer.byteAtImpl.

Doc from org.python.core.buffer.BaseBuffer.byteAtImpl.

Retrieve the byte at the given index in the underlying storage treated as a flat sequence of bytes. This byte-index will have been computed from the item index (which may have been multi-dimensional), taking into account index0, shape, strides, and the item size. The caller is responsible for validating the original item-index and raising (typically) an IndexOutOfBoundsException. Misuse of this method may still result in unchecked exceptions characteristic of the storage implementation.

This method uses String#charAt(int) rather than create an actual byte buffer.

Parameters

index:int

byte-index of location to retrieve

Returns:byte

the byte at byteIndex

Annotations

@Override

Overrides org.python.core.buffer.SimpleBuffer.byteIndex.

Implements org.python.core.PyBuffer.byteIndex.

Doc from org.python.core.buffer.SimpleBuffer.byteIndex.

Convert an item index (for a one-dimensional buffer) to an absolute byte index in the storage shared by the exporter. The storage exported as a PyBuffer is a linearly-indexed sequence of bytes, although it may not actually be a heap-allocated Java byte[] object. The purpose of this method is to allow the exporter to define the relationship between the item index (as used in byteAt(int)) and the byte-index (as used with the ByteBuffer returned by getNIOByteBuffer()). See byteIndex(int[]) for discussion of the multi-dimensional case.

In SimpleBuffer the calculation is specialised for one dimension, no striding, and an item size of 1.

In SimpleStringBuffer we can simply return the argument.

Parameters

index:int

Doc from org.python.core.PyBuffer.byteIndex.

item-index from consumer

Returns:int

Doc from org.python.core.PyBuffer.byteIndex.

corresponding byte-index in actual storage

Annotations

@Override

Overrides org.python.core.buffer.BaseArrayBuffer.copyTo.

Implements org.python.core.PyBuffer.copyTo.

Doc from org.python.core.buffer.BaseArrayBuffer.copyTo.

Copy a simple slice of the buffer-view to the destination byte array, defined by a starting item-index in the source buffer and the count of items to copy. This may validly be done only for a one-dimensional buffer, as the meaning of the starting item-index is otherwise not defined. count*itemsize bytes will be occupied in the destination.

The default implementation in BaseBuffer deals with the general one-dimensional case of arbitrary item size and stride, but is unable to optimise access to sequential bytes.

The implementation in BaseArrayBuffer deals with the general one-dimensional case of arbitrary item size and stride.

This method uses String#charAt(int) rather than create an actual byte buffer.

Parameters

srcIndex:int

Doc from org.python.core.PyBuffer.copyTo.

starting item-index in the source buffer

dest:byte[]

Doc from org.python.core.PyBuffer.copyTo.

destination byte array

destPos:int

Doc from org.python.core.PyBuffer.copyTo.

byte-index in the destination array of the source item [0,...]

count:int

Doc from org.python.core.PyBuffer.copyTo.

number of items to copy

Overrides org.python.core.buffer.BaseArrayBuffer.getBuf.

Implements org.python.core.PyBuffer.getBuf.

Doc from org.python.core.buffer.BaseArrayBuffer.getBuf.

Return a structure describing the slice of a byte array that holds the data being exported to the consumer. For a one-dimensional contiguous buffer, assuming the following client code where obj has type BufferProtocol:

PyBuffer a = obj.getBuffer(PyBUF.SIMPLE);
int itemsize = a.getItemsize();
PyBuffer.Pointer b = a.getBuf();

If the buffer is multidimensional or non-contiguous, storage[offset] is still the (first byte of) the item at index [0] or [0,...,0]. However, it is necessary to navigate b.storage using the shape, strides and maybe suboffsets provided by the API.

BaseArrayBuffer provides a reference to the storage array even when the buffer is intended not to be writable. There can be no enforcement of read-only character once a reference to the byte array has been handed out.

This method creates an actual byte array from the underlying String if none yet exists.

Returns:PyBuffer.Pointer

Doc from org.python.core.PyBuffer.getBuf.

structure defining the byte[] slice that is the shared data

Annotations

@SuppressWarnings:deprecation

@Override

Overrides org.python.core.buffer.SimpleBuffer.getBufferSlice.

Implements org.python.core.PyBuffer.getBufferSlice.

Doc from org.python.core.PyBuffer.getBufferSlice.

Equivalent to getBufferSlice(int, int, int, int) with stride 1.

The SimpleStringBuffer implementation avoids creation of a byte buffer.

Parameters

flags:int

specifying features demanded and the navigational capabilities of the consumer

start:int

index in the current buffer

count:int

number of items in the required slice

Overrides org.python.core.buffer.SimpleBuffer.getBufferSlice.

Implements org.python.core.PyBuffer.getBufferSlice.

Doc from org.python.core.buffer.SimpleBuffer.getBufferSlice.

Get a PyBuffer that represents a slice of the current one described in terms of a start index, number of items to include in the slice, and the stride in the current buffer. A consumer that obtains a PyBuffer with getBufferSlice must release it with PyBuffer#release just as if it had been obtained with PyBuffer#getBuffer(int)

Suppose that x(i) denotes the ith element of the current buffer, that is, the byte retrieved by this.byteAt(i) or the unit indicated by this.getPointer(i). A request for a slice where start = s, count = N and stride = m, results in a buffer y such that y(k) = x(s+km) where k=0..(N-1). In Python terms, this is the slice x[s : s+(N-1)m+1 : m] (if m>0) or the slice x[s : s+(N-1)m-1 : m] (if m<0). Implementations should check that this range is entirely within the current buffer.

In a simple buffer backed by a contiguous byte array, the result is a strided PyBuffer on the same storage but where the offset is adjusted by s and the stride is as supplied. If the current buffer is already strided and/or has an item size larger than single bytes, the new start index, count and stride will be translated from the arguments given, through this buffer's stride and item size. The caller always expresses start and strides in terms of the abstract view of this buffer.

SimpleBuffer provides an implementation for slicing contiguous bytes in one dimension. In that case, x(i) = u(r+i) for i = 0..L-1 where u is the underlying buffer, and r and L are the start and count with which x was created from u. Thus y(k) = u(r+s+km), that is, the composite offset is r+s and the stride is m.

The SimpleStringBuffer implementation creates an actual byte buffer.

Parameters

flags:int

Doc from org.python.core.PyBuffer.getBufferSlice.

specifying features demanded and the navigational capabilities of the consumer

start:int

Doc from org.python.core.PyBuffer.getBufferSlice.

index in the current buffer

count:int

Doc from org.python.core.PyBuffer.getBufferSlice.

number of items in the required slice

stride:int

Doc from org.python.core.PyBuffer.getBufferSlice.

index-distance in the current buffer between consecutive items in the slice

Overrides org.python.core.buffer.SimpleBuffer.getLen.

Implements org.python.core.PyBUF.getLen.

Doc from org.python.core.buffer.SimpleBuffer.getLen.

The total number of bytes represented by the view, which will be the product of the elements of the shape array, and the item size in bytes.

SimpleBuffer provides an implementation optimised for contiguous bytes in one-dimension.

This method uses String#length() rather than create an actual byte buffer.

Returns:int

Doc from org.python.core.PyBUF.getLen.

the total number of bytes represented.

Annotations

@Override

Overrides org.python.core.buffer.SimpleBuffer.getPointer.

Implements org.python.core.PyBuffer.getPointer.

Doc from org.python.core.PyBuffer.getPointer.

Return a structure describing the position in a byte array of a single item from the data being exported to the consumer. For a one-dimensional contiguous buffer, assuming the following client code where obj has type BufferProtocol:

int k = ... ;
PyBuffer a = obj.getBuffer(PyBUF.FULL);
int itemsize = a.getItemsize();
PyBuffer.Pointer b = a.getPointer(k);

Essentially this is a method for computing the offset of a particular index. The client is free to navigate the underlying buffer b.storage without respecting these boundaries.

This method creates an actual byte array from the underlying String if none yet exists.

Parameters

index:int

in the buffer to position the pointer

Returns:PyBuffer.Pointer

structure defining the byte[] slice that is the shared data

Annotations

@SuppressWarnings:deprecation

@Override

Overrides org.python.core.buffer.SimpleBuffer.getPointer.

Implements org.python.core.PyBuffer.getPointer.

Doc from org.python.core.PyBuffer.getPointer.

Return a structure describing the position in a byte array of a single item from the data being exported to the consumer, in the case that array may be multi-dimensional. For a 3-dimensional contiguous buffer, assuming the following client code where obj has type BufferProtocol:

int i, j, k;
// ... calculation that assigns i, j, k
PyBuffer a = obj.getBuffer(PyBUF.FULL);
int itemsize = a.getItemsize();
PyBuffer.Pointer b = a.getPointer(i,j,k);

Essentially this is a method for computing the offset of a particular index. The client is free to navigate the underlying buffer b.storage without respecting these boundaries. If the buffer is non-contiguous, the above description is still valid (since a multi-byte item must itself be contiguously stored), but in any additional navigation of b.storage[] to other items, the client must use the shape, strides and sub-offsets provided by the API. Normally one starts b = a.getBuf() in order to establish the offset of index [0,...,0].

This method creates an actual byte array from the underlying String if none yet exists.

Parameters

indices:int[]

multidimensional index at which to position the pointer

Returns:PyBuffer.Pointer

structure defining the byte[] slice that is the shared data

Annotations

@SuppressWarnings:deprecation

@Override

Overrides org.python.core.buffer.SimpleBuffer.toString.

Implements org.python.core.PyBuffer.toString.

The toString() method of a SimpleStringBuffer simply produces the underlying String.

Returns:String

Doc from java.lang.Object.toString.

a string representation of the object

Annotations

@Override