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https://github.com/0xFEEDC0DE64/arduino-esp32.git
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60 lines
2.4 KiB
C
60 lines
2.4 KiB
C
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/******************************************************************************
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*
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* Copyright (C) 2014 Google, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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******************************************************************************/
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#ifndef _BUFFER_H_
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#define _BUFFER_H_
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#include <stdbool.h>
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#include <stddef.h>
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typedef struct buffer_t buffer_t;
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// Returns a new buffer of |size| bytes. Returns NULL if a buffer could not be
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// allocated. |size| must be non-zero. The caller must release this buffer with
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// |buffer_free|.
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buffer_t *buffer_new(size_t size);
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// Creates a new reference to the buffer |buf|. A reference is indistinguishable
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// from the original: writes to the original will be reflected in the reference
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// and vice versa. In other words, this function creates an alias to |buf|. The
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// caller must release the returned buffer with |buffer_free|. Note that releasing
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// the returned buffer does not release |buf|. |buf| must not be NULL.
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buffer_t *buffer_new_ref(const buffer_t *buf);
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// Creates a new reference to the last |slice_size| bytes of |buf|. See
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// |buffer_new_ref| for a description of references. |slice_size| must be
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// greater than 0 and may be at most |buffer_length|
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// (0 < slice_size <= buffer_length). |buf| must not be NULL.
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buffer_t *buffer_new_slice(const buffer_t *buf, size_t slice_size);
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// Frees a buffer object. |buf| may be NULL.
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void buffer_free(buffer_t *buf);
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// Returns a pointer to a writeable memory region for |buf|. All references
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// and slices that share overlapping bytes will also be written to when
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// writing to the returned pointer. The caller may safely write up to
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// |buffer_length| consecutive bytes starting at the address returned by
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// this function. |buf| must not be NULL.
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void *buffer_ptr(const buffer_t *buf);
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// Returns the length of the writeable memory region referred to by |buf|.
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// |buf| must not be NULL.
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size_t buffer_length(const buffer_t *buf);
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#endif /*_BUFFER_H_*/
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