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+(*
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+ Copyright (C) 2000 Paul Davis
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+ Copyright (C) 2003 Rohan Drape
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+
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+ This program is free software; you can redistribute it and/or modify
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+ it under the terms of the GNU Lesser General Public License as published by
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+ the Free Software Foundation; either version 2.1 of the License, or
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+ (at your option) any later version.
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+
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+ This program is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ GNU Lesser General Public License for more details.
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+
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+ You should have received a copy of the GNU Lesser General Public License
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+ along with this program; if not, write to the Free Software
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+ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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+
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+*)
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+
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+{$ifndef _RINGBUFFER_H}
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+{$define _RINGBUFFER_H}
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+
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+//#ifdef __cplusplus
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+//extern "C"
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+//{
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+//#endif
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+
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+//#include <sys/types.h>
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+
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+(** @file ringbuffer.h
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+ *
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+ * A set of library functions to make lock-free ringbuffers available
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+ * to JACK clients. The `capture_client.c' (in the example_clients
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+ * directory) is a fully functioning user of this API.
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+ *
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+ * The key attribute of a ringbuffer is that it can be safely accessed
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+ * by two threads simultaneously -- one reading from the buffer and
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+ * the other writing to it -- without using any synchronization or
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+ * mutual exclusion primitives. For this to work correctly, there can
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+ * only be a single reader and a single writer thread. Their
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+ * identities cannot be interchanged.
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+ *)
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+
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+type
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+ PPjack_ringbuffer_data_t = ^Pjack_ringbuffer_data_t;
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+ Pjack_ringbuffer_data_t = ^jack_ringbuffer_data_t;
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+ jack_ringbuffer_data_t = record
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+ buf: PChar;
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+ len: csize_t;
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+ end;
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+
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+ PPjack_ringbuffer_t = ^Pjack_ringbuffer_t;
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+ Pjack_ringbuffer_t = ^jack_ringbuffer_t;
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+ jack_ringbuffer_t = record
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+ buf : PChar;
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+ write_ptr : csize_t;
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+ read_ptr : csize_t;
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+ size : csize_t;
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+ size_mask : csize_t;
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+ mlocked : cint;
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+ end;
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+
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+(**
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+ * Allocates a ringbuffer data structure of a specified size. The
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+ * caller must arrange for a call to jack_ringbuffer_free() to release
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+ * the memory associated with the ringbuffer.
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+ *
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+ * @param sz the ringbuffer size in bytes.
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+ *
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+ * @return a pointer to a new jack_ringbuffer_t, if successful; NULL
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+ * otherwise.
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+ *)
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+function jack_ringbuffer_create(sz: csize_t): Pjack_ringbuffer_t; cdecl; external libjack;
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+
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+(**
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+ * Frees the ringbuffer data structure allocated by an earlier call to
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+ * jack_ringbuffer_create().
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+ *
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+ * @param rb a pointer to the ringbuffer structure.
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+ *)
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+procedure jack_ringbuffer_free(rb: Pjack_ringbuffer_t); cdecl; external libjack;
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+
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+(**
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+ * Fill a data structure with a description of the current readable
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+ * data held in the ringbuffer. This description is returned in a two
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+ * element array of jack_ringbuffer_data_t. Two elements are needed
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+ * because the data to be read may be split across the end of the
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+ * ringbuffer.
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+ *
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+ * The first element will always contain a valid @a len field, which
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+ * may be zero or greater. If the @a len field is non-zero, then data
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+ * can be read in a contiguous fashion using the address given in the
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+ * corresponding @a buf field.
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+ *
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+ * If the second element has a non-zero @a len field, then a second
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+ * contiguous stretch of data can be read from the address given in
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+ * its corresponding @a buf field.
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+ *
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+ * @param rb a pointer to the ringbuffer structure.
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+ * @param vec a pointer to a 2 element array of jack_ringbuffer_data_t.
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+ *
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+ *)
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+procedure jack_ringbuffer_get_read_vector(const rb: Pjack_ringbuffer_t;
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+ vec: Pjack_ringbuffer_data_t); cdecl; external libjack;
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+
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+(**
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+ * Fill a data structure with a description of the current writable
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+ * space in the ringbuffer. The description is returned in a two
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+ * element array of jack_ringbuffer_data_t. Two elements are needed
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+ * because the space available for writing may be split across the end
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+ * of the ringbuffer.
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+ *
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+ * The first element will always contain a valid @a len field, which
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+ * may be zero or greater. If the @a len field is non-zero, then data
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+ * can be written in a contiguous fashion using the address given in
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+ * the corresponding @a buf field.
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+ *
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+ * If the second element has a non-zero @a len field, then a second
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+ * contiguous stretch of data can be written to the address given in
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+ * the corresponding @a buf field.
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+ *
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+ * @param rb a pointer to the ringbuffer structure.
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+ * @param vec a pointer to a 2 element array of jack_ringbuffer_data_t.
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+ *)
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+procedure jack_ringbuffer_get_write_vector(const rb: Pjack_ringbuffer_t;
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+ vec: Pjack_ringbuffer_data_t); cdecl; external libjack;
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+
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+(**
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+ * Read data from the ringbuffer.
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+ *
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+ * @param rb a pointer to the ringbuffer structure.
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+ * @param dest a pointer to a buffer where data read from the
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+ * ringbuffer will go.
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+ * @param cnt the number of bytes to read.
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+ *
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+ * @return the number of bytes read, which may range from 0 to cnt.
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+ *)
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+function jack_ringbuffer_read(rb: Pjack_ringbuffer_t; dest: PChar; cnt: csize_t): csize_t; cdecl; external libjack;
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+
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+(**
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+ * Read data from the ringbuffer. Opposed to jack_ringbuffer_read()
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+ * this function does not move the read pointer. Thus it's
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+ * a convenient way to inspect data in the ringbuffer in a
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+ * continuous fashion. The price is that the data is copied
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+ * into a user provided buffer. For "raw" non-copy inspection
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+ * of the data in the ringbuffer use jack_ringbuffer_get_read_vector().
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+ *
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+ * @param rb a pointer to the ringbuffer structure.
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+ * @param dest a pointer to a buffer where data read from the
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+ * ringbuffer will go.
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+ * @param cnt the number of bytes to read.
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+ *
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+ * @return the number of bytes read, which may range from 0 to cnt.
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+ *)
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+function jack_ringbuffer_peek(rb: Pjack_ringbuffer_t; dest: PChar; cnt: csize_t): csize_t; cdecl; external libjack;
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+
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+(**
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+ * Advance the read pointer.
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+ *
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+ * After data have been read from the ringbuffer using the pointers
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+ * returned by jack_ringbuffer_get_read_vector(), use this function to
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+ * advance the buffer pointers, making that space available for future
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+ * write operations.
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+ *
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+ * @param rb a pointer to the ringbuffer structure.
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+ * @param cnt the number of bytes read.
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+ *)
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+procedure jack_ringbuffer_read_advance(rb: Pjack_ringbuffer_t; cnt: csize_t); cdecl; external libjack;
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+
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+(**
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+ * Return the number of bytes available for reading.
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+ *
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+ * @param rb a pointer to the ringbuffer structure.
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+ *
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+ * @return the number of bytes available to read.
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+ *)
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+function jack_ringbuffer_read_space(const rb: Pjack_ringbuffer_t): csize_t; cdecl; external libjack;
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+
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+(**
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+ * Lock a ringbuffer data block into memory.
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+ *
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+ * Uses the mlock() system call. This is not a realtime operation.
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+ *
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+ * @param rb a pointer to the ringbuffer structure.
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+ *)
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+function jack_ringbuffer_mlock(rb: Pjack_ringbuffer_t): cint; cdecl; external libjack;
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+
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+(**
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+ * Reset the read and write pointers, making an empty buffer.
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+ *
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+ * This is not thread safe.
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+ *
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+ * @param rb a pointer to the ringbuffer structure.
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+ *)
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+procedure jack_ringbuffer_reset(rb: Pjack_ringbuffer_t); cdecl; external libjack;
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+
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+(**
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+ * Reset the internal "available" size, and read and write pointers, making an empty buffer.
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+ *
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+ * This is not thread safe.
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+ *
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+ * @param rb a pointer to the ringbuffer structure.
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+ * @param sz the new size, that must be less than allocated size.
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+ *)
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+procedure jack_ringbuffer_reset_size (rb: Pjack_ringbuffer_t; sz: csize_t); cdecl; external libjack;
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+
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+(**
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+ * Write data into the ringbuffer.
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+ *
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+ * @param rb a pointer to the ringbuffer structure.
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+ * @param src a pointer to the data to be written to the ringbuffer.
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+ * @param cnt the number of bytes to write.
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+ *
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+ * @return the number of bytes write, which may range from 0 to cnt
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+ *)
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+function jack_ringbuffer_write(rb: Pjack_ringbuffer_t; const src: PChar;
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+ cnt: csize_t): csize_t; cdecl; external libjack;
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+
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+(**
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+ * Advance the write pointer.
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+ *
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+ * After data have been written the ringbuffer using the pointers
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+ * returned by jack_ringbuffer_get_write_vector(), use this function
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+ * to advance the buffer pointer, making the data available for future
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+ * read operations.
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+ *
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+ * @param rb a pointer to the ringbuffer structure.
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+ * @param cnt the number of bytes written.
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+ *)
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+procedure jack_ringbuffer_write_advance(rb: Pjack_ringbuffer_t; cnt: csize_t); cdecl; external libjack;
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+
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+(**
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+ * Return the number of bytes available for writing.
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+ *
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+ * @param rb a pointer to the ringbuffer structure.
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+ *
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+ * @return the amount of free space (in bytes) available for writing.
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+ *)
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+function jack_ringbuffer_write_space(const rb: Pjack_ringbuffer_t): csize_t; cdecl; external libjack;
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+
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+//#ifdef __cplusplus
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+//}
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+//#endif
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+
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+{$endif}
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+
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