Add pipe()

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@779 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 117 insertions, 0 deletions

diff --git a/nuttx/drivers/pipe-common.h b/nuttx/drivers/pipe-common.h
new file mode 100644
index 000000000..36b424d93
--- /dev/null
+++ b/nuttx/drivers/pipe-common.h
@@ -0,0 +1,117 @@
+/****************************************************************************
+ * drivers/pipe-common.h
+ *
+ *   Copyright (C) 2008 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#ifndef __DRIVERS_PIPE_COMMON_H
+#define __DRIVERS_PIPE_COMMON_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+
+#ifndef CONFIG_DEV_FIFO_SIZE
+#  define CONFIG_DEV_FIFO_SIZE 1024
+#endif
+#if CONFIG_DEV_FIFO_SIZE > 0
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/* Maximum number of open's supported on FIFO */
+
+#define CONFIG_DEV_FIFO_MAXUSER 255
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/* Make the FIFO index as small as possible for the configured FIFO size */
+ 
+#if CONFIG_DEV_FIFO_SIZE > 65535
+typedef uint32 pipe_ndx_t;  /* 32-bit index */
+#elif CONFIG_DEV_FIFO_SIZE > 255
+typedef uint16 pipe_ndx_t;  /* 16-bit index */
+#else
+typedef ubyte pipe_ndx_t;   /*  8-bit index */
+#endif
+
+struct pipe_state_s
+{
+  sem_t      d_bfsem;       /* Used to serialize access to d_buffer and indices */
+  sem_t      d_rdsem;       /* Empty buffer - Reader waits for data write */
+  sem_t      d_wrsem;       /* Full buffer - Writer waits for data read */
+  pipe_ndx_t d_wrndx;       /* Index in d_buffer to save next byte written */
+  pipe_ndx_t d_rdndx;       /* Index in d_buffer to return the next byte read */
+  ubyte      d_refs;        /* References counts on FIFO (limited to 255) */
+  ubyte      d_nwriters;    /* Number of open counts for write access */
+  ubyte      d_rdwaiters;   /* Number of readers waiting for write data to empty buffer */
+  ubyte      d_nwrwaiters;  /* Number of writers wiating for data read out of full buffer */
+  ubyte      d_pipeno;      /* Pipe minor number */
+};
+
+struct pipe_dev_s
+{
+  struct pipe_state_s s;
+  ubyte d_buffer[CONFIG_DEV_FIFO_SIZE];
+};
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+#ifdef __cplusplus
+#  define EXTERN extern "C"
+extern "C" {
+#else
+#  define EXTERN extern
+#endif
+
+EXTERN FAR struct pipe_dev_s *pipecommon_allocdev(void);
+EXTERN void    pipecommon_freedev(FAR struct pipe_dev_s *dev);
+EXTERN int     pipecommon_open(FAR struct file *filep);
+EXTERN int     pipecommon_close(FAR struct file *filep);
+EXTERN ssize_t pipecommon_read(FAR struct file *, FAR char *, size_t);
+EXTERN ssize_t pipecommon_write(FAR struct file *, FAR const char *, size_t);
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* CONFIG_DEV_FIFO_SIZE > 0 */
+#endif /* __DRIVERS_PIPE_COMMON_H */