Add ring[.ch]

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 115 insertions, 0 deletions

diff --git a/src/ring.h b/src/ring.h
new file mode 100644
index 0000000..bf22226
--- /dev/null
+++ b/src/ring.h
@@ -0,0 +1,115 @@
+/**
+ * coopgammad -- Cooperative gamma server
+ * Copyright (C) 2016  Mattias Andrée (maandree@kth.se)
+ * 
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stddef.h>
+
+
+
+/**
+ * Ring buffer
+ */
+struct ring
+{
+  /**
+   * Buffer for the data
+   */
+  char* buffer;
+  
+  /**
+   * The first set byte in `.buffer`
+   */
+  size_t start;
+  
+  /**
+   * The last set byte in `.buffer`, plus 1
+   */
+  size_t end;
+  
+  /**
+   * The size of `.buffer`
+   */
+  size_t size;
+};
+
+
+
+/**
+ * Initialise a ring buffer
+ * 
+ * @param  this  The ring buffer
+ */
+void ring_initialise(struct ring* this);
+
+/**
+ * Release resource allocated to a ring buffer
+ * 
+ * @param  this  The ring buffer
+ */
+void ring_destroy(struct ring* this);
+
+/**
+ * Marshal a ring buffer
+ * 
+ * @param   this  The ring buffer
+ * @param   buf   Output buffer for the marshalled data,
+ *                `NULL` to only measure how large buffer
+ *                is needed
+ * @return        The number of marshalled bytes
+ */
+size_t ring_marshal(const struct ring* this, void* buf);
+
+/**
+ * Unmarshal a ring buffer
+ * 
+ * @param   this  Output parameter for the ring buffer
+ * @param   buf   Buffer with the marshalled data
+ * @return        The number of unmarshalled bytes, 0 on error
+ */
+size_t ring_unmarshal(struct ring* this, const void* buf);
+
+/**
+ * Append data to a ring buffer
+ * 
+ * @param   this  The ring buffer
+ * @param   data  The new data
+ * @param   n     The number of bytes in `data`
+ * @return        Zero on success, -1 on error
+ */
+int ring_push(struct ring* this, void* data, size_t n);
+
+/**
+ * Get queued data from a ring buffer
+ * 
+ * It can take up to two calls (with `ring_pop` between)
+ * to get all queued data
+ * 
+ * @param   this  The ring buffer
+ * @param   n     Output parameter for the length
+ *                of the returned segment
+ * @return        The beginning of the queued data,
+ *                `NULL` if there is nothing more
+ */
+void* ring_peek(struct ring* this, size_t* n);
+
+/**
+ * Dequeue data from a ring bubber
+ * 
+ * @param  this  The ring buffer
+ * @param  n     The number of bytes to dequeue
+ */
+void ring_pop(struct ring* this, size_t n);
+