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-rw-r--r--Makefile2
-rw-r--r--src/ring.c211
-rw-r--r--src/ring.h115
3 files changed, 327 insertions, 1 deletions
diff --git a/Makefile b/Makefile
index bb02f60..4e2139c 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,7 @@ COMMAND = coopgammad
KERNEL = $(shell uname | tr '[A-Z]_' '[a-z]-')
-SRC = filter coopgammad output ramps util message server
+SRC = filter coopgammad output ramps util message server ring
OPTIMISE = -Og -g
diff --git a/src/ring.c b/src/ring.c
new file mode 100644
index 0000000..e34ef6d
--- /dev/null
+++ b/src/ring.c
@@ -0,0 +1,211 @@
+/**
+ * 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 "ring.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+
+
+/**
+ * Initialise a ring buffer
+ *
+ * @param this The ring buffer
+ */
+void ring_initialise(struct ring* this)
+{
+ this->start = 0;
+ this->end = 0;
+ this->size = 0;
+ this->buffer = NULL;
+}
+
+
+/**
+ * Release resource allocated to a ring buffer
+ *
+ * @param this The ring buffer
+ */
+void ring_destroy(struct ring* this)
+{
+ free(this->buffer);
+}
+
+
+/**
+ * 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)
+{
+ size_t off = 0, n = this->end - this->start;
+ char* bs = buf;
+
+ if (bs != NULL)
+ *(size_t*)(bs + off) = n;
+ off += sizeof(size_t);
+
+ if (bs != NULL)
+ memcpy(bs + off, this->buffer + this->start, n);
+ off += n;
+
+ return off;
+}
+
+
+/**
+ * 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)
+{
+ size_t off = 0;
+ const char* bs = buf;
+
+ ring_initialise(this);
+
+ this->size = this->end = *(const size_t*)(bs + off);
+ off += sizeof(size_t);
+
+ if (this->end > 0)
+ {
+ if (!(this->buffer = malloc(this->end)))
+ return 0;
+
+ memcpy(this->buffer, bs + off, this->end);
+ off += this->end;
+ }
+
+ return off;
+}
+
+
+/**
+ * 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)
+{
+ size_t used = 0;
+
+ if (this->start == this->end)
+ {
+ if (this->buffer != NULL)
+ used = this->size;
+ }
+ else if (this->start > this->end)
+ used = this->size - this->start + this->end;
+ else
+ used = this->start - this->end;
+
+ if (used + n > this->size)
+ {
+ char* new = malloc(used + n);
+ if (new == NULL)
+ return -1;
+ if (this->buffer)
+ {
+ if (this->start < this->end)
+ memcpy(new, this->buffer + this->start, this->end - this->start);
+ else
+ {
+ memcpy(new, this->buffer + this->start, this->size - this->start);
+ memcpy(new + this->size - this->start, this->buffer, this->end);
+ }
+ }
+ memcpy(new + used, data, n);
+ this->buffer = new;
+ this->start = 0;
+ this->end = used + n;
+ this->size = used + n;
+ }
+ else if ((this->start >= this->end) || (this->end + n <= this->size))
+ {
+ memcpy(this->buffer + this->end, data, n);
+ this->end += n;
+ }
+ else
+ {
+ memcpy(this->buffer + this->end, data, this->size - this->end);
+ data = (char*)data + (this->size - this->end);
+ n -= this->size - this->end;
+ memcpy(this->buffer, data, n);
+ this->end = n;
+ }
+
+ return 0;
+}
+
+
+/**
+ * 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)
+{
+ if (this->buffer == NULL)
+ return *n = 0, NULL;
+
+ if (this->start < this->end)
+ *n = this->end - this->start;
+ else
+ *n = this->size - this->start;
+ return this->buffer + this->start;
+}
+
+
+/**
+ * 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)
+{
+ this->start += n;
+ this->start %= this->size;
+ if (this->start == this->end)
+ {
+ free(this->buffer);
+ this->start = 0;
+ this->end = 0;
+ this->size = 0;
+ this->buffer = NULL;
+ }
+}
+
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);
+
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-10 20:04:54 +0000