Add filter.[ch]

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

2 files changed, 280 insertions, 0 deletions

diff --git a/src/filter.c b/src/filter.c
new file mode 100644
index 0000000..fe239f1
--- /dev/null
+++ b/src/filter.c
@@ -0,0 +1,160 @@
+/**
+ * gammad -- 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/>.
+ */
+#define _GNU_SOURCE
+#include "filter.h"
+
+#include <string.h>
+
+
+
+/**
+ * Free all resources allocated to a filter.
+ * The allocation of `filter` itself is not freed.
+ * 
+ * @param  filter  The filter.
+ */
+void filter_destroy(struct filter* filter)
+{
+  free(filter->crtc);
+  free(filter->class);
+  free(filter->ramps);
+}
+
+
+/**
+ * Marshal a filter.
+ * 
+ * @param   filter      The filter.
+ * @param   buf         Output buffer for the marshalled filter.
+ *                      `NULL` just measure how large the buffers
+ *                      needs to be.
+ * @param   ramps_size  The byte-size of `filter->ramps`
+ * @return              The number of marshalled byte
+ */
+size_t filter_marshal(const struct filter* filter, char* buf, size_t ramps_size)
+{
+  size_t off = 0, n;
+  char nonnulls = 0;
+  
+  if (buf != NULL)
+    {
+      if (filter->crtc  != NULL)  nonnulls |= 1;
+      if (filter->class != NULL)  nonnulls |= 2;
+      if (filter->ramps != NULL)  nonnulls |= 4;
+      *(buf + off) = nonnulls;
+    }
+  off += 1;
+  
+  if (buf != NULL)
+    *(int64_t*)(buf + off) = filter->priority;
+  off += sizeof(int64_t);
+  
+  if (buf != NULL)
+    *(enum lifespan*)(buf + off) = filter->lifespan;
+  off += sizeof(enum lifespan);
+  
+  if (filter->crtc != NULL)
+    {
+      n = strlen(filter->crtc) + 1;
+      if (buf != NULL)
+	memcpy(buf + off, filter->crtc, n);
+      off += n;
+    }
+  
+  if (filter->class != NULL)
+    {
+      n = strlen(filter->class) + 1;
+      if (buf != NULL)
+	memcpy(buf + off, filter->class, n);
+      off += n;
+    }
+  
+  if (filter->ramps != NULL)
+    {
+      if (buf != NULL)
+	memcpy(buf + off, filter->ramps, ramps_size);
+      off += n;
+    }
+  
+  return off;
+}
+
+
+/**
+ * Unmarshal a filter.
+ * 
+ * @param   filter      Output for the filter, `NULL` to skip unmarshalling
+ * @param   buf         Buffer with the marshalled filter
+ * @param   ramps_size  The byte-size of `filter->ramps`
+ * @return              The number of unmarshalled bytes, 0 on error
+ */
+size_t filter_unmarshal(struct filter* filter, const char* buf, size_t ramps_size)
+{
+  size_t off = 0, n;
+  char nonnulls = 0;
+  
+  nonnulls = *(buf + off);
+  off += 1;
+  
+  if (filter != NULL)
+    {
+      filter->crtc  = NULL;
+      filter->class = NULL;
+      filter->ramps = NULL;
+    }
+  
+  if (filter != NULL)
+    filter->priority = *(int64_t*)(buf + off);
+  off += sizeof(int64_t);
+  
+  if (filter != NULL)
+    filter->lifespan = *(enum lifespan*)(buf + off);
+  off += sizeof(enum lifespan);
+  
+  if (nonnulls & 1)
+    {
+      n = strlen(buf + off) + 1;
+      if ((filter != NULL) && (!(filter->crtc = memdup(buf + off, n))))
+	goto fail;
+      off += n;
+    }
+  
+  if (nonnulls & 2)
+    {
+      n = strlen(buf + off) + 1;
+      if ((filter != NULL) && (!(filter->class = memdup(buf + off, n))))
+	goto fail;
+      off += n;
+    }
+  
+  if (nonnulls & 4)
+    {
+      if ((filter != NULL) && (!(filter->ramps = memdup(buf + off, ramps_size))))
+	goto fail;
+      off += n;
+    }
+  
+  return off;
+  
+ fail:
+  free(filter->crtc);
+  free(filter->class);
+  free(filter->ramps);
+  return 0;
+}
+
diff --git a/src/filter.h b/src/filter.h
new file mode 100644
index 0000000..5b46371
--- /dev/null
+++ b/src/filter.h
@@ -0,0 +1,120 @@
+/**
+ * gammad -- 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>
+#include <stdint.h>
+
+
+
+/**
+ * The lifespan of a filter
+ */
+enum lifespan
+{
+  /**
+   * The filter should be applied
+   * until it is explicitly removed
+   */
+  LIFESPAN_UNTIL_REMOVAL,
+  
+  /**
+   * The filter should be applied
+   * until the client exists
+   */
+  LIFESPAN_UNTIL_DEATH,
+  
+  /**
+   * The filter should be removed now
+   */
+  LIFESPAN_REMOVE
+};
+
+
+/**
+ * Information about a filter
+ */
+struct filter
+{
+  /**
+   * The client that applied it. This need not be
+   * set unless `.lifespan == LIFESPAN_UNTIL_DEATH`.
+   * This is the file descriptor of the client's
+   * connection.
+   */
+  int client;
+  
+  /**
+   * Identifier for the CRTC to which this filter
+   * should be applied. May be removed once applied.
+   */
+  char* crtc;
+  
+  /**
+   * The priority of the filter
+   */
+  int64_t priority;
+  
+  /**
+   * Identifier for the filter
+   */
+  char* class;
+  
+  /**
+   * The lifespan of the filter
+   */
+  enum lifespan lifespan;
+  
+  /**
+   * The gamma ramp adjustments for the filter.
+   * This is raw binary data. `NULL` iff
+   * `lifespan == LIFESPAN_REMOVE`.
+   */
+  void* ramps;
+};
+
+
+
+/**
+ * Free all resources allocated to a filter.
+ * The allocation of `filter` itself is not freed.
+ * 
+ * @param  filter  The filter.
+ */
+void filter_destroy(struct filter* filter);
+
+/**
+ * Marshal a filter.
+ * 
+ * @param   filter      The filter.
+ * @param   buf         Output buffer for the marshalled filter.
+ *                      `NULL` just measure how large the buffers
+ *                      needs to be.
+ * @param   ramps_size  The byte-size of `filter->ramps`
+ * @return              The number of marshalled byte
+ */
+size_t filter_marshal(const struct filter* filter, char* buf, size_t ramps_size);
+
+/**
+ * Unmarshal a filter.
+ * 
+ * @param   filter      Output for the filter, `NULL` to skip unmarshalling
+ * @param   buf         Buffer with the marshalled filter
+ * @param   ramps_size  The byte-size of `filter->ramps`
+ * @return              The number of unmarshalled bytes, 0 on error
+ */
+size_t filter_unmarshal(struct filter* filter, const char* buf, size_t ramps_size);
+