move files around

Signed-off-by: Mattias Andrée <maandree@operamail.com>

1 files changed, 916 insertions, 0 deletions

diff --git a/src/lib/gamma-x-randr.c b/src/lib/gamma-x-randr.c
new file mode 100644
index 0000000..9870f6b
--- /dev/null
+++ b/src/lib/gamma-x-randr.c
@@ -0,0 +1,916 @@
+/**
+ * libgamma — Display server abstraction layer for gamma ramp adjustments
+ * Copyright © 2014  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * 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/>.
+ */
+#ifndef HAVE_LIBGAMMA_METHOD_X_RANDR
+# error Compiling gamma-x-randr.c without HAVE_LIBGAMMA_METHOD_X_RANDR
+#endif
+
+#include "gamma-x-randr.h"
+
+#include "libgamma-error.h"
+#include "edid.h"
+
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <stdint.h>
+#ifdef DEBUG
+# include <stdio.h>
+#endif
+
+#include <xcb/xcb.h>
+#include <xcb/randr.h>
+
+
+/**
+ * The major version of RandR the library expects.
+ */
+#define RANDR_VERSION_MAJOR  1
+
+/**
+ * The minor version of RandR the library expects.
+ */
+#define RANDR_VERSION_MINOR  3
+
+
+
+/**
+ * Data structure for partition data.
+ */
+typedef struct libgamma_x_randr_partition_data
+{
+  /**
+   * Mapping from CRTC indices to CRTC identifiers.
+   */
+  xcb_randr_crtc_t* crtcs;
+  
+  /**
+   * Mapping from output indices to output identifiers.
+   */
+  xcb_randr_output_t* outputs;
+  
+  /**
+   * The number of outputs available.
+   */
+  size_t outputs_count;
+  
+  /**
+   * Mapping from CRTC indices to output indices.
+   * CRTC's without an output (should be impossible)
+   * have the value `SIZE_MAX` which is impossible
+   * for an existing mapping.
+   */
+  size_t* crtc_to_output;
+  
+  /**
+   * Screen configuration timestamp.
+   */
+  xcb_timestamp_t config_timestamp;
+  
+} libgamma_x_randr_partition_data_t;
+
+
+
+/**
+ * Translate an xcb error into a libgamma error.
+ * 
+ * @param   error_code     The xcb error.
+ * @param   default_error  The libgamma error to use if the xcb error is not recognised.
+ * @return                 The libgamma error.
+ */
+static int translate_error_(int error_code, int default_error)
+{
+  switch (error_code)
+    {
+    case XCB_CONN_ERROR:                    return errno = ECONNABORTED, LIBGAMMA_ERRNO_SET;
+    case XCB_CONN_CLOSED_EXT_NOTSUPPORTED:  return errno = ENOPROTOOPT, LIBGAMMA_ERRNO_SET;
+    case XCB_CONN_CLOSED_MEM_INSUFFICIENT:  return errno = ENOMEM, LIBGAMMA_ERRNO_SET;
+    case XCB_CONN_CLOSED_REQ_LEN_EXCEED:    return errno = EMSGSIZE, LIBGAMMA_ERRNO_SET;
+    case XCB_CONN_CLOSED_PARSE_ERR:         return LIBGAMMA_NO_SUCH_SITE;
+    case XCB_CONN_CLOSED_INVALID_SCREEN:    return LIBGAMMA_NO_SUCH_PARTITION;
+    case XCB_CONN_CLOSED_FDPASSING_FAILED:  return errno = EIO, LIBGAMMA_ERRNO_SET;
+    default:
+      return default_error;
+    }
+}
+
+
+/**
+ * Translate an xcb error into a libgamma error.
+ * 
+ * @param   error_code     The xcb error.
+ * @param   default_error  The libgamma error to use if the xcb error is not recognised.
+ * @param   return_errno   Whether an `errno` value may be returned.
+ * @return                 The libgamma error.
+ */
+static int translate_error(int error_code, int default_error, int return_errno)
+{
+  int r = translate_error_(error_code, default_error);
+  return return_errno ? (r > 0 ? errno : r) : r;
+}
+
+
+/**
+ * Return the capabilities of the adjustment method.
+ * 
+ * @param  this  The data structure to fill with the method's capabilities.
+ */
+void libgamma_x_randr_method_capabilities(libgamma_method_capabilities_t* restrict this)
+{
+  char* display = getenv("DISPLAY");
+  this->crtc_information = LIBGAMMA_CRTC_INFO_EDID
+			 | LIBGAMMA_CRTC_INFO_WIDTH_MM
+			 | LIBGAMMA_CRTC_INFO_HEIGHT_MM
+			 | LIBGAMMA_CRTC_INFO_WIDTH_MM_EDID
+			 | LIBGAMMA_CRTC_INFO_HEIGHT_MM_EDID
+			 | LIBGAMMA_CRTC_INFO_GAMMA_SIZE
+			 | LIBGAMMA_CRTC_INFO_GAMMA_DEPTH
+			 | LIBGAMMA_CRTC_INFO_SUBPIXEL_ORDER
+			 | LIBGAMMA_CRTC_INFO_CONNECTOR_NAME
+			 | LIBGAMMA_CRTC_INFO_CONNECTOR_TYPE
+			 | LIBGAMMA_CRTC_INFO_GAMMA;
+  this->default_site_known = (display && *display) ? 1 : 0;
+  this->multiple_sites = 1;
+  this->multiple_partitions = 1;
+  this->multiple_crtcs = 1;
+  this->partitions_are_graphics_cards = 0;
+  this->site_restore = 0;
+  this->partition_restore = 0;
+  this->crtc_restore = 0;
+  this->identical_gamma_sizes = 1;
+  this->fixed_gamma_size = 0;
+  this->fixed_gamma_depth = 1;
+  this->real = 1;
+  this->fake = 0;
+}
+
+
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Waggregate-return"
+
+
+/**
+ * Initialise an allocated site state.
+ * 
+ * @param   this    The site state to initialise.
+ * @param   site    The site identifier, unless it is `NULL` it must a
+ *                  `free`:able. One the state is destroyed the library
+ *                  will attempt to free it. There you should not free
+ *                  it yourself, and it must not be a string constant
+ *                  or allocate on the stack. Note however that it will
+ *                  not be free:d if this function fails.
+ * @return          Zero on success, otherwise (negative) the value of an
+ *                  error identifier provided by this library.
+ */
+int libgamma_x_randr_site_initialise(libgamma_site_state_t* restrict this,
+				     char* restrict site)
+{
+  xcb_generic_error_t* error = NULL;
+  xcb_connection_t* restrict connection;
+  xcb_randr_query_version_cookie_t cookie;
+  xcb_randr_query_version_reply_t* restrict reply;
+  const xcb_setup_t* restrict setup;
+  xcb_screen_iterator_t iter;
+  
+  this->data = connection = xcb_connect(site, NULL);
+  if (connection == NULL)
+    return LIBGAMMA_NO_SUCH_SITE;
+  
+  cookie = xcb_randr_query_version(connection, RANDR_VERSION_MAJOR, RANDR_VERSION_MINOR);
+  reply = xcb_randr_query_version_reply(connection, cookie, &error);
+  
+  if ((error != NULL) || (reply == NULL))
+    {
+      free(reply);
+      xcb_disconnect(connection);
+      if (error != NULL)
+	return translate_error(error->error_code, LIBGAMMA_PROTOCOL_VERSION_QUERY_FAILED, 0);
+      return LIBGAMMA_PROTOCOL_VERSION_QUERY_FAILED;
+    }
+  
+  if ((reply->major_version != RANDR_VERSION_MAJOR) ||
+      (reply->minor_version < RANDR_VERSION_MINOR))
+    {
+#ifdef DEBUG
+      fprintf(stderr, "libgamma: RandR protocol version: %u.%u", reply->major_version, reply->minor_version);
+#endif
+      free(reply);
+      xcb_disconnect(connection);
+      return LIBGAMMA_PROTOCOL_VERSION_NOT_SUPPORTED;
+    }
+  
+  free(reply);
+  
+  if ((setup = xcb_get_setup(connection)) == NULL)
+    {
+      xcb_disconnect(connection);
+      return LIBGAMMA_LIST_PARTITIONS_FAILED;
+    }
+  iter = xcb_setup_roots_iterator(setup);
+  this->partitions_available = (size_t)(iter.rem);
+  
+  return iter.rem < 0 ? LIBGAMMA_NEGATIVE_PARTITION_COUNT : 0;
+}
+
+
+/**
+ * Release all resources held by a site state.
+ * 
+ * @param  this  The site state.
+ */
+void libgamma_x_randr_site_destroy(libgamma_site_state_t* restrict this)
+{
+  xcb_disconnect((xcb_connection_t*)(this->data));
+}
+
+
+/**
+ * Restore the gamma ramps all CRTC:s with a site to the system settings.
+ * 
+ * @param   this  The site state.
+ * @return        Zero on success, otherwise (negative) the value of an
+ *                error identifier provided by this library.
+ */
+int libgamma_x_randr_site_restore(libgamma_site_state_t* restrict this)
+{
+  (void) this;
+  return errno = ENOTSUP, LIBGAMMA_ERRNO_SET;
+}
+
+
+/**
+ * Duplicate a memory area.
+ * 
+ * @param   ptr    The memory aree.
+ * @param   bytes  The size, in bytes, of the memory area.
+ * @return         A duplication of the memory, `NULL` if zero-length or on error.
+ */
+static inline void* memdup(void* restrict ptr, size_t bytes)
+{
+  char* restrict rc;
+  if (bytes == 0)
+    return NULL;
+  if ((rc = malloc(bytes)) == NULL)
+    return NULL;
+  memcpy(rc, ptr, bytes);
+  return rc;
+}
+
+
+/**
+ * Initialise an allocated partition state.
+ * 
+ * @param   this       The partition state to initialise.
+ * @param   site       The site state for the site that the partition belongs to.
+ * @param   partition  The the index of the partition within the site.
+ * @return             Zero on success, otherwise (negative) the value of an
+ *                     error identifier provided by this library.
+ */
+int libgamma_x_randr_partition_initialise(libgamma_partition_state_t* restrict this,
+					  libgamma_site_state_t* restrict site, size_t partition)
+{
+  int fail_rc = LIBGAMMA_ERRNO_SET;
+  xcb_connection_t* restrict connection = site->data;
+  const xcb_setup_t* restrict setup = xcb_get_setup(connection);
+  xcb_screen_t* restrict screen = NULL;
+  xcb_generic_error_t* error = NULL;
+  xcb_screen_iterator_t iter;
+  xcb_randr_get_screen_resources_current_cookie_t cookie;
+  xcb_randr_get_screen_resources_current_reply_t* restrict reply;
+  xcb_randr_crtc_t* restrict crtcs;
+  xcb_randr_output_t* restrict outputs;
+  libgamma_x_randr_partition_data_t* restrict data;
+  size_t i;
+  
+  if (setup == NULL)
+    return LIBGAMMA_LIST_PARTITIONS_FAILED;
+  
+  for (i = 0; iter.rem > 0; i++, xcb_screen_next(&iter))
+    if (i == partition)
+      {
+	screen = iter.data;
+	break;
+      }
+  if (iter.rem == 0)
+    return LIBGAMMA_NO_SUCH_PARTITION;
+  
+  if (screen == NULL)
+    return LIBGAMMA_NULL_PARTITION;
+  
+  cookie = xcb_randr_get_screen_resources_current(connection, screen->root);
+  reply = xcb_randr_get_screen_resources_current_reply(connection, cookie, &error);
+  if (error != NULL)
+    return translate_error(error->error_code, LIBGAMMA_LIST_CRTCS_FAILED, 0);
+  
+  this->crtcs_available = reply->num_crtcs;
+  crtcs = xcb_randr_get_screen_resources_current_crtcs(reply);
+  outputs = xcb_randr_get_screen_resources_current_outputs(reply);
+  if ((crtcs == NULL) || (outputs == NULL))
+    {
+      free(reply);
+      return LIBGAMMA_REPLY_VALUE_EXTRACTION_FAILED;
+    }
+  
+  /* We use `calloc` because we want `data`'s pointers to be `NULL` if not allocated at `fail`. */
+  data = calloc(1, sizeof(libgamma_x_randr_partition_data_t));
+  if (data == NULL)
+    goto fail;
+  
+  /* Copy the CRTC:s, just so we do not have to keep the reply in memory. */
+  data->crtcs = memdup(crtcs, (size_t)(reply->num_crtcs) * sizeof(xcb_randr_crtc_t));
+  if ((data->crtcs == NULL) && (reply->num_crtcs > 0))
+    goto fail;
+  
+  /* Copy the outputs as well. */
+  data->outputs = memdup(outputs, (size_t)(reply->num_outputs) * sizeof(xcb_randr_output_t));
+  if ((data->outputs == NULL) && (reply->num_outputs > 0))
+    goto fail;
+  
+  data->outputs_count = (size_t)(reply->num_outputs);
+  
+  data->crtc_to_output = malloc((size_t)(reply->num_crtcs) * sizeof(size_t));
+  if (data->crtc_to_output == NULL)
+    goto fail;
+  for (i = 0; i < (size_t)(reply->num_crtcs); i++)
+    data->crtc_to_output[i] = SIZE_MAX;
+  for (i = 0; i < (size_t)(reply->num_outputs); i++)
+    {
+      xcb_randr_get_output_info_cookie_t out_cookie;
+      xcb_randr_get_output_info_reply_t* out_reply;
+      uint16_t j;
+      
+      out_cookie = xcb_randr_get_output_info(connection, outputs[i], reply->config_timestamp);
+      out_reply = xcb_randr_get_output_info_reply(connection, out_cookie, &error);
+      if (error != NULL)
+	{
+	  fail_rc = translate_error(error->error_code, LIBGAMMA_OUTPUT_INFORMATION_QUERY_FAILED, 0);
+	  goto fail;
+	}
+      
+      for (j = 0; j < reply->num_crtcs; j++)
+	if (crtcs[j] == out_reply->crtc)
+	  {
+	    data->crtc_to_output[j] = i;
+	    break;
+	  }
+      
+      free(out_reply);
+    }
+  
+  data->config_timestamp = reply->config_timestamp;
+  this->data = data;
+  free(reply);
+  return 0;
+  
+ fail:
+  if (data != NULL)
+    {
+      free(data->crtcs);
+      free(data->outputs);
+      free(data->crtc_to_output);
+      free(data);
+    }
+  free(reply);
+  return fail_rc;
+}
+
+
+/**
+ * Release all resources held by a partition state.
+ * 
+ * @param  this  The partition state.
+ */
+void libgamma_x_randr_partition_destroy(libgamma_partition_state_t* restrict this)
+{
+  libgamma_x_randr_partition_data_t* restrict data = this->data;
+  free(data->crtcs);
+  free(data->outputs);
+  free(data->crtc_to_output);
+  free(data);
+}
+
+
+/**
+ * Restore the gamma ramps all CRTC:s with a partition to the system settings.
+ * 
+ * @param   this  The partition state.
+ * @return        Zero on success, otherwise (negative) the value of an
+ *                error identifier provided by this library.
+ */
+int libgamma_x_randr_partition_restore(libgamma_partition_state_t* restrict this)
+{
+  (void) this;
+  return errno = ENOTSUP, LIBGAMMA_ERRNO_SET;
+}
+
+
+
+/**
+ * Initialise an allocated CRTC state.
+ * 
+ * @param   this       The CRTC state to initialise.
+ * @param   partition  The partition state for the partition that the CRTC belongs to.
+ * @param   crtc       The the index of the CRTC within the site.
+ * @return             Zero on success, otherwise (negative) the value of an
+ *                     error identifier provided by this library.
+ */
+int libgamma_x_randr_crtc_initialise(libgamma_crtc_state_t* restrict this,
+				     libgamma_partition_state_t* restrict partition, size_t crtc)
+{
+  libgamma_x_randr_partition_data_t* restrict screen_data = partition->data;
+  xcb_randr_crtc_t* restrict crtc_ids = screen_data->crtcs;
+  if (crtc >= partition->crtcs_available)
+    return LIBGAMMA_NO_SUCH_CRTC;
+  this->data = crtc_ids + crtc;
+  return 0;
+}
+
+
+/**
+ * Release all resources held by a CRTC state.
+ * 
+ * @param  this  The CRTC state.
+ */
+void libgamma_x_randr_crtc_destroy(libgamma_crtc_state_t* restrict this)
+{
+  (void) this;
+}
+
+
+/**
+ * Restore the gamma ramps for a CRTC to the system settings for that CRTC.
+ * 
+ * @param   this  The CRTC state.
+ * @return        Zero on success, otherwise (negative) the value of an
+ *                error identifier provided by this library.
+ */
+int libgamma_x_randr_crtc_restore(libgamma_crtc_state_t* restrict this)
+{
+  (void) this;
+  return errno = ENOTSUP, LIBGAMMA_ERRNO_SET;
+}
+
+
+
+/**
+ * Get the gamma ramp size of a CRTC.
+ * 
+ * @param   this  Instance of a data structure to fill with the information about the CRTC.
+ * @param   crtc  The state of the CRTC whose information should be read.
+ * @return        Non-zero on error.
+ */
+static int get_gamma_ramp_size(libgamma_crtc_information_t* restrict out, libgamma_crtc_state_t* restrict crtc)
+{
+  xcb_connection_t* restrict connection = crtc->partition->site->data;
+  xcb_randr_crtc_t* restrict crtc_id = crtc->data;
+  xcb_randr_get_crtc_gamma_size_cookie_t cookie;
+  xcb_randr_get_crtc_gamma_size_reply_t* restrict reply;
+  xcb_generic_error_t* error;
+  
+  out->gamma_size_error = 0;
+  cookie = xcb_randr_get_crtc_gamma_size(connection, *crtc_id);
+  reply = xcb_randr_get_crtc_gamma_size_reply(connection, cookie, &error);
+  if (error != NULL)
+    return out->gamma_size_error = translate_error(error->error_code, LIBGAMMA_GAMMA_RAMPS_SIZE_QUERY_FAILED, 1);
+  if (reply->size < 2)
+    out->gamma_size_error = LIBGAMMA_SINGLETON_GAMMA_RAMP;
+  out->red_gamma_size = out->green_gamma_size = out->blue_gamma_size = reply->size;
+  free(reply);
+  return out->gamma_size_error;
+}
+
+
+/**
+ * Read information from the CRTC's output.
+ * 
+ * @param   out     Instance of a data structure to fill with the information about the CRTC.
+ * @param   output  The CRTC's output information.
+ * @return          Non-zero if at least on error occured.
+ */
+static int read_output_data(libgamma_crtc_information_t* restrict out, xcb_randr_get_output_info_reply_t* restrict output)
+{
+  switch (output->connection)
+    {
+    case XCB_RANDR_CONNECTION_CONNECTED:
+      out->active = 1;
+      out->width_mm = output->mm_width;
+      out->height_mm = output->mm_height;
+#define __select(value)  \
+  case XCB_RENDER_SUB_PIXEL_##value:  out->subpixel_order = LIBGAMMA_SUBPIXEL_ORDER_##value;  break
+      switch (output->subpixel_order)
+	{
+	__select (UNKNOWN);
+	__select (HORIZONTAL_RGB);
+	__select (HORIZONTAL_BGR);
+	__select (VERTICAL_RGB);
+	__select (VERTICAL_BGR);
+	__select (NONE);
+	default:
+	  out->subpixel_order_error = LIBGAMMA_SUBPIXEL_ORDER_NOT_RECOGNISED;
+	  break;
+	}
+#undef __select
+      return 0;
+      
+    case XCB_RANDR_CONNECTION_DISCONNECTED:
+      out->active = 0;
+      out->width_mm_error = LIBGAMMA_NOT_CONNECTED;
+      out->height_mm_error = LIBGAMMA_NOT_CONNECTED;
+      out->subpixel_order_error = LIBGAMMA_NOT_CONNECTED;
+      return 0;
+      
+    default:
+      out->active = 0;
+      out->active_error = LIBGAMMA_STATE_UNKNOWN;
+      out->width_mm_error = LIBGAMMA_NOT_CONNECTED;
+      out->height_mm_error = LIBGAMMA_NOT_CONNECTED;
+      out->subpixel_order_error = LIBGAMMA_NOT_CONNECTED;
+      return -1;
+    }
+}
+
+
+/**
+ * Determine the connector type from the connector name.
+ * 
+ * @param  this  The CRTC information to use and extend.
+ * @param        Non-zero on error.
+ */
+static int get_connector_type(libgamma_crtc_information_t* restrict this)
+{
+  if ((this->connector_type_error = this->connector_name_error))
+    return -1;
+  
+#define __select(name, type)                                           \
+  if (strstr(this->connector_name, name "-") == this->connector_name)  \
+    return this->connector_type = LIBGAMMA_CONNECTOR_TYPE_##type, 0
+  
+  __select ("None",         Unknown);
+  __select ("VGA",          VGA);
+  __select ("DVI-I",        DVII);
+  __select ("DVI-D",        DVID);
+  __select ("DVI-A",        DVIA);
+  __select ("Composite",    Composite);
+  __select ("S-Video",      SVIDEO);
+  __select ("Component",    Component);
+  __select ("LFP",          LFP);
+  __select ("Proprietary",  Unknown);
+  __select ("HDMI",         HDMI);
+  __select ("DisplayPort",  DisplayPort);
+  
+#undef __select
+  
+  this->connector_name_error = LIBGAMMA_CONNECTOR_TYPE_NOT_RECOGNISED;
+  return -1;
+}
+
+
+/**
+ * Get the output name of a CRTC.
+ * 
+ * @param   this    Instance of a data structure to fill with the information about the CRTC.
+ * @param   output  The CRTC's output's information.
+ * @return          Non-zero on error.
+ */
+static int get_output_name(libgamma_crtc_information_t* restrict out, xcb_randr_get_output_info_reply_t* restrict output)
+{
+  char* restrict store;
+  uint8_t* restrict name;
+  uint16_t length;
+  size_t i;
+  
+  name = xcb_randr_get_output_info_name(output);
+  length = output->name_len; /* There is no NUL-termination. */
+  if (name == NULL)
+    {
+      out->connector_name_error = LIBGAMMA_REPLY_VALUE_EXTRACTION_FAILED;
+      return -1;
+    }
+  
+  store = malloc(((size_t)length + 1) * sizeof(char));
+  if (store == NULL)
+    {
+      out->connector_name_error = errno;
+      return -1;
+    }
+  
+  /* char is guaranteed to be (u)int_least8_t, but it is only guaranteed to be (u)int8_t
+   * on POSIX, so to be truly portable we will not assume that char is (u)int8_t. */
+  for (i = 0; i < (size_t)length; i++)
+    store[i] = (char)(name[i]);
+  store[length] = '\0';
+  
+  return 0;
+}
+
+
+/**
+ * Get the Extended Display Information Data of the monitor connected to the connector of a CRTC.
+ * 
+ * @param   out     Instance of a data structure to fill with the information about the CRTC.
+ * @param   crtc    The state of the CRTC whose information should be read.
+ * @param   output  The CRTC's output.
+ * @return          Non-zero on error.
+ */
+static int get_edid(libgamma_crtc_information_t* restrict out,
+		    libgamma_crtc_state_t* restrict crtc, xcb_randr_output_t output)
+{
+  xcb_connection_t* restrict connection = crtc->partition->site->data;
+  xcb_randr_list_output_properties_cookie_t prop_cookie;
+  xcb_randr_list_output_properties_reply_t* restrict prop_reply;
+  xcb_atom_t* atoms;
+  xcb_atom_t* atoms_end;
+  xcb_generic_error_t* error;
+  
+  /* Acquire a list of all properties of the output. */
+  prop_cookie = xcb_randr_list_output_properties(connection, output);
+  prop_reply = xcb_randr_list_output_properties_reply(connection, prop_cookie, &error);
+  
+  if (error != NULL)
+    return out->edid_error = translate_error(error->error_code, LIBGAMMA_LIST_PROPERTIES_FAILED, 1);
+  
+  /* Extract the properties form the data structure that holds them, */
+  atoms = xcb_randr_list_output_properties_atoms(prop_reply);
+  /* and get the last one so that we can iterate over them nicely. */
+  atoms_end = atoms + xcb_randr_list_output_properties_atoms_length(prop_reply);
+  
+  if (atoms == NULL)
+    {
+      free(prop_reply);
+      return out->edid_error = LIBGAMMA_REPLY_VALUE_EXTRACTION_FAILED;;
+    }
+  
+  /* For each property */
+  for (; atoms != atoms_end; atoms++)
+    {
+      xcb_get_atom_name_cookie_t atom_name_cookie;
+      xcb_get_atom_name_reply_t* restrict atom_name_reply;
+      char* restrict atom_name;
+      int atom_name_len;
+      xcb_randr_get_output_property_cookie_t atom_cookie;
+      xcb_randr_get_output_property_reply_t* restrict atom_reply;
+      unsigned char* restrict atom_data;
+      int length;
+      
+      /* Acquire the atom name. */
+      atom_name_cookie = xcb_get_atom_name(connection, *atoms);
+      atom_name_reply = xcb_get_atom_name_reply(connection, atom_name_cookie, &error);
+      if (error)
+	continue;
+      
+      /* Extract the atom name from the data structure that holds it. */
+      atom_name = xcb_get_atom_name_name(atom_name_reply);
+      /* As well as the length of the name; it is not NUL-termianted.*/
+      atom_name_len = xcb_get_atom_name_name_length(atom_name_reply);
+      
+      if (/* Check for errors. */
+	  (atom_name == NULL) || /* (atom_name_len < 1) || */
+	  /* Check that the length is the expected length for the EDID property. */
+	  (atom_name_len != 4) ||
+	  /* Check that the property is the EDID property. */
+	  (atom_name[0] != 'E') || (atom_name[1] != 'D') || (atom_name[2] != 'I') || (atom_name[3] != 'D'))
+	{
+	  free(atom_name_reply);
+	  continue;
+	}
+      
+      /* Acquire the property's value, we know that it is either 128 or 256 byte long. */
+      atom_cookie = xcb_randr_get_output_property(connection, output, *atoms,
+						  XCB_GET_PROPERTY_TYPE_ANY, 0, 256, 0, 0);
+      atom_reply = xcb_randr_get_output_property_reply(connection, atom_cookie, &error);
+      /* (*) EDID version 1.0 through 1.4 define it as 128 bytes long,
+       * but version 2.0 define it as 256 bytes long. However,
+       * version 2.0 is rare(?) and has been deprecated and replaced
+       * by version 1.3 (I guess that is with a new version epoch,
+       * but I do not know.) */ 
+      if (error)
+	{
+	  free(atom_name_reply);
+	  free(prop_reply);
+	  return out->edid_error = LIBGAMMA_PROPERTY_VALUE_QUERY_FAILED;
+	}
+      
+      /* Extract the property's value, */
+      atom_data = xcb_randr_get_output_property_data(atom_reply);
+      /* and its actual length. */
+      length = xcb_randr_get_output_property_data_length(atom_reply);
+      if ((atom_data == NULL) || (length < 1))
+	{
+	  free(atom_reply);
+	  free(atom_name_reply);
+	  free(prop_reply);
+	  return out->edid_error = LIBGAMMA_REPLY_VALUE_EXTRACTION_FAILED;
+	}
+      
+      /* Store the EDID. */
+      out->edid = malloc((size_t)length * sizeof(unsigned char));
+      if (out->edid == NULL)
+	out->edid_error = errno;
+      else
+	memcpy(out->edid, atom_data, (size_t)length * sizeof(unsigned char));
+      
+      free(atom_reply);
+      free(atom_name_reply);
+      free(prop_reply);
+      
+      return out->edid_error;
+    }
+  
+  return out->edid_error = LIBGAMMA_EDID_NOT_FOUND;
+}
+
+
+/**
+ * Read information about a CRTC.
+ * 
+ * @param   this    Instance of a data structure to fill with the information about the CRTC.
+ * @param   crtc    The state of the CRTC whose information should be read.
+ * @param   fields  OR:ed identifiers for the information about the CRTC that should be read.
+ * @return          Zero on success, -1 on error. On error refer to the error reports in `this`..
+ */
+int libgamma_x_randr_get_crtc_information(libgamma_crtc_information_t* restrict this,
+					  libgamma_crtc_state_t* restrict crtc, int32_t fields)
+{
+#define _E(FIELD)  ((fields & FIELD) ? LIBGAMMA_CRTC_INFO_NOT_SUPPORTED : 0)
+  int e = 0;
+  xcb_randr_get_output_info_reply_t* restrict output_info = NULL;
+  xcb_randr_output_t output;
+  int free_edid;
+  
+  /* Wipe all error indicators. */
+  memset(this, 0, sizeof(libgamma_crtc_information_t));
+  
+  /* We need to free the EDID after us if it is not explicitly requested.  */
+  free_edid = (fields & LIBGAMMA_CRTC_INFO_EDID) == 0;
+  
+  /* Figure out what fields we need to get the data for to get the data for other fields. */
+  if ((fields & (LIBGAMMA_CRTC_INFO_WIDTH_MM_EDID | LIBGAMMA_CRTC_INFO_HEIGHT_MM_EDID | LIBGAMMA_CRTC_INFO_GAMMA)))
+    fields |= LIBGAMMA_CRTC_INFO_EDID;
+  if ((fields & LIBGAMMA_CRTC_INFO_CONNECTOR_TYPE))
+    fields |= LIBGAMMA_CRTC_INFO_CONNECTOR_NAME;
+  if ((fields & (LIBGAMMA_CRTC_INFO_WIDTH_MM | LIBGAMMA_CRTC_INFO_HEIGHT_MM | LIBGAMMA_CRTC_INFO_SUBPIXEL_ORDER)))
+    fields |= LIBGAMMA_CRTC_INFO_ACTIVE;
+  
+  /* Jump if the output information is not required. */
+  if ((fields & (LIBGAMMA_CRTC_INFO_ACTIVE | LIBGAMMA_CRTC_INFO_CONNECTOR_NAME)) == 0)
+    goto cont;
+  
+  /* Get connector and connector information. */
+  {
+    xcb_connection_t* restrict connection = crtc->partition->site->data;
+    libgamma_x_randr_partition_data_t* restrict screen_data = crtc->partition->data;
+    size_t output_index = screen_data->crtc_to_output[crtc->crtc];
+    xcb_randr_get_output_info_cookie_t cookie;
+    xcb_generic_error_t* error;
+    if (output_index == SIZE_MAX)
+      {
+	e |= this->edid_error = this->gamma_error = this->width_mm_edid_error
+	   = this->height_mm_edid_error = this->connector_type_error
+	   = this->connector_name_error = this->subpixel_order_error
+	   = this->width_mm_error = this->height_mm_error
+	   = this->active_error = LIBGAMMA_CONNECTOR_UNKNOWN;
+	goto cont;
+      }
+    output = screen_data->outputs[output_index];
+    cookie = xcb_randr_get_output_info(connection, output, screen_data->config_timestamp);
+    output_info = xcb_randr_get_output_info_reply(connection, cookie, &error);
+    if (error != NULL)
+      {
+	e |= this->edid_error = this->gamma_error = this->width_mm_edid_error
+	   = this->height_mm_edid_error = this->connector_type_error
+	   = this->connector_name_error = this->subpixel_order_error
+	   = this->width_mm_error = this->height_mm_error
+	   = this->active_error = LIBGAMMA_OUTPUT_INFORMATION_QUERY_FAILED;
+	goto cont;
+      }
+  }
+  
+  e |= get_output_name(this, output_info);
+  if ((fields & LIBGAMMA_CRTC_INFO_CONNECTOR_TYPE))
+    e |= get_connector_type(this);
+  e |= read_output_data(this, output_info);
+  if ((fields & (LIBGAMMA_CRTC_INFO_WIDTH_MM | LIBGAMMA_CRTC_INFO_HEIGHT_MM)))
+    e |= this->width_mm_error | this->height_mm_error;
+  e |= (fields & LIBGAMMA_CRTC_INFO_SUBPIXEL_ORDER) ? this->subpixel_order_error : 0;
+  
+  if ((fields & LIBGAMMA_CRTC_INFO_EDID) == 0)
+    goto cont;
+  if (this->active == 0)
+    {
+      e |= this->edid_error = this->gamma_error = this->width_mm_edid_error
+	 = this->height_mm_edid_error = LIBGAMMA_NOT_CONNECTED;
+      goto cont;
+    }
+  e |= get_edid(this, crtc, output);
+  if (this->edid == NULL)
+    {
+      this->gamma_error = this->width_mm_edid_error = this->height_mm_edid_error = this->edid_error;
+      goto cont;
+    }
+  if ((fields & (LIBGAMMA_CRTC_INFO_WIDTH_MM_EDID | LIBGAMMA_CRTC_INFO_HEIGHT_MM_EDID | LIBGAMMA_CRTC_INFO_GAMMA)))
+    e |= libgamma_parse_edid(this, fields);
+  
+ cont:
+  e |= (fields & LIBGAMMA_CRTC_INFO_GAMMA_SIZE) ? get_gamma_ramp_size(this, crtc) : 0;
+  this->gamma_depth = 16;
+  e |= this->gamma_support_error = _E(LIBGAMMA_CRTC_INFO_GAMMA_SUPPORT);
+  
+  /* Free the EDID after us. */
+  if (free_edid)
+    {
+      free(this->edid);
+      this->edid = NULL;
+    }
+  
+  free(output_info);
+  return e ? -1 : 0;
+#undef _E
+}
+
+
+/**
+ * Get current the gamma ramps for a CRTC, 16-bit gamma-depth version.
+ * 
+ * @param   this   The CRTC state.
+ * @param   ramps  The gamma ramps to fill with the current values.
+ * @return         Zero on success, otherwise (negative) the value of an
+ *                 error identifier provided by this library.
+ */
+int libgamma_x_randr_crtc_get_gamma_ramps(libgamma_crtc_state_t* restrict this,
+					  libgamma_gamma_ramps_t* restrict ramps)
+{
+  xcb_connection_t* restrict connection = this->partition->site->data;
+  xcb_randr_get_crtc_gamma_cookie_t cookie;
+  xcb_randr_get_crtc_gamma_reply_t* restrict reply;
+  xcb_generic_error_t* error;
+  uint16_t* restrict red;
+  uint16_t* restrict green;
+  uint16_t* restrict blue;
+  
+#ifdef DEBUG
+  if ((ramps->red_size != ramps->green_size) ||
+      (ramps->red_size != ramps->blue_size))
+    return LIBGAMMA_MIXED_GAMMA_RAMP_SIZE;
+#endif
+  
+  cookie = xcb_randr_get_crtc_gamma(connection, *(xcb_randr_crtc_t*)(this->data));
+  reply = xcb_randr_get_crtc_gamma_reply(connection, cookie, &error);
+  
+  if (error != NULL)
+    return translate_error(error->error_code, LIBGAMMA_GAMMA_RAMP_READ_FAILED, 0);
+  
+  red   = xcb_randr_get_crtc_gamma_red(reply);
+  green = xcb_randr_get_crtc_gamma_green(reply);
+  blue  = xcb_randr_get_crtc_gamma_blue(reply);
+  memcpy(ramps->red,   red,   ramps->red_size   * sizeof(uint16_t));
+  memcpy(ramps->green, green, ramps->green_size * sizeof(uint16_t));
+  memcpy(ramps->blue,  blue,  ramps->blue_size  * sizeof(uint16_t));
+  
+  free(reply);
+  return 0;
+}
+
+
+/**
+ * Set the gamma ramps for a CRTC, 16-bit gamma-depth version.
+ * 
+ * @param   this   The CRTC state.
+ * @param   ramps  The gamma ramps to apply.
+ * @return         Zero on success, otherwise (negative) the value of an
+ *                 error identifier provided by this library.
+ */
+int libgamma_x_randr_crtc_set_gamma_ramps(libgamma_crtc_state_t* restrict this,
+					  libgamma_gamma_ramps_t ramps)
+{
+  xcb_connection_t* restrict connection = this->partition->site->data;
+  xcb_void_cookie_t cookie;
+  xcb_generic_error_t* restrict error;
+#ifdef DEBUG
+  if ((ramps.red_size != ramps.green_size) ||
+      (ramps.red_size != ramps.blue_size))
+    return LIBGAMMA_MIXED_GAMMA_RAMP_SIZE;
+#endif
+  cookie = xcb_randr_set_crtc_gamma_checked(connection, *(xcb_randr_crtc_t*)(this->data),
+					    (uint16_t)(ramps.red_size), ramps.red, ramps.green, ramps.blue);
+  if ((error = xcb_request_check(connection, cookie)) != NULL)
+    return translate_error(error->error_code, LIBGAMMA_GAMMA_RAMP_WRITE_FAILED, 0);
+  return 0;
+}
+
+
+# pragma GCC diagnostic pop
+