gbm: Clarify acceptable formats for gbm_bo

[mesa.git] / src / gbm / main / gbm.c

diff --git a/src/gbm/main/gbm.c b/src/gbm/main/gbm.c
index 0bf2922bacdd408035049111cf30a464d3dfc010..250151871d9dc92c27de0e8b5e1958b3b55961fa 100644 (file)
--- a/src/gbm/main/gbm.c
+++ b/src/gbm/main/gbm.c
@@ -448,14 +448,14 @@ gbm_bo_destroy(struct gbm_bo *bo)
  * \param gbm The gbm device returned from gbm_create_device()
  * \param width The width for the buffer
  * \param height The height for the buffer
- * \param format The format to use for the buffer
+ * \param format The format to use for the buffer, from GBM_FORMAT_* or
+ * GBM_BO_FORMAT_* tokens
  * \param usage The union of the usage flags for this buffer
  *
  * \return A newly allocated buffer that should be freed with gbm_bo_destroy()
  * when no longer needed. If an error occurs during allocation %NULL will be
  * returned and errno set.
  *
- * \sa enum gbm_bo_format for the list of formats
  * \sa enum gbm_bo_flags for the list of usage flags
  */
 GBM_EXPORT struct gbm_bo *
@@ -695,3 +695,39 @@ gbm_surface_has_free_buffers(struct gbm_surface *surf)
 {
    return surf->gbm->surface_has_free_buffers(surf);
 }
+
+/* The two GBM_BO_FORMAT_[XA]RGB8888 formats alias the GBM_FORMAT_*
+ * formats of the same name. We want to accept them whenever someone
+ * has a GBM format, but never return them to the user. */
+uint32_t
+gbm_format_canonicalize(uint32_t gbm_format)
+{
+   switch (gbm_format) {
+   case GBM_BO_FORMAT_XRGB8888:
+      return GBM_FORMAT_XRGB8888;
+   case GBM_BO_FORMAT_ARGB8888:
+      return GBM_FORMAT_ARGB8888;
+   default:
+      return gbm_format;
+   }
+}
+
+/**
+ * Returns a string representing the fourcc format name.
+ *
+ * \param desc Caller-provided storage for the format name string.
+ * \return String containing the fourcc of the format.
+ */
+GBM_EXPORT char *
+gbm_format_get_name(uint32_t gbm_format, struct gbm_format_name_desc *desc)
+{
+   gbm_format = gbm_format_canonicalize(gbm_format);
+
+   desc->name[0] = gbm_format;
+   desc->name[1] = gbm_format >> 8;
+   desc->name[2] = gbm_format >> 16;
+   desc->name[3] = gbm_format >> 24;
+   desc->name[4] = 0;
+
+   return desc->name;
+}