[igt-dev] [PATCH i-g-t 4/4] lib/igt_kms: simplify pipe <-> name conversion

[Lucas De Marchi <lucas.demarchi@intel.com>]

Now that we can use _Static_assert() due to C11, make it future proof so
we remember to update this if IGT_MAX_PIPES changes. Also reduce
verbosity a little bit by calculating indexes instead of if/else chain.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
---
 lib/igt_kms.c | 27 ++++++++++-----------------
 1 file changed, 10 insertions(+), 17 deletions(-)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index 0438f641..40146867 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -324,9 +324,10 @@ const unsigned char* igt_kms_get_alt_edid(void)
  */
 const char *kmstest_pipe_name(enum pipe pipe)
 {
-	static const char * const str[] = {
-		"A", "B", "C", "D", "E", "F",
-	};
+	static const char str[] = "A\0B\0C\0D\0E\0F";
+
+	_Static_assert(sizeof(str) == IGT_MAX_PIPES * 2,
+		       "Missing pipe name");
 
 	if (pipe == PIPE_NONE)
 		return "None";
@@ -334,7 +335,7 @@ const char *kmstest_pipe_name(enum pipe pipe)
 	if (pipe >= IGT_MAX_PIPES)
 		return "invalid";
 
-	return str[pipe];
+	return str + (pipe * 2);
 }
 
 /**
@@ -345,20 +346,12 @@ const char *kmstest_pipe_name(enum pipe pipe)
  */
 int kmstest_pipe_to_index(char pipe)
 {
-	if (pipe == 'A')
-		return 0;
-	else if (pipe == 'B')
-		return 1;
-	else if (pipe == 'C')
-		return 2;
-	else if (pipe == 'D')
-		return 3;
-	else if (pipe == 'E')
-		return 4;
-	else if (pipe == 'F')
-		return 5;
-	else
+	int r = pipe - 'A';
+
+	if (r < 0 || r >= IGT_MAX_PIPES)
 		return -EINVAL;
+
+	return r;
 }
 
 /**
-- 
2.17.1

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