[PATCH v2 1/2] libv4lconvert: Port supported_src_formats to bit-ops

[Ricardo Ribalda Delgado <ricardo@ribalda.com>]

We have passed the barrier of 64 supported formats, therefore a int64_t
is not enough for holding the bitfield.

Instead use bit-ops ala kernel.

Signed-off-by: Ricardo Ribalda Delgado <ricardo@ribalda.com>
Suggested-by: Hans de Goede <hdegoede@redhat.com>
---
 lib/libv4lconvert/libv4lconvert-priv.h |  3 +-
 lib/libv4lconvert/libv4lconvert.c      | 40 ++++++++++++++++++++++----
 2 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/lib/libv4lconvert/libv4lconvert-priv.h b/lib/libv4lconvert/libv4lconvert-priv.h
index a8046ce2..5286a9b1 100644
--- a/lib/libv4lconvert/libv4lconvert-priv.h
+++ b/lib/libv4lconvert/libv4lconvert-priv.h
@@ -38,6 +38,7 @@
 #include "tinyjpeg.h"
 
 #define ARRAY_SIZE(x) ((int)sizeof(x)/(int)sizeof((x)[0]))
+#define BITS_PER_LONG (8 * sizeof(long))
 
 #define V4LCONVERT_ERROR_MSG_SIZE 256
 #define V4LCONVERT_MAX_FRAMESIZES 256
@@ -55,7 +56,7 @@ struct v4lconvert_data {
 	int flags; /* bitfield */
 	int control_flags; /* bitfield */
 	unsigned int no_formats;
-	int64_t supported_src_formats; /* bitfield */
+	unsigned long supported_src_formats[128 / BITS_PER_LONG];
 	char error_msg[V4LCONVERT_ERROR_MSG_SIZE];
 	struct jdec_private *tinyjpeg;
 #ifdef HAVE_JPEG
diff --git a/lib/libv4lconvert/libv4lconvert.c b/lib/libv4lconvert/libv4lconvert.c
index 78fb3432..0607cc8b 100644
--- a/lib/libv4lconvert/libv4lconvert.c
+++ b/lib/libv4lconvert/libv4lconvert.c
@@ -32,6 +32,29 @@
 #include "libv4lsyscall-priv.h"
 
 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
+#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
+#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
+
+static inline void __set_bit(int nr, volatile unsigned long *addr)
+{
+	unsigned long mask = BIT_MASK(nr);
+	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
+
+	*p  |= mask;
+}
+
+static inline void __clear_bit(int nr, volatile unsigned long *addr)
+{
+	unsigned long mask = BIT_MASK(nr);
+	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
+
+	*p &= ~mask;
+}
+
+static inline int __test_bit(int nr, const volatile unsigned long *addr)
+{
+	return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
+}
 
 static void *dev_init(int fd)
 {
@@ -231,7 +254,7 @@ struct v4lconvert_data *v4lconvert_create_with_dev_ops(int fd, void *dev_ops_pri
 				break;
 
 		if (j < ARRAY_SIZE(supported_src_pixfmts)) {
-			data->supported_src_formats |= 1ULL << j;
+			__set_bit(j, data->supported_src_formats);
 			v4lconvert_get_framesizes(data, fmt.pixelformat, j);
 			if (!supported_src_pixfmts[j].needs_conversion)
 				always_needs_conversion = 0;
@@ -316,8 +339,15 @@ int v4lconvert_supported_dst_format(unsigned int pixelformat)
 
 int v4lconvert_supported_dst_fmt_only(struct v4lconvert_data *data)
 {
-	return v4lcontrol_needs_conversion(data->control) &&
-		data->supported_src_formats;
+	int i;
+
+	for (i = 0 ; i < ARRAY_SIZE(data->supported_src_formats); i++)
+		if (data->supported_src_formats[i])
+			break;
+	if (i == ARRAY_SIZE(data->supported_src_formats))
+		return 0;
+
+	return v4lcontrol_needs_conversion(data->control);
 }
 
 /* See libv4lconvert.h for description of in / out parameters */
@@ -334,7 +364,7 @@ int v4lconvert_enum_fmt(struct v4lconvert_data *data, struct v4l2_fmtdesc *fmt)
 
 	for (i = 0; i < ARRAY_SIZE(supported_dst_pixfmts); i++)
 		if (v4lconvert_supported_dst_fmt_only(data) ||
-				!(data->supported_src_formats & (1ULL << i))) {
+		    !__test_bit(i, data->supported_src_formats)) {
 			faked_fmts[no_faked_fmts] = supported_dst_pixfmts[i].fmt;
 			no_faked_fmts++;
 		}
@@ -490,7 +520,7 @@ static int v4lconvert_do_try_format(struct v4lconvert_data *data,
 
 	for (i = 0; i < ARRAY_SIZE(supported_src_pixfmts); i++) {
 		/* is this format supported? */
-		if (!(data->supported_src_formats & (1ULL << i)))
+		if (!__test_bit(i, data->supported_src_formats))
 			continue;
 
 		try_fmt = *dest_fmt;
-- 
2.20.1