android: camera_buffer: Add method to get the JPEG blob size

To maintain compatibility with platforms that do not provide a memory
backend implementation add a method to be return the size of the buffer
used for JPEG encoding capped to a maximum size.

Platforms that implement a memory backend will always calculate the
correct buffer size.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>

2 files changed, 16 insertions, 0 deletions

diff --git a/src/android/camera_buffer.h b/src/android/camera_buffer.h
index 2311cdaf..784fbd50 100644
--- a/src/android/camera_buffer.h
+++ b/src/android/camera_buffer.h
@@ -26,6 +26,8 @@ public:
 
 	libcamera::Span<const uint8_t> plane(unsigned int plane) const;
 	libcamera::Span<uint8_t> plane(unsigned int plane);
+
+	size_t jpegBufferSize(size_t maxJpegBufferSize) const;
 };
 
 #endif /* __ANDROID_CAMERA_BUFFER_H__ */
diff --git a/src/android/mm/generic_camera_buffer.cpp b/src/android/mm/generic_camera_buffer.cpp
index 45a83c35..98e63dfa 100644
--- a/src/android/mm/generic_camera_buffer.cpp
+++ b/src/android/mm/generic_camera_buffer.cpp
@@ -27,6 +27,8 @@ public:
 	unsigned int numPlanes() const;
 
 	Span<uint8_t> plane(unsigned int plane);
+
+	size_t jpegBufferSize(size_t maxJpegBufferSize) const;
 };
 
 CameraBuffer::Private::Private(CameraBuffer *cameraBuffer,
@@ -77,6 +79,12 @@ Span<uint8_t> CameraBuffer::Private::plane(unsigned int plane)
 	return maps_[plane];
 }
 
+size_t CameraBuffer::Private::jpegBufferSize(size_t maxJpegBufferSize) const
+{
+	return std::min<unsigned int>(maps_[0].size(),
+				      maxJpegBufferSize);
+}
+
 CameraBuffer::CameraBuffer(buffer_handle_t camera3Buffer, int flags)
 	: Extensible(new Private(this, camera3Buffer, flags))
 {
@@ -109,3 +117,9 @@ Span<uint8_t> CameraBuffer::plane(unsigned int plane)
 	Private *const d = LIBCAMERA_D_PTR();
 	return d->plane(plane);
 }
+
+size_t CameraBuffer::jpegBufferSize(size_t maxJpegBufferSize) const
+{
+	const Private *const d = LIBCAMERA_D_PTR();
+	return d->jpegBufferSize(maxJpegBufferSize);
+}