[libcamera-devel] [RFC PATCH v2 04/10] cam: file_sink: Use offset in mapping FrameBuffer

[Hirokazu Honda]

This fixes the way of mapping FrameBuffer in FrameSink by
using offset.

Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
---
 src/cam/file_sink.cpp | 22 +++++++++++++++++-----
 src/cam/file_sink.h   |  1 +
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/cam/file_sink.cpp b/src/cam/file_sink.cpp
index 2d30694a..26a60058 100644
--- a/src/cam/file_sink.cpp
+++ b/src/cam/file_sink.cpp
@@ -51,12 +51,24 @@ int FileSink::configure(const libcamera::CameraConfiguration &config)
 
 void FileSink::mapBuffer(FrameBuffer *buffer)
 {
+	/* \todo use MappedFrameBuffer. */
 	for (const FrameBuffer::Plane &plane : buffer->planes()) {
-		void *memory = mmap(NULL, plane.length, PROT_READ, MAP_SHARED,
-				    plane.fd.fd(), 0);
+		const int fd = plane.fd.fd();
+		if (mappedBuffers_.find(fd) == mappedBuffers_.end()) {
+			/**
+                         * \todo Should we try to only map the portions of the
+                         * dmabuf that are used by planes ?
+                         */
+			size_t length = lseek(fd, 0, SEEK_END);
+			void *memory = mmap(NULL, plane.length, PROT_READ,
+					    MAP_SHARED, plane.fd.fd(), 0);
+			mappedBuffers_[plane.fd.fd()] =
+				std::make_pair(memory, length);
 
-		mappedBuffers_[plane.fd.fd()] =
-			std::make_pair(memory, plane.length);
+		}
+
+		void *memory = mappedBuffers_[fd].first;
+		planeData_[&plane] = static_cast<uint8_t *>(memory) + plane.offset;
 	}
 }
 
@@ -102,7 +114,7 @@ void FileSink::writeBuffer(const Stream *stream, FrameBuffer *buffer)
 		const FrameBuffer::Plane &plane = buffer->planes()[i];
 		const FrameMetadata::Plane &meta = buffer->metadata().planes[i];
 
-		void *data = mappedBuffers_[plane.fd.fd()].first;
+		uint8_t *data = planeData_[&plane];
 		unsigned int length = std::min(meta.bytesused, plane.length);
 
 		if (meta.bytesused > plane.length)
diff --git a/src/cam/file_sink.h b/src/cam/file_sink.h
index c3eb230a..c12325d9 100644
--- a/src/cam/file_sink.h
+++ b/src/cam/file_sink.h
@@ -33,6 +33,7 @@ private:
 	std::map<const libcamera::Stream *, std::string> streamNames_;
 	std::string pattern_;
 	std::map<int, std::pair<void *, unsigned int>> mappedBuffers_;
+	std::map<const libcamera::FrameBuffer::Plane *, uint8_t *> planeData_;
 };
 
 #endif /* __CAM_FILE_SINK_H__ */
-- 
2.33.0.rc2.250.ged5fa647cd-goog