Add movie.subframe_to_frame

include/library/portctrl-data.hpp

@@ -1243,6 +1243,10 @@ public:
  * Find subframe number corresponding to given frame (1-based).
  */
 	int64_t find_frame(uint64_t n);
+/**
+ * Find frame number corresponding to given subframe (0-based).
+ */
+	int64_t subframe_to_frame(uint64_t n);
 /**
  * Notify sync flag polarity change.
  *

lua.lyx

@@ -6704,6 +6704,25 @@ Returns starting subframe of given frame (frame numbers are 1-based).
  Returns -1 if frame number is bad.
 \end_layout
 
+\begin_layout Subsection
+movie.subframe_to_frame/INPUTMOVIE::subframe_to_frame: Find frame corresponding
+ to subframe
+\end_layout
+
+\begin_layout Itemize
+Syntax: number movie.subframe_to_frame([INPUTMOVIE/string movie], number
+ subframe)
+\end_layout
+
+\begin_layout Itemize
+Syntax: number INPUTMOVIE::subframe_to_frame(number subframe)
+\end_layout
+
+\begin_layout Standard
+Returns frame containing given subframe (subframe numbers are 0-based).
+ Returns -1 if subframe number is bad.
+\end_layout
+
 \begin_layout Subsection
 movie.blank_frame/INPUTMOVIE::blank_frame: Return a blank frame
 \end_layout

src/library/portctrl-data.cpp

@@ -819,6 +819,35 @@ int64_t frame_vector::find_frame(uint64_t n)
 	return -1;
 }
 
+int64_t frame_vector::subframe_to_frame(uint64_t n)
+{
+	int64_t ret = 1;
+	uint64_t stride = get_stride();
+	uint64_t pageframes = get_frames_per_page();
+	uint64_t vsize = size();
+	if(n >= vsize) return -1;
+	size_t pagenum = 0;
+	size_t cpage = n / pageframes;
+	for(uint64_t p = 0; p < cpage; p++) {
+		const unsigned char* content = get_page_buffer(pagenum++);
+		size_t offset = 0;
+		for(unsigned i = 0; i < pageframes; i++) {
+			if(frame::sync(content + offset)) ret++;
+			offset += stride;
+		}
+	}
+	{
+		const unsigned char* content = get_page_buffer(pagenum++);
+		size_t offset = 0;
+		unsigned idx = n % pageframes;
+		for(unsigned i = 0; i < idx; i++) {
+			if(frame::sync(content + offset)) ret++;
+			offset += stride;
+		}
+	}
+	return ret;
+}
+
 frame::frame() throw()
 {
 	memset(memory, 0, sizeof(memory));

src/lua/inputmovie.cpp

@@ -226,6 +226,17 @@ namespace
 		return 1;
 	}
 
+	int _subframe_to_frame(lua::state& L, lua::parameters& P)
+	{
+		uint64_t n;
+		portctrl::frame_vector& v = framevector(L, P);
+
+		P(n);
+
+		L.pushnumber(v.subframe_to_frame(n));
+		return 1;
+	}
+
 	int _blank_frame(lua::state& L, lua::parameters& P)
 	{
 		portctrl::frame_vector& v = framevector(L, P);
@@ -426,6 +437,10 @@ namespace
 		{
 			return _find_frame(L, P);
 		}
+		int subframe_to_frame(lua::state& L, lua::parameters& P)
+		{
+			return _subframe_to_frame(L, P);
+		}
 		int blank_frame(lua::state& L, lua::parameters& P)
 		{
 			return _blank_frame(L, P);
@@ -507,6 +522,11 @@ namespace
 		return _find_frame(L, P);
 	}
 
+	int subframe_to_frame(lua::state& L, lua::parameters& P)
+	{
+		return _subframe_to_frame(L, P);
+	}
+
 	int blank_frame(lua::state& L, lua::parameters& P)
 	{
 		return _blank_frame(L, P);
@@ -628,6 +648,7 @@ namespace
 			{"get_size", &lua_inputmovie::get_size},
 			{"count_frames", &lua_inputmovie::count_frames},
 			{"find_frame", &lua_inputmovie::find_frame},
+			{"subframe_to_frame", &lua_inputmovie::subframe_to_frame},
 			{"blank_frame", &lua_inputmovie::blank_frame},
 			{"append_frames", &lua_inputmovie::append_frames},
 			{"append_frame", &lua_inputmovie::append_frame},
@@ -657,6 +678,7 @@ namespace
 		{"get_size", get_size},
 		{"count_frames", count_frames},
 		{"find_frame", find_frame},
+		{"subframe_to_frame", subframe_to_frame},
 		{"blank_frame", blank_frame},
 		{"append_frames", append_frames},
 		{"append_frame", append_frame},