Initial code commit.

Little to no error reporting, still fairly brittle and not very well
tested.

src/plugin.c

@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2018 Diamond Light Source Ltd.
+ * Author: Charles Mita
+ */
+
+
+#include <hdf5.h>
+#include <stdlib.h>
+#include "file.h"
+#include "plugin.h"
+
+
+static hid_t file_id = 0;
+static struct data_description_t data_desc = {0};
+static struct dataset_properties_t ds_prop = {0};
+static int *mask_buffer = NULL;
+
+
+void apply_mask(int *data, int *mask, int size) {
+	int *dptr, *mptr;
+	dptr = data;
+	mptr = mask;
+	while (dptr < data + size && mptr < mask + size) {
+		/* mask bits loosely based on what Neggia does and what NeXus says should be done */
+		/* basically - anything in the low byte (& 0xFF) means "ignore this" */
+		if (*mptr & 0x01) *dptr = -1;
+		if (*mptr & 0xFE) *dptr = -2;
+		dptr++;
+		mptr++;
+	}
+}
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void plugin_open(
+		const char *filename,
+		int info[1024],
+		int *error_flag) {
+	int err = 0;
+	info[0] = DLS_CUSTOMER_ID;
+	info[1] = VERSION_MAJOR;
+	info[2] = VERSION_MINOR;
+	info[3] = VERSION_PATCH;
+	info[4] = VERSION_TIMESTAMP;
+	file_id = H5Fopen(filename, H5F_ACC_RDONLY, H5P_DEFAULT);
+	if (file_id < 0) {
+		/* TODO: backtrace */
+		*error_flag = -4;
+		return;
+	}
+
+	err = extract_detector_info(file_id, &data_desc, &ds_prop);
+	if (err < 0) {
+		*error_flag = -4;
+		return;
+	}
+
+	mask_buffer = malloc(ds_prop.dims[1] * ds_prop.dims[2] * sizeof(int));
+	if (mask_buffer) {
+		err = data_desc.get_pixel_mask(&data_desc, mask_buffer);
+		if (err < 0) {
+			fprintf(stderr, "WARNING: Could not read pixel mask - no masking will be applied\n");
+			free(mask_buffer);
+			mask_buffer = NULL;
+		}
+	}
+
+	*error_flag = 0;
+}
+
+
+void plugin_get_header(
+		int *nx, int *ny,
+		int *nbytes,
+		float *qx, float *qy,
+		int *number_of_frames,
+		int info[1024],
+		int *error_flag) {
+	int err = 0;
+	double x_pixel_size, y_pixel_size;
+
+	err = data_desc.get_pixel_properties(&data_desc, &x_pixel_size, &y_pixel_size);
+	if (err < 0) {
+		*error_flag = -4;
+		return;
+	}
+
+	*nx = ds_prop.dims[2];
+	*ny = ds_prop.dims[1];
+	*nbytes = ds_prop.dims[1] * ds_prop.dims[2] * ds_prop.data_width;
+	*number_of_frames = ds_prop.dims[0];
+	*qx = (float) x_pixel_size;
+	*qy = (float) y_pixel_size;
+	*error_flag = 0;
+}
+
+
+void plugin_get_data(
+		int *frame_number,
+		int *nx, int *ny,
+		int *data_array,
+		int info[1024],
+		int *error_flag) {
+	int err = 0;
+	err = data_desc.get_data_frame(&data_desc, &ds_prop, *frame_number, sizeof(int), data_array);
+	if (err < 0) {
+		*error_flag = -2;
+		return;
+	}
+	if (mask_buffer) {
+		apply_mask(data_array, mask_buffer, ds_prop.dims[1] * ds_prop.dims[2]);
+	}
+	*error_flag = 0;
+	return;
+}
+
+
+void plugin_close(int *error_flag) {
+	if (file_id) {
+		herr_t err = H5Fclose(file_id);
+		if (err) {
+			/* TODO: backtrace */
+			*error_flag = -1;
+		}
+	}
+	file_id = 0;
+
+	if (mask_buffer) free(mask_buffer);
+	if (data_desc.free_extra) data_desc.free_extra(&data_desc);
+	free_dataset_properties(&ds_prop);
+}
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif