lib: Remove num_stripes from fpi_assemble_frames()

We never used a number of stripes that didn't match the length of the
list anyway.

Closes: #132

libfprint/drivers/aes1610.c

@@ -611,8 +611,8 @@ static void capture_read_strip_cb(struct libusb_transfer *transfer)
 		/* send stop capture bits */
 		aes_write_regv(dev, capture_stop, G_N_ELEMENTS(capture_stop), stub_capture_stop_cb, NULL);
 		aesdev->strips = g_slist_reverse(aesdev->strips);
-		fpi_do_movement_estimation(&assembling_ctx, aesdev->strips, aesdev->strips_len);
-		img = fpi_assemble_frames(&assembling_ctx, aesdev->strips, aesdev->strips_len);
+		fpi_do_movement_estimation(&assembling_ctx, aesdev->strips);
+		img = fpi_assemble_frames(&assembling_ctx, aesdev->strips);
 		img->flags |= FP_IMG_PARTIAL;
 		g_slist_free_full(aesdev->strips, g_free);
 		aesdev->strips = NULL;

libfprint/drivers/aes2501.c

@@ -482,10 +482,8 @@ static void capture_read_strip_cb(struct libusb_transfer *transfer,
 			struct fp_img *img;
 
 			aesdev->strips = g_slist_reverse(aesdev->strips);
-			fpi_do_movement_estimation(&assembling_ctx,
-					aesdev->strips, aesdev->strips_len);
-			img = fpi_assemble_frames(&assembling_ctx,
-						  aesdev->strips, aesdev->strips_len);
+			fpi_do_movement_estimation(&assembling_ctx, aesdev->strips);
+			img = fpi_assemble_frames(&assembling_ctx, aesdev->strips);
 			img->flags |= FP_IMG_PARTIAL;
 			g_slist_free_full(aesdev->strips, g_free);
 			aesdev->strips = NULL;

libfprint/drivers/aes2550.c

@@ -244,8 +244,7 @@ static void capture_set_idle_reqs_cb(struct libusb_transfer *transfer)
 		struct fp_img *img;
 
 		aesdev->strips = g_slist_reverse(aesdev->strips);
-		img = fpi_assemble_frames(&assembling_ctx,
-					  aesdev->strips, aesdev->strips_len);
+		img = fpi_assemble_frames(&assembling_ctx, aesdev->strips);
 		img->flags |= FP_IMG_PARTIAL;
 		g_slist_free_full(aesdev->strips, g_free);
 		aesdev->strips = NULL;

libfprint/drivers/aesx660.c

@@ -305,7 +305,7 @@ static void capture_set_idle_cmd_cb(struct libusb_transfer *transfer)
 		struct fp_img *img;
 
 		aesdev->strips = g_slist_reverse(aesdev->strips);
-		img = fpi_assemble_frames(aesdev->assembling_ctx, aesdev->strips, aesdev->strips_len);
+		img = fpi_assemble_frames(aesdev->assembling_ctx, aesdev->strips);
 		img->flags |= aesdev->extra_img_flags;
 		g_slist_foreach(aesdev->strips, (GFunc) g_free, NULL);
 		g_slist_free(aesdev->strips);

libfprint/drivers/elan.c

@@ -307,8 +307,8 @@ static void elan_submit_image(struct fp_img_dev *dev)
 	assembling_ctx.frame_height = elandev->frame_height;
 	assembling_ctx.image_width = elandev->frame_width * 3 / 2;
 	g_slist_foreach(raw_frames, (GFunc) elandev->process_frame, &frames);
-	fpi_do_movement_estimation(&assembling_ctx, frames, num_frames);
-	img = fpi_assemble_frames(&assembling_ctx, frames, num_frames);
+	fpi_do_movement_estimation(&assembling_ctx, frames);
+	img = fpi_assemble_frames(&assembling_ctx, frames);
 
 	img->flags |= FP_IMG_PARTIAL;
 	fpi_imgdev_image_captured(dev, img);

libfprint/fpi-assembling.c

@@ -121,13 +121,12 @@ static void find_overlap(struct fpi_frame_asmbl_ctx *ctx,
 }
 
 static unsigned int do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
-			    GSList *stripes, size_t num_stripes,
-			    gboolean reverse)
+			    GSList *stripes, gboolean reverse)
 {
-	GSList *list_entry = stripes;
+	GSList *l;
 	GTimer *timer;
-	int frame = 1;
-	struct fpi_frame *prev_stripe = list_entry->data;
+	guint num_frames = 0;
+	struct fpi_frame *prev_stripe;
 	unsigned int min_error;
 	/* Max error is width * height * 255, for AES2501 which has the largest
 	 * sensor its 192*16*255 = 783360. So for 32bit value it's ~5482 frame before
@@ -135,39 +134,34 @@ static unsigned int do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
 	 */
 	unsigned long long total_error = 0;
 
-	list_entry = g_slist_next(list_entry);
-
 	timer = g_timer_new();
-	do {
-		struct fpi_frame *cur_stripe = list_entry->data;
+	prev_stripe = stripes->data;
+	for (l = stripes; l != NULL; l = l->next, num_frames++) {
+		struct fpi_frame *cur_stripe = l->data;
 
 		if (reverse) {
 			find_overlap(ctx, prev_stripe, cur_stripe, &min_error);
 			cur_stripe->delta_y = -cur_stripe->delta_y;
 			cur_stripe->delta_x = -cur_stripe->delta_x;
-		}
-		else
+		} else {
 			find_overlap(ctx, cur_stripe, prev_stripe, &min_error);
+		}
 		total_error += min_error;
 
-		frame++;
 		prev_stripe = cur_stripe;
-		list_entry = g_slist_next(list_entry);
-
-	} while (frame < num_stripes);
+	}
 
 	g_timer_stop(timer);
 	fp_dbg("calc delta completed in %f secs", g_timer_elapsed(timer, NULL));
 	g_timer_destroy(timer);
 
-	return total_error / num_stripes;
+	return total_error / num_frames;
 }
 
 /**
  * fpi_do_movement_estimation:
  * @ctx: #fpi_frame_asmbl_ctx - frame assembling context
  * @stripes: a singly-linked list of #fpi_frame
- * @num_stripes: number of items in @stripes to process
  *
  * fpi_do_movement_estimation() estimates the movement between adjacent
  * frames, populating @delta_x and @delta_y values for each #fpi_frame.
@@ -175,19 +169,17 @@ static unsigned int do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
  * This function is used for devices that don't do movement estimation
  * in hardware. If hardware movement estimation is supported, the driver
  * should populate @delta_x and @delta_y instead.
- *
- * Note that @num_stripes might be shorter than the length of the list,
- * if some stripes should be skipped.
  */
 void fpi_do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
-			    GSList *stripes, size_t num_stripes)
+				GSList                     *stripes)
 {
 	int err, rev_err;
-	err = do_movement_estimation(ctx, stripes, num_stripes, FALSE);
-	rev_err = do_movement_estimation(ctx, stripes, num_stripes, TRUE);
+
+	err = do_movement_estimation(ctx, stripes, FALSE);
+	rev_err = do_movement_estimation(ctx, stripes, TRUE);
 	fp_dbg("errors: %d rev: %d", err, rev_err);
 	if (err < rev_err) {
-		do_movement_estimation(ctx, stripes, num_stripes, FALSE);
+		do_movement_estimation(ctx, stripes, FALSE);
 	}
 }
 
@@ -256,45 +248,34 @@ static inline void aes_blit_stripe(struct fpi_frame_asmbl_ctx *ctx,
  * fpi_assemble_frames:
  * @ctx: #fpi_frame_asmbl_ctx - frame assembling context
  * @stripes: linked list of #fpi_frame
- * @num_stripes: number of items in @stripes to process
  *
  * fpi_assemble_frames() assembles individual frames into a single image.
  * It expects @delta_x and @delta_y of #fpi_frame to be populated.
  *
- * Note that @num_stripes might be shorter than the length of the list,
- * if some stripes should be skipped.
- *
  * Returns: a newly allocated #fp_img.
  */
 struct fp_img *fpi_assemble_frames(struct fpi_frame_asmbl_ctx *ctx,
-			    GSList *stripes, size_t num_stripes)
+				   GSList                     *stripes)
 {
-	GSList *stripe;
+	GSList *l;
 	struct fp_img *img;
 	int height = 0;
-	int i, y, x;
+	int y, x;
 	gboolean reverse = FALSE;
 	struct fpi_frame *fpi_frame;
 
 	//FIXME g_return_if_fail
-	BUG_ON(num_stripes == 0);
 	BUG_ON(ctx->image_width < ctx->frame_width);
 
-	/* Calculate height */
-	i = 0;
-	stripe = stripes;
-
 	/* No offset for 1st image */
-	fpi_frame = stripe->data;
+	fpi_frame = stripes->data;
 	fpi_frame->delta_x = 0;
 	fpi_frame->delta_y = 0;
-	do {
-		fpi_frame = stripe->data;
+	for (l = stripes; l != NULL; l = l->next) {
+		fpi_frame = l->data;
 
 		height += fpi_frame->delta_y;
-		i++;
-		stripe = g_slist_next(stripe);
-	} while (i < num_stripes);
+	}
 
 	fp_dbg("height is %d", height);
 
@@ -314,13 +295,11 @@ struct fp_img *fpi_assemble_frames(struct fpi_frame_asmbl_ctx *ctx,
 	img->height = height;
 
 	/* Assemble stripes */
-	i = 0;
-	stripe = stripes;
 	y = reverse ? (height - ctx->frame_height) : 0;
 	x = (ctx->image_width - ctx->frame_width) / 2;
 
-	do {
-		fpi_frame = stripe->data;
+	for (l = stripes; l != NULL; l = l->next) {
+		fpi_frame = l->data;
 
 		if(reverse) {
 			y += fpi_frame->delta_y;
@@ -333,10 +312,7 @@ struct fp_img *fpi_assemble_frames(struct fpi_frame_asmbl_ctx *ctx,
 			y += fpi_frame->delta_y;
 			x += fpi_frame->delta_x;
 		}
-
-		stripe = g_slist_next(stripe);
-		i++;
-	} while (i < num_stripes);
+	}
 
 	return img;
 }

libfprint/fpi-assembling.h

@@ -63,10 +63,10 @@ struct fpi_frame_asmbl_ctx {
 };
 
 void fpi_do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
-			    GSList *stripes, size_t num_stripes);
+				GSList                     *stripes);
 
 struct fp_img *fpi_assemble_frames(struct fpi_frame_asmbl_ctx *ctx,
-			    GSList *stripes, size_t num_stripes);
+				   GSList                     *stripes);
 
 /**
  * fpi_line_asmbl_ctx: