X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=filter.c;h=7c4fd0b5b0444478a9ee54a3066267c47b9b218b;hb=ecaf59db8d79286b69a489273f4262901c0588f8;hp=f9c9a09c78e9d8c056741e4a5fa49bbbdad27077;hpb=a1bb33afbde769156ad4bef7a60579da64aebbb7;p=libsigrok.git

diff --git a/filter.c b/filter.c
index f9c9a09c..7c4fd0b5 100644
--- a/filter.c
+++ b/filter.c
@@ -20,47 +20,61 @@
 #include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
-#include "sigrok.h"
+#include <sigrok.h>
 
-/* convert sample from maximum probes -- the way the hardware driver sent
+/**
+ * Remove unused probes from samples.
+ *
+ * Convert sample from maximum probes -- the way the hardware driver sent
  * it -- to a sample taking up only as much space as required, with
  * unused probes removed.
+ *
+ * @param in_unitsize The unit size of the input (data_in).
+ * @param out_unitsize The unit size of the output (data_out).
+ * @param probelist Pointer to a list of integers (probe numbers).
+ * @param data_in The input data.
+ * @param length_in The input data length.
+ * @param data_out The output data.
+ * @param length_out The output data length.
+ * @return SR_OK upon success, SR_ERR_MALLOC upon memory allocation errors.
  */
-int filter_probes(int in_unitsize, int out_unitsize, int *probelist,
-		char *data_in, uint64_t length_in, char **data_out, uint64_t *length_out)
+int sr_filter_probes(int in_unitsize, int out_unitsize, int *probelist,
+		     const char *data_in, uint64_t length_in, char **data_out,
+		     uint64_t *length_out)
 {
-	int num_enabled_probes, in_offset, out_offset, out_bit, i;
+	unsigned int in_offset, out_offset;
+	int num_enabled_probes, out_bit, i;
 	uint64_t sample_in, sample_out;
 
-	*data_out = malloc(length_in);
+	if (!(*data_out = malloc(length_in)))
+		return SR_ERR_MALLOC;
+
 	num_enabled_probes = 0;
-	for(i = 0; probelist[i]; i++)
+	for (i = 0; probelist[i]; i++)
 		num_enabled_probes++;
 
-	if(num_enabled_probes != in_unitsize * 8) {
-		in_offset = out_offset = 0;
-		while(in_offset <= length_in - in_unitsize) {
-			memcpy(&sample_in, data_in + in_offset, in_unitsize);
-			sample_out = 0;
-			out_bit = 0;
-			for(i = 0; probelist[i]; i++) {
-				if(sample_in & (1 << (probelist[i]-1)))
-					sample_out |= 1 << out_bit;
-				out_bit++;
-			}
-			memcpy((*data_out) + out_offset, &sample_out, out_unitsize);
-			in_offset += in_unitsize;
-			out_offset += out_unitsize;
-		}
-		*length_out = out_offset;
-	}
-	else {
-		/* all probes are used -- no need to compress anything */
+	if (num_enabled_probes == in_unitsize * 8) {
+		/* All probes are used -- no need to compress anything. */
 		memcpy(*data_out, data_in, length_in);
 		*length_out = length_in;
+		return SR_OK;
 	}
 
-	return SIGROK_OK;
-}
-
+	/* If we reached this point, not all probes are used, so "compress". */
+	in_offset = out_offset = 0;
+	while (in_offset <= length_in - in_unitsize) {
+		memcpy(&sample_in, data_in + in_offset, in_unitsize);
+		sample_out = out_bit = 0;
+		for (i = 0; probelist[i]; i++) {
+			if (sample_in & (1 << (probelist[i] - 1)))
+				sample_out |= (1 << out_bit);
+			out_bit++;
+		}
+		memcpy((*data_out) + out_offset, &sample_out, out_unitsize);
+		in_offset += in_unitsize;
+		out_offset += out_unitsize;
+	}
+	*length_out = out_offset;
 
+	return SR_OK;
+}