Make sr_analog_*_to_string() functions allocate the necessary buffers.

include/libsigrok/proto.h

@@ -30,10 +30,9 @@
 
 SR_API int sr_analog_to_float(const struct sr_datafeed_analog2 *analog,
 		float *buf);
-SR_API int sr_analog_float_to_string(float value, int digits, char *outbuf,
+SR_API int sr_analog_float_to_string(float value, int digits, char **result);
-		int bufsize);
 SR_API int sr_analog_unit_to_string(const struct sr_datafeed_analog2 *analog,
-		char *outbuf, int bufsize);
+		char **result);
 
 /*--- backend.c -------------------------------------------------------------*/
 

src/analog.c

@@ -165,25 +165,26 @@ SR_API int sr_analog_to_float(const struct sr_datafeed_analog2 *analog,
  *
  * @param value The value to convert.
  * @param digits Number of digits after the decimal point to print.
- * @param outbuf Buffer in which the resulting string will be placed.
+ * @param result Pointer to store result.
- * @param bufsize Size of the buffer in bytes.
+ *
+ * The string is allocated by the function and must be freed by the caller
+ * after use by calling g_free().
  *
  * @retval SR_OK
  *
  * @since 0.4.0
  */
-SR_API int sr_analog_float_to_string(float value, int digits, char *outbuf,
+SR_API int sr_analog_float_to_string(float value, int digits, char **result)
-		int bufsize)
 {
 	int cnt, i;
 
 	/* This produces at least one too many digits */
-	snprintf(outbuf, bufsize, "%.*f", digits, value);
+	*result = g_strdup_printf("%.*f", digits, value);
-	for (i = 0, cnt = 0; outbuf[i] && i < bufsize; i++) {
+	for (i = 0, cnt = 0; *result[i]; i++) {
-		if (isdigit(outbuf[i++]))
+		if (isdigit(*result[i++]))
 			cnt++;
 		if (cnt == digits) {
-			outbuf[i] = 0;
+			*result[i] = 0;
 			break;
 		}
 	}
@@ -195,33 +196,35 @@ SR_API int sr_analog_float_to_string(float value, int digits, char *outbuf,
  * Convert the unit/MQ/MQ flags in the analog struct to a string.
  *
  * @param analog Struct containing the unit, MQ and MQ flags.
- * @param outbuf Buffer in which the resulting string will be placed.
+ * @param result Pointer to store result.
- * @param bufsize Size of the buffer in bytes.
+ *
+ * The string is allocated by the function and must be freed by the caller
+ * after use by calling g_free().
  *
  * @retval SR_OK
  *
  * @since 0.4.0
  */
 SR_API int sr_analog_unit_to_string(const struct sr_datafeed_analog2 *analog,
-		char *outbuf, int bufsize)
+		char **result)
 {
-	int len, i;
+	int i;
+	GString *buf = g_string_new(NULL);
 
-	outbuf[0] = 0;
 	for (i = 0; unit_strings[i].value; i++) {
 		if (analog->meaning->unit == unit_strings[i].value) {
-			strncpy(outbuf, unit_strings[i].str, bufsize);
+			g_string_assign(buf, unit_strings[i].str);
 			break;
 		}
 	}
 
 	/* More than one MQ flag may apply. */
-	for (i = 0; mq_strings[i].value; i++) {
+	for (i = 0; mq_strings[i].value; i++)
-		if (analog->meaning->mqflags & mq_strings[i].value) {
+		if (analog->meaning->mqflags & mq_strings[i].value)
-			len = strlen(outbuf);
+			g_string_append(buf, mq_strings[i].str);
-			strncat(outbuf + len, mq_strings[i].str, bufsize - len);
+
-		}
+	*result = buf->str;
-	}
+	g_string_free(buf, FALSE);
 
 	return SR_OK;
 }

src/output/analog.c

@@ -241,7 +241,7 @@ static int receive(const struct sr_output *o, const struct sr_datafeed_packet *p
 	float *fdata;
 	unsigned int i;
 	int num_channels, c, ret, si, digits;
-	char number[32], suffix[32];
+	char *number, *suffix;
 
 	*out = NULL;
 	if (!o || !o->sdi)
@@ -285,20 +285,22 @@ static int receive(const struct sr_output *o, const struct sr_datafeed_packet *p
 			/* TODO we don't know how to print by number of bits yet. */
 			digits = 6;
 		}
-		sr_analog_unit_to_string(analog2, suffix, sizeof(suffix));
+		sr_analog_unit_to_string(analog2, &suffix);
 		num_channels = g_slist_length(analog2->meaning->channels);
 		for (i = 0; i < analog2->num_samples; i++) {
 			for (l = analog2->meaning->channels, c = 0; l; l = l->next, c++) {
 				ch = l->data;
 				g_string_append_printf(*out, "%s: ", ch->name);
 				sr_analog_float_to_string(fdata[i * num_channels + c],
-						digits, number, sizeof(number));
+						digits, &number);
 				g_string_append(*out, number);
+				g_free(number);
 				g_string_append(*out, " ");
 				g_string_append(*out, suffix);
 				g_string_append(*out, "\n");
 			}
 		}
+		g_free(suffix);
 		break;
 	}