bladeRF-cli: fix tx buffer malloc for 8b sample format

closes #936

host/utilities/bladeRF-cli/src/cmd/tx.c

@@ -44,7 +44,7 @@ static int tx_task_exec_running(struct rxtx_data *tx, struct cli_state *s)
 {
     int status = 0;
     unsigned int samples_per_buffer;
-    int16_t *tx_buffer;
+    void *tx_buffer;
     struct tx_params *tx_params = tx->params;
     unsigned int repeats_remaining;
     unsigned int delay_us;
@@ -55,6 +55,9 @@ static int tx_task_exec_running(struct rxtx_data *tx, struct cli_state *s)
     bladerf_sample_rate sample_rate = 0;
     int i;
 
+    unsigned int size_of_format =
+        (s->bit_mode_8bit) ? sizeof(int8_t) : sizeof(int16_t);
+
     enum state { INIT, READ_FILE, DELAY, PAD_TRAILING, DONE };
     enum state state = INIT;
 
@@ -93,7 +96,7 @@ static int tx_task_exec_running(struct rxtx_data *tx, struct cli_state *s)
     delay_samples_remaining = delay_samples;
 
     /* Allocate a buffer to hold each block of samples to transmit */
-    tx_buffer = (int16_t *)malloc(samples_per_buffer * 2 * sizeof(int16_t));
+    tx_buffer = malloc(samples_per_buffer * 2 * size_of_format);
     if (tx_buffer == NULL) {
         status = CLI_RET_MEM;
         set_last_error(&tx->last_error, ETYPE_ERRNO,
@@ -105,7 +108,7 @@ static int tx_task_exec_running(struct rxtx_data *tx, struct cli_state *s)
     while (state != DONE && status == 0) {
         unsigned char requests;
         unsigned int buffer_samples_remaining = samples_per_buffer;
-        int16_t *tx_buffer_current            = tx_buffer;
+        void *tx_buffer_current = tx_buffer;
 
         /* Stop stream on STOP or SHUTDOWN, but only clear STOP. This will keep
          * the SHUTDOWN request around so we can read it when determining
@@ -127,7 +130,7 @@ static int tx_task_exec_running(struct rxtx_data *tx, struct cli_state *s)
 
                     /* Read from the input file */
                     samples_populated =
-                        fread(tx_buffer_current, 2 * sizeof(int16_t),
+                        fread(tx_buffer_current, 2 * size_of_format,
                               buffer_samples_remaining, tx->file_mgmt.file);
 
                     assert(samples_populated <= UINT_MAX);
@@ -168,7 +171,7 @@ static int tx_task_exec_running(struct rxtx_data *tx, struct cli_state *s)
                                                  delay_samples_remaining);
 
                     memset(tx_buffer_current, 0,
-                           samples_populated * 2 * sizeof(uint16_t));
+                           samples_populated * 2 * size_of_format);
 
                     delay_samples_remaining -= (unsigned int)samples_populated;
 
@@ -180,7 +183,7 @@ static int tx_task_exec_running(struct rxtx_data *tx, struct cli_state *s)
                 case PAD_TRAILING:
                     /* Populate the remainder of the buffer with zeros */
                     memset(tx_buffer_current, 0,
-                           buffer_samples_remaining * 2 * sizeof(uint16_t));
+                           buffer_samples_remaining * 2 * size_of_format);
 
                     state = DONE;
                     break;
@@ -193,7 +196,9 @@ static int tx_task_exec_running(struct rxtx_data *tx, struct cli_state *s)
             /* Advance the buffer pointer.
              * Remember, two int16_t's make up 1 sample in the SC16Q11 format */
             buffer_samples_remaining -= (unsigned int)samples_populated;
-            tx_buffer_current += (2 * samples_populated);
+            /* GCC allows for void pointer arithmetic, but not the C standard */
+            tx_buffer_current = (int8_t*) tx_buffer_current
+                + (2 * samples_populated * size_of_format);
         }
 
         /* If there were no errors, transmit the data buffer */
@@ -211,7 +216,7 @@ static int tx_task_exec_running(struct rxtx_data *tx, struct cli_state *s)
         const unsigned int num_buffers = tx->data_mgmt.num_buffers;
         unsigned int i;
 
-        memset(tx_buffer, 0, samples_per_buffer * 2 * sizeof(int16_t));
+        memset(tx_buffer, 0, samples_per_buffer * 2 * size_of_format);
         for (i = 0; i < (num_buffers + 1) && status == 0; i++) {
             status = bladerf_sync_tx(s->dev, tx_buffer, samples_per_buffer,
                                      NULL, timeout_ms);