fixed bit helpers

256dpi · Oct 24, 2017 · 72231e0 · 72231e0
1 parent 9b50975
commit 72231e0
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Showing 2 changed files with 6 additions and 6 deletions.
diff --git a/src/helpers.c b/src/helpers.c
@@ -2,12 +2,12 @@
 
 #include "helpers.h"
 
-uint8_t lwmqtt_read_bits(uint8_t byte, uint8_t pos, uint8_t num) {
-  return (byte & (uint8_t)((~((~0) << num)) << pos)) >> pos;
+uint8_t lwmqtt_read_bits(uint8_t byte, int pos, int num) {
+  return (byte & (uint8_t)((~(0xFF << num)) << pos)) >> pos;
 }
 
-void lwmqtt_write_bits(uint8_t *byte, uint8_t value, uint8_t pos, uint8_t num) {
-  *byte = (*byte & ~(uint8_t)((~((~0) << num)) << pos)) | (value << pos);
+void lwmqtt_write_bits(uint8_t *byte, uint8_t value, int pos, int num) {
+  *byte = (*byte & ~(uint8_t)((~(0xFF << num)) << pos)) | (value << pos);
 }
 
 lwmqtt_err_t lwmqtt_read_data(uint8_t **buf, const uint8_t *buf_end, uint8_t **data, size_t len) {

diff --git a/src/helpers.h b/src/helpers.h
@@ -11,7 +11,7 @@
  * @param num - The number of bits to read.
  * @return The read bits as a byte.
  */
-uint8_t lwmqtt_read_bits(uint8_t byte, uint8_t pos, uint8_t num);
+uint8_t lwmqtt_read_bits(uint8_t byte, int pos, int num);
 
 /**
  * Write bits to a byte.
@@ -21,7 +21,7 @@ uint8_t lwmqtt_read_bits(uint8_t byte, uint8_t pos, uint8_t num);
  * @param pos - The position of the first bit.
  * @param num - The number of bits to write.
  */
-void lwmqtt_write_bits(uint8_t *byte, uint8_t value, uint8_t pos, uint8_t num);
+void lwmqtt_write_bits(uint8_t *byte, uint8_t value, int pos, int num);
 
 /**
  * Reads arbitrary data from the specified buffer. The pointer is incremented by bytes read.