added support function for left shifting arrays

common/commonutil.c

@@ -433,11 +433,21 @@ void xor(uint8_t *dest, const uint8_t *src, size_t n) {
     }
 }
 
-void lsl(uint8_t *data, size_t len) {
-    for (size_t n = 0; n < len - 1; n++) {
-        data[n] = (data[n] << 1) | (data[n + 1] >> 7);
+// left shift an array of length one bit
+void lsl(uint8_t *d, size_t n) {
+    for (size_t i = 0; i < n - 1; i++) {
+        d[i] = (d[i] << 1) | (d[i + 1] >> 7);
+    }
+    d[n - 1] <<= 1;
+}
+
+void lslx(uint8_t *d, size_t n, uint8_t shifts) {
+    for (uint8_t i = 0; i < shifts; i++) {
+        for (size_t j = 0; j < n - 1; j++) {
+            d[j] = (d[j] << 1) | (d[j + 1] >> 7);
+        }
+        d[n - 1] <<= 1;
     }
-    data[len - 1] <<= 1;
 }
 
 
@@ -562,6 +572,7 @@ void reverse_arraybytes_copy(uint8_t *arr, uint8_t *dest, size_t len) {
  */
 size_t concatbits(uint8_t *dest, int dest_offset, const uint8_t *src, int src_offset, size_t nbits, bool src_lsb) {
     int i, end, step;
+
     // overlap
     if ((src - dest) * 8 + src_offset - dest_offset > 0) {
         i = 0;

common/commonutil.h

@@ -132,7 +132,9 @@ void rol(uint8_t *data, const size_t n);
 void ror(uint8_t *data, const size_t n);
 void xor(uint8_t *dest, const uint8_t *src, size_t n);
 
-void lsl(uint8_t *data, size_t len);
+void lsl(uint8_t *d, size_t n);
+void lslx(uint8_t *d, size_t n, uint8_t shifts);
+
 uint32_t le24toh(const uint8_t data[3]);
 void htole24(uint32_t val, uint8_t data[3]);