Extend bit-buffer library with reading total byte

This is useful to read in a full byte. Note this cannot be done using simple
fread, as we need to consider the bit cursor.

bit-buffer.c

@@ -132,3 +132,36 @@ bb_read (struct BIT_BUFFER *buffer, int size)
 
   return bin;
 }
+
+/*
+ * Read byte from file, taking bit pos into account.
+ *
+ * The return value must be freed after being used.
+ */
+int *
+bb_readbyte (struct BIT_BUFFER *buffer)
+{
+  int i, shift_pos;
+  int *bin = malloc(sizeof(int));
+  *bin = 0;
+
+  for (i = 0; i < BYTE_BIT; i++)
+    {
+      if (!buffer->first_read || buffer->pos == BYTE_BIT)
+        {
+          /* When we reach EOF, that mens any read bit was just fillers from
+             the bb_flush function. We actually don't have any more data */
+          if (!(fread (&(buffer->bits), sizeof (byte), 1, buffer->fp)))
+            return NULL;
+          buffer->first_read = 1;
+          buffer->pos = 0;
+        }
+
+      shift_pos = BYTE_BIT - buffer->pos - 1;
+      *bin |= ((buffer->bits >> shift_pos) & 1) << (BYTE_BIT - 1 - i);
+
+      (buffer->pos)++;
+    }
+
+  return bin;
+}

bit-buffer.h

@@ -16,3 +16,4 @@ void bb_flush (struct BIT_BUFFER *buffer);
 void bb_write (struct BIT_BUFFER *buffer, int *bits, int size);
 void bb_writebyte (struct BIT_BUFFER *buffer, byte byte);
 int *bb_read (struct BIT_BUFFER *buffer, int size);
+int *bb_readbyte (struct BIT_BUFFER *buffer);