-/* Read/write "x" from/to "file" as bigendian representation of "size" bits. */
+/* Read/write "x" from/to "file" as bigendian representation of "size" bits.
+ * Only multiples of 8 allowed for "size". On failure, return 1, else 0.
+ *
+ * As of of now, all other read/write functions build on top of these. TODO:
+ * Consider externing these so-far internal functions and dropping the
+ * interfaces to them, instead relying on their internal validity checks.
+ * (Usage of padded memory copies instead of directly manipulating * x as is
+ * done in read_uint* would need to be added, though.)
+ */
static uint8_t read_uintX_bigendian(FILE * file, uint32_t * x, uint8_t size);
static uint8_t write_uintX_bigendian(FILE * file, uint32_t x, uint8_t size);
static uint8_t read_uintX_bigendian(FILE * file, uint32_t * x, uint8_t size)
{
- if (0 != size % 8)
- {
- return 1;
- }
+ if (0 != size % 8) /* This bit number validity check is redundant */
+ { /* as long as this function is only available */
+ return 1; /* through extern interfaces pre-defining the */
+ } /* bit number. TODO: Consider dropping it. */
int16_t bitshift = size - 8;
* x = 0;
static uint8_t write_uintX_bigendian(FILE * file, uint32_t x, uint8_t size)
{
- if (0 != size % 8)
- {
- return 1;
- }
+ if (0 != size % 8) /* See comment */
+ { /* on identical */
+ return 1; /* code block in */
+ } /* read_uintX_bigendian(). */
int16_t bitshift = size - 8;
for (; bitshift >= 0; bitshift = bitshift - 8)
extern uint8_t read_uint8(FILE * file, uint8_t * x)
{
- /* Since read_uintX_bigendian() works on -- and zeroes -- four bytes, work
- * on values of fewer bytes corrupts their immediate neighbor bytes. This
- * necessitates working on newly acquired separate memory areas (* y), only
- * copying the sufficiently small end result to * x.
+ /* Since read_uintX_bigendian() works on -- and zeroes -- four bytes, direct
+ * work on values of fewer bytes would corrupt immediate neighbor values.
*/
uint32_t y = * x;
uint8_t err = read_uintX_bigendian(file, &y, 8);