Re: [Qemu-devel] [PATCH v5 13/20] hw/acpi/aml-build: Add ToUUID macro

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 28 Apr 2015 16:52:19 +0800
Shannon Zhao <zhaoshenglong@huawei.com> wrote:

> On 2015/4/28 16:15, Igor Mammedov wrote:
> >>> btw:
> >>> > > whole thing might be simpler if an intermediate conversion is avoided,
> >>> > > just pack buffer as in spec byte by byte:
> >>> > > 
> >>> > > /* format: aabbccdd-eeff-gghh-iijj-kkllmmnnoopp */
> >>> > > assert(strlen(uuid) == ...);
> >>> > > build_append_byte(var->buf, HEX2BYTE(uuid[3]); /* dd */
> >> > 
> >> > use build_append_byte(var->buf, HEX2BYTE(uuid + 7); ?
> >> > 
> >>> > > build_append_byte(var->buf, HEX2BYTE(uuid[2]); /* cc */
> >> > 
> >> > use build_append_byte(var->buf, HEX2BYTE(uuid + 5); ?
> > if you mean hyphens /-/ then they are not encoded,
> > but you surely can add checks for them to make sure that
> > UUID format is as expected.
> > 
> 
> I mean uuid[3] points to b not dd. Maybe use following way:
> 
> static uint8_t Hex2Byte(char *src)
or even better:
Hex2Byte(char *src, byte_idx)
  and do pointer arithmetic inside

[...]
> build_append_byte(var->buf, Hex2Byte(uuid + (3 * 2))); /* dd */
build_append_byte(var->buf, Hex2Byte(uuid, 3)); /* dd - at offset 00 */
build_append_byte(var->buf, Hex2Byte(uuid, 2)); /* cc - at offset 01 */
...