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

[Shannon Zhao]

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)
{
    int hi = Hex2Digit(*src++);
    int lo = Hex2Digit(*src);

    if ((hi < 0) || (lo < 0))
        return -1;

    return (hi << 4) | lo;
}

g_assert((strlen(uuid) == 36) && (uuid[8] == '-') && (uuid[13] == '-')
          && (uuid[18] == '-') && (uuid[23] == '-'));

build_append_byte(var->buf, Hex2Byte(uuid + (3 * 2))); /* dd */
build_append_byte(var->buf, Hex2Byte(uuid + (2 * 2))); /* cc */
build_append_byte(var->buf, Hex2Byte(uuid + (1 * 2))); /* bb */
build_append_byte(var->buf, Hex2Byte(uuid + (0 * 2))); /* aa */

build_append_byte(var->buf, Hex2Byte(uuid + (5 * 2 + 1))); /* ff */
build_append_byte(var->buf, Hex2Byte(uuid + (4 * 2 + 1))); /* ee */

build_append_byte(var->buf, Hex2Byte(uuid + (7 * 2 + 2))); /* hh */
build_append_byte(var->buf, Hex2Byte(uuid + (6 * 2 + 2))); /* gg */

build_append_byte(var->buf, Hex2Byte(uuid + (8 * 2 + 3))); /* ii */
build_append_byte(var->buf, Hex2Byte(uuid + (9 * 2 + 3))); /* jj */

build_append_byte(var->buf, Hex2Byte(uuid + (10 * 2 + 4))); /* kk */
build_append_byte(var->buf, Hex2Byte(uuid + (11 * 2 + 4))); /* ll */
build_append_byte(var->buf, Hex2Byte(uuid + (12 * 2 + 4))); /* mm */
build_append_byte(var->buf, Hex2Byte(uuid + (13 * 2 + 4))); /* nn */
build_append_byte(var->buf, Hex2Byte(uuid + (14 * 2 + 4))); /* oo */
build_append_byte(var->buf, Hex2Byte(uuid + (15 * 2 + 4))); /* pp */

-- 
Thanks,
Shannon