Revive Tag() function

Removed TAG() macro and revived Tag() function for big endian platform.

BUG=124629
TEST=ran test_{un,}malicious_fonts.sh

[bashi, 2012-05-01 00:38:51]

Hi yusuke-san,

Could you take a look?

[Yusuke Sato, 2012-05-01 02:23:31]

https://chromiumcodereview.appspot.com/10273021/diff/1/src/ots.cc
File src/ots.cc (right):

https://chromiumcodereview.appspot.com/10273021/diff/1/src/ots.cc#newcode86
src/ots.cc:86: // Try endianness checks with zero, one and two leading
underscores,
The #ifdefs look too complex to me. What about reviving Tag() and then using the
following simple solution?

const struct {
  const char* tag;
...
} table_parsers[] = {
  { "maxp", ...

...

if (Tag(table_parsers[i].tag) == Tag("head")) {

[bashi, 2012-05-01 04:05:48]

http://codereview.chromium.org/10273021/diff/1/src/ots.cc
File src/ots.cc (right):

http://codereview.chromium.org/10273021/diff/1/src/ots.cc#newcode86
src/ots.cc:86: // Try endianness checks with zero, one and two leading
underscores,
On 2012/05/01 02:23:31, Yusuke Sato wrote:
> The #ifdefs look too complex to me. What about reviving Tag() and then using
the
> following simple solution?
> 
> const struct {
>   const char* tag;
> ...
> } table_parsers[] = {
>   { "maxp", ...
> 
> ...
> 
> if (Tag(table_parsers[i].tag) == Tag("head")) {
> 

Done. Thank you for suggestion!

[Yusuke Sato, 2012-05-02 06:22:20]

lgtm, but please wait for comments from agl and jfkthame.

On 2012/05/01 04:05:48, bashik wrote:
> http://codereview.chromium.org/10273021/diff/1/src/ots.cc
> File src/ots.cc (right):
> 
> http://codereview.chromium.org/10273021/diff/1/src/ots.cc#newcode86
> src/ots.cc:86: // Try endianness checks with zero, one and two leading
> underscores,
> On 2012/05/01 02:23:31, Yusuke Sato wrote:
> > The #ifdefs look too complex to me. What about reviving Tag() and then using
> the
> > following simple solution?
> > 
> > const struct {
> >   const char* tag;
> > ...
> > } table_parsers[] = {
> >   { "maxp", ...
> > 
> > ...
> > 
> > if (Tag(table_parsers[i].tag) == Tag("head")) {
> > 
> 
> Done. Thank you for suggestion!

[jfkthame, 2012-05-14 15:26:31]

Sorry, I haven't had an opportunity to test this on various big-endian systems,
but both Cameron Kaiser (who maintains TenFourFox for PPC) and I expect that it
will be fine. I'd suggest you go ahead with this change in OTS, as the current
#ifdef solution is definitely broken on some platforms.

On 2012/05/02 06:22:20, Yusuke Sato wrote:
> lgtm, but please wait for comments from agl and jfkthame.
> 
> On 2012/05/01 04:05:48, bashik wrote:
> > http://codereview.chromium.org/10273021/diff/1/src/ots.cc
> > File src/ots.cc (right):
> > 
> > http://codereview.chromium.org/10273021/diff/1/src/ots.cc#newcode86
> > src/ots.cc:86: // Try endianness checks with zero, one and two leading
> > underscores,
> > On 2012/05/01 02:23:31, Yusuke Sato wrote:
> > > The #ifdefs look too complex to me. What about reviving Tag() and then
using
> > the
> > > following simple solution?
> > > 
> > > const struct {
> > >   const char* tag;
> > > ...
> > > } table_parsers[] = {
> > >   { "maxp", ...
> > > 
> > > ...
> > > 
> > > if (Tag(table_parsers[i].tag) == Tag("head")) {
> > > 
> > 
> > Done. Thank you for suggestion!

[bashi, 2012-05-14 23:52:28]

Ok, I'm going to submit the CL. Please let me know if there is any problems.
Thank you for the help.

On 2012/05/14 15:26:31, jfkthame wrote:
> Sorry, I haven't had an opportunity to test this on various big-endian
systems,
> but both Cameron Kaiser (who maintains TenFourFox for PPC) and I expect that
it
> will be fine. I'd suggest you go ahead with this change in OTS, as the current
> #ifdef solution is definitely broken on some platforms.
> 
> On 2012/05/02 06:22:20, Yusuke Sato wrote:
> > lgtm, but please wait for comments from agl and jfkthame.
> > 
> > On 2012/05/01 04:05:48, bashik wrote:
> > > http://codereview.chromium.org/10273021/diff/1/src/ots.cc
> > > File src/ots.cc (right):
> > > 
> > > http://codereview.chromium.org/10273021/diff/1/src/ots.cc#newcode86
> > > src/ots.cc:86: // Try endianness checks with zero, one and two leading
> > > underscores,
> > > On 2012/05/01 02:23:31, Yusuke Sato wrote:
> > > > The #ifdefs look too complex to me. What about reviving Tag() and then
> using
> > > the
> > > > following simple solution?
> > > > 
> > > > const struct {
> > > >   const char* tag;
> > > > ...
> > > > } table_parsers[] = {
> > > >   { "maxp", ...
> > > > 
> > > > ...
> > > > 
> > > > if (Tag(table_parsers[i].tag) == Tag("head")) {
> > > > 
> > > 
> > > Done. Thank you for suggestion!