Add validation checks (part 1/2)

This CL adds some validation checks. Following CLs will add further checks.

This CL also changes pointer declarations from "type *variable" to "type* variable" to follow other OTS code.

BUG=none
TEST=compiled

[bashi, 2012-05-01 09:17:49]

Hi Raph,

Could you take a look? I'd like to add validation checks before committing
woff2.{cc,h} to OTS repository.

[agl, 2012-05-01 14:39:31]

LGTM

https://codereview.appspot.com/6139064/diff/1/cpp/woff2.cc
File cpp/woff2.cc (right):

https://codereview.appspot.com/6139064/diff/1/cpp/woff2.cc#newcode766
cpp/woff2.cc:766: if ((flag_byte & 0x1f) >= (sizeof(known_tags) /
sizeof(uint32_t))) {
sizeof(known_tags) / sizeof(known_tags[0]), in case the type ever changes.

https://codereview.appspot.com/6139064/diff/1/cpp/woff2.cc#newcode863
cpp/woff2.cc:863: uint64_t dst_offset = kSfntHeaderSize + kSfntEntrySize *
num_tables;
kSfntEntrySize is defined some way away, so num_tables should be
static_cast<uint64_t>(num_tables) to make it locally clear that the arithmetic
is ok.

[raph, 2012-05-01 15:55:34]

Looks good to me. Thanks!

https://codereview.appspot.com/6139064/diff/1/cpp/woff2.cc
File cpp/woff2.cc (right):

https://codereview.appspot.com/6139064/diff/1/cpp/woff2.cc#newcode772
cpp/woff2.cc:772: if (flags == 3) {
I'm thinking this should be a constant too, like kShortFlagsContinue

[bashi, 2012-05-02 00:03:39]

Thank you for review agl and raph!

http://codereview.appspot.com/6139064/diff/1/cpp/woff2.cc
File cpp/woff2.cc (right):

http://codereview.appspot.com/6139064/diff/1/cpp/woff2.cc#newcode766
cpp/woff2.cc:766: if ((flag_byte & 0x1f) >= (sizeof(known_tags) /
sizeof(uint32_t))) {
On 2012/05/01 14:39:31, agl wrote:
> sizeof(known_tags) / sizeof(known_tags[0]), in case the type ever changes.

Done.

http://codereview.appspot.com/6139064/diff/1/cpp/woff2.cc#newcode772
cpp/woff2.cc:772: if (flags == 3) {
On 2012/05/01 15:55:35, raph wrote:
> I'm thinking this should be a constant too, like kShortFlagsContinue

Done.

http://codereview.appspot.com/6139064/diff/1/cpp/woff2.cc#newcode863
cpp/woff2.cc:863: uint64_t dst_offset = kSfntHeaderSize + kSfntEntrySize *
num_tables;
On 2012/05/01 14:39:31, agl wrote:
> kSfntEntrySize is defined some way away, so num_tables should be
> static_cast<uint64_t>(num_tables) to make it locally clear that the arithmetic
> is ok.

Done.