Fix nodes and links bounds check.

[malortie]

For example, consider the following in nodes.cpp:

hlsdk-portable/dlls/nodes.cpp

Lines 1413 to 1416 in 13086d3

	for( i = 0; i < m_cNodes; i++ )
	{
	pSrcNode = &m_pNodes[i];

hlsdk-portable/dlls/nodes.cpp

Lines 2651 to 2655 in 13086d3

	for( i = 0; i < m_cLinks; i++ )
	{
	// go through all of the links
	if( m_pLinkPool[i].m_pLinkEnt != NULL )
	{

For nodes, i should always be less than m_cNodes and less than m_cLinks for links. Assuming it's the case, if m_cNodes = 11 then m_pNodes[11] should be invalid. If m_cLinks = 18 then m_pLinkPool[18] should also be invalid.

Methods Node(int i) and Link(int i) check whether i is a valid index.

hlsdk-portable/dlls/nodes.h

Lines 219 to 220 in 13086d3

	if ( !m_pNodes || i < 0 || i > m_cNodes )
	ALERT( at_error, "Bad Node!\n" );

hlsdk-portable/dlls/nodes.h

Lines 228 to 229 in 13086d3

	if ( !m_pLinkPool || i < 0 || i > m_cLinks )
	ALERT( at_error, "Bad link!\n" );

In the case of Node(int i), the last out of bound check is i > m_cNodes. If m_cNodes = 11 and i = 11, it shouldn't be valid but still passes. The same applies to Link(int i).

Quick test

1. Build the latest version
2. Open a map (e.g. c2a5a, used in the test)
3. Put a breakpoint on both lines
4. Upon hitting the breakpoint, change i to each of the following values and assert:

Note: m_cNodes = 11 and m_cLinks = 18 in c2a5a.

Node(int i)

i = -1, invalid index (OK) (because of i < 0)
i = 0, valid index (OK)
i = 10, valid index (OK)
i = 11, invalid index (FAIL) (because of i > m_cNodes)

Link(int i)

i = -1, invalid index (OK) (because of i < 0)
i = 0, valid index (OK)
i = 17, valid index (OK)
i = 18, invalid index (FAIL) (because of i > m_cLinks)

Changing to i >= m_cNodes and i >= m_cLinks makes the check work correctly. However, both methods should return NULL if it's invalid.

Conclusion

Note that it's just from a first look and a quick test. I don't know if there are cases or reasons that justify i > m_cNodes and i > m_cLinks. Further tests may or may not be required but I won't have time to make an in depth testing for now , so I'll leave this PR as draft . Feel free to leave open, merge or close.