HomeHook.c

/**************************************************
***	Project Title: Super Start (sstart)			***
***	Author: Greg Dietsche						***
***	Date:	11/21/2002							***
*** Platforms:	TI-89, TI89T, TI-92p, V200		***
*** Supported Hardware Revisions: 1, 2, 3		***
***	Description: An Application designed to		***
*** 			 Simplify the launching of ppg	***
***				 programs as well as normal		***
***				 asm and TI-BASIC programs		***
***************************************************/
// $Id$
/*
    This file is part of Super Start.

    Super Start is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

	You may use portions of the Super Start source code for your own projects
	if you give me credit and a link to my website: http://calc.gregd.org/ 
	in the project source code and documentation.
    
*/

#include <tiams.h>
#include "sstart.h"
#include "Resources.h"
#include "HomeHook.h"
#include "HWPatch.h"
#include "oo.h"


#define addr_HomeExecute ((char *)AMS_Global_Variables[0x10E])
#define addr_TE_select ((char *)AMS_Global_Variables[0xB1])

#define SymFindPtr tiamsapi_643
SYM_ENTRY * tiamsapi_643(char* ptr, short flags);

static void AutoStart(BOOL IgnoreAsmPrgmSize);
static TERecord *TE_findHomeScreen(void);

FRAME(HookFrame, OO_SYSTEM_FRAME, 0, OO_APP_PROCESS_EVENT, 1)
	ATTR(OO_APP_PROCESS_EVENT, 		&HomeHook)					//0x0004
ENDFRAME

BOOL InstallHook(void)
{
	pFrame RetFrame;
	OO_InstallAppHook(EV_getAppID(ti_home), (pFrame)&HookFrame, &RetFrame);
	OO_appSetPublicStorage(RetFrame);
}

BOOL RemoveHook(void)
{
	OO_UninstallAppHook(EV_getAppID(ti_home), OO_appGetPublicStorage());
}

BOOL CanDelete(AppID self)
{
	Access_AMS_Global_Variables;

//EV_runningApp is important here.
	if(HomeHookConflict())
	{
		DlgNotice(OO_AbsoluteGet(XR_LongAppName + OO_FIRST_APP_STRING), OO_AbsoluteGet(XR_Fail_HS_Active + OO_FIRST_APP_STRING));
		return FALSE;
	}

	return TRUE;
}

//This small event loop provides the Auto Start feature.
void HomeHook(pFrame self, PEvent e)
{
	Access_AMS_Global_Variables;
	pFrame super=OO_SuperFrame;
	
	if(e->command==CM_KEY_PRESS)
	{	
		if(e->info.keyInfo.keyCode==KB_ENTER || e->info.keyInfo.keyCode==KB_ENTER+KB_OPTION)
		{
			AutoStart(UseLeakWatch() && EV_getAppID(cmd_post_app_id));
		}
	}

//this is an important piece of code! Otherwise you will see semi-random errors thrown by the AMS.	
	if(super) AppProcessEvent(super, e);
}

//Credits to Samuel Stearley for this hack.
//I (Greg) have converted his ASM code into a C function.
//Finds the Home Screen Text Editor / Entry Line in an AMS independant manner.
static TERecord *TE_findHomeScreen(void)
{
	Access_AMS_Global_Variables;
	register char *a=addr_HomeExecute;

	while(*(unsigned long*)a!=(unsigned long)addr_TE_select)
		a+=2;

//Technically, the commented lines should be uncommented to properly support ams 3.00 which
//uses long word references, but because we are scanning backwards, and the variable is located
//at an address that is less than 0xFFFF, this code still works.
    //if(EX_getBasecodeParmBlock()->version_number < 0x0300)
	    return (TERecord*)(unsigned long)(*(unsigned short*)(a-4));
	//else
	    //return (TERecord*)(unsigned long)(*(unsigned long*)(a-6));
}

//This does the actual work of the AutoStart feature.
//It finds the home screen text editor, processs it... and
//prepares for the os to handle the *+KB_ENTER
static void AutoStart(BOOL IgnoreAsmPrgmSize)
{
	TERecord *hste;
	char tmp[30];		//1 8 1 8 1 ()
	char *ptr;
	char *ptr2;
	SYM_ENTRY *sym;
	static const char PackagedTag[]={'p','p','g',0,0xF8};
	static const char * const text[]={"()","\")" };
	char *HomeText;
	int i;
	unsigned char ParenCount=1;

    hste = TE_findHomeScreen();
    if (!hste) return;
    HomeText=HeapDeref(hste->b.hBuf);
	//////////////////////////////////////////
	//begin check for function, prgm, asm, ppg programs
		//Check if the home screen text edit line isn't active so don't peform the Auto Start		
		//check the max length of an program with a path associated with it (yes, this feature only
		//works when the program name is the only text on the entry line).
		if(!(hste->flags&TE_FOCUSED) || hste->datlen>19 ) return;
	
	//just converting it to a TIOS style file name...
		tmp[0]=0;
		i=hste->datlen;
		
		ptr=strcpy(ptr2=(tmp+1),HomeText)+i;

	//count parenthesis and prepare ptr2 for SymFindPtr
		if((ptr2=strchr(ptr2,'(')))
		{
			if(strlen(ptr2)==1 || *(ptr2+1)==')')
			{
				if(*(ptr2+1)==')')
				{
					if(ptr2[2]!=0)return;	//there is something written after the 'prgrm()' string
					ParenCount=2;
				}

				*ptr2=0;
				ptr=ptr2;
			}
		}
		else
			ParenCount=0;
			
		if((sym=SymFindPtr(ptr,0)))
		{
			unsigned short varsize;
			//the maximum size on AMS < 3.00 is 24 KB. The maximum size on AMS 3.00 is the full 65520 bytes so no launcher is needed with AMS 3.00
			//64K is larger than is possible, so on ams 3.00 and above, super start will not try to use its internal launcher to launch the program.
			unsigned short max_var_size = (EX_getBasecodeParmBlock()->version_number < 0x0300) ?(64*1024):(24*1024);

	//designed to avoid errors with any variable that is "in use" or for some other reason has no handle associated with it.
	//this takes care of problems when launching a ti-basic program that is also being edited.
	//yes, the double check is a bit redundant, but i would rather be safe than sorry.			
			if(sym->Flags&SF_INUSE || sym->hVal==H_NULL)	ER_throw(FIRST_IN_USE_ERR);
			
			ptr=HeapDeref(sym->hVal);
			varsize=*(unsigned short*)ptr;
			ptr=&ptr[varsize+1];			//the same as: ptr=(char*)HToESI(sym->hVal);
			
			if(!memcmp(PackagedTag,ptr-4,5) || (*(unsigned char*)ptr==ASM_PRGM_TAG && (varsize>( max_var_size )||IgnoreAsmPrgmSize) ) )
			{						
				TE_select(hste,0,0);
	
				if(SymFind((BYTE*)OO_AbsoluteGet(OO_FIRST_APP_STRING + XR_SSTART_TOK)+strlen(((char*)OO_AbsoluteGet(OO_FIRST_APP_STRING + XR_SSTART_TOK))+1)+1))	//use the full app extension if there is a variable by the same name
					TE_pasteText(hste,(UCHAR*)OO_AbsoluteGet(OO_FIRST_APP_STRING + XR_SSTART_EXT),strlen(OO_AbsoluteGet(OO_FIRST_APP_STRING + XR_SSTART_EXT)));
				
				//Paste the sstart(" text
					TE_pasteText(hste,(UCHAR*)OO_AbsoluteGet(OO_FIRST_APP_STRING + XR_SSTART_MINIMAL),strlen(OO_AbsoluteGet(OO_FIRST_APP_STRING + XR_SSTART_MINIMAL)));
				
				TE_select(hste, hste->datlen, hste->datlen);
				TE_pasteText(hste,(UCHAR*)text[1], 2);	//paste the terminating ")
			}
			else if(*(unsigned char*)ptr==USER_DEF_TAG || (*(unsigned char*)ptr==ASM_PRGM_TAG))	//&& varsize<=(24*1024)
			{
				TE_select(hste, hste->datlen, hste->datlen-ParenCount);
				TE_pasteText(hste,(UCHAR*)text[0], 2);
			}
		}
}