CException/lib/CException.c
2024-03-16 22:41:16 -04:00

60 lines
3.5 KiB
C

/* =========================================================================
CException - Simple Exception Handling in C
ThrowTheSwitch.org
Copyright (c) 2007-24 Mark VanderVoord
SPDX-License-Identifier: MIT
========================================================================= */
#include "CException.h"
#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wmissing-field-initializers"
#endif
volatile CEXCEPTION_FRAME_T CExceptionFrames[CEXCEPTION_NUM_ID] = {{ 0 }};
#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif
//------------------------------------------------------------------------------------------
// Throw
//------------------------------------------------------------------------------------------
void Throw(CEXCEPTION_T ExceptionID)
{
unsigned int MY_ID = CEXCEPTION_GET_ID;
CExceptionFrames[MY_ID].Exception = ExceptionID;
if (CExceptionFrames[MY_ID].pFrame)
{
longjmp(*CExceptionFrames[MY_ID].pFrame, 1);
}
CEXCEPTION_NO_CATCH_HANDLER(ExceptionID);
}
//------------------------------------------------------------------------------------------
// Explanation of what it's all for:
//------------------------------------------------------------------------------------------
/*
#define Try
{ <- give us some local scope. most compilers are happy with this
jmp_buf *PrevFrame, NewFrame; <- prev frame points to the last try block's frame. new frame gets created on stack for this Try block
unsigned int MY_ID = CEXCEPTION_GET_ID; <- look up this task's id for use in frame array. always 0 if single-tasking
PrevFrame = CExceptionFrames[CEXCEPTION_GET_ID].pFrame; <- set pointer to point at old frame (which array is currently pointing at)
CExceptionFrames[MY_ID].pFrame = &NewFrame; <- set array to point at my new frame instead, now
CExceptionFrames[MY_ID].Exception = CEXCEPTION_NONE; <- initialize my exception id to be NONE
if (setjmp(NewFrame) == 0) { <- do setjmp. it returns 1 if longjump called, otherwise 0
if (&PrevFrame) <- this is here to force proper scoping. it requires braces or a single line to be but after Try, otherwise won't compile. This is always true at this point.
#define Catch(e)
else { } <- this also forces proper scoping. Without this they could stick their own 'else' in and it would get ugly
CExceptionFrames[MY_ID].Exception = CEXCEPTION_NONE; <- no errors happened, so just set the exception id to NONE (in case it was corrupted)
}
else <- an exception occurred
{ e = CExceptionFrames[MY_ID].Exception; e=e;} <- assign the caught exception id to the variable passed in.
CExceptionFrames[MY_ID].pFrame = PrevFrame; <- make the pointer in the array point at the previous frame again, as if NewFrame never existed.
} <- finish off that local scope we created to have our own variables
if (CExceptionFrames[CEXCEPTION_GET_ID].Exception != CEXCEPTION_NONE) <- start the actual 'catch' processing if we have an exception id saved away
*/