array_boundchk.c

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/* Array bound checking functions */

#include "fb.h"

static void *hThrowError( int linenum, const char *fname )
{
        /* call user handler if any defined */
    return (void *)fb_ErrorThrowEx( FB_RTERROR_OUTOFBOUNDS, linenum, fname, NULL, NULL );
}

FBCALL void *fb_ArrayBoundChk
        (
                ssize_t idx,
                ssize_t lbound,
                ssize_t ubound,
                int linenum,
                const char *fname
        )
{
        if( (idx < lbound) || (idx > ubound) )
                return hThrowError( linenum, fname );
        else
                return NULL;
}

FBCALL void *fb_ArraySngBoundChk
        (
                size_t idx,
                size_t ubound,
                int linenum,
                const char *fname
        )
{
        /* Assuming lbound is 0, we know ubound must be >= 0, and we can treat
           index as unsigned too, possibly letting it overflow to a very big
           value (if it was negative), reducing the bound check to a single
           unsigned comparison. */
        if( idx > ubound )
                return hThrowError( linenum, fname );
        else
                return NULL;
}