#if defined(PERL_EXT_RE_DEBUG) && !defined(DEBUGGING)
#  define DEBUGGING
#endif

#define PERL_NO_GET_CONTEXT
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include "re_comp.h"


START_EXTERN_C

extern REGEXP*	my_re_compile (pTHX_ const SV * const pattern, const U32 pm_flags);
extern I32	my_regexec (pTHX_ REGEXP * const prog, char* stringarg, char* strend,
			    char* strbeg, I32 minend, SV* screamer,
			    void* data, U32 flags);

extern char*	my_re_intuit_start (pTHX_ REGEXP * const prog, SV *sv, char *strpos,
				    char *strend, const U32 flags,
				    struct re_scream_pos_data_s *data);
extern SV*	my_re_intuit_string (pTHX_ REGEXP * const prog);

extern void	my_regfree (pTHX_ REGEXP * const r);

extern void	my_reg_numbered_buff_fetch(pTHX_ REGEXP * const rx, const I32 paren,
					   SV * const usesv);
extern void	my_reg_numbered_buff_store(pTHX_ REGEXP * const rx, const I32 paren,
					   SV const * const value);
extern I32	my_reg_numbered_buff_length(pTHX_ REGEXP * const rx,
					    const SV * const sv, const I32 paren);

extern SV*	my_reg_named_buff(pTHX_ REGEXP * const, SV * const, SV * const,
                              const U32);
extern SV*	my_reg_named_buff_iter(pTHX_ REGEXP * const rx,
                                   const SV * const lastkey, const U32 flags);

extern SV*      my_reg_qr_package(pTHX_ REGEXP * const rx);
#if defined(USE_ITHREADS)
extern void*	my_regdupe (pTHX_ REGEXP * const r, CLONE_PARAMS *param);
#endif

EXTERN_C const struct regexp_engine my_reg_engine;

END_EXTERN_C

const struct regexp_engine my_reg_engine = { 
        my_re_compile, 
        my_regexec, 
        my_re_intuit_start, 
        my_re_intuit_string, 
        my_regfree, 
        my_reg_numbered_buff_fetch,
        my_reg_numbered_buff_store,
        my_reg_numbered_buff_length,
        my_reg_named_buff,
        my_reg_named_buff_iter,
        my_reg_qr_package,
#if defined(USE_ITHREADS)
        my_regdupe 
#endif
};

MODULE = re	PACKAGE = re

void
install()
    PPCODE:
        PL_colorset = 0;	/* Allow reinspection of ENV. */
        /* PL_debug |= DEBUG_r_FLAG; */
	XPUSHs(sv_2mortal(newSViv(PTR2IV(&my_reg_engine))));
	

void
regexp_pattern(sv)
    SV * sv
PROTOTYPE: $
PREINIT:
    REGEXP *re;
PPCODE:
{
    /*
       Checks if a reference is a regex or not. If the parameter is
       not a ref, or is not the result of a qr// then returns false
       in scalar context and an empty list in list context.
       Otherwise in list context it returns the pattern and the
       modifiers, in scalar context it returns the pattern just as it
       would if the qr// was stringified normally, regardless as
       to the class of the variable and any strigification overloads
       on the object. 
    */

    if ((re = SvRX(sv))) /* assign deliberate */
    {
        /* Housten, we have a regex! */
        SV *pattern;
        STRLEN patlen = 0;
        STRLEN left = 0;
        char reflags[6];
        
        if ( GIMME_V == G_ARRAY ) {
            /*
               we are in list context so stringify
               the modifiers that apply. We ignore "negative
               modifiers" in this scenario. 
            */

            char *fptr = INT_PAT_MODS;
            char ch;
            U16 match_flags = (U16)((re->extflags & PMf_COMPILETIME) >> 12);

            while((ch = *fptr++)) {
                if(match_flags & 1) {
                    reflags[left++] = ch;
                }
                match_flags >>= 1;
            }

            pattern = sv_2mortal(newSVpvn(re->precomp,re->prelen));
            if (re->extflags & RXf_UTF8) SvUTF8_on(pattern);

            /* return the pattern and the modifiers */
            XPUSHs(pattern);
            XPUSHs(sv_2mortal(newSVpvn(reflags,left)));
            XSRETURN(2);
        } else {
            /* Scalar, so use the string that Perl would return */
            /* return the pattern in (?msix:..) format */
            pattern = sv_2mortal(newSVpvn(re->wrapped,re->wraplen));
            if (re->extflags & RXf_UTF8) 
                SvUTF8_on(pattern);
            XPUSHs(pattern);
            XSRETURN(1);
        }
    } else {
        /* It ain't a regexp folks */
        if ( GIMME_V == G_ARRAY ) {
            /* return the empty list */
            XSRETURN_UNDEF;
        } else {
            /* Because of the (?:..) wrapping involved in a 
               stringified pattern it is impossible to get a 
               result for a real regexp that would evaluate to 
               false. Therefore we can return PL_sv_no to signify
               that the object is not a regex, this means that one 
               can say
               
                 if (regex($might_be_a_regex) eq '(?:foo)') { }
               
               and not worry about undefined values.
            */
            XSRETURN_NO;
        }    
    }
    /* NOT-REACHED */
}


void
regmust(sv)
    SV * sv
PROTOTYPE: $
PREINIT:
    REGEXP *re;
PPCODE:
{
    if ((re = SvRX(sv))) /* assign deliberate */
    {
        SV *an = &PL_sv_no;
        SV *fl = &PL_sv_no;
        if (re->anchored_substr) {
            an = newSVsv(re->anchored_substr);
        } else if (re->anchored_utf8) {
            an = newSVsv(re->anchored_utf8);
        }
        if (re->float_substr) {
            fl = newSVsv(re->float_substr);
        } else if (re->float_utf8) {
            fl = newSVsv(re->float_utf8);
        }
        XPUSHs(an);
        XPUSHs(fl);
        XSRETURN(2);
    }
    XSRETURN_UNDEF;
}