/* $Id: Base64.xs,v 3.4 2004/08/24 16:29:35 gisle Exp $

Copyright 1997-2004 Gisle Aas

This library is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.


The tables and some of the code that used to be here was borrowed from
metamail, which comes with this message:

  Copyright (c) 1991 Bell Communications Research, Inc. (Bellcore)

  Permission to use, copy, modify, and distribute this material
  for any purpose and without fee is hereby granted, provided
  that the above copyright notice and this permission notice
  appear in all copies, and that the name of Bellcore not be
  used in advertising or publicity pertaining to this
  material without the specific, prior written permission
  of an authorized representative of Bellcore.	BELLCORE
  MAKES NO REPRESENTATIONS ABOUT THE ACCURACY OR SUITABILITY
  OF THIS MATERIAL FOR ANY PURPOSE.  IT IS PROVIDED "AS IS",
  WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES.

*/


#ifdef __cplusplus
extern "C" {
#endif
#define PERL_NO_GET_CONTEXT     /* we want efficiency */
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#ifdef __cplusplus
}
#endif

#ifndef PATCHLEVEL
#    include <patchlevel.h>
#    if !(defined(PERL_VERSION) || (SUBVERSION > 0 && defined(PATCHLEVEL)))
#        include <could_not_find_Perl_patchlevel.h>
#    endif
#endif

#if PATCHLEVEL <= 4 && !defined(PL_dowarn)
   #define PL_dowarn dowarn
#endif

#ifdef G_WARN_ON
   #define DOWARN (PL_dowarn & G_WARN_ON)
#else
   #define DOWARN PL_dowarn
#endif


#define MAX_LINE  76 /* size of encoded lines */

static char basis_64[] =
   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

#define XX      255	/* illegal base64 char */
#define EQ      254	/* padding */
#define INVALID XX

static unsigned char index_64[256] = {
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,62, XX,XX,XX,63,
    52,53,54,55, 56,57,58,59, 60,61,XX,XX, XX,EQ,XX,XX,
    XX, 0, 1, 2,  3, 4, 5, 6,  7, 8, 9,10, 11,12,13,14,
    15,16,17,18, 19,20,21,22, 23,24,25,XX, XX,XX,XX,XX,
    XX,26,27,28, 29,30,31,32, 33,34,35,36, 37,38,39,40,
    41,42,43,44, 45,46,47,48, 49,50,51,XX, XX,XX,XX,XX,

    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
    XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX, XX,XX,XX,XX,
};

#ifdef SvPVbyte
#   if PERL_REVISION == 5 && PERL_VERSION < 7
       /* SvPVbyte does not work in perl-5.6.1, borrowed version for 5.7.3 */
#       undef SvPVbyte
#       define SvPVbyte(sv, lp) \
          ((SvFLAGS(sv) & (SVf_POK|SVf_UTF8)) == (SVf_POK) \
           ? ((lp = SvCUR(sv)), SvPVX(sv)) : my_sv_2pvbyte(aTHX_ sv, &lp))
       static char *
       my_sv_2pvbyte(pTHX_ register SV *sv, STRLEN *lp)
       {   
           sv_utf8_downgrade(sv,0);
           return SvPV(sv,*lp);
       }
#   endif
#else
#   define SvPVbyte SvPV
#endif

#ifndef isXDIGIT
#   define isXDIGIT isxdigit
#endif

#ifndef NATIVE_TO_ASCII
#   define NATIVE_TO_ASCII(ch) (ch)
#endif

MODULE = MIME::Base64		PACKAGE = MIME::Base64

SV*
encode_base64(sv,...)
	SV* sv
	PROTOTYPE: $;$

	PREINIT:
	char *str;     /* string to encode */
	SSize_t len;   /* length of the string */
	char *eol;     /* the end-of-line sequence to use */
	STRLEN eollen; /* length of the EOL sequence */
	char *r;       /* result string */
	STRLEN rlen;   /* length of result string */
	unsigned char c1, c2, c3;
	int chunk;

	CODE:
#if PERL_REVISION == 5 && PERL_VERSION >= 6
	sv_utf8_downgrade(sv, FALSE);
#endif
	str = SvPV(sv, rlen); /* SvPV(sv, len) gives warning for signed len */
	len = (SSize_t)rlen;

	/* set up EOL from the second argument if present, default to "\n" */
	if (items > 1 && SvOK(ST(1))) {
	    eol = SvPV(ST(1), eollen);
	} else {
	    eol = "\n";
	    eollen = 1;
	}

	/* calculate the length of the result */
	rlen = (len+2) / 3 * 4;	 /* encoded bytes */
	if (rlen) {
	    /* add space for EOL */
	    rlen += ((rlen-1) / MAX_LINE + 1) * eollen;
	}

	/* allocate a result buffer */
	RETVAL = newSV(rlen ? rlen : 1);
	SvPOK_on(RETVAL);	
	SvCUR_set(RETVAL, rlen);
	r = SvPVX(RETVAL);

	/* encode */
	for (chunk=0; len > 0; len -= 3, chunk++) {
	    if (chunk == (MAX_LINE/4)) {
		char *c = eol;
		char *e = eol + eollen;
		while (c < e)
		    *r++ = *c++;
		chunk = 0;
	    }
	    c1 = *str++;
	    c2 = len > 1 ? *str++ : '\0';
	    *r++ = basis_64[c1>>2];
	    *r++ = basis_64[((c1 & 0x3)<< 4) | ((c2 & 0xF0) >> 4)];
	    if (len > 2) {
		c3 = *str++;
		*r++ = basis_64[((c2 & 0xF) << 2) | ((c3 & 0xC0) >>6)];
		*r++ = basis_64[c3 & 0x3F];
	    } else if (len == 2) {
		*r++ = basis_64[(c2 & 0xF) << 2];
		*r++ = '=';
	    } else { /* len == 1 */
		*r++ = '=';
		*r++ = '=';
	    }
	}
	if (rlen) {
	    /* append eol to the result string */
	    char *c = eol;
	    char *e = eol + eollen;
	    while (c < e)
		*r++ = *c++;
	}
	*r = '\0';  /* every SV in perl should be NUL-terminated */

	OUTPUT:
	RETVAL

SV*
decode_base64(sv)
	SV* sv
	PROTOTYPE: $

	PREINIT:
	STRLEN len;
	register unsigned char *str = (unsigned char*)SvPVbyte(sv, len);
	unsigned char const* end = str + len;
	char *r;
	unsigned char c[4];

	CODE:
	{
	    /* always enough, but might be too much */
	    STRLEN rlen = len * 3 / 4;
	    RETVAL = newSV(rlen ? rlen : 1);
	}
        SvPOK_on(RETVAL);
        r = SvPVX(RETVAL);

	while (str < end) {
	    int i = 0;
            do {
		unsigned char uc = index_64[NATIVE_TO_ASCII(*str++)];
		if (uc != INVALID)
		    c[i++] = uc;

		if (str == end) {
		    if (i < 4) {
			if (i && DOWARN)
			    warn("Premature end of base64 data");
			if (i < 2) goto thats_it;
			if (i == 2) c[2] = EQ;
			c[3] = EQ;
		    }
		    break;
		}
            } while (i < 4);
	
	    if (c[0] == EQ || c[1] == EQ) {
		if (DOWARN) warn("Premature padding of base64 data");
		break;
            }
	    /* printf("c0=%d,c1=%d,c2=%d,c3=%d\n", c[0],c[1],c[2],c[3]);*/

	    *r++ = (c[0] << 2) | ((c[1] & 0x30) >> 4);

	    if (c[2] == EQ)
		break;
	    *r++ = ((c[1] & 0x0F) << 4) | ((c[2] & 0x3C) >> 2);

	    if (c[3] == EQ)
		break;
	    *r++ = ((c[2] & 0x03) << 6) | c[3];
	}

      thats_it:
	SvCUR_set(RETVAL, r - SvPVX(RETVAL));
	*r = '\0';

	OUTPUT:
	RETVAL


MODULE = MIME::Base64		PACKAGE = MIME::QuotedPrint

#define qp_isplain(c) ((c) == '\t' || (((c) >= ' ' && (c) <= '~') && (c) != '='))

SV*
encode_qp(sv,...)
	SV* sv
	PROTOTYPE: $;$$

	PREINIT:
	char *eol;
	STRLEN eol_len;
	int binary;
	STRLEN sv_len;
	STRLEN linelen;
	char *beg;
	char *end;
	char *p;
	char *p_beg;
	STRLEN p_len;

	CODE:
#if PERL_REVISION == 5 && PERL_VERSION >= 6
	sv_utf8_downgrade(sv, FALSE);
#endif
	/* set up EOL from the second argument if present, default to "\n" */
	if (items > 1 && SvOK(ST(1))) {
	    eol = SvPV(ST(1), eol_len);
	} else {
	    eol = "\n";
	    eol_len = 1;
	}

	binary = (items > 2 && SvTRUE(ST(2)));

	beg = SvPV(sv, sv_len);
	end = beg + sv_len;

	RETVAL = newSV(sv_len + 1);
	sv_setpv(RETVAL, "");
	linelen = 0;

	p = beg;
	while (1) {
	    p_beg = p;

	    /* skip past as much plain text as possible */
	    while (p < end && qp_isplain(*p)) {
	        p++;
	    }
	    if (p == end || *p == '\n') {
		/* whitespace at end of line must be encoded */
		while (p > p_beg && (*(p - 1) == '\t' || *(p - 1) == ' '))
		    p--;
	    }

	    p_len = p - p_beg;
	    if (p_len) {
	        /* output plain text (with line breaks) */
	        if (eol_len) {
		    STRLEN max_last_line = (p == end || *p == '\n')
					      ? MAX_LINE         /* .......\n */
					      : ((p + 1) == end || *(p + 1) == '\n')
	                                        ? MAX_LINE - 3   /* ....=XX\n */
	                                        : MAX_LINE - 4;  /* ...=XX=\n */
		    while (p_len + linelen > max_last_line) {
			STRLEN len = MAX_LINE - 1 - linelen;
			if (len > p_len)
			    len = p_len;
			sv_catpvn(RETVAL, p_beg, len);
			p_beg += len;
			p_len -= len;
			sv_catpvn(RETVAL, "=", 1);
			sv_catpvn(RETVAL, eol, eol_len);
		        linelen = 0;
		    }
                }
		if (p_len) {
	            sv_catpvn(RETVAL, p_beg, p_len);
	            linelen += p_len;
		}
	    }

	    if (p == end) {
		break;
            }
	    else if (*p == '\n' && eol_len && !binary) {
	        sv_catpvn(RETVAL, eol, eol_len);
	        p++;
		linelen = 0;
	    }
	    else {
		/* output escaped char (with line breaks) */
	        assert(p < end);
		if (eol_len && linelen > MAX_LINE - 4) {
		    sv_catpvn(RETVAL, "=", 1);
		    sv_catpvn(RETVAL, eol, eol_len);
		    linelen = 0;
		}
	        sv_catpvf(RETVAL, "=%02X", (unsigned char)*p);
	        p++;
	        linelen += 3;
	    }

	    /* optimize reallocs a bit */
	    if (SvLEN(RETVAL) > 80 && SvLEN(RETVAL) - SvCUR(RETVAL) < 3) {
		STRLEN expected_len = (SvCUR(RETVAL) * sv_len) / (p - beg);
     		SvGROW(RETVAL, expected_len);
	    }
        }

	if (SvCUR(RETVAL) && eol_len && linelen) {
	    sv_catpvn(RETVAL, "=", 1);
	    sv_catpvn(RETVAL, eol, eol_len);
	}

	OUTPUT:
	RETVAL

SV*
decode_qp(sv)
	SV* sv
	PROTOTYPE: $

        PREINIT:
	STRLEN len;
	char *str = SvPVbyte(sv, len);
	char const* end = str + len;
	char *r;
	char *whitespace = 0;

        CODE:
	RETVAL = newSV(len ? len : 1);
        SvPOK_on(RETVAL);
        r = SvPVX(RETVAL);
	while (str < end) {
	    if (*str == ' ' || *str == '\t') {
		if (!whitespace)
		    whitespace = str;
		str++;
	    }
	    else if (*str == '\r' && (str + 1) < end && str[1] == '\n') {
		str++;
	    }
	    else if (*str == '\n') {
		whitespace = 0;
		*r++ = *str++;
	    }
	    else {
		if (whitespace) {
		    while (whitespace < str) {
			*r++ = *whitespace++;
		    }
		    whitespace = 0;
                }
            	if (*str == '=') {
		    if ((str + 2) < end && isXDIGIT(str[1]) && isXDIGIT(str[2])) {
	                char buf[3];
                        str++;
	                buf[0] = *str++;
		        buf[1] = *str++;
	                buf[2] = '\0';
		        *r++ = (char)strtol(buf, 0, 16);
	            }
		    else {
		        /* look for soft line break */
		        char *p = str + 1;
		        while (p < end && (*p == ' ' || *p == '\t'))
		            p++;
		        if (p < end && *p == '\n')
		     	    str = p + 1;
		        else if ((p + 1) < end && *p == '\r' && *(p + 1) == '\n')
		            str = p + 2;
		        else
		            *r++ = *str++; /* give up */
		    }
		}
		else {
		    *r++ = *str++;
		}
	    }
	}
	if (whitespace) {
	    while (whitespace < str) {
		*r++ = *whitespace++;
	    }
        }
	*r = '\0';
	SvCUR_set(RETVAL, r - SvPVX(RETVAL));

        OUTPUT:
	RETVAL


MODULE = MIME::Base64		PACKAGE = MIME::Base64
