/*
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <lha_internal.h>
#include <syslog.h>
#include <string.h>
#include <stdlib.h>
#include "clplumbing/base64.h"

/*
 *
 * Base64 conversion functions.
 * They convert from a binary array into a single string
 * in base 64.  This is almost (but not quite) like section 5.2 of RFC 1341
 * The only difference is that we don't care about line lengths.
 * We do use their encoding algorithm.
 *
 */


static char b64chars[]
=	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

#define	EQUALS	'='
#define	MASK6	(077)
#define	MASK24	(077777777)


/* Convert from binary to a base64 string (~ according to RFC1341) */
int
binary_to_base64(const void * data, int nbytes, char * output, int outlen)
{
	int	requiredlen = B64_stringlen(nbytes)+1; /* EOS */
	char *		outptr;
	const unsigned char *	inmax;
	const unsigned char *	inlast;
	const unsigned char *	inptr;
	int	bytesleft;

	if (outlen < requiredlen) {
		syslog(LOG_ERR, "binary_to_base64: output area too small.");
		return -1;
	}

	inptr = data;
	/* Location of last whole 3-byte chunk */
	inmax = inptr + ((nbytes / B64inunit)*B64inunit);
	inlast = inptr + nbytes;
	outptr = output;
	

	/* Convert whole 3-byte chunks */
	for (;inptr < inmax; inptr += B64inunit) {
		unsigned long	chunk;
		unsigned int	sixbits;

		chunk =	((*inptr) << 16
		|	((*(inptr+1)) << 8)
		|	(*(inptr+2))) & MASK24;

		sixbits = (chunk >> 18) & MASK6;
		*outptr = b64chars[sixbits]; ++outptr;

		sixbits = (chunk >> 12) & MASK6;
		*outptr = b64chars[sixbits]; ++outptr;

		sixbits = (chunk >> 6) & MASK6;
		*outptr = b64chars[sixbits]; ++outptr;

		sixbits = (chunk & MASK6);
		*outptr = b64chars[sixbits]; ++outptr;
	}

	/* Do we have anything left over? */

	bytesleft = inlast - inptr;
	if (bytesleft > 0) {
		/* bytesleft can only be 1 or 2 */

		unsigned long	chunk;
		unsigned int	sixbits;


		/* Grab first byte */
		chunk =	(*inptr) << 16;

		if (bytesleft == 2) {
			/* Grab second byte */
			chunk |= ((*(inptr+1)) << 8);
		}
		chunk &= MASK24;

		/* OK, now we have our chunk... */
		sixbits = (chunk >> 18) & MASK6;
		*outptr = b64chars[sixbits]; ++outptr;
		sixbits = (chunk >> 12) & MASK6;
		*outptr = b64chars[sixbits]; ++outptr;

		if (bytesleft == 2) {
			sixbits = (chunk >> 6) & MASK6;
			*outptr = b64chars[sixbits];
		}else{
			*outptr = EQUALS;
		}
		++outptr;

		*outptr = EQUALS; ++outptr;
	}
	*outptr = EOS;	/* Don't increment */
	return (outptr - output);
}


/* This macro is only usable by the base64_to_binary() function.
 *
 * There are faster ways of doing this, but I didn't spend the time
 * to implement one of them.  If we have an array of six bit values, 
 * sized by 256 or so, then we could look it up.
 * FIXME: This is how it really ought to be done...
 */

static unsigned char b64values [256];
#define	BADVALUE	0xff

static void
init_b64_values(void)
{
	int	j;
	memset(b64values, BADVALUE, sizeof(b64values));

	for (j=0; b64chars[j] != EOS; ++j) {
		b64values[(int)b64chars[j]] = (unsigned char)j;
	}
}


#define	Char2SixBits(in, out)  {				\
	unsigned char  ch;					\
	ch = b64values[(unsigned int)in];			\
	if (ch == BADVALUE) {					\
		syslog(LOG_ERR					\
		,	"base64_to_binary: invalid input [%c]!"	\
					,	in);		\
		return -1;					\
	}							\
	out = ch;						\
	}							\
	

/* Convert from a base64 string (~ according to RFC1341) to binary */
int
base64_to_binary(const char * in, int inlen, void * output, int outlen)
{
	int maxbinlen = B64_maxbytelen(inlen); /* Worst case size */
	const char *		input = in;
	const char *		lastinput = in + inlen - B64outunit;
	int		equalcount = 0;
	unsigned char *	startout;
	unsigned char *	out;
	unsigned	sixbits1;
	unsigned	sixbits2;
	unsigned	sixbits3;
	unsigned	sixbits4;
	unsigned long	chunk;
	static	int	inityet = 0;

	if (!inityet) {
		inityet=1;
		init_b64_values();
	}

	/* Make sure we have enough room */
	if (outlen < maxbinlen) {
		int	residue = maxbinlen - outlen;

		if (residue > 2
		||	input[inlen-1] != EQUALS
		||	(residue == 2 && input[inlen-2] != EQUALS))  {
			syslog(LOG_ERR
			,	"base64_to_binary: output area too small.");
			return -1;
		}
	}
	if ((inlen % 4) != 0) {
		syslog(LOG_ERR
		,	"base64_to_binary: input length invalid.");
		return -1;
	}

	if (inlen == 0) {
		return 0;
	}

	/* We have enough space.  We are happy :-)  */

	startout = out = (unsigned char *)output;

	while (input < lastinput) {
		Char2SixBits(*input, sixbits1); ++input;
		Char2SixBits(*input, sixbits2); ++input;
		Char2SixBits(*input, sixbits3); ++input;
		Char2SixBits(*input, sixbits4); ++input;

		chunk = (sixbits1 << 18)
		|	(sixbits2 << 12) | (sixbits3 << 6) | sixbits4;

		*out = ((chunk >> 16) & 0xff);	++out;
		*out = ((chunk >>  8) & 0xff);	++out;
		*out = (chunk & 0xff);		++out;
	}

	/* Process last 4 chars of input (1 to 3 bytes of output) */

	/* The first two input chars must be normal chars */
	Char2SixBits(*input, sixbits1); ++input;
	Char2SixBits(*input, sixbits2); ++input;

	/* We should find one of: (char,char) (char,=) or (=,=) */
	/* We then output:         (3 bytes)  (2 bytes)  (1 byte) */

	if (*input == EQUALS) {
		/* The (=,=): 1 byte case */
		equalcount=2;
		sixbits3 = 0;
		sixbits4 = 0;
		/* We assume the 2nd char is an = sign :-) */
	}else{
		/* We have either the (char,char) or (char,=) case */
		Char2SixBits(*input, sixbits3); ++input;
		if (*input == EQUALS) {
			/* The (char, =): 2 bytes case */
			equalcount=1;
			sixbits4 = 0;
		}else{
			/* The (char, char): 3 bytes case */
			Char2SixBits(*input, sixbits4); ++input;
			equalcount=0;
		}
	}

	chunk = (sixbits1 << 18)
	|	(sixbits2 << 12) | (sixbits3 << 6) | sixbits4;

	/* We always have one more char to output... */
	*out = ((chunk >> 16) & 0xff); ++out;

	if (equalcount < 2) {
		/* Zero or one equal signs: total of 2 or 3 bytes output */
		*out = ((chunk >> 8) & 0xff); ++out;

		if (equalcount < 1) {
			/* No equal signs:  total of 3 bytes output */
			*out = (chunk & 0xff); ++out;
		}
	}

	return out - startout;
}

#if 0
#define RAND(upb)	(rand()%(upb))

void dumpbin(void * Bin, int length);
void randbin(void * Bin, int length);

void
dumpbin(void * Bin, int length)
{
	unsigned char *	bin = Bin;

	int	j;

	for (j=0; j < length; ++j) {
		fprintf(stderr, "%02x ", bin[j]);
		if ((j % 32) == 31) {
			fprintf(stderr, "\n");
		}
	}
	fprintf(stderr, "\n");
}

void
randbin(void * Bin, int length)
{
	unsigned char *	bin = Bin;
	int	j;

	for (j=0; j < length; ++j) {
		bin[j] = (unsigned char)RAND(256);
	}
	
}

#define MAXLEN	320
#define	MAXSTRING B64_stringlen(MAXLEN)+1
#define	MAXITER	300000
int
main(int argc, char ** argv)
{
	int	errcount = 0;
	char	origbin[MAXLEN+1];
	char	sourcebin[MAXLEN+1];
	char	destbin[MAXLEN+1];
	char	deststr[MAXSTRING];
	int	maxiter = MAXITER;
	int	j;
	
	for (j=0; j < maxiter; ++j) {
		int	iterlen = RAND(MAXLEN+1);
		int	slen;
		int	blen;

		if ((j%100) == 99) {
			fprintf(stderr, "+");
		}

		memset(origbin, 0, MAXLEN+1);
		memset(sourcebin, 0, MAXLEN+1);
		memset(destbin, 0, MAXLEN+1);
		randbin(origbin, iterlen);
		origbin[iterlen] = 0x1;
		memcpy(sourcebin, origbin, iterlen);
		sourcebin[iterlen] = 0x2;
		slen = binary_to_base64(sourcebin, iterlen, deststr, MAXSTRING);
		if (slen < 0) {
			fprintf(stderr
			,	"binary_to_base64 failure: length %d\n"
			,	iterlen);
			++errcount;
			continue;
		}
		if (strlen(deststr) != slen) {
			fprintf(stderr
			,	"binary_to_base64 failure: length was %d (strlen) vs %d (ret value)\n"
			,	strlen(deststr), slen);
			fprintf(stderr, "binlen: %d, deststr: [%s]\n"
			,	iterlen, deststr);
			continue;
			++errcount;
		}
		destbin[iterlen] = 0x3;
		blen = base64_to_binary(deststr, slen, destbin, iterlen);

		if (blen != iterlen) {
			fprintf(stderr
			,	"base64_to_binary failure: length was %d vs %d\n"
			,	blen, iterlen);
			dumpbin(origbin, iterlen);
			fprintf(stderr
			,	"Base64 intermediate: [%s]\n", deststr);
			++errcount;
			continue;
		}
		if (memcmp(destbin, origbin, iterlen) != 0) {
			fprintf(stderr
			,	"base64_to_binary mismatch. Orig:\n");
			dumpbin(origbin, iterlen);
			fprintf(stderr, "Dest:\n");
			dumpbin(destbin, iterlen);
			fprintf(stderr
			,	"Base64 intermediate: [%s]\n", deststr);
			++errcount;
		}
		if (destbin[iterlen] != 0x3) {
			fprintf(stderr
			,	"base64_to_binary corruption. dest byte: 0x%02x\n"
			,	destbin[iterlen]);
			++errcount;
		}

		if (sourcebin[iterlen] != 0x2) {
			fprintf(stderr
			,	"base64_to_binary corruption. source byte: 0x%02x\n"
			,	sourcebin[iterlen]);
			++errcount;
		}
		sourcebin[iterlen] = 0x0;
		origbin[iterlen] = 0x0;
		if (memcmp(sourcebin, origbin, MAXLEN+1) != 0) {
			fprintf(stderr
			,	"base64_to_binary corruption. origbin:\n");
			dumpbin(origbin, MAXLEN+1);
			fprintf(stderr, "sourcebin:\n");
			dumpbin(sourcebin, MAXLEN+1);
			++errcount;
		}

	}

	fprintf(stderr, "\n%d iterations, %d errors.\n"
	,	maxiter, errcount);

	return errcount;
}
/* HA-logging function */
void
ha_log(int priority, const char * fmt, ...)
{
	va_list		ap;
	char		buf[MAXLINE];

	va_start(ap, fmt);
	vsnprintf(buf, MAXLINE, fmt, ap);
	va_end(ap);

	fprintf(stderr, "%s\n",  buf);

}
#endif