/* crypto/evp/encode.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>
#include "cryptlib.h"
#include <openssl/evp.h>

#ifndef CHARSET_EBCDIC
#define conv_bin2ascii(a)	(data_bin2ascii[(a)&0x3f])
#define conv_ascii2bin(a)	(data_ascii2bin[(a)&0x7f])
#else
/* We assume that PEM encoded files are EBCDIC files
 * (i.e., printable text files). Convert them here while decoding.
 * When encoding, output is EBCDIC (text) format again.
 * (No need for conversion in the conv_bin2ascii macro, as the
 * underlying textstring data_bin2ascii[] is already EBCDIC)
 */
#define conv_bin2ascii(a)	(data_bin2ascii[(a)&0x3f])
#define conv_ascii2bin(a)	(data_ascii2bin[os_toascii[a]&0x7f])
#endif

/* 64 char lines
 * pad input with 0
 * left over chars are set to =
 * 1 byte  => xx==
 * 2 bytes => xxx=
 * 3 bytes => xxxx
 */
#define BIN_PER_LINE    (64/4*3)
#define CHUNKS_PER_LINE (64/4)
#define CHAR_PER_LINE   (64+1)

static const unsigned char data_bin2ascii[65]="ABCDEFGHIJKLMNOPQRSTUVWXYZ\
abcdefghijklmnopqrstuvwxyz0123456789+/";

/* 0xF0 is a EOLN
 * 0xF1 is ignore but next needs to be 0xF0 (for \r\n processing).
 * 0xF2 is EOF
 * 0xE0 is ignore at start of line.
 * 0xFF is error
 */

#define B64_EOLN		0xF0
#define B64_CR			0xF1
#define B64_EOF			0xF2
#define B64_WS			0xE0
#define B64_ERROR       	0xFF
#define B64_NOT_BASE64(a)	(((a)|0x13) == 0xF3)

static const unsigned char data_ascii2bin[128]={
	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
	0xFF,0xE0,0xF0,0xFF,0xFF,0xF1,0xFF,0xFF,
	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
	0xE0,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
	0xFF,0xFF,0xFF,0x3E,0xFF,0xF2,0xFF,0x3F,
	0x34,0x35,0x36,0x37,0x38,0x39,0x3A,0x3B,
	0x3C,0x3D,0xFF,0xFF,0xFF,0x00,0xFF,0xFF,
	0xFF,0x00,0x01,0x02,0x03,0x04,0x05,0x06,
	0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,
	0x0F,0x10,0x11,0x12,0x13,0x14,0x15,0x16,
	0x17,0x18,0x19,0xFF,0xFF,0xFF,0xFF,0xFF,
	0xFF,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F,0x20,
	0x21,0x22,0x23,0x24,0x25,0x26,0x27,0x28,
	0x29,0x2A,0x2B,0x2C,0x2D,0x2E,0x2F,0x30,
	0x31,0x32,0x33,0xFF,0xFF,0xFF,0xFF,0xFF,
	};

void EVP_EncodeInit(EVP_ENCODE_CTX *ctx)
	{
	ctx->length=48;
	ctx->num=0;
	ctx->line_num=0;
	}

void EVP_EncodeUpdate(EVP_ENCODE_CTX *ctx, unsigned char *out, int *outl,
	     const unsigned char *in, int inl)
	{
	int i,j;
	unsigned int total=0;

	*outl=0;
	if (inl == 0) return;
	OPENSSL_assert(ctx->length <= (int)sizeof(ctx->enc_data));
	if ((ctx->num+inl) < ctx->length)
		{
		memcpy(&(ctx->enc_data[ctx->num]),in,inl);
		ctx->num+=inl;
		return;
		}
	if (ctx->num != 0)
		{
		i=ctx->length-ctx->num;
		memcpy(&(ctx->enc_data[ctx->num]),in,i);
		in+=i;
		inl-=i;
		j=EVP_EncodeBlock(out,ctx->enc_data,ctx->length);
		ctx->num=0;
		out+=j;
		*(out++)='\n';
		*out='\0';
		total=j+1;
		}
	while (inl >= ctx->length)
		{
		j=EVP_EncodeBlock(out,in,ctx->length);
		in+=ctx->length;
		inl-=ctx->length;
		out+=j;
		*(out++)='\n';
		*out='\0';
		total+=j+1;
		}
	if (inl != 0)
		memcpy(&(ctx->enc_data[0]),in,inl);
	ctx->num=inl;
	*outl=total;
	}

void EVP_EncodeFinal(EVP_ENCODE_CTX *ctx, unsigned char *out, int *outl)
	{
	unsigned int ret=0;

	if (ctx->num != 0)
		{
		ret=EVP_EncodeBlock(out,ctx->enc_data,ctx->num);
		out[ret++]='\n';
		out[ret]='\0';
		ctx->num=0;
		}
	*outl=ret;
	}

int EVP_EncodeBlock(unsigned char *t, const unsigned char *f, int dlen)
	{
	int i,ret=0;
	unsigned long l;

	for (i=dlen; i > 0; i-=3)
		{
		if (i >= 3)
			{
			l=	(((unsigned long)f[0])<<16L)|
				(((unsigned long)f[1])<< 8L)|f[2];
			*(t++)=conv_bin2ascii(l>>18L);
			*(t++)=conv_bin2ascii(l>>12L);
			*(t++)=conv_bin2ascii(l>> 6L);
			*(t++)=conv_bin2ascii(l     );
			}
		else
			{
			l=((unsigned long)f[0])<<16L;
			if (i == 2) l|=((unsigned long)f[1]<<8L);

			*(t++)=conv_bin2ascii(l>>18L);
			*(t++)=conv_bin2ascii(l>>12L);
			*(t++)=(i == 1)?'=':conv_bin2ascii(l>> 6L);
			*(t++)='=';
			}
		ret+=4;
		f+=3;
		}

	*t='\0';
	return(ret);
	}

void EVP_DecodeInit(EVP_ENCODE_CTX *ctx)
	{
	ctx->length=30;
	ctx->num=0;
	ctx->line_num=0;
	ctx->expect_nl=0;
	}

/* -1 for error
 *  0 for last line
 *  1 for full line
 */
int EVP_DecodeUpdate(EVP_ENCODE_CTX *ctx, unsigned char *out, int *outl,
	     const unsigned char *in, int inl)
	{
	int seof= -1,eof=0,rv= -1,ret=0,i,v,tmp,n,ln,exp_nl;
	unsigned char *d;

	n=ctx->num;
	d=ctx->enc_data;
	ln=ctx->line_num;
	exp_nl=ctx->expect_nl;

	/* last line of input. */
	if ((inl == 0) || ((n == 0) && (conv_ascii2bin(in[0]) == B64_EOF)))
		{ rv=0; goto end; }
		
	/* We parse the input data */
	for (i=0; i<inl; i++)
		{
		/* If the current line is > 80 characters, scream alot */
		if (ln >= 80) { rv= -1; goto end; }

		/* Get char and put it into the buffer */
		tmp= *(in++);
		v=conv_ascii2bin(tmp);
		/* only save the good data :-) */
		if (!B64_NOT_BASE64(v))
			{
			OPENSSL_assert(n < (int)sizeof(ctx->enc_data));
			d[n++]=tmp;
			ln++;
			}
		else if (v == B64_ERROR)
			{
			rv= -1;
			goto end;
			}

		/* have we seen a '=' which is 'definitly' the last
		 * input line.  seof will point to the character that
		 * holds it. and eof will hold how many characters to
		 * chop off. */
		if (tmp == '=')
			{
			if (seof == -1) seof=n;
			eof++;
			}

		if (v == B64_CR)
			{
			ln = 0;
			if (exp_nl)
				continue;
			}

		/* eoln */
		if (v == B64_EOLN)
			{
			ln=0;
			if (exp_nl)
				{
				exp_nl=0;
				continue;
				}
			}
		exp_nl=0;

		/* If we are at the end of input and it looks like a
		 * line, process it. */
		if (((i+1) == inl) && (((n&3) == 0) || eof))
			{
			v=B64_EOF;
			/* In case things were given us in really small
			   records (so two '=' were given in separate
			   updates), eof may contain the incorrect number
			   of ending bytes to skip, so let's redo the count */
			eof = 0;
			if (d[n-1] == '=') eof++;
			if (d[n-2] == '=') eof++;
			/* There will never be more than two '=' */
			}

		if ((v == B64_EOF && (n&3) == 0) || (n >= 64))
			{
			/* This is needed to work correctly on 64 byte input
			 * lines.  We process the line and then need to
			 * accept the '\n' */
			if ((v != B64_EOF) && (n >= 64)) exp_nl=1;
			if (n > 0)
				{
				v=EVP_DecodeBlock(out,d,n);
				n=0;
				if (v < 0) { rv=0; goto end; }
				ret+=(v-eof);
				}
			else
				{
				eof=1;
				v=0;
				}

			/* This is the case where we have had a short
			 * but valid input line */
			if ((v < ctx->length) && eof)
				{
				rv=0;
				goto end;
				}
			else
				ctx->length=v;

			if (seof >= 0) { rv=0; goto end; }
			out+=v;
			}
		}
	rv=1;
end:
	*outl=ret;
	ctx->num=n;
	ctx->line_num=ln;
	ctx->expect_nl=exp_nl;
	return(rv);
	}

int EVP_DecodeBlock(unsigned char *t, const unsigned char *f, int n)
	{
	int i,ret=0,a,b,c,d;
	unsigned long l;

	/* trim white space from the start of the line. */
	while ((conv_ascii2bin(*f) == B64_WS) && (n > 0))
		{
		f++;
		n--;
		}

	/* strip off stuff at the end of the line
	 * ascii2bin values B64_WS, B64_EOLN, B64_EOLN and B64_EOF */
	while ((n > 3) && (B64_NOT_BASE64(conv_ascii2bin(f[n-1]))))
		n--;

	if (n%4 != 0) return(-1);

	for (i=0; i<n; i+=4)
		{
		a=conv_ascii2bin(*(f++));
		b=conv_ascii2bin(*(f++));
		c=conv_ascii2bin(*(f++));
		d=conv_ascii2bin(*(f++));
		if (	(a & 0x80) || (b & 0x80) ||
			(c & 0x80) || (d & 0x80))
			return(-1);
		l=(	(((unsigned long)a)<<18L)|
			(((unsigned long)b)<<12L)|
			(((unsigned long)c)<< 6L)|
			(((unsigned long)d)     ));
		*(t++)=(unsigned char)(l>>16L)&0xff;
		*(t++)=(unsigned char)(l>> 8L)&0xff;
		*(t++)=(unsigned char)(l     )&0xff;
		ret+=3;
		}
	return(ret);
	}

int EVP_DecodeFinal(EVP_ENCODE_CTX *ctx, unsigned char *out, int *outl)
	{
	int i;

	*outl=0;
	if (ctx->num != 0)
		{
		i=EVP_DecodeBlock(out,ctx->enc_data,ctx->num);
		if (i < 0) return(-1);
		ctx->num=0;
		*outl=i;
		return(1);
		}
	else
		return(1);
	}

#ifdef undef
int EVP_DecodeValid(unsigned char *buf, int len)
	{
	int i,num=0,bad=0;

	if (len == 0) return(-1);
	while (conv_ascii2bin(*buf) == B64_WS)
		{
		buf++;
		len--;
		if (len == 0) return(-1);
		}

	for (i=len; i >= 4; i-=4)
		{
		if (	(conv_ascii2bin(buf[0]) >= 0x40) ||
			(conv_ascii2bin(buf[1]) >= 0x40) ||
			(conv_ascii2bin(buf[2]) >= 0x40) ||
			(conv_ascii2bin(buf[3]) >= 0x40))
			return(-1);
		buf+=4;
		num+=1+(buf[2] != '=')+(buf[3] != '=');
		}
	if ((i == 1) && (conv_ascii2bin(buf[0]) == B64_EOLN))
		return(num);
	if ((i == 2) && (conv_ascii2bin(buf[0]) == B64_EOLN) &&
		(conv_ascii2bin(buf[0]) == B64_EOLN))
		return(num);
	return(1);
	}
#endif