/* 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 "internal/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 a lot */
        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;
                }
                if (eof > v) {
                    rv = -1;
                    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);
}
