Sylpheed

/*

 * Sylpheed -- a GTK+ based, lightweight, and fast e-mail client

 * Copyright (C) 1999-2002 Hiroyuki Yamamoto

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

 */

#include <glib.h>

#include <ctype.h>

#include <string.h>

#include "base64.h"

static const gchar base64char[64] =

        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

static const gchar base64val[128] = {

        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,

        52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,

        -1,  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, -1, -1, -1, -1, -1,

        -1, 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, -1, -1, -1, -1, -1

};

#define BASE64VAL(c)        (isascii((guchar)c) ? base64val[(gint)(c)] : -1)

void base64_encode(gchar *out, const guchar *in, gint inlen)

{

        const guchar *inp = in;

        gchar *outp = out;

        while (inlen >= 3) {

                *outp++ = base64char[(inp[0] >> 2) & 0x3f];

                *outp++ = base64char[((inp[0] & 0x03) << 4) |

                                     ((inp[1] >> 4) & 0x0f)];

                *outp++ = base64char[((inp[1] & 0x0f) << 2) |

                                     ((inp[2] >> 6) & 0x03)];

                *outp++ = base64char[inp[2] & 0x3f];

                inp += 3;

                inlen -= 3;

        }

        if (inlen > 0) {

                *outp++ = base64char[(inp[0] >> 2) & 0x3f];

                if (inlen == 1) {

                        *outp++ = base64char[(inp[0] & 0x03) << 4];

                        *outp++ = '=';

                } else {

                        *outp++ = base64char[((inp[0] & 0x03) << 4) |

                                             ((inp[1] >> 4) & 0x0f)];

                        *outp++ = base64char[((inp[1] & 0x0f) << 2)];

                }

                *outp++ = '=';

        }

        *outp = '\0';

}

gint base64_decode(guchar *out, const gchar *in, gint inlen)

{

        const gchar *inp = in;

        guchar *outp = out;

        gchar buf[4];

        if (inlen < 0)

                inlen = G_MAXINT;

        while (inlen >= 4 && *inp != '\0') {

                buf[0] = *inp++;

                inlen--;

                if (BASE64VAL(buf[0]) == -1) break;

                buf[1] = *inp++;

                inlen--;

                if (BASE64VAL(buf[1]) == -1) break;

                buf[2] = *inp++;

                inlen--;

                if (buf[2] != '=' && BASE64VAL(buf[2]) == -1) break;

                buf[3] = *inp++;

                inlen--;

                if (buf[3] != '=' && BASE64VAL(buf[3]) == -1) break;

                *outp++ = ((BASE64VAL(buf[0]) << 2) & 0xfc) |

                          ((BASE64VAL(buf[1]) >> 4) & 0x03);

                if (buf[2] != '=') {

                        *outp++ = ((BASE64VAL(buf[1]) & 0x0f) << 4) |

                                  ((BASE64VAL(buf[2]) >> 2) & 0x0f);

                        if (buf[3] != '=') {

                                *outp++ = ((BASE64VAL(buf[2]) & 0x03) << 6) |

                                           (BASE64VAL(buf[3]) & 0x3f);

                        }

                }

        }

        return outp - out;

}

Base64Decoder *base64_decoder_new(void)

{

        Base64Decoder *decoder;

        decoder = g_new0(Base64Decoder, 1);

        return decoder;

}

void base64_decoder_free(Base64Decoder *decoder)

{

        g_free(decoder);

}

gint base64_decoder_decode(Base64Decoder *decoder,

                           const gchar *in, guchar *out)

{

        gint len, total_len = 0;

        gint buf_len;

        gchar buf[4];

        g_return_val_if_fail(decoder != NULL, -1);

        g_return_val_if_fail(in != NULL, -1);

        g_return_val_if_fail(out != NULL, -1);

        buf_len = decoder->buf_len;

        memcpy(buf, decoder->buf, sizeof(buf));

        for (;;) {

                while (buf_len < 4) {

                        gchar c = *in;

                        in++;

                        if (c == '\0') break;

                        if (c == '\r' || c == '\n') continue;

                        if (c != '=' && BASE64VAL(c) == -1)

                                return -1;

                        buf[buf_len++] = c;

                }

                if (buf_len < 4 || buf[0] == '=' || buf[1] == '=') {

                        decoder->buf_len = buf_len;

                        memcpy(decoder->buf, buf, sizeof(buf));

                        return total_len;

                }

                len = base64_decode(out, buf, 4);

                out += len;

                total_len += len;

                buf_len = 0;

                if (len < 3) {

                        decoder->buf_len = 0;

                        return total_len;

                }

        }

}