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/*
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 * LibSylph -- E-Mail client library
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 * Copyright (C) 1999-2005 Hiroyuki Yamamoto
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 *
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 * This library is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * This library is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
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 */
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#include <glib.h>
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#include <ctype.h>
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#include <string.h>
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#include "base64.h"
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static const gchar base64char[64] =
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        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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static const gchar base64val[128] = {
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        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
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        52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
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        -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
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        15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
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        -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
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        41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1
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};
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#define BASE64VAL(c)        (isascii((guchar)c) ? base64val[(gint)(c)] : -1)
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void base64_encode(gchar *out, const guchar *in, gint inlen)
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{
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        const guchar *inp = in;
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        gchar *outp = out;
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        while (inlen >= 3) {
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                *outp++ = base64char[(inp[0] >> 2) & 0x3f];
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                *outp++ = base64char[((inp[0] & 0x03) << 4) |
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                                     ((inp[1] >> 4) & 0x0f)];
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                *outp++ = base64char[((inp[1] & 0x0f) << 2) |
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                                     ((inp[2] >> 6) & 0x03)];
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                *outp++ = base64char[inp[2] & 0x3f];
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                inp += 3;
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                inlen -= 3;
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        }
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        if (inlen > 0) {
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                *outp++ = base64char[(inp[0] >> 2) & 0x3f];
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                if (inlen == 1) {
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                        *outp++ = base64char[(inp[0] & 0x03) << 4];
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                        *outp++ = '=';
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                } else {
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                        *outp++ = base64char[((inp[0] & 0x03) << 4) |
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                                             ((inp[1] >> 4) & 0x0f)];
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                        *outp++ = base64char[((inp[1] & 0x0f) << 2)];
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                }
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                *outp++ = '=';
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        }
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        *outp = '\0';
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}
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gint base64_decode(guchar *out, const gchar *in, gint inlen)
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{
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        const gchar *inp = in;
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        guchar *outp = out;
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        gchar buf[4];
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        if (inlen < 0)
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                inlen = G_MAXINT;
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        while (inlen >= 4 && *inp != '\0') {
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                buf[0] = *inp++;
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                inlen--;
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                if (BASE64VAL(buf[0]) == -1) break;
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                buf[1] = *inp++;
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                inlen--;
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                if (BASE64VAL(buf[1]) == -1) break;
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                buf[2] = *inp++;
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                inlen--;
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                if (buf[2] != '=' && BASE64VAL(buf[2]) == -1) break;
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                buf[3] = *inp++;
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                inlen--;
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                if (buf[3] != '=' && BASE64VAL(buf[3]) == -1) break;
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                *outp++ = ((BASE64VAL(buf[0]) << 2) & 0xfc) |
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                          ((BASE64VAL(buf[1]) >> 4) & 0x03);
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                if (buf[2] != '=') {
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                        *outp++ = ((BASE64VAL(buf[1]) & 0x0f) << 4) |
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                                  ((BASE64VAL(buf[2]) >> 2) & 0x0f);
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                        if (buf[3] != '=') {
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                                *outp++ = ((BASE64VAL(buf[2]) & 0x03) << 6) |
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                                           (BASE64VAL(buf[3]) & 0x3f);
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                        }
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                }
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        }
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        return outp - out;
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}
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Base64Decoder *base64_decoder_new(void)
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{
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        Base64Decoder *decoder;
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        decoder = g_new0(Base64Decoder, 1);
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        return decoder;
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}
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void base64_decoder_free(Base64Decoder *decoder)
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{
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        g_free(decoder);
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}
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gint base64_decoder_decode(Base64Decoder *decoder,
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                           const gchar *in, guchar *out)
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{
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        gint len, total_len = 0;
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        gint buf_len;
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        gchar buf[4];
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        g_return_val_if_fail(decoder != NULL, -1);
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        g_return_val_if_fail(in != NULL, -1);
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        g_return_val_if_fail(out != NULL, -1);
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        buf_len = decoder->buf_len;
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        memcpy(buf, decoder->buf, sizeof(buf));
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        for (;;) {
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                while (buf_len < 4) {
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                        gchar c = *in;
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                        in++;
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                        if (c == '\0') break;
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                        if (c == '\r' || c == '\n') continue;
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                        if (c != '=' && BASE64VAL(c) == -1)
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                                return -1;
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                        buf[buf_len++] = c;
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                }
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                if (buf_len < 4 || buf[0] == '=' || buf[1] == '=') {
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                        decoder->buf_len = buf_len;
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                        memcpy(decoder->buf, buf, sizeof(buf));
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                        return total_len;
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                }
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                len = base64_decode(out, buf, 4);
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                out += len;
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                total_len += len;
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                buf_len = 0;
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                if (len < 3) {
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                        decoder->buf_len = 0;
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                        return total_len;
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                }
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        }
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}