path: root/camel/camel-mime-utils.c

/*
 *  Copyright (C) 2000 Helix Code Inc.
 *
 *  Authors: Michael Zucchi <notzed@helixcode.com>
 *           Jeffrey Stedfast <fejj@helixcode.com>
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library 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 Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public
 *  License along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* dont touch this file without my permission - Michael */

#include <config.h>

#include <stdio.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <unicode.h>
#include <iconv.h>

#include <glib.h>
#include <time.h>

#include <ctype.h>
#include <errno.h>

#include <regex.h>

#include "camel-mime-utils.h"
#include "camel-charset-map.h"

#ifndef CLEAN_DATE
#include "broken-date-parser.h"
#endif

#if 0
int strdup_count = 0;
int malloc_count = 0;
int free_count = 0;

#define g_strdup(x) (strdup_count++, g_strdup(x))
#define g_malloc(x) (malloc_count++, g_malloc(x))
#define g_free(x) (free_count++, g_free(x))
#endif

/* for all warnings ... */
#define w(x) x

#define d(x)
#define d2(x)

#define CAMEL_UUDECODE_CHAR(c)  (((c) - ' ') & 077)

static char *base64_alphabet =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

static unsigned char tohex[16] = {
    '0', '1', '2', '3', '4', '5', '6', '7',
    '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
};

static unsigned short camel_mime_special_table[256] = {
      5,  5,  5,  5,  5,  5,  5,  5,  5,231,  7,  5,  5, 39,  5,  5,
      5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,
    242,448, 76,192,192,192,192,192, 76, 76,448,448, 76,448, 72,324,
    448,448,448,448,448,448,448,448,448,448, 76, 76, 76,  4, 76, 68,
     76,448,448,448,448,448,448,448,448,448,448,448,448,448,448,448,
    448,448,448,448,448,448,448,448,448,448,448,108,236,108,192, 64,
    192,448,448,448,448,448,448,448,448,448,448,448,448,448,448,448,
    448,448,448,448,448,448,448,448,448,448,448,192,192,192,192,  5,
      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
};

static unsigned char camel_mime_base64_rank[256] = {
    255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
    255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
    255,255,255,255,255,255,255,255,255,255,255, 62,255,255,255, 63,
     52, 53, 54, 55, 56, 57, 58, 59, 60, 61,255,255,255,  0,255,255,
    255,  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, 25,255,255,255,255,255,
    255, 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, 51,255,255,255,255,255,
    255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
    255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
    255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
    255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
    255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
    255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
    255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
    255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
};

/*
  if any of these change, then the tables above should be regenerated
  by compiling this with -DBUILD_TABLE, and running.

  gcc -DCLEAN_DATE -o buildtable -I.. `glib-config --cflags --libs` -lunicode -DBUILD_TABLE camel-mime-utils.c camel-charset-map.c
  ./buildtable

*/
enum {
    IS_CTRL     = 1<<0,
    IS_LWSP     = 1<<1,
    IS_TSPECIAL = 1<<2,
    IS_SPECIAL  = 1<<3,
    IS_SPACE    = 1<<4,
    IS_DSPECIAL = 1<<5,
    IS_QPSAFE   = 1<<6,
    IS_ESAFE    = 1<<7, /* encoded word safe */
    IS_PSAFE    = 1<<8, /* encoded word in phrase safe */
};

#define is_ctrl(x) ((camel_mime_special_table[(unsigned char)(x)] & IS_CTRL) != 0)
#define is_lwsp(x) ((camel_mime_special_table[(unsigned char)(x)] & IS_LWSP) != 0)
#define is_tspecial(x) ((camel_mime_special_table[(unsigned char)(x)] & IS_TSPECIAL) != 0)
#define is_type(x, t) ((camel_mime_special_table[(unsigned char)(x)] & (t)) != 0)
#define is_ttoken(x) ((camel_mime_special_table[(unsigned char)(x)] & (IS_TSPECIAL|IS_LWSP|IS_CTRL)) == 0)
#define is_atom(x) ((camel_mime_special_table[(unsigned char)(x)] & (IS_SPECIAL|IS_SPACE|IS_CTRL)) == 0)
#define is_dtext(x) ((camel_mime_special_table[(unsigned char)(x)] & IS_DSPECIAL) == 0)
#define is_fieldname(x) ((camel_mime_special_table[(unsigned char)(x)] & (IS_CTRL|IS_SPACE)) == 0)
#define is_qpsafe(x) ((camel_mime_special_table[(unsigned char)(x)] & IS_QPSAFE) != 0)
#define is_especial(x) ((camel_mime_special_table[(unsigned char)(x)] & IS_ESPECIAL) != 0)
#define is_psafe(x) ((camel_mime_special_table[(unsigned char)(x)] & IS_PSAFE) != 0)

/* only needs to be run to rebuild the tables above */
#ifdef BUILD_TABLE

#define CHARS_LWSP " \t\n\r"
#define CHARS_TSPECIAL "()<>@,;:\\\"/[]?="
#define CHARS_SPECIAL "()<>@,;:\\\".[]"
#define CHARS_CSPECIAL "()\\\r" /* not in comments */
#define CHARS_DSPECIAL "[]\\\r \t"  /* not in domains */
#define CHARS_ESPECIAL "()<>@,;:\"/[]?.=_" /* list of characters that must be encoded.
                          encoded word in text specials: rfc 2047 5(1)*/
#define CHARS_PSPECIAL "!*+-/" /* list of additional characters that can be left unencoded.
                  encoded word in phrase specials: rfc 2047 5(3) */

static void
header_remove_bits(unsigned short bit, unsigned char *vals)
{
    int i;

    for (i=0;vals[i];i++)
        camel_mime_special_table[vals[i]] &= ~ bit;
}

static void
header_init_bits(unsigned short bit, unsigned short bitcopy, int remove, unsigned char *vals)
{
    int i;
    int len = strlen(vals);

    if (!remove) {
        for (i=0;i<len;i++) {
            camel_mime_special_table[vals[i]] |= bit;
        }
        if (bitcopy) {
            for (i=0;i<256;i++) {
                if (camel_mime_special_table[i] & bitcopy)
                    camel_mime_special_table[i] |= bit;
            }
        }
    } else {
        for (i=0;i<256;i++)
            camel_mime_special_table[i] |= bit;
        for (i=0;i<len;i++) {
            camel_mime_special_table[vals[i]] &= ~bit;
        }
        if (bitcopy) {
            for (i=0;i<256;i++) {
                if (camel_mime_special_table[i] & bitcopy)
                    camel_mime_special_table[i] &= ~bit;
            }
        }
    }
}

static void
header_decode_init(void)
{
    int i;

    for (i=0;i<256;i++) {
        camel_mime_special_table[i] = 0;
        if (i<32)
            camel_mime_special_table[i] |= IS_CTRL;
        if ((i>=33 && i<=60) || (i>=62 && i<=126) || i==32 || i==9)
            camel_mime_special_table[i] |= (IS_QPSAFE|IS_ESAFE);
        if ((i>='0' && i<='9') || (i>='a' && i<='z') || (i>='A' && i<= 'Z'))
            camel_mime_special_table[i] |= IS_PSAFE;
    }
    camel_mime_special_table[127] |= IS_CTRL;
    camel_mime_special_table[' '] |= IS_SPACE;
    header_init_bits(IS_LWSP, 0, 0, CHARS_LWSP);
    header_init_bits(IS_TSPECIAL, IS_CTRL, 0, CHARS_TSPECIAL);
    header_init_bits(IS_SPECIAL, 0, 0, CHARS_SPECIAL);
    header_init_bits(IS_DSPECIAL, 0, FALSE, CHARS_DSPECIAL);
    header_remove_bits(IS_ESAFE, CHARS_ESPECIAL);
    header_init_bits(IS_PSAFE, 0, 0, CHARS_PSPECIAL);
}

void
base64_init(void)
{
    int i;

    memset(camel_mime_base64_rank, 0xff, sizeof(camel_mime_base64_rank));
    for (i=0;i<64;i++) {
        camel_mime_base64_rank[(unsigned int)base64_alphabet[i]] = i;
    }
    camel_mime_base64_rank['='] = 0;
}

int main(int argc, char **argv)
{
    int i;
    void run_test(void);

    header_decode_init();
    base64_init();

    printf("static unsigned short camel_mime_special_table[256] = {\n\t");
    for (i=0;i<256;i++) {
        printf("%3d,", camel_mime_special_table[i]);
        if ((i&15) == 15) {
            printf("\n");
            if (i!=255) {
                printf("\t");
            }
        }
    }
    printf("};\n");

    printf("static unsigned char camel_mime_base64_rank[256] = {\n\t");
    for (i=0;i<256;i++) {
        printf("%3d,", camel_mime_base64_rank[i]);
        if ((i&15) == 15) {
            printf("\n");
            if (i!=255) {
                printf("\t");
            }
        }
    }
    printf("};\n");

    run_test();

    return 0;
}

#endif


/* call this when finished encoding everything, to
   flush off the last little bit */
int
base64_encode_close(unsigned char *in, int inlen, gboolean break_lines, unsigned char *out, int *state, int *save)
{
    int c1, c2;
    unsigned char *outptr = out;

    if (inlen>0)
        outptr += base64_encode_step(in, inlen, break_lines, outptr, state, save);

    c1 = ((unsigned char *)save)[1];
    c2 = ((unsigned char *)save)[2];
    
    d(printf("mode = %d\nc1 = %c\nc2 = %c\n",
         (int)((char *)save)[0],
         (int)((char *)save)[1],
         (int)((char *)save)[2]));

    switch (((char *)save)[0]) {
    case 2:
        outptr[2] = base64_alphabet[ ( (c2 &0x0f) << 2 ) ];
        g_assert(outptr[2] != 0);
        goto skip;
    case 1:
        outptr[2] = '=';
    skip:
        outptr[0] = base64_alphabet[ c1 >> 2 ];
        outptr[1] = base64_alphabet[ c2 >> 4 | ( (c1&0x3) << 4 )];
        outptr[3] = '=';
        outptr += 4;
        break;
    }
    if (break_lines)
        *outptr++ = '\n';

    *save = 0;
    *state = 0;

    return outptr-out;
}

/*
  performs an 'encode step', only encodes blocks of 3 characters to the
  output at a time, saves left-over state in state and save (initialise to
  0 on first invocation).
*/
int
base64_encode_step(unsigned char *in, int len, gboolean break_lines, unsigned char *out, int *state, int *save)
{
    register unsigned char *inptr, *outptr;

    if (len<=0)
        return 0;

    inptr = in;
    outptr = out;

    d(printf("we have %d chars, and %d saved chars\n", len, ((char *)save)[0]));

    if (len + ((char *)save)[0] > 2) {
        unsigned char *inend = in+len-2;
        register int c1, c2, c3;
        register int already;

        already = *state;

        switch (((char *)save)[0]) {
        case 1: c1 = ((unsigned char *)save)[1]; goto skip1;
        case 2: c1 = ((unsigned char *)save)[1];
            c2 = ((unsigned char *)save)[2]; goto skip2;
        }
        
        /* yes, we jump into the loop, no i'm not going to change it, it's beautiful! */
        while (inptr < inend) {
            c1 = *inptr++;
        skip1:
            c2 = *inptr++;
        skip2:
            c3 = *inptr++;
            *outptr++ = base64_alphabet[ c1 >> 2 ];
            *outptr++ = base64_alphabet[ c2 >> 4 | ( (c1&0x3) << 4 ) ];
            *outptr++ = base64_alphabet[ ( (c2 &0x0f) << 2 ) | (c3 >> 6) ];
            *outptr++ = base64_alphabet[ c3 & 0x3f ];
            /* this is a bit ugly ... */
            if (break_lines && (++already)>=19) {
                *outptr++='\n';
                already = 0;
            }
        }

        ((char *)save)[0] = 0;
        len = 2-(inptr-inend);
        *state = already;
    }

    d(printf("state = %d, len = %d\n",
         (int)((char *)save)[0],
         len));

    if (len>0) {
        register char *saveout;

        /* points to the slot for the next char to save */
        saveout = & (((char *)save)[1]) + ((char *)save)[0];

        /* len can only be 0 1 or 2 */
        switch(len) {
        case 2: *saveout++ = *inptr++;
        case 1: *saveout++ = *inptr++;
        }
        ((char *)save)[0]+=len;
    }

    d(printf("mode = %d\nc1 = %c\nc2 = %c\n",
         (int)((char *)save)[0],
         (int)((char *)save)[1],
         (int)((char *)save)[2]));

    return outptr-out;
}


/**
 * base64_decode_step: decode a chunk of base64 encoded data
 * @in: input stream
 * @len: max length of data to decode
 * @out: output stream
 * @state: holds the number of bits that are stored in @save
 * @save: leftover bits that have not yet been decoded
 *
 * Decodes a chunk of base64 encoded data
 **/
int
base64_decode_step(unsigned char *in, int len, unsigned char *out, int *state, unsigned int *save)
{
    register unsigned char *inptr, *outptr;
    unsigned char *inend, c;
    register unsigned int v;
    int i;

    inend = in+len;
    outptr = out;

    /* convert 4 base64 bytes to 3 normal bytes */
    v=*save;
    i=*state;
    inptr = in;
    while (inptr<inend) {
        c = camel_mime_base64_rank[*inptr++];
        if (c != 0xff) {
            v = (v<<6) | c;
            i++;
            if (i==4) {
                *outptr++ = v>>16;
                *outptr++ = v>>8;
                *outptr++ = v;
                i=0;
            }
        }
    }

    *save = v;
    *state = i;

    /* quick scan back for '=' on the end somewhere */
    /* fortunately we can drop 1 output char for each trailing = (upto 2) */
    i=2;
    while (inptr>in && i) {
        inptr--;
        if (camel_mime_base64_rank[*inptr] != 0xff) {
            if (*inptr == '=')
                outptr--;
            i--;
        }
    }

    /* if i!= 0 then there is a truncation error! */
    return outptr-out;
}


/**
 * uudecode_step: uudecode a chunk of data
 * @in: input stream
 * @len: max length of data to decode ( normally strlen(in) ??)
 * @out: output stream
 * @state: holds the number of bits that are stored in @save
 * @save: leftover bits that have not yet been decoded
 * @uulen: holds the value of the length-char which is used to calculate
 *         how many more chars need to be decoded for that 'line'
 *
 * uudecodes a chunk of data. Assumes the "begin <mode> <file name>" line
 * has been stripped off.
 **/
int
uudecode_step (unsigned char *in, int len, unsigned char *out, int *state, guint32 *save, char *uulen)
{
    register unsigned char *inptr, *outptr;
    unsigned char *inend, ch;
    register guint32 saved;
    gboolean last_was_eoln;
    int i;

    if (*uulen <= 0)
        last_was_eoln = TRUE;
    else
        last_was_eoln = FALSE;
    
    inend = in + len;
    outptr = out;
    saved = *save;
    i = *state;
    inptr = in;
    while (inptr < inend && *inptr) {
        if (*inptr == '\n' || last_was_eoln) {
            if (last_was_eoln) {
                *uulen = CAMEL_UUDECODE_CHAR (*inptr);
                last_was_eoln = FALSE;
            } else {
                last_was_eoln = TRUE;
            }

            inptr++;
            continue;
        }

        ch = *inptr++;
        
        if (*uulen > 0) {
            /* save the byte */
            saved = (saved << 8) | ch;
            i++;
            if (i == 4) {
                /* convert 4 uuencoded bytes to 3 normal bytes */
                unsigned char b0, b1, b2, b3;

                b0 = saved >> 24;
                b1 = saved >> 16 & 0xff;
                b2 = saved >> 8 & 0xff;
                b3 = saved & 0xff;

                if (*uulen >= 3) {
                    *outptr++ = CAMEL_UUDECODE_CHAR (b0) << 2 | CAMEL_UUDECODE_CHAR (b1) >> 4;
                    *outptr++ = CAMEL_UUDECODE_CHAR (b1) << 4 | CAMEL_UUDECODE_CHAR (b2) >> 2;
                        *outptr++ = CAMEL_UUDECODE_CHAR (b2) << 6 | CAMEL_UUDECODE_CHAR (b3);
                } else {
                    if (*uulen >= 1) {
                        *outptr++ = CAMEL_UUDECODE_CHAR (b0) << 2 | CAMEL_UUDECODE_CHAR (b1) >> 4;
                    }
                    if (*uulen >= 2) {
                        *outptr++ = CAMEL_UUDECODE_CHAR (b1) << 4 | CAMEL_UUDECODE_CHAR (b2) >> 2;
                    }
                }

                i = 0;
                saved = 0;
                *uulen -= 3;
            }
        } else {
            break;
        }
    }

    *save = saved;
    *state = i;

    return outptr - out;
}

/* complete qp encoding */
int
quoted_encode_close(unsigned char *in, int len, unsigned char *out, int *state, int *save)
{
    register unsigned char *outptr = out;
    int last;

    if (len>0)
        outptr += quoted_encode_step(in, len, outptr, state, save);

    last = *state;
    if (last != -1) {
        /* space/tab must be encoded if it's the last character on
           the line */
        if (is_qpsafe(last) && last!=' ' && last!=9) {
            *outptr++ = last;
        } else {
            *outptr++ = '=';
            *outptr++ = tohex[(last>>4) & 0xf];
            *outptr++ = tohex[last & 0xf];
        }
    }

    *save = 0;
    *state = -1;

    return outptr-out;
}

/* perform qp encoding, initialise state to -1 and save to 0 on first invocation */
int
quoted_encode_step (unsigned char *in, int len, unsigned char *out, int *statep, int *save)
{
    register guchar *inptr, *outptr, *inend;
    guchar c;
    register int sofar = *save;  /* keeps track of how many chars on a line */
    register int last = *statep; /* keeps track if last char to end was a space cr etc */
    
    inptr = in;
    inend = in + len;
    outptr = out;
    while (inptr < inend) {
        c = *inptr++;
        if (c == '\r') {
            if (last != -1) {
                *outptr++ = '=';
                *outptr++ = tohex[(last >> 4) & 0xf];
                *outptr++ = tohex[last & 0xf];
                sofar += 3;
            }
            last = c;
        } else if (c == '\n') {
            if (last != -1 && last != '\r') {
                *outptr++ = '=';
                *outptr++ = tohex[(last >> 4) & 0xf];
                *outptr++ = tohex[last & 0xf];
            }
            *outptr++ = '\n';
            sofar = 0;
            last = -1;
        } else {
            if (last != -1) {
                if (is_qpsafe(last)) {
                    *outptr++ = last;
                    sofar++;
                } else {
                    *outptr++ = '=';
                    *outptr++ = tohex[(last >> 4) & 0xf];
                    *outptr++ = tohex[last & 0xf];
                    sofar += 3;
                }
            }
            
            if (is_qpsafe(c)) {
                if (sofar > 74) {
                    *outptr++ = '=';
                    *outptr++ = '\n';
                    sofar = 0;
                }
                
                /* delay output of space char */
                if (c==' ' || c=='\t') {
                    last = c;
                } else {
                    *outptr++ = c;
                    sofar++;
                    last = -1;
                }
            } else {
                if (sofar > 72) {
                    *outptr++ = '=';
                    *outptr++ = '\n';
                    sofar = 3;
                } else
                    sofar += 3;
                
                *outptr++ = '=';
                *outptr++ = tohex[(c >> 4) & 0xf];
                *outptr++ = tohex[c & 0xf];
                last = -1;
            }
        }
    }
    *save = sofar;
    *statep = last;
    
    return (outptr - out);
}

/*
  FIXME: this does not strip trailing spaces from lines (as it should, rfc 2045, section 6.7)
  Should it also canonicalise the end of line to CR LF??

  Note: Trailing rubbish (at the end of input), like = or =x or =\r will be lost.
*/ 

int
quoted_decode_step(unsigned char *in, int len, unsigned char *out, int *savestate, int *saveme)
{
    register unsigned char *inptr, *outptr;
    unsigned char *inend, c;
    int state, save;

    inend = in+len;
    outptr = out;

    d(printf("quoted-printable, decoding text '%.*s'\n", len, in));

    state = *savestate;
    save = *saveme;
    inptr = in;
    while (inptr<inend) {
        switch (state) {
        case 0:
            while (inptr<inend) {
                c = *inptr++;
                if (c=='=') { 
                    state = 1;
                    break;
                }
#ifdef CANONICALISE_EOL
                /*else if (c=='\r') {
                    state = 3;
                } else if (c=='\n') {
                    *outptr++ = '\r';
                    *outptr++ = c;
                    } */
#endif
                else {
                    *outptr++ = c;
                }
            }
            break;
        case 1:
            c = *inptr++;
            if (c=='\n') {
                /* soft break ... unix end of line */
                state = 0;
            } else {
                save = c;
                state = 2;
            }
            break;
        case 2:
            c = *inptr++;
            if (isxdigit(c) && isxdigit(save)) {
                c = toupper(c);
                save = toupper(save);
                *outptr++ = (((save>='A'?save-'A'+10:save-'0')&0x0f) << 4)
                    | ((c>='A'?c-'A'+10:c-'0')&0x0f);
            } else if (c=='\n' && save == '\r') {
                /* soft break ... canonical end of line */
            } else {
                /* just output the data */
                *outptr++ = '=';
                *outptr++ = save;
                *outptr++ = c;
            }
            state = 0;
            break;
#ifdef CANONICALISE_EOL
        case 3:
            /* convert \r -> to \r\n, leaves \r\n alone */
            c = *inptr++;
            if (c=='\n') {
                *outptr++ = '\r';
                *outptr++ = c;
            } else {
                *outptr++ = '\r';
                *outptr++ = '\n';
                *outptr++ = c;
            }
            state = 0;
            break;
#endif
        }
    }

    *savestate = state;
    *saveme = save;

    return outptr-out;
}

/*
  this is for the "Q" encoding of international words,
  which is slightly different than plain quoted-printable (mainly by allowing 0x20 <> _)
*/
static int
quoted_decode(const unsigned char *in, int len, unsigned char *out)
{
    register const unsigned char *inptr;
    register unsigned char *outptr;
    unsigned const char *inend;
    unsigned char c, c1;
    int ret = 0;

    inend = in+len;
    outptr = out;

    d(printf("decoding text '%.*s'\n", len, in));

    inptr = in;
    while (inptr<inend) {
        c = *inptr++;
        if (c=='=') {
            /* silently ignore truncated data? */
            if (inend-in>=2) {
                c = toupper(*inptr++);
                c1 = toupper(*inptr++);
                *outptr++ = (((c>='A'?c-'A'+10:c-'0')&0x0f) << 4)
                    | ((c1>='A'?c1-'A'+10:c1-'0')&0x0f);
            } else {
                ret = -1;
                break;
            }
        } else if (c=='_') {
            *outptr++ = 0x20;
        } else if (c==' ' || c==0x09) {
            /* FIXME: this is an error! ignore for now ... */
            ret = -1;
            break;
        } else {
            *outptr++ = c;
        }
    }
    if (ret==0) {
        return outptr-out;
    }
    return -1;
}

/* rfc2047 version of quoted-printable */
/* safemask is the mask to apply to the camel_mime_special_table to determine what
   characters can safely be included without encoding */
static int
quoted_encode(const unsigned char *in, int len, unsigned char *out, unsigned short safemask)
{
    register const unsigned char *inptr, *inend;
    unsigned char *outptr;
    unsigned char c;

    inptr = in;
    inend = in + len;
    outptr = out;
    while (inptr < inend) {
        c = *inptr++;
        if (c==' ') {
            *outptr++ = '_';
        } else if (camel_mime_special_table[c] & safemask) {
            *outptr++ = c;
        } else {
            *outptr++ = '=';
            *outptr++ = tohex[(c >> 4) & 0xf];
            *outptr++ = tohex[c & 0xf];
        }
    }

    d(printf("encoding '%.*s' = '%.*s'\n", len, in, outptr-out, out));

    return (outptr - out);
}


static void
header_decode_lwsp(const char **in)
{
    const char *inptr = *in;
    char c;

    d2(printf("is ws: '%s'\n", *in));

    while (is_lwsp(*inptr) || (*inptr =='(' && *inptr != '\0')) {
        while (is_lwsp(*inptr) && inptr != '\0') {
            d2(printf("(%c)", *inptr));
            inptr++;
        }
        d2(printf("\n"));

        /* check for comments */
        if (*inptr == '(') {
            int depth = 1;
            inptr++;
            while (depth && (c=*inptr) && *inptr != '\0') {
                if (c=='\\' && inptr[1]) {
                    inptr++;
                } else if (c=='(') {
                    depth++;
                } else if (c==')') {
                    depth--;
                }
                inptr++;
            }
        }
    }
    *in = inptr;
}

/* decode rfc 2047 encoded string segment */
static char *
rfc2047_decode_word(const char *in, int len)
{
    const char *inptr = in+2;
    const char *inend = in+len-2;
    char *encname;
    int tmplen;
    int ret;
    char *decword = NULL;
    char *decoded = NULL;
    char *outbase = NULL;
    char *inbuf, *outbuf;
    int inlen, outlen;
    iconv_t ic;

    d(printf("rfc2047: decoding '%.*s'\n", len, in));

    /* just make sure we're not passed shit */
    if (len<7
        || !(in[0]=='=' && in[1]=='?' && in[len-1]=='=' && in[len-2]=='?')) {
        d(printf("invalid\n"));
        return NULL;
    }

    inptr = memchr(inptr, '?', inend-inptr);
    if (inptr!=NULL
        && inptr<inend+2
        && inptr[2]=='?') {
        d(printf("found ?, encoding is '%c'\n", inptr[0]));
        inptr++;
        tmplen = inend-inptr-2;
        decword = alloca(tmplen); /* this will always be more-than-enough room */
        switch(toupper(inptr[0])) {
        case 'Q':
            inlen = quoted_decode(inptr+2, tmplen, decword);
            break;
        case 'B': {
            int state=0;
            unsigned int save=0;
            inlen = base64_decode_step((char *)inptr+2, tmplen, decword, &state, &save);
            /* if state != 0 then error? */
            break;
        }
        }
        d(printf("The encoded length = %d\n", inlen));
        if (inlen>0) {
            /* yuck, all this snot is to setup iconv! */
            tmplen = inptr-in-3;
            encname = alloca(tmplen+1);
            encname[tmplen]=0;
            memcpy(encname, in+2, tmplen);

            inbuf = decword;

            outlen = inlen*6+16;
            outbase = alloca(outlen);
            outbuf = outbase;

            /* TODO: Should this cache iconv converters? */
            ic = iconv_open("UTF-8", encname);
            if (ic != (iconv_t)-1) {
                ret = iconv(ic, (const char **)&inbuf, &inlen, &outbuf, &outlen);
                if (ret>=0) {
                    iconv(ic, NULL, 0, &outbuf, &outlen);
                    *outbuf = 0;
                    decoded = g_strdup(outbase);
                }
                iconv_close(ic);
            } else {
                w(g_warning("Cannot decode charset, header display may be corrupt: %s: %s", encname, strerror(errno)));
                /* TODO: Should this do this, or just leave the encoded strings? */
                decword[inlen] = 0;
                decoded = g_strdup(decword);
            }
        }
    }

    d(printf("decoded '%s'\n", decoded));

    return decoded;
}

/* grrr, glib should have this ! */
static GString *
g_string_append_len(GString *st, const char *s, int l)
{
    char *tmp;

    tmp = alloca(l+1);
    tmp[l]=0;
    memcpy(tmp, s, l);
    return g_string_append(st, tmp);
}

/* ok, a lot of mailers are BROKEN, and send iso-latin1 encoded
   headers, when they should just be sticking to US-ASCII
   according to the rfc's.  Anyway, since the conversion to utf-8
   is trivial, just do it here without iconv */
static GString *
append_latin1(GString *out, const char *in, int len)
{
    unsigned int c;

    while (len) {
        c = (unsigned int)*in++;
        len--;
        if (c & 0x80) {
            out = g_string_append_c(out, 0xc0 | ((c>>6) & 0x3));        /* 110000xx */
            out = g_string_append_c(out, 0x80 | (c&0x3f));  /* 10xxxxxx */
        } else {
            out = g_string_append_c(out, c);
        }
    }
    return out;
}

/* decodes a simple text, rfc822 */
static char *
header_decode_text (const char *in, int inlen)
{
    GString *out;
    char *inptr, *inend, *start;
    char *decoded;
    unsigned char lastc = 0;
    int wasdword = FALSE;

    out = g_string_new ("");
    start = inptr = (char *) in;
    inend = inptr + inlen;
    
    while (inptr && inptr < inend) {
        unsigned char c = *inptr++;
        
        if (is_lwsp(c)) {
            char *word, *dword;
            guint len;
            
            len = inptr - start - 1;
            word = start;
            
            dword = rfc2047_decode_word (word, len);

            if (dword) {
                if (!wasdword && lastc)
                    g_string_append_c(out, lastc);
                    
                g_string_append (out, dword);
                g_free (dword);
                lastc = c;
                wasdword = TRUE;
            } else {
                if (lastc)
                    g_string_append_c(out, lastc);
                out = append_latin1 (out, word, len);
                lastc = c;
                wasdword = FALSE;
            }
                        
            start = inptr;
        }
    }
    
    if (inptr - start) {
        char *word, *dword;
        guint len;
        
        len = inptr - start;
        word = start;
        
        dword = rfc2047_decode_word (word, len);
        
        if (dword) {
            if (!wasdword && lastc)
                g_string_append_c(out, lastc);
            g_string_append (out, dword);
            g_free (dword);
        } else {
            if (lastc)
                g_string_append_c(out, lastc);
            out = g_string_append_len (out, word, len);
        }
    }
    
    decoded = out->str;
    g_string_free (out, FALSE);
    
    return decoded;
}

#if 0     /* This is broken */

/* so in what way is it broken? */

/* decodes a simple text, rfc822 */
static char *
header_decode_text(const char *in, int inlen)
{
    GString *out;
    const char *inptr = in;
    const char *inend = in+inlen;
    char *encstart, *encend;
    char *decword;

    out = g_string_new("");
    while ( (encstart = strstr(inptr, "=?"))
        && (encend = strstr(encstart+2, "?=")) ) {

        decword = rfc2047_decode_word(encstart, encend-encstart+2);
        if (decword) {
            out = g_string_append_len(out, inptr, encstart-inptr);
            out = g_string_append_len(out, decword, strlen(decword));
            g_free (decword);
        } else {
            out = append_latin1(out, inptr, encend-inptr+2);
        }
        inptr = encend+2;
    }
    out = append_latin1(out, inptr, inend-inptr);

    encstart = out->str;
    g_string_free(out, FALSE);

    return encstart;
}
#endif

char *
header_decode_string(const char *in)
{
    if (in == NULL)
        return NULL;
    return header_decode_text(in, strlen(in));
}

/* how long a sequence of pre-encoded words should be less than, to attempt to 
   fit into a properly folded word.  Only a guide. */
#define CAMEL_FOLD_PREENCODED (24)

/* FIXME: needs a way to cache iconv opens for different charsets? */
static void
rfc2047_encode_word(GString *outstring, const char *in, int len, const char *type, unsigned short safemask)
{
    iconv_t ic = (iconv_t *)-1;
    char *buffer, *out, *ascii;
    size_t inlen, outlen, enclen, bufflen;
    const char *inptr, *p;
    int first = 1;

    d(printf("Converting [%d] '%.*s' to %s\n", len, len, in, type));

    /* convert utf8->encoding */
    bufflen = len*6+16;
    buffer = alloca(bufflen);
    inlen = len;
    inptr = in;

    ascii = alloca(bufflen);

    if (strcasecmp(type, "UTF-8") != 0)
        ic = iconv_open(type, "UTF-8");

    while (inlen) {
        int convlen, i, proclen;

        /* break up words into smaller bits, what we really want is encoded + overhead < 75,
           but we'll just guess what that means in terms of input chars, and assume its good enough */

        out = buffer;
        outlen = bufflen;

        if (ic == (iconv_t) -1) {
            /* native encoding case, the easy one (?) */
            /* we work out how much we can convert, and still be in length */
            /* proclen will be the result of input characters that we can convert, to the nearest
               (approximated) valid utf8 char */
            convlen = 0;
            proclen = 0;
            p = inptr;
            i = 0;
            while (p < (in+len) && convlen < (75 - strlen("=?utf-8?q??="))) {
                unsigned char c = *p++;

                if (c >= 0xc0)
                    proclen = i;
                i++;
                if (c < 0x80)
                    proclen = i;
                if (camel_mime_special_table[c] & safemask)
                    convlen += 1;
                else
                    convlen += 3;
            }
            /* well, we probably have broken utf8, just copy it anyway what the heck */
            if (proclen == 0) {
                w(g_warning("Appear to have truncated utf8 sequence"));
                proclen = inlen;
            }
            memcpy(out, inptr, proclen);
            inptr += proclen;
            inlen -= proclen;
            out += proclen;
        } else {
            /* well we could do similar, but we can't (without undue effort), we'll just break it up into
               hopefully-small-enough chunks, and leave it at that */
            convlen = MIN(inlen, CAMEL_FOLD_PREENCODED);
            p = inptr;
            if (iconv(ic, &inptr, &convlen, &out, &outlen) == -1) {
                w(g_warning("Conversion problem: conversion truncated: %s", strerror(errno)));
                /* blah, we include it anyway, better than infinite loop ... */
                inptr = p + convlen;
            } else {
                /* make sure we flush out any shift state */
                iconv(ic, NULL, 0, &out, &outlen);
            }
            inlen -= (inptr - p);
        }

        enclen = out-buffer;

        /* create token */
        out = ascii;
        if (first)
            first = 0;
        else
            *out++ = ' ';
        out += sprintf(out, "=?%s?Q?", type);
        out += quoted_encode(buffer, enclen, out, safemask);
        sprintf(out, "?=");

        d(printf("converted part = %s\n", ascii));

        g_string_append(outstring, ascii);
    }

    if (ic == (iconv_t) -1) {
        iconv_close(ic);
    }
}


/* TODO: Should this worry about quotes?? */
char *
header_encode_string(const unsigned char *in)
{
    GString *out;
    const unsigned char *inptr = in, *start;
    int encoding;
    char *outstr;

    if (in == NULL)
        return NULL;

    /* do a quick us-ascii check (the common case?) */
    while (*inptr) {
        if (*inptr > 127)
            break;
        inptr++;
    }
    if (*inptr == 0)
        return g_strdup(in);

    /* This gets each word out of the input, and checks to see what charset
       can be used to encode it. */
    /* TODO: Work out when to merge subsequent words, or across word-parts */
    out = g_string_new("");
    inptr = in;
    encoding = 0;
    start = inptr;
    while (inptr && *inptr) {
        unicode_char_t c;
        const char *newinptr;
        newinptr = unicode_get_utf8(inptr, &c);
        if (newinptr == NULL) {
            w(g_warning("Invalid UTF-8 sequence encountered (pos %d, char '%c'): %s", (inptr-in), inptr[0], in));
            inptr++;
            continue;
        }
        inptr = newinptr;
        if (unicode_isspace(c)) {
            /* we've reached the end of a 'word' */
            switch (encoding) {
            case 0:
                out = g_string_append_len(out, start, inptr-start);
                break;
            case 1:
                rfc2047_encode_word(out, start, inptr-start-1, "ISO-8859-1", IS_ESAFE);
                out = g_string_append_c (out, c);
                break;
            case 2:
                rfc2047_encode_word(out, start, inptr-start-1,
                            camel_charset_best(start, inptr-start-1), IS_ESAFE);
                out = g_string_append_c(out, c);
                break;
            }
            start = inptr;
            encoding = 0;
        } else if (c > 127 && c < 256) {
            encoding = MAX(encoding, 1);
        } else if (c >= 256) {
            encoding = MAX(encoding, 2);
        }
    }
    if (inptr-start) {
        switch (encoding) {
        case 0:
            out = g_string_append_len(out, start, inptr-start);
            break;
        case 1:
            rfc2047_encode_word(out, start, inptr-start, "ISO-8859-1", IS_ESAFE);
            break;
        case 2:
            rfc2047_encode_word(out, start, inptr-start,
                        camel_charset_best(start, inptr-start-1), IS_ESAFE);
            break;
        }
    }
    outstr = out->str;
    g_string_free(out, FALSE);
    return outstr;
}

/* apply quoted-string rules to a string */
static void
quote_word(GString *out, gboolean do_quotes, const char *start, int len)
{
    int i, c;

    /* TODO: What about folding on long lines? */
    if (do_quotes)
        g_string_append_c(out, '"');
    for (i=0;i<len;i++) {
        c = *start++;
        if (c == '\"' || c=='\\' || c=='\r')
            g_string_append_c(out, '\\');
        g_string_append_c(out, c);
    }
    if (do_quotes)
        g_string_append_c(out, '"');
}

/* incrementing possibility for the word type */
enum _phrase_word_t {
    WORD_ATOM,
    WORD_QSTRING,
    WORD_2047
};

struct _phrase_word {
    const unsigned char *start, *end;
    enum _phrase_word_t type;
    int encoding;
};

/* split the input into words
   with info about each word
   merge common word types
   clean up
*/
/* encodes a phrase sequence (different quoting/encoding rules to strings) */
char *
header_encode_phrase(const unsigned char *in)
{
    GString *out;
    const unsigned char *inptr = in, *start, *last;
    int encoding;
    char *outstr;
    struct _phrase_word *word, *next;
    enum _phrase_word_t type;
    GList *words = NULL, *wordl, *nextl;
    int count;

    if (in == NULL)
        return NULL;

    out = g_string_new("");

#if 0
    {
        int i;

        printf("encoding phrase: %s\n", in);
        for (i=0;in[i];i++) {
            printf(" %02x", in[i]);
            if (((i) & 15) == 15)
                printf("\n");
        }
        printf("\n");
    }
#endif

    /* break the input into words */
    type = WORD_ATOM;
    count = 0;
    last = inptr;
    start = inptr;
    encoding = 0;
    while (inptr && *inptr) {
        unicode_char_t c;
        const char *newinptr;
        newinptr = unicode_get_utf8(inptr, &c);
        if (newinptr == NULL) {
            w(g_warning("Invalid UTF-8 sequence encountered (pos %d, char '%c'): %s", (inptr-in), inptr[0], in));
            inptr++;
            continue;
        }
        inptr = newinptr;
        /* save this word out, multiple whitespace is not explicitly counted (?) */
        if (unicode_isspace(c)) {
            if (count > 0) {
                word = g_malloc0(sizeof(*word));
                word->start = start;
                word->end = last;
                word->type = type;
                word->encoding = encoding;
                words = g_list_append(words, word);
                count = 0;
            }
            start = inptr;
            type = WORD_ATOM;
            encoding = 0;
        } else {
            count++;
            if (c<128) {
                if (!is_atom(c))
                    type = MAX(type, WORD_QSTRING);
            } else if (c>127 && c < 256) {
                type = WORD_2047;
                encoding = MAX(encoding, 1);
            } else if (c >=256) {
                type = WORD_2047;
                encoding = MAX(encoding, 2);
            }
        }
        last = inptr;
    }
    if (count > 0) {
        word = g_malloc0(sizeof(*word));
        word->start = start;
        word->end = last;
        word->type = type;
        word->encoding = encoding;
        words = g_list_append(words, word);
    }

    /* now scan the list, checking for words of similar types that can be merged */
    wordl = words;
    while (wordl) {
        word = wordl->data;
        /* leave atoms as atoms (unless they're surrounded by quoted words??) */
        if (word->type != WORD_ATOM) {
            nextl = g_list_next(wordl);
            while (nextl) {
                next = nextl->data;
                /* merge nodes of the same type AND we are not creating too long a string */
                if (word->type == next->type) {
                    if (next->end - word->start < CAMEL_FOLD_PREENCODED) {
                        word->end = next->end;
                        words = g_list_remove_link(words, nextl);
                        g_free(next);
                        nextl = g_list_next(wordl);
                    } else {
                        /* if it is going to be too long, make sure we include the separating whitespace */
                        word->end = next->start;
                        break;
                    }
                } else {
                    break;
                }
            }
        }
        wordl = g_list_next(wordl);
    }

    /* output words now with spaces between them */
    wordl = words;
    while (wordl) {
        word = wordl->data;
        switch (word->type) {
        case WORD_ATOM:
            out = g_string_append_len(out, word->start, word->end-word->start);
            break;
        case WORD_QSTRING:
            quote_word(out, TRUE, word->start, word->end-word->start);
            break;
        case WORD_2047:
            if (word->encoding == 1)
                rfc2047_encode_word(out, word->start, word->end-word->start, "ISO-8859-1", IS_PSAFE);
            else
                rfc2047_encode_word(out, word->start, word->end-word->start,
                            camel_charset_best(word->start, word->end-word->start), IS_PSAFE);
            break;
        }

        /* copy across the right number of spaces between words */
        nextl = g_list_next(wordl);
        if (nextl) {
            int i;
            next = nextl->data;
            /* if they are adjacent, it means we already had the spaces encoded internally,
               so now we just need to output 1 space */
            i=next->start-word->end;
            if (i==0)
                i=1;
            for (;i>0;i--)
                out = g_string_append_c(out, ' ');
        }

        g_free(word);
        wordl = g_list_next(wordl);
    }
    /* and we no longer need the list */
    g_list_free(words);

    outstr = out->str;
    g_string_free(out, FALSE);
    return outstr;
}


/* these are all internal parser functions */

static char *
decode_token(const char **in)
{
    const char *inptr = *in;
    const char *start;

    header_decode_lwsp(&inptr);
    start = inptr;
    while (is_ttoken(*inptr))
        inptr++;
    if (inptr>start) {
        *in = inptr;
        return g_strndup(start, inptr-start);
    } else {
        return NULL;
    }
}

char *
header_token_decode(const char *in)
{
    if (in == NULL)
        return NULL;

    return decode_token(&in);
}

/*
   <"> * ( <any char except <"> \, cr  /  \ <any char> ) <">
*/
static char *
header_decode_quoted_string(const char **in)
{
    const char *inptr = *in;
    char *out = NULL, *outptr;
    int outlen;
    int c;

    header_decode_lwsp(&inptr);
    if (*inptr == '"') {
        const char *intmp;
        int skip = 0;

        /* first, calc length */
        inptr++;
        intmp = inptr;
        while ( (c = *intmp++) && c!= '"') {
            if (c=='\\' && *intmp) {
                intmp++;
                skip++;
            }
        }
        outlen = intmp-inptr-skip;
        out = outptr = g_malloc(outlen+1);
        while ( (c = *inptr++) && c!= '"') {
            if (c=='\\' && *inptr) {
                c = *inptr++;
            }
            *outptr++ = c;
        }
        *outptr = 0;
    }
    *in = inptr;
    return out;
}

static char *
header_decode_atom(const char **in)
{
    const char *inptr = *in, *start;

    header_decode_lwsp(&inptr);
    start = inptr;
    while (is_atom(*inptr))
        inptr++;
    *in = inptr;
    if (inptr > start)
        return g_strndup(start, inptr-start);
    else
        return NULL;
}

static char *
header_decode_word(const char **in)
{
    const char *inptr = *in;

    header_decode_lwsp(&inptr);
    if (*inptr == '"') {
        *in = inptr;
        return header_decode_quoted_string(in);
    } else {
        *in = inptr;
        return header_decode_atom(in);
    }
}

static char *
header_decode_value(const char **in)
{
    const char *inptr = *in;

    header_decode_lwsp(&inptr);
    if (*inptr == '"') {
        d(printf("decoding quoted string\n"));
        return header_decode_quoted_string(in);
    } else if (is_ttoken(*inptr)) {
        d(printf("decoding token\n"));
        /* this may not have the right specials for all params? */
        return decode_token(in);
    }
    return NULL;
}

/* shoudl this return -1 for no int? */
static int
header_decode_int(const char **in)
{
    const char *inptr = *in;
    int c, v=0;

    header_decode_lwsp(&inptr);
    while ( (c=*inptr++ & 0xff)
        && isdigit(c) ) {
        v = v*10+(c-'0');
    }
    *in = inptr-1;
    return v;
}

static int
header_decode_param(const char **in, char **paramp, char **valuep)
{
    const char *inptr = *in;
    char *param, *value=NULL;

    param = decode_token(&inptr);
    header_decode_lwsp(&inptr);
    if (*inptr == '=') {
        inptr++;
        value = header_decode_value(&inptr);
    }

    if (param && value) {
        *paramp = param;
        *valuep = value;
        *in = inptr;
        return 0;
    } else {
        g_free(param);
        g_free(value);
        return 1;
    }
}

char *
header_param(struct _header_param *p, const char *name)
{
    while (p && strcasecmp(p->name, name) != 0)
        p = p->next;
    if (p)
        return p->value;
    return NULL;
}

struct _header_param *
header_set_param(struct _header_param **l, const char *name, const char *value)
{
    struct _header_param *p = (struct _header_param *)l, *pn;

    while (p->next) {
        pn = p->next;
        if (!strcasecmp(pn->name, name)) {
            g_free(pn->value);
            if (value) {
                pn->value = g_strdup(value);
                return pn;
            } else {
                p->next = pn->next;
                g_free(pn);
                return NULL;
            }
        }
        p = pn;
    }

    if (value == NULL)
        return NULL;

    pn = g_malloc(sizeof(*pn));
    pn->next = 0;
    pn->name = g_strdup(name);
    pn->value = g_strdup(value);
    p->next = pn;

    return pn;
}

const char *
header_content_type_param(struct _header_content_type *t, const char *name)
{
    if (t==NULL)
        return NULL;
    return header_param(t->params, name);
}

void header_content_type_set_param(struct _header_content_type *t, const char *name, const char *value)
{
    header_set_param(&t->params, name, value);
}

/**
 * header_content_type_is:
 * @ct: A content type specifier, or #NULL.
 * @type: A type to check against.
 * @subtype: A subtype to check against, or "*" to match any subtype.
 * 
 * Returns #TRUE if the content type @ct is of type @type/@subtype.
 * The subtype of "*" will match any subtype.  If @ct is #NULL, then
 * it will match the type "text/plain".
 * 
 * Return value: #TRUE or #FALSE depending on the matching of the type.
 **/
int
header_content_type_is(struct _header_content_type *ct, const char *type, const char *subtype)
{
    /* no type == text/plain or text/"*" */
    if (ct==NULL || (ct->type == NULL && ct->subtype == NULL)) {
        return (!strcasecmp(type, "text")
            && (!strcasecmp(subtype, "plain")
                || !strcasecmp(subtype, "*")));
    }

    return (ct->type != NULL
        && (!strcasecmp(ct->type, type)
            && ((ct->subtype != NULL
             && !strcasecmp(ct->subtype, subtype))
            || !strcasecmp("*", subtype))));
}

void
header_param_list_free(struct _header_param *p)
{
    struct _header_param *n;

    while (p) {
        n = p->next;
        g_free(p->name);
        g_free(p->value);
        g_free(p);
        p = n;
    }
}

struct _header_content_type *
header_content_type_new(const char *type, const char *subtype)
{
    struct _header_content_type *t = g_malloc(sizeof(*t));

    t->type = g_strdup(type);
    t->subtype = g_strdup(subtype);
    t->params = NULL;
    t->refcount = 1;
    return t;
}

void
header_content_type_ref(struct _header_content_type *ct)
{
    if (ct)
        ct->refcount++;
}


void
header_content_type_unref(struct _header_content_type *ct)
{
    if (ct) {
        if (ct->refcount <= 1) {
            header_param_list_free(ct->params);
            g_free(ct->type);
            g_free(ct->subtype);
            g_free(ct);
        } else {
            ct->refcount--;
        }
    }
}

/* for decoding email addresses, canonically */
static char *
header_decode_domain(const char **in)
{
    const char *inptr = *in, *start;
    int go = TRUE;
    char *ret;
    GString *domain = g_string_new("");

                /* domain ref | domain literal */
    header_decode_lwsp(&inptr);
    while (go) {
        if (*inptr == '[') { /* domain literal */
            domain = g_string_append(domain, "[ ");
            inptr++;
            header_decode_lwsp(&inptr);
            start = inptr;
            while (is_dtext(*inptr)) {
                domain = g_string_append_c(domain, *inptr);
                inptr++;
            }
            if (*inptr == ']') {
                domain = g_string_append(domain, " ]");
                inptr++;
            } else {
                w(g_warning("closing ']' not found in domain: %s", *in));
            }
        } else {
            char *a = header_decode_atom(&inptr);
            if (a) {
                domain = g_string_append(domain, a);
                g_free(a);
            } else {
                w(g_warning("missing atom from domain-ref"));
                break;
            }
        }
        header_decode_lwsp(&inptr);
        if (*inptr == '.') { /* next sub-domain? */
            domain = g_string_append_c(domain, '.');
            inptr++;
            header_decode_lwsp(&inptr);
        } else
            go = FALSE;
    }

    *in = inptr;

    ret = domain->str;
    g_string_free(domain, FALSE);
    return ret;
}

static char *
header_decode_addrspec(const char **in)
{
    const char *inptr = *in;
    char *word;
    GString *addr = g_string_new("");

    header_decode_lwsp(&inptr);

    /* addr-spec */
    word = header_decode_word(&inptr);
    if (word) {
        addr = g_string_append(addr, word);
        header_decode_lwsp(&inptr);
        g_free(word);
        while (*inptr == '.' && word) {
            inptr++;
            addr = g_string_append_c(addr, '.');
            word = header_decode_word(&inptr);
            if (word) {
                addr = g_string_append(addr, word);
                header_decode_lwsp(&inptr);
                g_free(word);
            } else {
                w(g_warning("Invalid address spec: %s", *in));
            }
        }
        if (*inptr == '@') {
            inptr++;
            addr = g_string_append_c(addr, '@');
            word = header_decode_domain(&inptr);
            if (word) {
                addr = g_string_append(addr, word);
                g_free(word);
            } else {
                w(g_warning("Invalid address, missing domain: %s", *in));
            }
        } else {
            w(g_warning("Invalid addr-spec, missing @: %s", *in));
        }
    } else {
        w(g_warning("invalid addr-spec, no local part"));
    }

    /* FIXME: return null on error? */

    *in = inptr;
    word = addr->str;
    g_string_free(addr, FALSE);
    return word;
}

/*
  address:
   word *('.' word) @ domain |
   *(word) '<' [ *('@' domain ) ':' ] word *( '.' word) @ domain |

   1*word ':' [ word ... etc (mailbox, as above) ] ';'
 */

/* mailbox:
   word *( '.' word ) '@' domain
   *(word) '<' [ *('@' domain ) ':' ] word *( '.' word) @ domain
   */

static struct _header_address *
header_decode_mailbox(const char **in)
{
    const char *inptr = *in;
    char *pre;
    int closeme = FALSE;
    GString *addr;
    GString *name = NULL;
    struct _header_address *address = NULL;
    const char *comment = NULL;

    addr = g_string_new("");

    /* for each address */
    pre = header_decode_word(&inptr);
    header_decode_lwsp(&inptr);
    if (!(*inptr == '.' || *inptr == '@' || *inptr==',' || *inptr=='\0')) {
        /* ',' and '\0' required incase it is a simple address, no @ domain part (buggy writer) */
        name = g_string_new("");
        while (pre) {
            char *text, *last;

            /* perform internationalised decoding, and append */
            text = header_decode_string(pre);
            name = g_string_append(name, text);
            last = pre;
            g_free(text);

            pre = header_decode_word(&inptr);
            if (pre) {
                int l = strlen(last);
                int p = strlen(pre);
                /* dont append ' ' between sucsessive encoded words */
                if ((l>6 && last[l-2] == '?' && last[l-1] == '=')
                    && (p>6 && pre[0] == '=' && pre[1] == '?')) {
                    /* dont append ' ' */
                } else {
                    name = g_string_append_c(name, ' ');
                }
            }
            g_free(last);
        }
        header_decode_lwsp(&inptr);
        if (*inptr == '<') {
            closeme = TRUE;
            inptr++;
            header_decode_lwsp(&inptr);
            if (*inptr == '@') {
                while (*inptr == '@') {
                    inptr++;
                    header_decode_domain(&inptr);
                    header_decode_lwsp(&inptr);
                    if (*inptr == ',') {
                        inptr++;
                        header_decode_lwsp(&inptr);
                    }
                }
                if (*inptr == ':') {
                    inptr++;
                } else {
                    w(g_warning("broken route-address, missing ':': %s", *in));
                }
            }
            pre = header_decode_word(&inptr);
            header_decode_lwsp(&inptr);
        } else {
            w(g_warning("broken address? %s", *in));
        }
    }

    if (pre) {
        addr = g_string_append(addr, pre);
    } else {
        w(g_warning("No local-part for email address: %s", *in));
    }

    /* should be at word '.' localpart */
    while (*inptr == '.' && pre) {
        inptr++;
        g_free(pre);
        pre = header_decode_word(&inptr);
        if (pre) {
            addr = g_string_append_c(addr, '.');
            addr = g_string_append(addr, pre);
        }
        comment = inptr;
        header_decode_lwsp(&inptr);
    }
    g_free(pre);

    /* now at '@' domain part */
    if (*inptr == '@') {
        char *dom;

        inptr++;
        addr = g_string_append_c(addr, '@');
        comment = inptr;
        dom = header_decode_domain(&inptr);
        addr = g_string_append(addr, dom);
        g_free(dom);
    } else {
        w(g_warning("invalid address, no '@' domain part at %c: %s", *inptr, *in));
    }

    if (closeme) {
        header_decode_lwsp(&inptr);
        if (*inptr == '>') {
            inptr++;
        } else {
            w(g_warning("invalid route address, no closing '>': %s", *in));
        } 
    } else if (name == NULL && comment != NULL && inptr>comment) { /* check for comment after address */
        char *text, *tmp;
        const char *comstart, *comend;

        /* this is a bit messy, we go from the last known position, because
           decode_domain/etc skip over any comments on the way */
        /* FIXME: This wont detect comments inside the domain itself,
           but nobody seems to use that feature anyway ... */

        d(printf("checking for comment from '%s'\n", comment));

        comstart = strchr(comment, '(');
        if (comstart) {
            comstart++;
            header_decode_lwsp(&inptr);
            comend = inptr-1;
            while (comend > comstart && comend[0] != ')')
                comend--;
            
            if (comend > comstart) {
                d(printf("  looking at subset '%.*s'\n", comend-comstart, comstart));
                tmp = g_strndup(comstart, comend-comstart);
                text = header_decode_string(tmp);
                name = g_string_new(text);
                g_free(tmp);
                g_free(text);
            }
        }
    }

    *in = inptr;

    if (addr->len > 0) {
        address = header_address_new_name(name?name->str:"", addr->str);
    }

    g_string_free(addr, TRUE);
    if (name)
        g_string_free(name, TRUE);

    d(printf("got mailbox: %s\n", addr->str));
    return address;
}

static struct _header_address *
header_decode_address(const char **in)
{
    const char *inptr = *in;
    char *pre;
    GString *group = g_string_new("");
    struct _header_address *addr = NULL, *member;

    /* pre-scan, trying to work out format, discard results */
    header_decode_lwsp(&inptr);
    while ( (pre = header_decode_word(&inptr)) ) {
        group = g_string_append(group, pre);
        group = g_string_append(group, " ");
        g_free(pre);
    }
    header_decode_lwsp(&inptr);
    if (*inptr == ':') {
        d(printf("group detected: %s\n", group->str));
        addr = header_address_new_group(group->str);
        /* that was a group spec, scan mailbox's */
        inptr++;
        /* FIXME: check rfc 2047 encodings of words, here or above in the loop */
        header_decode_lwsp(&inptr);
        if (*inptr != ';') {
            int go = TRUE;
            do {
                member = header_decode_mailbox(&inptr);
                if (member)
                    header_address_add_member(addr, member);
                header_decode_lwsp(&inptr);
                if (*inptr == ',')
                    inptr++;
                else
                    go = FALSE;
            } while (go);
            if (*inptr == ';') {
                inptr++;
            } else {
                w(g_warning("Invalid group spec, missing closing ';': %s", *in));
            }
        } else {
            inptr++;
        }
        *in = inptr;
    } else {
        addr = header_decode_mailbox(in);
    }

    g_string_free(group, TRUE);

    return addr;
}

static char *
header_msgid_decode_internal(const char **in)
{
    const char *inptr = *in;
    char *msgid = NULL;

    d(printf("decoding Message-ID: '%s'\n", *in));

    header_decode_lwsp(&inptr);
    if (*inptr == '<') {
        inptr++;
        header_decode_lwsp(&inptr);
        msgid = header_decode_addrspec(&inptr);
        if (msgid) {
            header_decode_lwsp(&inptr);
            if (*inptr == '>') {
                inptr++;
            } else {
                w(g_warning("Missing closing '>' on message id: %s", *in));
            }
        } else {
            w(g_warning("Cannot find message id in: %s", *in));
        }
    } else {
        w(g_warning("missing opening '<' on message id: %s", *in));
    }
    *in = inptr;

    return msgid;
}

char *
header_msgid_decode(const char *in)
{
    if (in == NULL)
        return NULL;

    return header_msgid_decode_internal(&in);
}

void
header_references_list_append_asis(struct _header_references **list, char *ref)
{
    struct _header_references *w = (struct _header_references *)list, *n;
    while (w->next)
        w = w->next;
    n = g_malloc(sizeof(*n));
    n->id = ref;
    n->next = 0;
    w->next = n;
}

int
header_references_list_size(struct _header_references **list)
{
    int count = 0;
    struct _header_references *w = *list;
    while (w) {
        count++;
        w = w->next;
    }
    return count;
}

void
header_references_list_clear(struct _header_references **list)
{
    struct _header_references *w = *list, *n;
    while (w) {
        n = w->next;
        g_free(w->id);
        g_free(w);
        w = n;
    }
    *list = NULL;
}

/* generate a list of references, from most recent up */
struct _header_references *
header_references_decode(const char *in)
{
    const char *inptr = in;
    struct _header_references *head = NULL, *node;
    char *id, *word;

    if (in == NULL || in[0] == '\0')
        return NULL;

    while (*inptr) {
        header_decode_lwsp(&inptr);
        if (*inptr == '<') {
            id = header_msgid_decode_internal(&inptr);
            if (id) {
                node = g_malloc(sizeof(*node));
                node->next = head;
                head = node;
                node->id = id;
            }
        } else {
            word = header_decode_word(&inptr);
            if (word)
                g_free (word);
            else if (*inptr != '\0')
                inptr++; /* Stupid mailer tricks */
        }
    }

    return head;
}

struct _header_references *
header_references_dup(const struct _header_references *list)
{
    struct _header_references *new = NULL, *tmp;

    while (list) {
        tmp = g_new(struct _header_references, 1);
        tmp->next = new;
        tmp->id = g_strdup(list->id);
        new = tmp;
        list = list->next;
    }
    return new;
}

struct _header_address *
header_mailbox_decode(const char *in)
{
    if (in == NULL)
        return NULL;

    return header_decode_mailbox(&in);
}

struct _header_address *
header_address_decode(const char *in)
{
    const char *inptr = in, *last;
    struct _header_address *list = NULL, *addr;

    d(printf("decoding To: '%s'\n", in));

    if (in == NULL)
        return NULL;

    do {
        last = inptr;
        addr = header_decode_address(&inptr);
        if (addr)
            header_address_list_append(&list, addr);
        header_decode_lwsp(&inptr);
        if (*inptr == ',')
            inptr++;
        else
            break;
    } while (inptr != last);

    if (*inptr) {
        w(g_warning("Invalid input detected at %c (%d): %s\n or at: %s", *inptr, inptr-in, in, inptr));
    }

    if (inptr == last) {
        w(g_warning("detected invalid input loop at : %s", last));
    }

    return list;
}

void
header_mime_decode(const char *in, int *maj, int *min)
{
    const char *inptr = in;
    int major=-1, minor=-1;

    d(printf("decoding MIME-Version: '%s'\n", in));

    if (in != NULL) {
        header_decode_lwsp(&inptr);
        if (isdigit(*inptr)) {
            major = header_decode_int(&inptr);
            header_decode_lwsp(&inptr);
            if (*inptr == '.') {
                inptr++;
                header_decode_lwsp(&inptr);
                if (isdigit(*inptr))
                    minor = header_decode_int(&inptr);
            }
        }
    }

    if (maj)
        *maj = major;
    if (min)
        *min = minor;

    d(printf("major = %d, minor = %d\n", major, minor));
}

static struct _header_param *
header_decode_param_list(const char **in)
{
    const char *inptr = *in;
    struct _header_param *head = NULL, *tail = NULL;

    header_decode_lwsp(&inptr);
    while (*inptr == ';') {
        char *param, *value;
        struct _header_param *p;

        inptr++;
        /* invalid format? */
        if (header_decode_param(&inptr, &param, &value) != 0)
            break;

        p = g_malloc(sizeof(*p));
        p->name = param;
        p->value = value;
        p->next = NULL;
        if (head == NULL)
            head = p;
        if (tail)
            tail->next = p;
        tail = p;
        header_decode_lwsp(&inptr);
    }
    *in = inptr;
    return head;
}

struct _header_param *
header_param_list_decode(const char *in)
{
    if (in == NULL)
        return NULL;

    return header_decode_param_list(&in);
}

void
header_param_list_format_append(GString *out, struct _header_param *p)
{
    int len = out->len;
    char *ch;

    while (p) {
        int here = out->len;
        if (len+strlen(p->name)+strlen(p->value)>60) {
            out = g_string_append(out, ";\n\t");
            len = 0;
        } else
            out = g_string_append (out, "; ");
        
        g_string_sprintfa(out, "%s=", p->name);

        for (ch = p->value; *ch; ch++) {
            if (is_tspecial(*ch))
                break;
        }
        if (!*ch)
            g_string_append(out, p->value);
        else
            quote_word(out, TRUE, p->value, strlen(p->value));

        len += (out->len - here);
        p = p->next;
    }
}

char *
header_param_list_format(struct _header_param *p)
{
    GString *out = g_string_new("");
    char *ret;

    header_param_list_format_append(out, p);
    ret = out->str;
    g_string_free(out, FALSE);
    return ret;
}

struct _header_content_type *
header_content_type_decode(const char *in)
{
    const char *inptr = in;
    char *type, *subtype = NULL;
    struct _header_content_type *t = NULL;

    if (in==NULL)
        return NULL;

    type = decode_token(&inptr);
    header_decode_lwsp(&inptr);
    if (type) {
        if  (*inptr == '/') {
            inptr++;
            subtype = decode_token(&inptr);
        }
        if (subtype == NULL && (!strcasecmp(type, "text"))) {
            w(g_warning("text type with no subtype, resorting to text/plain: %s", in));
            subtype = g_strdup("plain");
        }
        if (subtype == NULL) {
            w(g_warning("MIME type with no subtype: %s", in));
        }

        t = header_content_type_new(type, subtype);
        t->params = header_decode_param_list(&inptr);
        g_free(type);
        g_free(subtype);
    } else {
        g_free(type);
        d(printf("cannot find MIME type in header (2) '%s'", in));
    }
    return t;
}

void
header_content_type_dump(struct _header_content_type *ct)
{
    struct _header_param *p;

    printf("Content-Type: ");
    if (ct==NULL) {
        printf("<NULL>\n");
        return;
    }
    printf("%s / %s", ct->type, ct->subtype);
    p = ct->params;
    if (p) {
        while (p) {
            printf(";\n\t%s=\"%s\"", p->name, p->value);
            p = p->next;
        }
    }
    printf("\n");
}

char *
header_content_type_format(struct _header_content_type *ct)
{
    GString *out;
    char *ret;

    if (ct==NULL)
        return NULL;

    out = g_string_new("");
    if (ct->type == NULL) {
        g_string_sprintfa(out, "text/plain");
        w(g_warning("Content-Type with no main type"));
    } else if (ct->subtype == NULL) {
        w(g_warning("Content-Type with no sub type: %s", ct->type));
        if (!strcasecmp(ct->type, "multipart"))
            g_string_sprintfa(out, "%s/mixed", ct->type);
        else
            g_string_sprintfa(out, "%s", ct->type);
    } else {
        g_string_sprintfa(out, "%s/%s", ct->type, ct->subtype);
    }
    header_param_list_format_append(out, ct->params);

    ret = out->str;
    g_string_free(out, FALSE);
    return ret;
}

char *
header_content_type_simple(struct _header_content_type *ct)
{
    return g_strdup_printf("%s/%s", ct->type, ct->subtype);
}

char *
header_content_encoding_decode(const char *in)
{
    if (in)
        return decode_token(&in);
    return NULL;
}

CamelMimeDisposition *header_disposition_decode(const char *in)
{
    CamelMimeDisposition *d = NULL;
    const char *inptr = in;

    if (in == NULL)
        return NULL;

    d = g_malloc(sizeof(*d));
    d->refcount = 1;
    d->disposition = decode_token(&inptr);
    if (d->disposition == NULL)
        w(g_warning("Empty disposition type"));
    d->params = header_decode_param_list(&inptr);
    return d;
}

void header_disposition_ref(CamelMimeDisposition *d)
{
    if (d)
        d->refcount++;
}
void header_disposition_unref(CamelMimeDisposition *d)
{
    if (d) {
        if (d->refcount<=1) {
            header_param_list_free(d->params);
            g_free(d->disposition);
            g_free(d);
        } else {
            d->refcount--;
        }
    }
}

char *header_disposition_format(CamelMimeDisposition *d)
{
    GString *out;
    char *ret;

    if (d==NULL)
        return NULL;

    out = g_string_new("");
    if (d->disposition)
        out = g_string_append(out, d->disposition);
    else
        out = g_string_append(out, "attachment");
    header_param_list_format_append(out, d->params);

    ret = out->str;
    g_string_free(out, FALSE);
    return ret;
}

/* hrm, is there a library for this shit? */
static struct {
    char *name;
    int offset;
} tz_offsets [] = {
    { "UT", 0 },
    { "GMT", 0 },
    { "EST", -500 },    /* these are all US timezones.  bloody yanks */
    { "EDT", -400 },
    { "CST", -600 },
    { "CDT", -500 },
    { "MST", -700 },
    { "MDT", -600 },
    { "PST", -800 },
    { "PDT", -700 },
    { "Z", 0 },
    { "A", -100 },
    { "M", -1200 },
    { "N", 100 },
    { "Y", 1200 },
};

static char *tz_months [] = {
    "Jan", "Feb", "Mar", "Apr", "May", "Jun",
    "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};

char *
header_format_date(time_t time, int offset)
{
    struct tm tm;

    d(printf("offset = %d\n", offset));

    d(printf("converting date %s", ctime(&time)));

    time += ((offset / 100) * (60*60)) + (offset % 100)*60;

    d(printf("converting date %s", ctime(&time)));

    memcpy(&tm, gmtime(&time), sizeof(tm));

    return g_strdup_printf("%02d %s %04d %02d:%02d:%02d %+05d",
                   tm.tm_mday, tz_months[tm.tm_mon],
                   tm.tm_year + 1900,
                   tm.tm_hour, tm.tm_min, tm.tm_sec,
                   offset);
}

/* convert a date to time_t representation */
/* this is an awful mess oh well */
time_t
header_decode_date(const char *in, int *saveoffset)
{
    const char *inptr = in;
    char *monthname;
    int year, offset = 0;
    struct tm tm;
    int i;
    time_t t;

    if (in == NULL) {
        if (saveoffset)
            *saveoffset = 0;
        return 0;
    }

    d(printf ("\ndecoding date '%s'\n", inptr));

    memset (&tm, 0, sizeof(tm));

    header_decode_lwsp (&inptr);
    if (!isdigit (*inptr)) {
        char *day = decode_token (&inptr);
        /* we dont really care about the day, it's only for display */
        if (day) {
            d(printf ("got day: %s\n", day));
            g_free (day);
            header_decode_lwsp (&inptr);
            if (*inptr == ',') {
                inptr++;
            } else {
#ifndef CLEAN_DATE
                char *newdate;

                w(g_warning("day not followed by ',' it's probably a broken mail client, so we'll ignore its date entirely"));
                printf ("Giving it one last chance...\n");
                newdate = parse_broken_date (in);
                if (newdate) {
                    printf ("Got: %s\n", newdate);
                    t = header_decode_date (newdate, saveoffset);
                    g_free (newdate);
                    return t;
                }
#endif
                if (saveoffset)
                    *saveoffset = 0;
                return 0;
            }
        }
    }
    tm.tm_mday = header_decode_int(&inptr);
    monthname = decode_token(&inptr);
    if (monthname) {
        for (i=0;i<sizeof(tz_months)/sizeof(tz_months[0]);i++) {
            if (!strcasecmp(tz_months[i], monthname)) {
                tm.tm_mon = i;
                break;
            }
        }
        g_free(monthname);
    }
    year = header_decode_int(&inptr);
    if (year<100) {
        tm.tm_year = year;
    } else {
        tm.tm_year = year-1900;
    }
    /* get the time ... yurck */
    tm.tm_hour = header_decode_int(&inptr);
    header_decode_lwsp(&inptr);
    if (*inptr == ':')
        inptr++;
    tm.tm_min = header_decode_int(&inptr);
    header_decode_lwsp(&inptr);
    if (*inptr == ':')
        inptr++;
    tm.tm_sec = header_decode_int(&inptr);
    header_decode_lwsp(&inptr);
    if (*inptr == '+'
        || *inptr == '-') {
        offset = (*inptr++)=='-'?-1:1;
        offset = offset * header_decode_int(&inptr);
        d(printf("abs signed offset = %d\n", offset));
    } else if (isdigit(*inptr)) {
        offset = header_decode_int(&inptr);
        d(printf("abs offset = %d\n", offset));
    } else {
        char *tz = decode_token(&inptr);

        if (tz) {
            for (i=0;i<sizeof(tz_offsets)/sizeof(tz_offsets[0]);i++) {
                if (!strcasecmp(tz_offsets[i].name, tz)) {
                    offset = tz_offsets[i].offset;
                    break;
                }
            }
            g_free(tz);
        }
        /* some broken mailers seem to put in things like GMT+1030 instead of just +1030 */
        header_decode_lwsp(&inptr);
        if (*inptr == '+' || *inptr == '-') {
            int sign = (*inptr++)=='-'?-1:1;
            offset = offset + (header_decode_int(&inptr)*sign);
        }
        d(printf("named offset = %d\n", offset));
    }

    t = mktime(&tm);
#if defined(HAVE_TIMEZONE)
    t -= timezone;
#elif defined(HAVE_TM_GMTOFF)
    t += tm.tm_gmtoff;
#else
#error Neither HAVE_TIMEZONE nor HAVE_TM_GMTOFF defined. Rerun autoheader, autoconf, etc.
#endif

    /* t is now GMT of the time we want, but not offset by the timezone ... */

    d(printf(" gmt normalized? = %s\n", ctime(&t)));

    /* this should convert the time to the GMT equiv time */
    t -= ( (offset/100) * 60*60) + (offset % 100)*60;

    d(printf(" gmt normalized for timezone? = %s\n", ctime(&t)));

    d({
        char *tmp;
        tmp = header_format_date(t, offset);
        printf(" encoded again: %s\n", tmp);
        g_free(tmp);
    });

    if (saveoffset)
        *saveoffset = offset;

    return t;
}

/* extra rfc checks */
#define CHECKS

#ifdef CHECKS
static void
check_header(struct _header_raw *h)
{
    unsigned char *p;

    p = h->value;
    while (p && *p) {
        if (!isascii(*p)) {
            w(g_warning("Appending header violates rfc: %s: %s", h->name, h->value));
            return;
        }
        p++;
    }
}
#endif

void
header_raw_append_parse(struct _header_raw **list, const char *header, int offset)
{
    register const char *in;
    int fieldlen;
    char *name;

    in = header;
    while (is_fieldname(*in) || *in==':')
        in++;
    fieldlen = in-header-1;
    while (is_lwsp(*in))
        in++;
    if (fieldlen == 0 || header[fieldlen] != ':') {
        printf("Invalid header line: '%s'\n", header);
        return;
    }
    name = alloca(fieldlen+1);
    memcpy(name, header, fieldlen);
    name[fieldlen] = 0;

    header_raw_append(list, name, in, offset);
}

void
header_raw_append(struct _header_raw **list, const char *name, const char *value, int offset)
{
    struct _header_raw *l, *n;

    d(printf("Header: %s: %s\n", name, value));

    n = g_malloc(sizeof(*n));
    n->next = NULL;
    n->name = g_strdup(name);
    n->value = g_strdup(value);
    n->offset = offset;
#ifdef CHECKS
    check_header(n);
#endif
    l = (struct _header_raw *)list;
    while (l->next) {
        l = l->next;
    }
    l->next = n;

    /* debug */
#if 0
    if (!strcasecmp(name, "To")) {
        printf("- Decoding To\n");
        header_to_decode(value);
    } else if (!strcasecmp(name, "Content-type")) {
        printf("- Decoding content-type\n");
        header_content_type_dump(header_content_type_decode(value));        
    } else if (!strcasecmp(name, "MIME-Version")) {
        printf("- Decoding mime version\n");
        header_mime_decode(value);
    }
#endif
}

static struct _header_raw *
header_raw_find_node(struct _header_raw **list, const char *name)
{
    struct _header_raw *l;

    l = *list;
    while (l) {
        if (!strcasecmp(l->name, name))
            break;
        l = l->next;
    }
    return l;
}

const char *
header_raw_find(struct _header_raw **list, const char *name, int *offset)
{
    struct _header_raw *l;

    l = header_raw_find_node(list, name);
    if (l) {
        if (offset)
            *offset = l->offset;
        return l->value;
    } else
        return NULL;
}

const char *
header_raw_find_next(struct _header_raw **list, const char *name, int *offset, const char *last)
{
    struct _header_raw *l;

    if (last == NULL || name == NULL)
        return NULL;

    l = *list;
    while (l && l->value != last)
        l = l->next;
    return header_raw_find(&l, name, offset);
}

static void
header_raw_free(struct _header_raw *l)
{
    g_free(l->name);
    g_free(l->value);
    g_free(l);
}

void
header_raw_remove(struct _header_raw **list, const char *name)
{
    struct _header_raw *l, *p;

    /* the next pointer is at the head of the structure, so this is safe */
    p = (struct _header_raw *)list;
    l = *list;
    while (l) {
        if (!strcasecmp(l->name, name)) {
            p->next = l->next;
            header_raw_free(l);
            l = p->next;
        } else {
            p = l;
            l = l->next;
        }
    }
}

void
header_raw_replace(struct _header_raw **list, const char *name, const char *value, int offset)
{
    header_raw_remove(list, name);
    header_raw_append(list, name, value, offset);
}

void
header_raw_clear(struct _header_raw **list)
{
    struct _header_raw *l, *n;
    l = *list;
    while (l) {
        n = l->next;
        header_raw_free(l);
        l = n;
    }
    *list = NULL;
}

static struct {
    char *name;
    char *pattern;
} mail_list_magic[] = {
    { "Sender", "^Sender: owner-([^@]+)" },
    { "X-BeenThere", "^X-BeenThere: ([^@]+)" },
    { "Delivered-To", "^Delivered-To: mailing list ([^@]+)" },
    { "X-Mailing-List", "^X-Mailing-List: ([^@]+)" },
    { "X-Loop", "^X-Loop: ([^@]+)" },
    { "List-Id", "^List-Id: ([^<]+)" },
};

char *
header_raw_check_mailing_list(struct _header_raw **list)
{
    const char *v;
    regex_t pattern;
    regmatch_t match[1];
    int i;

    for (i=0;i<sizeof(mail_list_magic)/sizeof(mail_list_magic[0]);i++) {
        if (regcomp(&pattern, mail_list_magic[i].pattern, REG_EXTENDED|REG_ICASE) == -1) {
            g_warning("Internal error, compiling regex failed: %s: %s", mail_list_magic[i].pattern, strerror(errno));
            continue;
        }

        v = header_raw_find(list, mail_list_magic[i].name, NULL);
        if (v != NULL && regexec(&pattern, v, 1, match, 0) == 0 && match[0].rm_so != -1) {
            regfree(&pattern);
            return g_strndup(v+match[0].rm_so, match[0].rm_eo-match[0].rm_so);
        }
        regfree(&pattern);
    }

    return NULL;
}

/* ok, here's the address stuff, what a mess ... */
struct _header_address *header_address_new(void)
{
    struct _header_address *h;
    h = g_malloc0(sizeof(*h));
    h->type = HEADER_ADDRESS_NONE;
    h->refcount = 1;
    return h;
}

struct _header_address *header_address_new_name(const char *name, const char *addr)
{
    struct _header_address *h;

    h = header_address_new();
    h->type = HEADER_ADDRESS_NAME;
    h->name = g_strdup(name);
    h->v.addr = g_strdup(addr);
    return h;
}

struct _header_address *header_address_new_group(const char *name)
{
    struct _header_address *h;

    h = header_address_new();
    h->type = HEADER_ADDRESS_GROUP;
    h->name = g_strdup(name);
    return h;
}

void header_address_ref(struct _header_address *h)
{
    if (h)
        h->refcount++;
}

void header_address_unref(struct _header_address *h)
{
    if (h) {
        if (h->refcount <= 1) {
            if (h->type == HEADER_ADDRESS_GROUP) {
                header_address_list_clear(&h->v.members);
            } else if (h->type == HEADER_ADDRESS_NAME) {
                g_free(h->v.addr);
            }
            g_free(h->name);
            g_free(h);
        } else {
            h->refcount--;
        }
    }
}

void header_address_set_name(struct _header_address *h, const char *name)
{
    if (h) {
        g_free(h->name);
        h->name = g_strdup(name);
    }
}

void header_address_set_addr(struct _header_address *h, const char *addr)
{
    if (h) {
        if (h->type == HEADER_ADDRESS_NAME
            || h->type == HEADER_ADDRESS_NONE) {
            h->type = HEADER_ADDRESS_NAME;
            g_free(h->v.addr);
            h->v.addr = g_strdup(addr);
        } else {
            g_warning("Trying to set the address on a group");
        }
    }
}

void header_address_set_members(struct _header_address *h, struct _header_address *group)
{
    if (h) {
        if (h->type == HEADER_ADDRESS_GROUP
            || h->type == HEADER_ADDRESS_NONE) {
            h->type = HEADER_ADDRESS_GROUP;
            header_address_list_clear(&h->v.members);
            /* should this ref them? */
            h->v.members = group;
        } else {
            g_warning("Trying to set the members on a name, not group");
        }
    }
}

void header_address_add_member(struct _header_address *h, struct _header_address *member)
{
    if (h) {
        if (h->type == HEADER_ADDRESS_GROUP
            || h->type == HEADER_ADDRESS_NONE) {
            h->type = HEADER_ADDRESS_GROUP;
            header_address_list_append(&h->v.members, member);
        }           
    }
}

void header_address_list_append_list(struct _header_address **l, struct _header_address **h)
{
    if (l) {
        struct _header_address *n = (struct _header_address *)l;

        while (n->next)
            n = n->next;
        n->next = *h;
    }
}


void header_address_list_append(struct _header_address **l, struct _header_address *h)
{
    if (h) {
        header_address_list_append_list(l, &h);
        h->next = NULL;
    }
}

void header_address_list_clear(struct _header_address **l)
{
    struct _header_address *a, *n;
    a = *l;
    while (a) {
        n = a->next;
        header_address_unref(a);
        a = n;
    }
    *l = NULL;
}

/* if encode is true, then the result is suitable for mailing, otherwise
   the result is suitable for display only (and may not even be re-parsable) */
static void
header_address_list_encode_append(GString *out, int encode, struct _header_address *a)
{
    char *text;

    while (a) {
        switch (a->type) {
        case HEADER_ADDRESS_NAME:
            if (encode)
                text = header_encode_phrase (a->name);
            else
                text = a->name;
            if (text && *text)
                g_string_sprintfa(out, "%s <%s>", text, a->v.addr);
            else
                g_string_append(out, a->v.addr);
            if (encode)
                g_free(text);
            break;
        case HEADER_ADDRESS_GROUP:
            if (encode)
                text = header_encode_phrase(a->name);
            else
                text = a->name;
            g_string_sprintfa(out, "%s: ", text);
            header_address_list_encode_append(out, encode, a->v.members);
            g_string_sprintfa(out, ";");
            if (encode)
                g_free(text);
            break;
        default:
            g_warning("Invalid address type");
            break;
        }
        a = a->next;
        if (a)
            g_string_append(out, ", ");
    }
}

char *
header_address_list_encode(struct _header_address *a)
{
    GString *out;
    char *ret;

    if (a == NULL)
        return NULL;

    out = g_string_new("");

    header_address_list_encode_append(out, TRUE, a);
    ret = out->str;
    g_string_free(out, FALSE);
    return ret;
}

char *
header_address_list_format(struct _header_address *a)
{
    GString *out;
    char *ret;

    if (a == NULL)
        return NULL;

    out = g_string_new("");

    header_address_list_encode_append(out, FALSE, a);
    ret = out->str;
    g_string_free(out, FALSE);
    return ret;
}

/* simple header folding */
/* will work even if the header is already folded */
char *
header_fold(const char *in, int headerlen)
{
    int len, outlen, i;
    const char *inptr = in, *space, *p, *n;
    GString *out;
    char *ret;
    int needunfold = FALSE;

    if (in == NULL)
        return NULL;

    /* first, check to see if we even need to fold */
    len = headerlen + 2;
    p = in;
    while (*p) {
        n = strchr(p, '\n');
        if (n == NULL) {
            n = p+strlen(p);
        } else {
            needunfold = TRUE;
        }
        len += n-p;
        
        if (len >= CAMEL_FOLD_SIZE)
            break;
        len = 0;
        p = n + 1;
    }
    if (len < CAMEL_FOLD_SIZE)
        return g_strdup(in);

    /* we need to fold, so first unfold (if we need to), then process */
    if (needunfold)
        inptr = in = header_unfold(in);

    out = g_string_new("");
    outlen = headerlen+2;
    while (*inptr) {
        space = strchr(inptr, ' ');
        if (space) {
            len = space-inptr+1;
        } else {
            len = strlen(inptr);
        }
        d(printf("next word '%.*s'\n", len, inptr));
        if (outlen + len > CAMEL_FOLD_SIZE) {
            d(printf("outlen = %d wordlen = %d\n", outlen, len));
            /* strip trailing space */
            if (out->len > 0 && out->str[out->len-1] == ' ')
                g_string_truncate(out, out->len-1);
            g_string_append(out, "\n\t");
            outlen = 1;
            /* check for very long words, just cut them up */
            while (outlen+len > CAMEL_FOLD_SIZE) {
                for (i=0;i<CAMEL_FOLD_SIZE-outlen;i++)
                    g_string_append_c(out, inptr[i]);
                inptr += CAMEL_FOLD_SIZE-outlen;
                len -= CAMEL_FOLD_SIZE-outlen;
                g_string_append(out, "\n\t");
                outlen = 1;
            }
        }
        outlen += len;
        for (i=0;i<len;i++) {
            g_string_append_c(out, inptr[i]);
        }
        inptr += len;
    }
    ret = out->str;
    g_string_free(out, FALSE);

    if (needunfold)
        g_free((char *)in);

    return ret; 
}

char *
header_unfold(const char *in)
{
    char *out = g_malloc(strlen(in)+1);
    const char *inptr = in;
    char c, *o = out;

    o = out;
    while ((c = *inptr++)) {
        if (c == '\n') {
            if (is_lwsp(*inptr)) {
                do {
                    inptr++;
                } while (is_lwsp(*inptr));
                *o++ = ' ';
            } else {
                *o++ = c;
            }
        } else {
            *o++ = c;
        }
    }
    *o = 0;

    return out;
}

#ifdef BUILD_TABLE

/* for debugging tests */
/* should also have some regression tests somewhere */

void test_phrase(const char *in)
{
    printf("'%s' -> '%s'\n", in, header_encode_phrase(in));
}

void test_fold(const char *in)
{
    printf("'%s'\n ->\n '%s'\n", in, header_fold(in));
}

void run_test(void)
{
    char *to = "gnome hacker dudes: license-discuss@opensource.org,
        \"Richard M. Stallman\" <rms@gnu.org>,
        Barry Chester <barry_che@antdiv.gov.au>,
        Michael Zucchi <zucchi.michael(this (is a nested) comment)@zedzone.mmc.com.au>,
        Miguel de Icaza <miguel@gnome.org>;,
    zucchi@zedzone.mmc.com.au, \"Foo bar\" <zed@zedzone>,
    <frob@frobzone>";

#if 0
    header_to_decode(to);

    header_mime_decode("1.0", 0, 0);
    header_mime_decode("1.3 (produced by metasend V1.0)", 0, 0);
    header_mime_decode("(produced by metasend V1.0) 5.2", 0, 0);
    header_mime_decode("7(produced by metasend 1.0) . (produced by helix/send/1.0) 9 . 5", 0, 0);
    header_mime_decode("3.", 0, 0);
    header_mime_decode(".", 0, 0);
    header_mime_decode(".5", 0, 0);
    header_mime_decode("c.d", 0, 0);
    header_mime_decode("", 0, 0);

    header_msgid_decode(" <\"L3x2i1.0.Nm5.Xd-Wu\"@lists.redhat.com>");
    header_msgid_decode("<200001180446.PAA02065@beaker.htb.com.au>");
#endif

    test_fold("Header: This is a long header that should be folded properly at the right place, or so i hope.  I should probably set the fold value to something lower for testing");
    test_fold("Header: nowletstryfoldingsomethingthatistoolongtofold,iwonderwhatitshoulddointsteadtofoldit?hmm,iguessicanjusttruncateitatsomepointortrytorefoldthepreviousstuff(yuck)tofit");
    test_phrase("Michael Zucchi (NotZed)");
    test_phrase("Zucchi, ( \\ NotZed \\ ) Michael");
    {
        int ic;
        char *outbuf, *inbuf, buffer[256];
        int inlen, outlen;

        outlen = 256;
        inbuf = "Dra¾en Kaèar";
        inlen = strlen(inbuf);
        outbuf = buffer;
        ic = iconv_open("UTF-8", "ISO-8859-1");
        iconv(ic, &inbuf, &inlen, &outbuf, &outlen);
        test_phrase(buffer);

        outlen = 256;
        inbuf = "This is an encoded phrase Tomasz K³oczko";
        inlen = strlen(inbuf);
        outbuf = buffer;
        ic = iconv_open("UTF-8", "ISO-8859-2");
        iconv(ic, &inbuf, &inlen, &outbuf, &outlen);
        test_phrase(buffer);

    }

    {
        char *str = "Blah blah\n\t = ? =? ?= This is a TEST For quoted-printable-encoding-encoding-of
    long lines, and lines that end in spaces                                                                       
    and line sthat end in tabs                      
    And lines that just end.";

        char encoded[256];
        int state=-1,save=0;
        int len;

        len = quoted_encode_step(str, strlen(str), encoded, &state, &save);
        len += quoted_encode_close("", 0, encoded+len, &state, &save);
        printf("encoded = '%.*s'\n", len, encoded);
    }
}

#endif /* BUILD_TABLE */

char *
header_msgid_generate (void)
{
    gchar host [256], domain [768];
    static gint count = 0;
    gint hrv, drv;

    hrv = gethostname (host, sizeof (host));
    drv = getdomainname (domain, sizeof (domain));

    return g_strdup_printf ("%d.%d.%d.camel@%s.%s", (gint) time (NULL), getpid (), count++,
                (hrv == 0 && host && *host) ? host : "unknown.host",
                (drv && domain && *domain) ? domain : "unknown.domain");
}