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

/*
 *  Copyright (C) 2000 Helix Code Inc.
 *
 *  Authors: Michael Zucchi <notzed@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.
 */

#include <config.h>

#include <stdio.h>

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

#include <unicode.h>

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

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

#include "camel-mime-utils.h"

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))

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

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

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 char camel_mime_special_table[256] = {
      5,  5,  5,  5,  5,  5,  5,  5,  5,167,  7,  5,  5, 39,  5,  5,
      5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,  5,
    178,128,140,128,128,128,128,128,140,140,128,128,140,128,136,132,
    128,128,128,128,128,128,128,128,128,128,204,140,140,  4,140,132,
    140,128,128,128,128,128,128,128,128,128,128,128,128,128,128,128,
    128,128,128,128,128,128,128,128,128,128,128,172,172,172,128,128,
    128,128,128,128,128,128,128,128,128,128,128,128,128,128,128,128,
    128,128,128,128,128,128,128,128,128,128,128,128,128,128,128,  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 -o buildtable `glib-config --cflags --libs` -DBUILD_TABLE camel-mime-utils.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_COLON    = 1<<6, /* rather wasteful of space ... */
    IS_QPSAFE   = 1<<7
};

#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|IS_COLON)) == 0)
#define is_qpsafe(x) ((camel_mime_special_table[(unsigned char)(x)] & IS_QPSAFE) != 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 */

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

    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;
    for (i=0;i<32;i++) camel_mime_special_table[i] |= IS_CTRL;
    camel_mime_special_table[127] = IS_CTRL;
    camel_mime_special_table[' '] = IS_SPACE;
    camel_mime_special_table[':'] = IS_COLON;
    header_init_bits(IS_LWSP, 0, 0, CHARS_LWSP, sizeof(CHARS_LWSP)-1);
    header_init_bits(IS_TSPECIAL, IS_CTRL, 0, CHARS_TSPECIAL, sizeof(CHARS_TSPECIAL)-1);
    header_init_bits(IS_SPECIAL, 0, 0, CHARS_SPECIAL, sizeof(CHARS_SPECIAL)-1);
    header_init_bits(IS_DSPECIAL, 0, FALSE, CHARS_DSPECIAL, sizeof(CHARS_DSPECIAL)-1);
    for (i=0;i<256;i++) if ((i>=33 && i<=60) || (i>=62 && i<=126) || i==32 || i==9) camel_mime_special_table[i] |= IS_QPSAFE;
}

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 char 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, unsigned char *out, int *state, int *save)
{
    int c1, c2;
    unsigned char *outptr = out;

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

    c1 = ((char *)save)[1];
    c2 = ((char *)save)[2];

    switch (((char *)save)[0]) {
    case 2:
        outptr[2] = base64_alphabet [ ( (c2 &0x0f) << 2 ) ];
        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;
    }
    *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, 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 = ((char *)save)[1]; goto skip1;
        case 2: c1 = ((char *)save)[1];
            c2 = ((char *)save)[2]; goto skip2;
        }
        
        /* yes, we jump into the loop, no i'm not going to change it, its 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 ((++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;
}

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;
}

int
quoted_encode_close(unsigned char *in, int len, unsigned char *out, int *state, int *save)
{
    register unsigned char *outptr = out;

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

    /* hmm, not sure if this should really be added here, we dont want
       to add it to the content, afterall ...? */
    *outptr++ = '\n';

    *save = 0;
    *state = 0;

    return outptr-out;
}

/*
  FIXME: does not handle trailing spaces/tabs before end of line
*/
int
quoted_encode_step(unsigned char *in, int len, unsigned char *out, int *state, int *save)
{
    register unsigned char *inptr, *outptr, *inend;
    unsigned char c;
    register int sofar = *state;

    inptr = in;
    inend = in+len;
    outptr = out;
    while (inptr<inend) {
        c = *inptr++;
        if (is_qpsafe(c)) {
                /* check for soft line-break */
            if ((++sofar)>74) {
                *outptr++='=';
                *outptr++='\n';
                sofar = 1;
            }
            *outptr++=c;
        } else {
            if ((++sofar)>72) {
                *outptr++='=';
                *outptr++='\n';
                sofar = 3;
            }
            *outptr++ = '=';
            *outptr++ = tohex[(c>>4) & 0xf];
            *outptr++ = tohex[c & 0xf];
        }
    }
    *state = sofar;
    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++;
                /* FIXME: use a specials table to avoid 3 comparisons for the common case */
                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
*/
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 */
static int
quoted_encode(const unsigned char *in, int len, unsigned char *out)
{
    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 (is_qpsafe(c) && !(c=='_' || c=='?')) {
            if (c==' ')
                c='_';
            *outptr++=c;
        } else {
            *outptr++ = '=';
            *outptr++ = tohex[(c>>4) & 0xf];
            *outptr++ = tohex[c & 0xf];
        }
    }

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

        /* check for comments */
        if (*inptr == '(') {
            int depth = 1;
            inptr++;
            while (depth && (c=*inptr)) {
                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;
    unicode_iconv_t ic;

    d(printf("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;
            outbase = alloca(outlen);
            outbuf = outbase;

            /* TODO: Should this cache iconv converters? */
            ic = unicode_iconv_open("utf-8", encname);
            if (ic != (unicode_iconv_t)-1) {
                ret = unicode_iconv(ic, (const char **)&inbuf, &inlen, &outbuf, &outlen);
                unicode_iconv_close(ic);
                if (ret>=0) {
                    *outbuf = 0;
                    decoded = g_strdup(outbase);
                }
            } 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);
}

/* 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));
            free(decword);
        } else {
            out = g_string_append_len(out, inptr, encend-inptr+2);
        }
        inptr = encend+2;
    }
    out = g_string_append_len(out, inptr, inend-inptr);

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

    return encstart;
}

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

static char *encoding_map[] = {
    "US-ASCII",
    "ISO-8859-1",
    "UTF-8"
};

/* FIXME: needs a way to cache iconv opens for different charsets? */
static
char *rfc2047_encode_word(const char *in, int len, char *type)
{
    unicode_iconv_t ic;
    char *buffer, *out, *ascii;
    size_t inlen, outlen, enclen;

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

    /* convert utf8->encoding */
    outlen = len*6;
    buffer = alloca(outlen);
    inlen = len;
    out = buffer;

    /* if we can't convert from utf-8, just encode as utf-8 */
    if (!strcasecmp(type, "UTF-8")
        || (ic = unicode_iconv_open(type, "UTF-8")) == (unicode_iconv_t)-1) {
        memcpy(buffer, in, len);
        out = buffer+len;
        type = "UTF-8";
    } else {
        if (unicode_iconv(ic, &in, &inlen, &out, &outlen) == -1) {
            w(g_warning("Conversion problem: conversion truncated: %s", strerror(errno)));
        }
        unicode_iconv_close(ic);
    }
    enclen = out-buffer;

    /* now create qp version */
    ascii = alloca(enclen*3 + strlen(type) + 8);
    out = ascii;
    /* should determine which encoding is smaller, and use that? */
    out += sprintf(out, "=?%s?Q?", type);
    out += quoted_encode(buffer, enclen, out);
    sprintf(out, "?=");

    d(printf("converted = %s\n", ascii));
    return g_strdup(ascii);
}


/* 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 */
    /* FIXME: Make sure a converted word is less than the encoding size */
    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)) {
            if (encoding == 0) {
                out = g_string_append_len(out, start, inptr-start);
            } else {
                char *text = rfc2047_encode_word(start, inptr-start-1, encoding_map[encoding]);
                out = g_string_append(out, text);
                out = g_string_append_c(out, c);
                g_free(text);
            }
            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) {
        if (encoding == 0) {
            out = g_string_append_len(out, start, inptr-start);
        } else {
            char *text = rfc2047_encode_word(start, inptr-start, encoding_map[encoding]);
            out = g_string_append(out, text);
            g_free(text);
        }
    }
    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) {
        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);
        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);
            } 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);
            } 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;

    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;

            text = header_decode_string(pre);
            name = g_string_append(name, text);
            g_free(pre);

            /* rfc_decode(pre) */
            pre = header_decode_word(&inptr);
            if (pre)
                name = g_string_append_c(name, ' ');
        }
        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);
        addr = g_string_append_c(addr, '.');
        addr = g_string_append(addr, pre);
        header_decode_lwsp(&inptr);
    }
    g_free(pre);

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

        inptr++;
        addr = g_string_append_c(addr, '@');
        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) { /* check for comment after address */
        char *text, *tmp;
        const char *comment = inptr;

        header_decode_lwsp(&inptr);
        if (inptr-comment > 3) { /* just guess ... */
            tmp = g_strndup(comment, inptr-comment);
            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;
}

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

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

    if (in == NULL)
        return NULL;

    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));
    }

    return msgid;
}

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));

#warning header_to_decode needs to return some structure

    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_param_list_decode(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;
}

static void
header_param_list_format_append(GString *out, struct _header_param *p)
{
    int len = out->len;
    while (p) {
        int here = out->len;
        if (len+strlen(p->name)+strlen(p->value)>60) {
            out = g_string_append(out, "\n\t");
            len = 0;
        }
        /* FIXME: format the value properly */
        g_string_sprintfa(out, " ; %s=\"%s\"", p->name, p->value);
        len += (out->len - here);
        p = p->next;
    }
}

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_param_list_decode(&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_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_param_list_decode(&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, its only for display */
        if (day) {
            d(printf("got day: %s\n", day));
            g_free(day);
            header_decode_lwsp(&inptr);
            if (*inptr == ',')
                inptr++;
            else
                w(g_warning("day not followed by ','"));
        }
    }
    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++;
    fieldlen = in-header;
    while (is_lwsp(*in))
        in++;
    if (fieldlen == 0 || *in != ':') {
        printf("Invalid header line: '%s'\n", header);
        return;
    }
    in++;
    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;
}


/* 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 = (struct _header_address *)l;
    while (a && a->next) {
        n = a->next;
        a = n->next;
        header_address_unref(n);
    }
}

static void
header_address_list_format_append(GString *out, struct _header_address *a)
{
    char *text;

    while (a) {
        switch (a->type) {
        case HEADER_ADDRESS_NAME:
#warning needs to rfc2047 encode address phrase
            /* FIXME: 2047 encoding?? */
            if (a->name)
                g_string_sprintfa(out, "\"%s\" <%s>", a->name, a->v.addr);
            else
                g_string_sprintfa(out, "<%s>", a->v.addr);
            break;
        case HEADER_ADDRESS_GROUP:
            text = header_encode_string(a->name);
            g_string_sprintfa(out, "%s:\n ", text);
            header_address_list_format_append(out, a->v.members);
            g_string_sprintfa(out, ";");
            break;
        default:
            g_warning("Invalid address type");
            break;
        }
        a = a->next;
    }
}

/* FIXME: need a 'display friendly' version, as well as a 'rfc friendly' version? */
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_format_append(out, a);
    ret = out->str;
    g_string_free(out, FALSE);
    return ret;
}

#ifdef BUILD_TABLE

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

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>";

    header_to_decode(to);

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

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

}

#endif /* BUILD_TABLE */