rfc822/encodeautodetect.c

   1 /*
   2 ** Copyright 2003-2004 Double Precision, Inc.  See COPYING for
   3 ** distribution information.
   4 */
   5
   6 /*
   7 ** $Id: encodeautodetect.c,v 1.1 2004/10/21 00:10:51 mrsam Exp $
   8 */
   9 #include        "encode.h"
  10 #include        <string.h>
  11 #include        <stdlib.h>
  12 #if     HAVE_LIBUNICODE
  13 #include        "../unicode/unicode.h"
  14 #endif
  15
  16 static const char *libmail_encode_autodetect(const char *charset,
  17                                              int (*func)(void *), void *arg)
  18 {
  19         const char *encoding="7bit";
  20         int     l=0;
  21         int     longline=0;
  22         int c;
  23 #if     HAVE_LIBUNICODE
  24         const struct unicode_info *ci = unicode_find(charset);
  25 #endif
  26
  27         while ((c = (*func)(arg)) != EOF)
  28         {
  29                 unsigned char ch= (unsigned char)c;
  30
  31                 if (ch >= 0x80)
  32                 {
  33
  34 #if     HAVE_LIBUNICODE
  35                         if (!charset || !*charset)
  36                                 encoding="8bit";
  37                         else if (ci && ci->flags & UNICODE_BODY_QUOPRI)
  38                                 encoding="quoted-printable";
  39                         else if (!ci || ci->flags & UNICODE_BODY_BASE64)
  40                                 encoding="base64";
  41                         else
  42                                 encoding="8bit";
  43 #else
  44                         encoding="8bit";
  45 #endif
  46                 }
  47
  48                 if (ch < 0x20 &&
  49                     ch != '\t' && ch != '\r' && ch != '\n')
  50                 {
  51 #if     HAVE_LIBUNICODE
  52                         if (!charset || !*charset)
  53                                 ;
  54                         else if (ci && ci->flags & UNICODE_BODY_QUOPRI)
  55                                 encoding="quoted-printable";
  56                         else if (!ci || ci->flags & UNICODE_BODY_BASE64)
  57                                 encoding="base64";
  58 #else
  59                         if (charset && *charset)
  60                                 encoding="quoted-printable";
  61 #endif
  62                 }
  63
  64                 if (ch == 0)
  65                         return "base64";
  66
  67                 if (ch == '\n') l=0;
  68                 else if (++l > 990)
  69                 {
  70                         longline=1;
  71 #if     HAVE_LIBUNICODE
  72                         if (ci && ci->flags & UNICODE_BODY_QUOPRI)
  73                                 encoding="quoted-printable";
  74 #else
  75                         if (charset && *charset)
  76                                 encoding="quoted-printable";
  77 #endif
  78                 }
  79
  80         }
  81
  82         if (longline)
  83         {
  84 #if     HAVE_LIBUNICODE
  85                 if (ci && ci->flags & UNICODE_BODY_QUOPRI)
  86                         encoding="quoted-printable";
  87                 else
  88                         encoding="base64";
  89 #else
  90                 if (charset && *charset)
  91                         encoding="quoted-printable";
  92                 else
  93                         encoding="base64";
  94 #endif
  95         }
  96         return encoding;
  97 }
  98
  99 struct file_info {
 100         FILE *fp;
 101         off_t pos;
 102         off_t end;
 103 };
 104
 105 static int read_file(void *arg)
 106 {
 107 int c;
 108 struct file_info *fi = (struct file_info *)arg;
 109         if (fi->end >= 0 && fi->pos > fi->end)
 110                 return EOF;
 111         c = getc(fi->fp);
 112         fi->pos++;
 113         return c;
 114 }
 115
 116 static int read_string(void * arg)
 117 {
 118 int c;
 119 unsigned char **strp = (unsigned char **)arg;
 120         if (**strp == 0)
 121                 return EOF;
 122         c = (int)**strp;
 123         (*strp)++;
 124         return c;
 125 }
 126
 127 const char *libmail_encode_autodetect_fp(FILE *fp, int okQp)
 128 {
 129         if (okQp)
 130                 return libmail_encode_autodetect_fppos(fp, "ISO-8859-1", 0, -1);
 131         else
 132                 return libmail_encode_autodetect_fppos(fp, NULL, 0, -1);
 133 }
 134
 135 const char *libmail_encode_autodetect_fppos(FILE *fp, const char *charset,
 136                                             off_t start_pos, off_t end_pos)
 137 {
 138 struct file_info fi;
 139 off_t orig_pos = ftell(fp);
 140 off_t pos = orig_pos;
 141 const char *rc;
 142
 143         if (start_pos >= 0)
 144         {
 145                 if (fseek(fp, start_pos, SEEK_SET) == (off_t)-1)
 146                         return NULL;
 147                 else
 148                         pos = start_pos;
 149         }
 150
 151         fi.fp = fp;
 152         fi.pos = pos;
 153         fi.end = end_pos;
 154         rc = libmail_encode_autodetect(charset, &read_file, &fi);
 155
 156         if (fseek(fp, orig_pos, SEEK_SET) == (off_t)-1)
 157                 return NULL;
 158         return rc;
 159 }
 160
 161 const char *libmail_encode_autodetect_str(const char *str, const char *charset)
 162 {
 163         return libmail_encode_autodetect(charset, &read_string, &str);
 164 }