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b0322a85 CE |
1 | /* |
2 | ** Copyright 2003-2011 Double Precision, Inc. See COPYING for | |
3 | ** distribution information. | |
4 | */ | |
5 | ||
6 | /* | |
7 | */ | |
8 | #include "encode.h" | |
9 | #include <string.h> | |
10 | #include <stdlib.h> | |
11 | #include "../unicode/unicode.h" | |
12 | ||
13 | static const char *libmail_encode_autodetect(int use7bit, | |
14 | int (*func)(void *), void *arg, | |
15 | int *binaryflag) | |
16 | { | |
17 | int l=0; | |
18 | int longline=0; | |
19 | int c; | |
20 | ||
21 | size_t charcnt=0; | |
22 | size_t bit8cnt=0; | |
23 | ||
24 | if (binaryflag) | |
25 | *binaryflag=0; | |
26 | ||
27 | while ((c = (*func)(arg)) != EOF) | |
28 | { | |
29 | unsigned char ch= (unsigned char)c; | |
30 | ||
31 | ++charcnt; | |
32 | ||
33 | ++l; | |
34 | if (ch < 0x20 || ch >= 0x80) | |
35 | { | |
36 | if (ch != '\t' && ch != '\r' && ch != '\n') | |
37 | { | |
38 | ++bit8cnt; | |
39 | l += 2; | |
40 | } | |
41 | } | |
42 | ||
43 | if (ch == 0) | |
44 | { | |
45 | if (binaryflag) | |
46 | *binaryflag=1; | |
47 | ||
48 | return "base64"; | |
49 | } | |
50 | ||
51 | if (ch == '\n') l=0; | |
52 | else if (l > 990) | |
53 | { | |
54 | longline=1; | |
55 | } | |
56 | ||
57 | } | |
58 | ||
59 | if (use7bit || longline) | |
60 | { | |
61 | if (bit8cnt > charcnt / 10) | |
62 | return "base64"; | |
63 | ||
64 | return "quoted-printable"; | |
65 | } | |
66 | ||
67 | return bit8cnt ? "8bit":"7bit"; | |
68 | } | |
69 | ||
70 | struct file_info { | |
71 | FILE *fp; | |
72 | off_t pos; | |
73 | off_t end; | |
74 | }; | |
75 | ||
76 | static int read_file(void *arg) | |
77 | { | |
78 | int c; | |
79 | struct file_info *fi = (struct file_info *)arg; | |
80 | if (fi->end >= 0 && fi->pos > fi->end) | |
81 | return EOF; | |
82 | c = getc(fi->fp); | |
83 | fi->pos++; | |
84 | return c; | |
85 | } | |
86 | ||
87 | static int read_string(void * arg) | |
88 | { | |
89 | int c; | |
90 | unsigned char **strp = (unsigned char **)arg; | |
91 | if (**strp == 0) | |
92 | return EOF; | |
93 | c = (int)**strp; | |
94 | (*strp)++; | |
95 | return c; | |
96 | } | |
97 | ||
98 | const char *libmail_encode_autodetect_fp(FILE *fp, int use7bit, | |
99 | int *binaryflag) | |
100 | { | |
101 | return libmail_encode_autodetect_fpoff(fp, use7bit, 0, -1, | |
102 | binaryflag); | |
103 | } | |
104 | ||
105 | const char *libmail_encode_autodetect_fpoff(FILE *fp, int use7bit, | |
106 | off_t start_pos, off_t end_pos, | |
107 | int *binaryflag) | |
108 | { | |
109 | struct file_info fi; | |
110 | off_t orig_pos = ftell(fp); | |
111 | off_t pos = orig_pos; | |
112 | const char *rc; | |
113 | ||
114 | if (start_pos >= 0) | |
115 | { | |
116 | if (fseek(fp, start_pos, SEEK_SET) == (off_t)-1) | |
117 | return NULL; | |
118 | else | |
119 | pos = start_pos; | |
120 | } | |
121 | ||
122 | fi.fp = fp; | |
123 | fi.pos = pos; | |
124 | fi.end = end_pos; | |
125 | ||
126 | rc = libmail_encode_autodetect(use7bit, &read_file, &fi, | |
127 | binaryflag); | |
128 | ||
129 | if (fseek(fp, orig_pos, SEEK_SET) == (off_t)-1) | |
130 | return NULL; | |
131 | return rc; | |
132 | } | |
133 | ||
134 | const char *libmail_encode_autodetect_buf(const char *str, int use7bit) | |
135 | { | |
136 | return libmail_encode_autodetect(use7bit, &read_string, &str, | |
137 | NULL); | |
138 | } |