diff options
Diffstat (limited to 'mimehead.c')
| -rw-r--r-- | mimehead.c | 306 |
1 files changed, 306 insertions, 0 deletions
diff --git a/mimehead.c b/mimehead.c new file mode 100644 index 0000000..90dcceb --- /dev/null +++ b/mimehead.c @@ -0,0 +1,306 @@ + +/* + * MIME header support by Akinori ITO + */ + +#include <sys/types.h> +#include "Str.h" + +#define LINELEN 4096 + +#define MIME_ENCODED_LINE_LIMIT 80 +#define MIME_ENCODED_WORD_LENGTH_OFFSET 18 +#define MIME_ENCODED_WORD_LENGTH_ESTIMATION(x) \ + (((x)+2)*4/3+MIME_ENCODED_WORD_LENGTH_OFFSET) +#define MIME_DECODED_WORD_LENGTH_ESTIMATION(x) \ + (((x)-MIME_ENCODED_WORD_LENGTH_OFFSET)/4*3) +#define J_CHARSET "ISO-2022-JP" + +#define BAD_BASE64 255 + +static +unsigned char +c2e(char x) +{ + if ('A' <= x && x <= 'Z') + return (x) - 'A'; + if ('a' <= x && x <= 'z') + return (x) - 'a' + 26; + if ('0' <= x && x <= '9') + return (x) - '0' + 52; + if (x == '+') + return 62; + if (x == '/') + return 63; + return BAD_BASE64; +} + +static +int +ha2d(char x, char y) +{ + int r = 0; + + if ('0' <= x && x <= '9') + r = x - '0'; + else if ('A' <= x && x <= 'F') + r = x - 'A' + 10; + else if ('a' <= x && x <= 'f') + r = x - 'a' + 10; + + r <<= 4; + + if ('0' <= y && y <= '9') + r += y - '0'; + else if ('A' <= y && y <= 'F') + r += y - 'A' + 10; + else if ('a' <= y && y <= 'f') + r += y - 'a' + 10; + + return r; + +} + +Str +decodeB(char **ww) +{ + unsigned char c[4]; + char *wp = *ww; + char d[3]; + int i, n_pad; + Str ap = Strnew_size(strlen(wp)); + + n_pad = 0; + while (1) { + for (i = 0; i < 4; i++) { + c[i] = *(wp++); + if (*wp == '\0' || *wp == '?') { + i++; + for (; i < 4; i++) { + c[i] = '='; + } + break; + } + } + if (c[3] == '=') { + n_pad++; + c[3] = 'A'; + if (c[2] == '=') { + n_pad++; + c[2] = 'A'; + } + } + for (i = 0; i < 4; i++) { + c[i] = c2e(c[i]); + if (c[i] == BAD_BASE64) { + *ww = wp; + return ap; + } + } + d[0] = ((c[0] << 2) | (c[1] >> 4)); + d[1] = ((c[1] << 4) | (c[2] >> 2)); + d[2] = ((c[2] << 6) | c[3]); + for (i = 0; i < 3 - n_pad; i++) { + Strcat_char(ap, d[i]); + } + if (n_pad || *wp == '\0' || *wp == '?') + break; + } + *ww = wp; + return ap; +} + +/* RFC2047 (4.2. The "Q" encoding) */ +Str +decodeQ(char **ww) +{ + char *w = *ww; + Str a = Strnew_size(strlen(w)); + + for (; *w != '\0' && *w != '?'; w++) { + if (*w == '=') { + w++; + Strcat_char(a, ha2d(*w, *(w + 1))); + w++; + } + else if (*w == '_') { + Strcat_char(a, ' '); + } + else + Strcat_char(a, *w); + } + *ww = w; + return a; +} + +/* RFC2045 (6.7. Quoted-Printable Content-Transfer-Encoding) */ +Str +decodeQP(char **ww) +{ + char *w = *ww; + Str a = Strnew_size(strlen(w)); + + for (; *w != '\0'; w++) { + if (*w == '=') { + w++; + if (*w == '\n' || *w == '\r' || *w == ' ' || *w == '\t') { + while (*w != '\n' && *w != '\0') + w++; + if (*w == '\0') + break; + } + else { + if (*w == '\0' || *(w + 1) == '\0') + break; + Strcat_char(a, ha2d(*w, *(w + 1))); + w++; + } + } + else + Strcat_char(a, *w); + } + *ww = w; + return a; +} + +Str +decodeWord(char **ow) +{ + char charset[32]; + char *p, *w = *ow; + char method; + Str a = Strnew(); + + if (*w != '=' || *(w + 1) != '?') + goto convert_fail; + w += 2; + for (p = charset; *w != '?'; w++) { + if (*w == '\0') + goto convert_fail; + *(p++) = *w; + } + *p = '\0'; + if (strcasecmp(charset, J_CHARSET) != 0) { + /* NOT ISO-2022-JP encoding ... don't convert */ + goto convert_fail; + } + w++; + method = *(w++); + if (*w != '?') + goto convert_fail; + w++; + p = w; + switch (method) { + case 'B': + a = decodeB(&w); + break; + case 'Q': + a = decodeQ(&w); + break; + default: + goto convert_fail; + } + if (p == w) + goto convert_fail; + if (*w == '?') { + w++; + if (*w == '=') + w++; + } + *ow = w; + return a; + + convert_fail: + return Strnew(); +} + +/* + * convert MIME encoded string to the original one + */ +Str +decodeMIME(char *orgstr) +{ + char *org = orgstr; + char *org0, *p; + Str cnv = Strnew_size(strlen(orgstr)); + + while (*org) { + if (*org == '=' && *(org + 1) == '?') { + nextEncodeWord: + p = org; + Strcat(cnv, decodeWord(&org)); + if (org == p) { /* Convert failure */ + Strcat_charp(cnv, org); + return cnv; + } + org0 = org; + SPCRLoop: + switch (*org0) { + case ' ': + case '\t': + case '\n': + case '\r': + org0++; + goto SPCRLoop; + case '=': + if (org0[1] == '?') { + org = org0; + goto nextEncodeWord; + } + default: + break; + } + } + else + Strcat_char(cnv, *(org++)); + } + return cnv; +} + +/* encoding */ + +static char Base64Table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; + +Str +encodeB(char *a) +{ + unsigned char d[3]; + unsigned char c1, c2, c3, c4; + int i, n_pad; + Str w = Strnew(); + + while (1) { + if (*a == '\0') + break; + n_pad = 0; + d[1] = d[2] = 0; + for (i = 0; i < 3; i++) { + d[i] = a[i]; + if (a[i] == '\0') { + n_pad = 3 - i; + break; + } + } + c1 = d[0] >> 2; + c2 = (((d[0] << 4) | (d[1] >> 4)) & 0x3f); + if (n_pad == 2) { + c3 = c4 = 64; + } + else if (n_pad == 1) { + c3 = ((d[1] << 2) & 0x3f); + c4 = 64; + } + else { + c3 = (((d[1] << 2) | (d[2] >> 6)) & 0x3f); + c4 = (d[2] & 0x3f); + } + Strcat_char(w, Base64Table[c1]); + Strcat_char(w, Base64Table[c2]); + Strcat_char(w, Base64Table[c3]); + Strcat_char(w, Base64Table[c4]); + if (n_pad) + break; + a += 3; + } + return w; +} |