/*
* 使用方法大致如下: innbbsd 中 在 SUBJECT 從 news 讀進來後, 呼叫
* str_decode_M3(SUBJECT) 就行了
*/
/*
* bsd 底下使用要編譯時要加 -I/usr/local/include -L/usr/local/lib -liconv
* 並安裝 libiconv, 若真的沒有iconv就把底下的 #define USE_ICONV 1 刪了
*/
/*-------------------------------------------------------*/
/* lib/str_decode.c ( NTHU CS MapleBBS Ver 3.00 ) */
/*-------------------------------------------------------*/
/* target : included C for QP/BASE64 decoding */
/* create : 95/03/29 */
/* update : 97/03/29 */
/*-------------------------------------------------------*/
/* ----------------------------------------------------- */
/* QP code : "0123456789ABCDEF" */
/* ----------------------------------------------------- */
#include <stdio.h>
#include <errno.h>
#include <string.h>
#define USE_ICONV 1
/*
* bsd 底下使用要編譯時要加 -I/usr/local/include -L/usr/local/lib -liconv
* 若真的沒有iconv就把上面這行 #define 刪了
*/
#ifdef USE_ICONV
#include <iconv.h>
#endif
static int
qp_code(int x)
{
if (x >= '0' && x <= '9')
return x - '0';
if (x >= 'a' && x <= 'f')
return x - 'a' + 10;
if (x >= 'A' && x <= 'F')
return x - 'A' + 10;
return -1;
}
/* ------------------------------------------------------------------ */
/* BASE64 : */
/* "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" */
/* ------------------------------------------------------------------ */
static int
base64_code(int x)
{
if (x >= 'A' && x <= 'Z')
return x - 'A';
if (x >= 'a' && x <= 'z')
return x - 'a' + 26;
if (x >= '0' && x <= '9')
return x - '0' + 52;
if (x == '+')
return 62;
if (x == '/')
return 63;
return -1;
}
/* ----------------------------------------------------- */
/* judge & decode QP / BASE64 */
/* ----------------------------------------------------- */
static inline int
isreturn(unsigned char c)
{
return c == '\r' || c == '\n';
}
static inline int
isspace(unsigned char c)
{
return c == ' ' || c == '\t' || isreturn(c);
}
/* static inline */
int
mmdecode(unsigned char *src, unsigned char encode, unsigned char *dst)
{
/* Thor.980901: src和dst可相同, 但src 一定有?或\0結束 */
/* Thor.980901: 注意, decode出的結果不會自己加上 \0 */
unsigned char *t = dst;
int pattern = 0, bits = 0;
encode |= 0x20; /* Thor: to lower */
switch (encode) {
case 'q': /* Thor: quoted-printable */
while (*src && *src != '?') { /* Thor: delimiter *//* Thor.980901:
* 0 算是 delimiter */
if (*src == '=') {
int x = *++src, y = x ? *++src : 0;
if (isreturn(x))
continue;
if ((x = qp_code(x)) < 0 || (y = qp_code(y)) < 0)
return -1;
*t++ = (x << 4) + y, src++;
} else if (*src == '_')
*t++ = ' ', src++;
#if 0
else if (!*src) /* Thor: no delimiter is not successful */
return -1;
#endif
else /* Thor: *src != '=' '_' */
*t++ = *src++;
}
return t - dst;
case 'b': /* Thor: base 64 */
while (*src && *src != '?') { /* Thor: delimiter */
/*
* Thor.980901: 0也算 *//* Thor: pattern & bits are cleared
* outside
*/
int x;
#if 0
if (!*src)
return -1; /* Thor: no delimiter is not successful */
#endif
x = base64_code(*src++);
if (x < 0)
continue; /* Thor: ignore everything not in the
* base64,=,.. */
pattern = (pattern << 6) | x;
bits += 6; /* Thor: 1 code gains 6 bits */
if (bits >= 8) { /* Thor: enough to form a byte */
bits -= 8;
*t++ = (pattern >> bits) & 0xff;
}
}
return t - dst;
}
return -1;
}
#ifdef USE_ICONV
size_t
str_iconv(
const char *fromcode, /* charset of source string */
const char *tocode, /* charset of destination string */
char *src, /* source string */
size_t srclen, /* source string length */
char *dst, /* destination string */
size_t dstlen)
{ /* destination string length */
/*
* 這個函式會將一個字串 (src) 從 charset=fromcode 轉成 charset=tocode,
* srclen 是 src 的長度, dst 是輸出的buffer, dstlen 則指定了 dst 的大小,
* 最後會補 '\0', 所以要留一個byte給'\0'. 如果遇到 src 中有非字集的字,
* 或是 src 中有未完整的 byte, 都會砍掉.
*/
iconv_t iconv_descriptor;
size_t iconv_ret, dstlen_old;
dstlen--; /* keep space for '\0' */
dstlen_old = dstlen;
/* Open a descriptor for iconv */
iconv_descriptor = iconv_open(tocode, fromcode);
if (iconv_descriptor == ((iconv_t) (-1))) { /* if open fail */
strncpy(dst, src, dstlen);
return dstlen;
}
/* Start translation */
while (srclen > 0 && dstlen > 0) {
iconv_ret = iconv(iconv_descriptor, (const char **)&src, &srclen,
&dst, &dstlen);
if (iconv_ret != 0) {
switch (errno) {
/* invalid multibyte happened */
case EILSEQ:
/* forward that byte */
*dst = *src;
src++;
srclen--;
dst++;
dstlen--;
break;
/* incomplete multibyte happened */
case EINVAL:
/* forward that byte (maybe wrong) */
*dst = *src;
src++;
srclen--;
dst++;
dstlen--;
break;
/* dst no rooms */
case E2BIG:
/* break out the while loop */
srclen = 0;
break;
}
}
}
*dst = '\0';
/* close descriptor of iconv */
iconv_close(iconv_descriptor);
return (dstlen_old - dstlen);
}
#endif
void
str_decode_M3(unsigned char *str)
{
int adj;
int i;
unsigned char *src, *dst;
unsigned char buf[512];
unsigned char charset[512], dst1[512];
src = str;
dst = buf;
adj = 0;
while (*src && (dst - buf) < sizeof(buf) - 1) {
if (*src != '=') { /* Thor: not coded */
unsigned char *tmp = src;
while (adj && *tmp && isspace(*tmp))
tmp++;
if (adj && *tmp == '=') { /* Thor: jump over space */
adj = 0;
src = tmp;
} else
*dst++ = *src++;
/* continue; *//* Thor: take out */
} else { /* Thor: *src == '=' */
unsigned char *tmp = src + 1;
if (*tmp == '?') { /* Thor: =? coded */
/* "=?%s?Q?" for QP, "=?%s?B?" for BASE64 */
tmp++;
i = 0;
while (*tmp && *tmp != '?') {
if (i + 1 < sizeof(charset)) {
charset[i] = *tmp;
charset[i + 1] = '\0';
i++;
}
tmp++;
}
if (*tmp && tmp[1] && tmp[2] == '?') { /* Thor: *tmp == '?' */
#ifdef USE_ICONV
int i = mmdecode(tmp + 3, tmp[1], dst1);
i = str_iconv(charset, "big5", dst1, i, dst,
sizeof(buf) - ((int)(dst - buf)));
#else
int i = mmdecode(tmp + 3, tmp[1], dst);
#endif
if (i >= 0) {
tmp += 3; /* Thor: decode's src */
#if 0
while (*tmp++ != '?'); /* Thor: no ? end, mmdecode
* -1 */
#endif
while (*tmp && *tmp++ != '?'); /* Thor: no ? end,
* mmdecode -1 */
/* Thor.980901: 0 也算 decode 結束 */
if (*tmp == '=')
tmp++;
src = tmp; /* Thor: decode over */
dst += i;
adj = 1;/* Thor: adjcent */
}
}
}
while (src != tmp) /* Thor: not coded */
*dst++ = *src++;
}
}
*dst = 0;
strcpy(str, buf);
}
