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/*
* For decoding the files that get passed to validateattachment.
* NOT a general mime decoder.
*/
#include <u.h>
#include <libc.h>
#include <bio.h>
enum { None, Base64, Quoted };
static int decquoted(char *out, char *in, char *e);
void
main(void)
{
Biobuf b, b1;
char *p, *encoding;
int e, len;
Binit(&b, 0, OREAD);
Binit(&b1, 1, OWRITE);
/* header */
encoding = nil;
while((p = Brdstr(&b, '\n', 1)) != nil){
if(p[0] == 0)
break;
if(cistrncmp(p, "Content-Transfer-Encoding: ", 27) == 0)
encoding = strdup(p+27);
free(p);
}
e = None;
if(encoding == nil)
e = None;
else if(strcmp(encoding, "base64") == 0)
e = Base64;
else if(strcmp(encoding, "quoted-printable") == 0)
e = Quoted;
while((p = Brdstr(&b, '\n', 0)) != nil){
if(strncmp(p, "--", 2) == 0 && e != None)
break;
len = strlen(p);
switch(e){
case None:
break;
case Base64:
len = dec64((uchar*)p, len, p, len);
break;
case Quoted:
len = decquoted(p, p, p+len);
break;
}
Bwrite(&b1, p, len);
free(p);
}
exits(0);
}
/*
* decode quoted
*/
enum
{
Self= 1,
Hex= 2
};
uchar tableqp[256];
static void
initquoted(void)
{
int c;
memset(tableqp, 0, 256);
for(c = ' '; c <= '<'; c++)
tableqp[c] = Self;
for(c = '>'; c <= '~'; c++)
tableqp[c] = Self;
tableqp['\t'] = Self;
tableqp['='] = Hex;
}
static int
hex2int(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 0;
}
static char*
decquotedline(char *out, char *in, char *e)
{
int c, soft;
/* dump trailing white space */
while(e >= in && (*e == ' ' || *e == '\t' || *e == '\r' || *e == '\n'))
e--;
/* trailing '=' means no newline */
if(*e == '='){
soft = 1;
e--;
} else
soft = 0;
while(in <= e){
c = (*in++) & 0xff;
switch(tableqp[c]){
case Self:
*out++ = c;
break;
case Hex:
c = hex2int(*in++)<<4;
c |= hex2int(*in++);
*out++ = c;
break;
}
}
if(!soft)
*out++ = '\n';
*out = 0;
return out;
}
static int
decquoted(char *out, char *in, char *e)
{
char *p, *nl;
if(tableqp[' '] == 0)
initquoted();
p = out;
while((nl = strchr(in, '\n')) != nil && nl < e){
p = decquotedline(p, in, nl);
in = nl + 1;
}
if(in < e)
p = decquotedline(p, in, e-1);
/* make sure we end with a new line */
if(*(p-1) != '\n'){
*p++ = '\n';
*p = 0;
}
return p - out;
}
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