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/*
** Copyright 2003-2025 Double Precision, Inc. See COPYING for
** distribution information.
*/
/*
*/
#include "encode.h"
#include <string.h>
#include <stdlib.h>
#include <courier-unicode.h>
#include <functional>
#include "rfc2045/rfc2045.h"
namespace {
#if 0
}
#endif
struct libmail_encode_autodetect {
bool use7bit{false};
bool binaryflag{false};
size_t l{0};
bool longline{false};
size_t charcnt{0};
size_t bit8cnt{0};
const char *encoding{0};
void operator()(unsigned char ch)
{
++charcnt;
++l;
if (ch < 0x20 || ch >= 0x80)
{
if (ch != '\t' && ch != '\r' && ch != '\n')
{
++bit8cnt;
l += 2;
}
}
if (ch == 0)
{
binaryflag=true;
encoding="base64";
}
if (ch == '\n') l=0;
else if (l > 990)
{
longline=true;
}
}
operator const char *()
{
if (!encoding)
{
if (use7bit || longline)
{
if (bit8cnt > charcnt / 10)
encoding="base64";
else
encoding="quoted-printable";
}
else
{
encoding=bit8cnt ? "8bit":"7bit";
}
}
return encoding;
}
};
#if 0
{
#endif
}
const char *libmail_encode_autodetect_fp(FILE *fp, int use7bit,
int *binaryflag)
{
return libmail_encode_autodetect_fpoff(fp, use7bit, 0, -1,
binaryflag);
}
const char *libmail_encode_autodetect_fpoff(FILE *fp, int use7bit,
off_t start_pos, off_t end_pos,
int *binaryflag)
{
off_t orig_pos = ftell(fp);
off_t pos = orig_pos;
const char *rc;
if (start_pos >= 0)
{
if (fseek(fp, start_pos, SEEK_SET) == (off_t)-1)
return NULL;
else
pos = start_pos;
}
libmail_encode_autodetect detect;
detect.use7bit=use7bit != 0;
while (!detect.encoding)
{
if (end_pos >= 0 && pos > end_pos)
break;
++pos;
auto ch=getc(fp);
if (ch == EOF)
break;
detect(ch);
}
rc=detect;
if (binaryflag)
*binaryflag=detect.binaryflag ? 1:0;
if (fseek(fp, orig_pos, SEEK_SET) == (off_t)-1)
return NULL;
return rc;
}
const char *libmail_encode_autodetect_buf(const char *str, int use7bit)
{
libmail_encode_autodetect detect;
detect.use7bit=use7bit != 0;
while (*str)
{
if (detect.encoding)
break;
detect(*str++);
}
return detect;
}
std::tuple<const char *, bool>
rfc822::libmail_encode_autodetect(std::streambuf &i,
bool use7bit)
{
char buf[BUFSIZ];
::libmail_encode_autodetect detect;
detect.use7bit=use7bit;
for (auto cnt=i.sgetn(buf, BUFSIZ); cnt > 0;
cnt=i.sgetn(buf, BUFSIZ))
{
char *b=buf;
char *e=buf+cnt;
while (b != e)
{
if (detect.encoding)
break;
detect(*b++);
}
if (detect.encoding)
break;
}
const char *encoding=detect;
return std::tuple{encoding, detect.binaryflag};
}
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