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/*
* Worldvisions Weaver Software:
* Copyright (C) 2002 Net Integration Technologies, Inc.
*
* Performs C-style backslash escaping and unescaping of strings.
*/
#include <ctype.h>
#include "wvbackslash.h"
static const char *escapein = "\a\b\f\n\r\t\v";
static const char *escapeout = "abfnrtv";
static inline char tohex(int digit, char alphabase = ('a' - 10))
{
return (digit < 10 ? '0' : alphabase) + digit;
}
static inline int fromhex(char digit)
{
if (isdigit(digit))
return digit - '0';
if (digit >= 'A' && digit <= 'F')
return digit - 'A' + 10;
if (digit >= 'a' && digit <= 'f')
return digit - 'a' + 10;
return -1;
}
static inline int fromoctal(char digit)
{
if (digit >= '0' && digit <= '7')
return digit - '0';
return -1;
}
/***** WvBackslashEncoder *****/
WvBackslashEncoder::WvBackslashEncoder(WvStringParm _nasties) :
nasties(_nasties)
{
}
bool WvBackslashEncoder::_encode(WvBuf &inbuf, WvBuf &outbuf,
bool flush)
{
size_t avail = outbuf.free();
size_t len;
while ((len = inbuf.optgettable()) != 0)
{
const unsigned char *datain = inbuf.get(len);
for (size_t i = 0; i < len; ++i)
{
int c = datain[i];
// handle 1 character escape sequences
if (avail < 1)
{ outbuf.unget(len - i); return ! flush; }
const char *foundnasty = NULL;
const char *foundspecial = NULL;
if (c != '\0')
{
foundnasty = strchr(nasties.cstr(), c);
if (! foundnasty)
{
foundspecial = strchr(escapein, c);
if (! foundspecial && isprint(c))
{
outbuf.putch(c);
avail -= 1;
continue;
}
}
}
// handle 2 character escape sequences
if (avail < 2)
{ outbuf.unget(len - i); return ! flush; }
if (foundnasty != NULL)
{
outbuf.putch('\\');
outbuf.putch(c);
avail -= 2;
continue;
}
if (foundspecial != NULL)
{
outbuf.putch('\\');
outbuf.putch(escapeout[foundspecial - escapein]);
avail -= 2;
continue;
}
// handle 4 character escape sequences
if (avail < 4)
{ outbuf.unget(len - i); return ! flush; }
outbuf.put("\\x", 2);
outbuf.putch(tohex(c >> 4));
outbuf.putch(tohex(c & 15));
avail -= 4;
}
}
return true;
}
bool WvBackslashEncoder::_reset()
{
return true;
}
/***** WvBackslashDecoder *****/
WvBackslashDecoder::WvBackslashDecoder() : tmpbuf(4)
{
_reset();
}
bool WvBackslashDecoder::_encode(WvBuf &inbuf, WvBuf &outbuf,
bool flush)
{
if (outbuf.free() == 0)
return inbuf.used() == 0;
if (! flushtmpbuf(outbuf))
return false;
size_t len;
while ((len = inbuf.optgettable()) != 0)
{
const unsigned char *datain = inbuf.get(len);
for (size_t i = 0; i < len; ++i)
{
int c = datain[i];
switch (state)
{
case Initial:
if (c == '\\')
state = Escape;
tmpbuf.putch(c);
break;
case Escape:
if (c >= '0' && c <= '3')
{
tmpbuf.unalloc(1);
value = c - '0';
state = Octal1;
}
else if (c == 'x')
{
tmpbuf.putch(c);
state = Hex1;
}
else if (c == '\n')
{
// line continuation sequence
tmpbuf.unalloc(1);
tmpbuf.putch(' ');
state = Initial;
}
else
{
const char *found = strchr(escapeout, c);
tmpbuf.unalloc(1);
if (found != NULL)
c = escapein[found - escapeout];
// else we just drop the backslash
tmpbuf.putch(c);
state = Initial;
}
break;
case Hex2:
case Hex1: {
int digit = fromhex(c);
if (digit >= 0)
{
if (state == Hex1)
{
tmpbuf.unalloc(2);
value = digit;
state = Hex2;
}
else
{
value = (value << 4) | digit;
state = Initial;
}
}
else
{
i -= 1;
state = Initial;
}
break;
}
case Octal3:
case Octal2:
case Octal1: {
int digit = fromoctal(c);
if (digit >= 0)
{
value = (value << 3) | digit;
if (state != Octal3)
state = State(state + 1);
else
state = Initial;
}
else
{
i -= 1;
state = Initial;
}
break;
}
}
flushtmpbuf(outbuf);
if (outbuf.free() == 0)
{
inbuf.unget(len - i);
break;
}
}
}
if (flush)
{
if (inbuf.used() != 0)
return false;
state = Initial;
return flushtmpbuf(outbuf);
}
return true;
}
bool WvBackslashDecoder::_reset()
{
state = Initial;
value = -1;
tmpbuf.zap();
return true;
}
bool WvBackslashDecoder::flushtmpbuf(WvBuf &outbuf)
{
if (state != Initial)
return true;
if (value != -1)
{
tmpbuf.putch(value);
value = -1;
}
size_t len = tmpbuf.used();
if (len == 0)
return true;
size_t avail = outbuf.free();
if (avail > len)
avail = len;
outbuf.merge(tmpbuf, avail);
len -= avail;
if (len == 0)
{
tmpbuf.zap();
return true;
}
return false;
}
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