chresc.c revision 3f54fd611f536639ec30dd53c48e5ec1897cc7d9
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2012 AT&T Intellectual Property *
* and is licensed under the *
* Eclipse Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.eclipse.org/org/documents/epl-v10.html *
* (with md5 checksum b35adb5213ca9657e911e9befb180842) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
/*
* Glenn Fowler
* AT&T Research
*
* return the next character in the string s
* \ character constants are expanded
* *p is updated to point to the next character in s
* *m is 1 if return value is wide
*/
#include <ast.h>
#include <ctype.h>
#include <ccode.h>
#if !_PACKAGE_astsa
#include <regex.h>
#endif
int
chrexp(register const char* s, char** p, int* m, register int flags)
{
register const char* q;
register int c;
const char* e;
const char* b;
char* r;
int n;
int w;
w = 0;
for (;;)
{
b = s;
switch (c = mbchar(s))
{
case 0:
s--;
break;
case '\\':
switch (c = *s++)
{
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
if (!(flags & FMT_EXP_CHAR))
goto noexpand;
c -= '0';
q = s + 2;
while (s < q)
switch (*s)
{
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
c = (c << 3) + *s++ - '0';
break;
default:
q = s;
break;
}
break;
case 'a':
if (!(flags & FMT_EXP_CHAR))
goto noexpand;
c = CC_bel;
break;
case 'b':
if (!(flags & FMT_EXP_CHAR))
goto noexpand;
c = '\b';
break;
case 'c': /*DEPRECATED*/
case 'C':
if (!(flags & FMT_EXP_CHAR))
goto noexpand;
if (c = *s)
{
s++;
if (c == '\\')
{
c = chrexp(s - 1, &r, 0, flags);
s = (const char*)r;
}
if (islower(c))
c = toupper(c);
c = ccmapc(c, CC_NATIVE, CC_ASCII);
c ^= 0x40;
c = ccmapc(c, CC_ASCII, CC_NATIVE);
}
break;
case 'e': /*DEPRECATED*/
case 'E':
if (!(flags & FMT_EXP_CHAR))
goto noexpand;
c = CC_esc;
break;
case 'f':
if (!(flags & FMT_EXP_CHAR))
goto noexpand;
c = '\f';
break;
case 'M':
if (!(flags & FMT_EXP_CHAR))
goto noexpand;
if (*s == '-')
{
s++;
c = CC_esc;
}
break;
case 'n':
if (flags & FMT_EXP_NONL)
continue;
if (!(flags & FMT_EXP_LINE))
goto noexpand;
c = '\n';
break;
case 'r':
if (flags & FMT_EXP_NOCR)
continue;
if (!(flags & FMT_EXP_LINE))
goto noexpand;
c = '\r';
break;
case 't':
if (!(flags & FMT_EXP_CHAR))
goto noexpand;
c = '\t';
break;
case 'v':
if (!(flags & FMT_EXP_CHAR))
goto noexpand;
c = CC_vt;
break;
case 'u':
case 'U':
case 'x':
if (q = c == 'u' ? (s + 4) : c == 'U' ? (s + 8) : (char*)0)
{
if (!(flags & FMT_EXP_WIDE))
goto noexpand;
w = 1;
}
b = e = s;
n = 0;
c = 0;
while (!e || !q || s < q)
{
switch (*s)
{
case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
c = (c << 4) + *s++ - 'a' + 10;
n++;
continue;
case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
c = (c << 4) + *s++ - 'A' + 10;
n++;
continue;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
c = (c << 4) + *s++ - '0';
n++;
continue;
case '{':
case '[':
if (s != e)
break;
e = 0;
s++;
if (w && *s == 'U' && *(s + 1) == '+')
s += 2;
continue;
case '}':
case ']':
if (!e)
s++;
break;
default:
break;
}
break;
}
if (n <= 2 && !(flags & FMT_EXP_CHAR) || n > 2 && (w = 1) && !(flags & FMT_EXP_WIDE))
{
c = '\\';
s = b;
}
break;
case 0:
s--;
break;
}
break;
default:
if ((s - b) > 1)
w = 1;
break;
}
break;
}
normal:
if (p)
*p = (char*)s;
if (m)
*m = w;
return c;
noexpand:
c = '\\';
s--;
goto normal;
}
int
chresc(register const char* s, char** p)
{
return chrexp(s, p, NiL, FMT_EXP_CHAR|FMT_EXP_LINE|FMT_EXP_WIDE);
}