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/*************************************************************************
* Copyright (c) 2011 AT&T Intellectual Property
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-v10.html
*
* Contributors: Details at https://graphviz.org
*************************************************************************/
/*
* Glenn Fowler
* AT&T Research
*
* return the next character in the string s
* \ character constants are converted
* p is updated to point to the next character in s
*/
#include <ast/ast.h>
int chresc(const char *s, char **p)
{
const char *q;
int c;
switch (c = *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':
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':
c = CC_bel;
break;
case 'b':
c = '\b';
break;
case 'f':
c = '\f';
break;
case 'n':
c = '\n';
break;
case 'r':
c = '\r';
break;
case 's':
c = ' ';
break;
case 't':
c = '\t';
break;
case 'v':
c = CC_vt;
break;
case 'x':
c = 0;
q = s;
while (q)
switch (*s) {
case 'a':
case 'b':
case 'c':
case 'd':
case 'e':
case 'f':
c = (c << 4) + *s++ - 'a' + 10;
break;
case 'A':
case 'B':
case 'C':
case 'D':
case 'E':
case 'F':
c = (c << 4) + *s++ - 'A' + 10;
break;
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';
break;
default:
q = 0;
break;
}
break;
case 'E':
c = CC_esc;
break;
case 0:
s--;
break;
default:
break;
}
break;
default:
break;
}
if (p)
*p = (char *) s;
return c;
}
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