chrtoi.c

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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 Bell Laboratories
 *
 * convert a 0 terminated character constant string to an int
 */
 
#include <ast/ast.h>
#include <limits.h>
#include <stddef.h>
 
int chrtoi(const char *s)
{
    int c;
    int x;
    char *p;
 
    c = 0;
    for (size_t n = 0; n < sizeof(int) * CHAR_BIT; n += CHAR_BIT) {
        switch (x = *((const unsigned char *) s++)) {
        case '\\':
            x = chresc(s - 1, &p);
            s = p;
            break;
        case 0:
            return (c);
        default: // nothing required
            break;
        }
        c = (c << CHAR_BIT) | x;
    }
    return (c);
}