1 /* -*- Mode: C; tab-width: 4 -*-
2 *
3 * Copyright (c) 2008 Apple Inc. All rights reserved.
4 *
5 * Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Computer, Inc.
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9 * please do not use, install, modify or redistribute this Apple software.
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13 * copyrights in this original Apple software (the "Apple Software"), to use,
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26 * The Apple Software is provided by Apple on an "AS IS" basis. APPLE MAKES NO
27 * WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
28 * WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN
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39 */
40
41 #include <ctype.h>
42 #include <stdio.h> // For stdout, stderr
43
44 #include "ClientCommon.h"
45
GetNextLabel(const char * cstr,char label[64])46 const char *GetNextLabel(const char *cstr, char label[64])
47 {
48 char *ptr = label;
49 while (*cstr && *cstr != '.') // While we have characters in the label...
50 {
51 char c = *cstr++;
52 if (c == '\\' && *cstr) // If we have a backslash, and it's not the last character of the string
53 {
54 c = *cstr++;
55 if (isdigit(cstr[-1]) && isdigit(cstr[0]) && isdigit(cstr[1]))
56 {
57 int v0 = cstr[-1] - '0'; // then interpret as three-digit decimal
58 int v1 = cstr[ 0] - '0';
59 int v2 = cstr[ 1] - '0';
60 int val = v0 * 100 + v1 * 10 + v2;
61 // If valid three-digit decimal value, use it
62 // Note that although ascii nuls are possible in DNS labels
63 // we're building a C string here so we have no way to represent that
64 if (val == 0) val = '-';
65 if (val <= 255) { c = (char)val; cstr += 2; }
66 }
67 }
68 *ptr++ = c;
69 if (ptr >= label+64) { label[63] = 0; return(NULL); } // Illegal label more than 63 bytes
70 }
71 *ptr = 0; // Null-terminate label text
72 if (ptr == label) return(NULL); // Illegal empty label
73 if (*cstr) cstr++; // Skip over the trailing dot (if present)
74 return(cstr);
75 }
76