aosp12/external/mdnsresponder/Clients/ClientCommon.c

76 lines
3.6 KiB
C

/* -*- Mode: C; tab-width: 4 -*-
*
* Copyright (c) 2008 Apple Inc. All rights reserved.
*
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#include <ctype.h>
#include <stdio.h> // For stdout, stderr
#include "ClientCommon.h"
const char *GetNextLabel(const char *cstr, char label[64])
{
char *ptr = label;
while (*cstr && *cstr != '.') // While we have characters in the label...
{
char c = *cstr++;
if (c == '\\' && *cstr) // If we have a backslash, and it's not the last character of the string
{
c = *cstr++;
if (isdigit(cstr[-1]) && isdigit(cstr[0]) && isdigit(cstr[1]))
{
int v0 = cstr[-1] - '0'; // then interpret as three-digit decimal
int v1 = cstr[ 0] - '0';
int v2 = cstr[ 1] - '0';
int val = v0 * 100 + v1 * 10 + v2;
// If valid three-digit decimal value, use it
// Note that although ascii nuls are possible in DNS labels
// we're building a C string here so we have no way to represent that
if (val == 0) val = '-';
if (val <= 255) { c = (char)val; cstr += 2; }
}
}
*ptr++ = c;
if (ptr >= label+64) { label[63] = 0; return(NULL); } // Illegal label more than 63 bytes
}
*ptr = 0; // Null-terminate label text
if (ptr == label) return(NULL); // Illegal empty label
if (*cstr) cstr++; // Skip over the trailing dot (if present)
return(cstr);
}