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pjs/xpcom/ds/nsCRT.cpp

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C++
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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/**
* MODULE NOTES:
* @update gess7/30/98
*
* Much as I hate to do it, we were using string compares wrong.
* Often, programmers call functions like strcmp(s1,s2), and pass
* one or more null strings. Rather than blow up on these, I've
* added quick checks to ensure that cases like this don't cause
* us to fail.
*
* In general, if you pass a null into any of these string compare
* routines, we simply return 0.
*/
#include "nsCRT.h"
#include "nsIServiceManager.h"
#include "nsCharTraits.h"
#include "prbit.h"
#define ADD_TO_HASHVAL(hashval, c) \
hashval = PR_ROTATE_LEFT32(hashval, 4) ^ (c);
//----------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
// My lovely strtok routine
#define IS_DELIM(m, c) ((m)[(c) >> 3] & (1 << ((c) & 7)))
#define SET_DELIM(m, c) ((m)[(c) >> 3] |= (1 << ((c) & 7)))
#define DELIM_TABLE_SIZE 32
char* nsCRT::strtok(char* string, const char* delims, char* *newStr)
{
NS_ASSERTION(string, "Unlike regular strtok, the first argument cannot be null.");
char delimTable[DELIM_TABLE_SIZE];
PRUint32 i;
char* result;
char* str = string;
for (i = 0; i < DELIM_TABLE_SIZE; i++)
delimTable[i] = '\0';
for (i = 0; delims[i]; i++) {
SET_DELIM(delimTable, static_cast<PRUint8>(delims[i]));
}
NS_ASSERTION(delims[i] == '\0', "too many delimiters");
// skip to beginning
while (*str && IS_DELIM(delimTable, static_cast<PRUint8>(*str))) {
str++;
}
result = str;
// fix up the end of the token
while (*str) {
if (IS_DELIM(delimTable, static_cast<PRUint8>(*str))) {
*str++ = '\0';
break;
}
str++;
}
*newStr = str;
return str == result ? NULL : result;
}
////////////////////////////////////////////////////////////////////////////////
/**
* Compare unichar string ptrs, stopping at the 1st null
* NOTE: If both are null, we return 0.
* NOTE: We terminate the search upon encountering a NULL
*
* @update gess 11/10/99
* @param s1 and s2 both point to unichar strings
* @return 0 if they match, -1 if s1<s2; 1 if s1>s2
*/
PRInt32 nsCRT::strcmp(const PRUnichar* s1, const PRUnichar* s2) {
if(s1 && s2) {
for (;;) {
PRUnichar c1 = *s1++;
PRUnichar c2 = *s2++;
if (c1 != c2) {
if (c1 < c2) return -1;
return 1;
}
if ((0==c1) || (0==c2)) break;
}
}
else {
if (s1) // s2 must have been null
return -1;
if (s2) // s1 must have been null
return 1;
}
return 0;
}
/**
* Compare unichar string ptrs, stopping at the 1st null or nth char.
* NOTE: If either is null, we return 0.
* NOTE: We DO NOT terminate the search upon encountering NULL's before N
*
* @update gess 11/10/99
* @param s1 and s2 both point to unichar strings
* @return 0 if they match, -1 if s1<s2; 1 if s1>s2
*/
PRInt32 nsCRT::strncmp(const PRUnichar* s1, const PRUnichar* s2, PRUint32 n) {
if(s1 && s2) {
if(n != 0) {
do {
PRUnichar c1 = *s1++;
PRUnichar c2 = *s2++;
if (c1 != c2) {
if (c1 < c2) return -1;
return 1;
}
} while (--n != 0);
}
}
return 0;
}
PRUnichar* nsCRT::strdup(const PRUnichar* str)
{
PRUint32 len = nsCRT::strlen(str);
return strndup(str, len);
}
PRUnichar* nsCRT::strndup(const PRUnichar* str, PRUint32 len)
{
nsCppSharedAllocator<PRUnichar> shared_allocator;
PRUnichar* rslt = shared_allocator.allocate(len + 1); // add one for the null
// PRUnichar* rslt = new PRUnichar[len + 1];
if (rslt == NULL) return NULL;
memcpy(rslt, str, len * sizeof(PRUnichar));
rslt[len] = 0;
return rslt;
}
/**
* |nsCRT::HashCode| is identical to |PL_HashString|, which tests
* (http://bugzilla.mozilla.org/showattachment.cgi?attach_id=26596)
* show to be the best hash among several other choices.
*
* We re-implement it here rather than calling it for two reasons:
* (1) in this interface, we also calculate the length of the
* string being hashed; and (2) the narrow and wide and `buffer' versions here
* will hash equivalent strings to the same value, e.g., "Hello" and L"Hello".
*/
PRUint32 nsCRT::HashCode(const char* str, PRUint32* resultingStrLen)
{
PRUint32 h = 0;
const char* s = str;
if (!str) return h;
unsigned char c;
while ( (c = *s++) )
ADD_TO_HASHVAL(h, c);
if ( resultingStrLen )
*resultingStrLen = (s-str)-1;
return h;
}
PRUint32 nsCRT::HashCode(const char* start, PRUint32 length)
{
PRUint32 h = 0;
const char* s = start;
const char* end = start + length;
unsigned char c;
while ( s < end ) {
c = *s++;
ADD_TO_HASHVAL(h, c);
}
return h;
}
PRUint32 nsCRT::HashCode(const PRUnichar* str, PRUint32* resultingStrLen)
{
PRUint32 h = 0;
const PRUnichar* s = str;
if (!str) return h;
PRUnichar c;
while ( (c = *s++) )
ADD_TO_HASHVAL(h, c);
if ( resultingStrLen )
*resultingStrLen = (s-str)-1;
return h;
}
PRUint32 nsCRT::HashCodeAsUTF8(const PRUnichar* start, PRUint32 length)
{
PRUint32 h = 0;
const PRUnichar* s = start;
const PRUnichar* end = start + length;
PRUint16 W1 = 0; // the first UTF-16 word in a two word tuple
PRUint32 U = 0; // the current char as UCS-4
int code_length = 0; // the number of bytes in the UTF-8 sequence for the current char
PRUint16 W;
while ( s < end )
{
W = *s++;
/*
* On the fly, decoding from UTF-16 (and/or UCS-2) into UTF-8 as per
* http://www.ietf.org/rfc/rfc2781.txt
* http://www.ietf.org/rfc/rfc3629.txt
*/
if ( !W1 )
{
if ( !IS_SURROGATE(W) )
{
U = W;
if ( W <= 0x007F )
code_length = 1;
else if ( W <= 0x07FF )
code_length = 2;
else
code_length = 3;
}
else if ( NS_IS_HIGH_SURROGATE(W) && s < end)
{
W1 = W;
continue;
}
else
{
// Treat broken characters as the Unicode replacement
// character 0xFFFD
U = 0xFFFD;
code_length = 3;
NS_WARNING("Got low surrogate but no previous high surrogate");
}
}
else
{
// as required by the standard, this code is careful to
// throw out illegal sequences
if ( NS_IS_LOW_SURROGATE(W) )
{
U = SURROGATE_TO_UCS4(W1, W);
NS_ASSERTION(IS_VALID_CHAR(U), "How did this happen?");
code_length = 4;
}
else
{
// Treat broken characters as the Unicode replacement
// character 0xFFFD
U = 0xFFFD;
code_length = 3;
NS_WARNING("High surrogate not followed by low surrogate");
// The pointer to the next character points to the second 16-bit
// value, not beyond it, as per Unicode 5.0.0 Chapter 3 C10, only
// the first code unit of an illegal sequence must be treated as
// an illegally terminated code unit sequence (also Chapter 3
// D91, "isolated [not paired and ill-formed] UTF-16 code units
// in the range D800..DFFF are ill-formed").
--s;
}
W1 = 0;
}
static const PRUint16 sBytePrefix[5] = { 0x0000, 0x0000, 0x00C0, 0x00E0, 0x00F0 };
static const PRUint16 sShift[5] = { 0, 0, 6, 12, 18 };
/*
* Unlike the algorithm in
* http://www.ietf.org/rfc/rfc3629.txt we must calculate the
* bytes in left to right order so that our hash result
* matches what the narrow version would calculate on an
* already UTF-8 string.
*/
// hash the first (and often, only, byte)
ADD_TO_HASHVAL(h, (sBytePrefix[code_length] | (U>>sShift[code_length])));
// an unrolled loop for hashing any remaining bytes in this
// sequence
switch ( code_length )
{ // falling through in each case
case 4: ADD_TO_HASHVAL(h, (0x80 | ((U>>12) & 0x003F)));
case 3: ADD_TO_HASHVAL(h, (0x80 | ((U>>6 ) & 0x003F)));
case 2: ADD_TO_HASHVAL(h, (0x80 | ( U & 0x003F)));
default: code_length = 0;
break;
}
}
return h;
}
PRUint32 nsCRT::BufferHashCode(const PRUnichar* s, PRUint32 len)
{
PRUint32 h = 0;
const PRUnichar* done = s + len;
while ( s < done )
h = PR_ROTATE_LEFT32(h, 4) ^ PRUint16(*s++); // cast to unsigned to prevent possible sign extension
return h;
}
// This should use NSPR but NSPR isn't exporting its PR_strtoll function
// Until then...
PRInt64 nsCRT::atoll(const char *str)
{
if (!str)
return LL_Zero();
PRInt64 ll = LL_Zero(), digitll = LL_Zero();
while (*str && *str >= '0' && *str <= '9') {
LL_MUL(ll, ll, 10);
LL_UI2L(digitll, (*str - '0'));
LL_ADD(ll, ll, digitll);
str++;
}
return ll;
}
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