gecko-dev/xpcom/ds/nsCRT.cpp
2014-07-09 08:15:21 -07:00

187 lines
4.5 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/**
* 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 "nsDebug.h"
//----------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
// 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* aString, const char* aDelims, char** aNewStr)
{
NS_ASSERTION(aString,
"Unlike regular strtok, the first argument cannot be null.");
char delimTable[DELIM_TABLE_SIZE];
uint32_t i;
char* result;
char* str = aString;
for (i = 0; i < DELIM_TABLE_SIZE; ++i) {
delimTable[i] = '\0';
}
for (i = 0; aDelims[i]; i++) {
SET_DELIM(delimTable, static_cast<uint8_t>(aDelims[i]));
}
NS_ASSERTION(aDelims[i] == '\0', "too many delimiters");
// skip to beginning
while (*str && IS_DELIM(delimTable, static_cast<uint8_t>(*str))) {
str++;
}
result = str;
// fix up the end of the token
while (*str) {
if (IS_DELIM(delimTable, static_cast<uint8_t>(*str))) {
*str++ = '\0';
break;
}
str++;
}
*aNewStr = str;
return str == result ? nullptr : 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 nullptr
*
* @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
*/
int32_t
nsCRT::strcmp(const char16_t* aStr1, const char16_t* aStr2)
{
if (aStr1 && aStr2) {
for (;;) {
char16_t c1 = *aStr1++;
char16_t c2 = *aStr2++;
if (c1 != c2) {
if (c1 < c2) {
return -1;
}
return 1;
}
if (c1 == 0 || c2 == 0) {
break;
}
}
} else {
if (aStr1) { // aStr2 must have been null
return -1;
}
if (aStr2) { // aStr1 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 nullptr'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
*/
int32_t
nsCRT::strncmp(const char16_t* aStr1, const char16_t* aStr2, uint32_t aNum)
{
if (aStr1 && aStr2) {
if (aNum != 0) {
do {
char16_t c1 = *aStr1++;
char16_t c2 = *aStr2++;
if (c1 != c2) {
if (c1 < c2) {
return -1;
}
return 1;
}
} while (--aNum != 0);
}
}
return 0;
}
const char*
nsCRT::memmem(const char* aHaystack, uint32_t aHaystackLen,
const char* aNeedle, uint32_t aNeedleLen)
{
// Sanity checking
if (!(aHaystack && aNeedle && aHaystackLen && aNeedleLen &&
aNeedleLen <= aHaystackLen)) {
return nullptr;
}
#ifdef HAVE_MEMMEM
return (const char*)::memmem(aHaystack, aHaystackLen, aNeedle, aNeedleLen);
#else
// No memmem means we need to roll our own. This isn't really optimized
// for performance ... if that becomes an issue we can take some inspiration
// from the js string compare code in jsstr.cpp
for (uint32_t i = 0; i < aHaystackLen - aNeedleLen; i++) {
if (!memcmp(aHaystack + i, aNeedle, aNeedleLen)) {
return aHaystack + i;
}
}
#endif
return nullptr;
}
// This should use NSPR but NSPR isn't exporting its PR_strtoll function
// Until then...
int64_t
nsCRT::atoll(const char* aStr)
{
if (!aStr) {
return 0;
}
int64_t ll = 0;
while (*aStr && *aStr >= '0' && *aStr <= '9') {
ll *= 10;
ll += *aStr - '0';
aStr++;
}
return ll;
}