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/*
* Copyright (c) 2015-2016, Intel Corporation
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Intel Corporation nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef COMPARE_H
#define COMPARE_H
#include "unaligned.h"
#include "ue2common.h"
/* Our own definitions of tolower, toupper and isalpha are provided to prevent
* us from going out to libc for these tests. */
static really_inline
char myisupper(const char c) {
return ((c >= 'A') && (c <= 'Z'));
}
static really_inline
char myislower(const char c) {
return ((c >= 'a') && (c <= 'z'));
}
static really_inline
char mytolower(const char c) {
if (myisupper(c)) {
return c + 0x20;
}
return c;
}
static really_inline
char mytoupper(const char c) {
if (myislower(c)) {
return c - 0x20;
}
return c;
}
/* this is a slightly warped definition of `alpha'. What we really
* mean is: does this character have different uppercase and lowercase forms?
*/
static really_inline char ourisalpha(const char c) {
return mytolower(c) != mytoupper(c);
}
static really_inline char ourisprint(const char c) {
return c >= 0x20 && c <= 0x7e;
}
// Paul Hsieh's SWAR toupper; used because it doesn't
// matter whether we go toupper or tolower. We should
// probably change the other one
static really_inline
u32 theirtoupper32(const u32 x) {
u32 b = 0x80808080ul | x;
u32 c = b - 0x61616161ul;
u32 d = ~(b - 0x7b7b7b7bul);
u32 e = (c & d) & (~x & 0x80808080ul);
return x - (e >> 2);
}
// 64-bit variant.
static really_inline
u64a theirtoupper64(const u64a x) {
u64a b = 0x8080808080808080ull | x;
u64a c = b - 0x6161616161616161ull;
u64a d = ~(b - 0x7b7b7b7b7b7b7b7bull);
u64a e = (c & d) & (~x & 0x8080808080808080ull);
u64a v = x - (e >> 2);
return v;
}
static really_inline
int cmpNocaseNaive(const u8 *p1, const u8 *p2, size_t len) {
const u8 *pEnd = p1 + len;
for (; p1 < pEnd; p1++, p2++) {
assert(!ourisalpha(*p2) || myisupper(*p2)); // Already upper-case.
if ((u8)mytoupper(*p1) != *p2) {
return 1;
}
}
return 0;
}
static really_inline
int cmpCaseNaive(const u8 *p1, const u8 *p2, size_t len) {
const u8 *pEnd = p1 + len;
for (; p1 < pEnd; p1++, p2++) {
if (*p1 != *p2) {
return 1;
}
}
return 0;
}
#ifdef ARCH_64_BIT
# define CMP_T u64a
# define ULOAD(x) unaligned_load_u64a(x)
# define TOUPPER(x) theirtoupper64(x)
#else
# define CMP_T u32
# define ULOAD(x) unaligned_load_u32(x)
# define TOUPPER(x) theirtoupper32(x)
#endif
#define CMP_SIZE sizeof(CMP_T)
/**
* \brief Compare two strings, optionally caselessly.
*
* Note: If nocase is true, p2 is assumed to be already upper-case.
*/
#if defined(ARCH_IA32)
static UNUSED never_inline
#else
static really_inline
#endif
int cmpForward(const u8 *p1, const u8 *p2, size_t len, char nocase) {
if (len < CMP_SIZE) {
return nocase ? cmpNocaseNaive(p1, p2, len)
: cmpCaseNaive(p1, p2, len);
}
const u8 *p1_end = p1 + len - CMP_SIZE;
const u8 *p2_end = p2 + len - CMP_SIZE;
if (nocase) { // Case-insensitive version.
for (; p1 < p1_end; p1 += CMP_SIZE, p2 += CMP_SIZE) {
assert(ULOAD(p2) == TOUPPER(ULOAD(p2))); // Already upper-case.
if (TOUPPER(ULOAD(p1)) != ULOAD(p2)) {
return 1;
}
}
assert(ULOAD(p2_end) == TOUPPER(ULOAD(p2_end))); // Already upper-case.
if (TOUPPER(ULOAD(p1_end)) != ULOAD(p2_end)) {
return 1;
}
} else { // Case-sensitive version.
for (; p1 < p1_end; p1 += CMP_SIZE, p2 += CMP_SIZE) {
if (ULOAD(p1) != ULOAD(p2)) {
return 1;
}
}
if (ULOAD(p1_end) != ULOAD(p2_end)) {
return 1;
}
}
return 0;
}
#undef CMP_T
#undef ULOAD
#undef TOUPPER
#undef CMP_SIZE
#endif
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