/*
* Copyright (c) 2020 Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* $Id: //eng/uds-releases/jasper/src/uds/bits.c#1 $
*/
#include "bits.h"
#include "compiler.h"
/**
* This is the largest field size supported by getBigField & setBigField.
* Any field that is larger is not guaranteed to fit in a single, byte
* aligned uint64_t.
**/
enum { MAX_BIG_FIELD_BITS = (sizeof(uint64_t) - 1) * CHAR_BIT + 1 };
/**
* Get a big bit field from a bit stream
*
* @param memory The base memory byte address
* @param offset The bit offset into the memory for the start of the field
* @param size The number of bits in the field
*
* @return the bit field
**/
static INLINE uint64_t getBigField(const byte *memory,
uint64_t offset,
int size)
{
const void *addr = memory + offset / CHAR_BIT;
return (getUInt64LE(addr) >> (offset % CHAR_BIT)) & ((1UL << size) - 1);
}
/**
* Set a big bit field in a bit stream
*
* @param value The value to put into the field
* @param memory The base memory byte address
* @param offset The bit offset into the memory for the start of the field
* @param size The number of bits in the field
*
* @return the bit field
**/
static INLINE void setBigField(uint64_t value, byte *memory, uint64_t offset,
int size)
{
void *addr = memory + offset / CHAR_BIT;
int shift = offset % CHAR_BIT;
uint64_t data = getUInt64LE(addr);
data &= ~(((1UL << size) - 1) << shift);
data |= value << shift;
storeUInt64LE(addr, data);
}
/***********************************************************************/
void getBytes(const byte *memory, uint64_t offset, byte *destination, int size)
{
const byte *addr = memory + offset / CHAR_BIT;
int shift = offset % CHAR_BIT;
while (--size >= 0) {
*destination++ = getUInt16LE(addr++) >> shift;
}
}
/***********************************************************************/
void setBytes(byte *memory, uint64_t offset, const byte *source, int size)
{
byte *addr = memory + offset / CHAR_BIT;
int shift = offset % CHAR_BIT;
uint16_t mask = ~((uint16_t) 0xFF << shift);
while (--size >= 0) {
uint16_t data = (getUInt16LE(addr) & mask) | (*source++ << shift);
storeUInt16LE(addr++, data);
}
}
/***********************************************************************/
void moveBits(const byte *sMemory, uint64_t source, byte *dMemory,
uint64_t destination, int size)
{
enum { UINT32_BIT = sizeof(uint32_t) * CHAR_BIT };
if (size > MAX_BIG_FIELD_BITS) {
if (source > destination) {
// This is a large move from a higher to a lower address. We move
// the lower addressed bits first. Start by moving one field that
// ends on a destination int boundary
int count
= MAX_BIG_FIELD_BITS - (destination + MAX_BIG_FIELD_BITS) % UINT32_BIT;
uint64_t field = getBigField(sMemory, source, count);
setBigField(field, dMemory, destination, count);
source += count;
destination += count;
size -= count;
// Now do the main loop to copy 32 bit chunks that are int-aligned
// at the destination.
int offset = source % UINT32_BIT;
const byte *src = sMemory + (source - offset) / CHAR_BIT;
byte *dest = dMemory + destination / CHAR_BIT;
while (size > MAX_BIG_FIELD_BITS) {
storeUInt32LE(dest, getUInt64LE(src) >> offset);
src += sizeof(uint32_t);
dest += sizeof(uint32_t);
source += UINT32_BIT;
destination += UINT32_BIT;
size -= UINT32_BIT;
}
} else {
// This is a large move from a lower to a higher address. We move
// the higher addressed bits first. Start by moving one field that
// begins on a destination int boundary
int count = (destination + size) % UINT32_BIT;
if (count > 0) {
size -= count;
uint64_t field = getBigField(sMemory, source + size, count);
setBigField(field, dMemory, destination + size, count);
}
// Now do the main loop to copy 32 bit chunks that are int-aligned
// at the destination.
int offset = (source + size) % UINT32_BIT;
const byte *src = sMemory + (source + size - offset) / CHAR_BIT;
byte *dest = dMemory + (destination + size) / CHAR_BIT;
while (size > MAX_BIG_FIELD_BITS) {
src -= sizeof(uint32_t);
dest -= sizeof(uint32_t);
size -= UINT32_BIT;
storeUInt32LE(dest, getUInt64LE(src) >> offset);
}
}
}
// Finish up by doing the last chunk, which can have any arbitrary alignment
if (size > 0) {
uint64_t field = getBigField(sMemory, source, size);
setBigField(field, dMemory, destination, size);
}
}
/***********************************************************************/
bool sameBits(const byte *mem1, uint64_t offset1, const byte *mem2,
uint64_t offset2, int size)
{
while (size >= MAX_FIELD_BITS) {
unsigned int field1 = getField(mem1, offset1, MAX_FIELD_BITS);
unsigned int field2 = getField(mem2, offset2, MAX_FIELD_BITS);
if (field1 != field2) return false;
offset1 += MAX_FIELD_BITS;
offset2 += MAX_FIELD_BITS;
size -= MAX_FIELD_BITS;
}
if (size > 0) {
unsigned int field1 = getField(mem1, offset1, size);
unsigned int field2 = getField(mem2, offset2, size);
if (field1 != field2) return false;
}
return true;
}