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/*
This file is part of the KDE libraries
SPDX-FileCopyrightText: 2008 Jakub Stachowski <qbast@go2.pl>
SPDX-License-Identifier: LGPL-2.0-or-later
*/
#ifndef BUFFERFRAGMENT_H
#define BUFFERFRAGMENT_H
#include "kconfigini_p.h"
#define bf_isspace(str) ((str == ' ') || (str == '\t') || (str == '\r'))
// This class provides wrapper around fragment of existing buffer (array of bytes).
// If underlying buffer gets deleted, all BufferFragment objects referencing it become invalid.
// Use toByteArray() to make deep copy of the buffer fragment.
//
// API is designed to subset of QByteArray methods with some changes:
// - trim() is like QByteArray.trimmed(), but it modifies current object
// - truncateLeft() provides way to cut off beginning of the buffer
// - split() works more like strtok_r than QByteArray.split()
// - truncateLeft() and mid() require position argument to be valid
class KConfigIniBackend::BufferFragment
{
public:
BufferFragment() : d(nullptr), len(0)
{
}
BufferFragment(char *buf, int size) : d(buf), len(size)
{
}
int length() const
{
return len;
}
char at(unsigned int i) const
{
Q_ASSERT(i < len);
return d[i];
}
void clear()
{
len = 0;
}
const char *constData() const
{
return d;
}
char *data() const
{
return d;
}
void trim()
{
while (bf_isspace(*d) && len > 0) {
d++;
len--;
}
while (len > 0 && bf_isspace(d[len - 1])) {
len--;
}
}
// similar to strtok_r . On first call variable pointed by start should be set to 0.
// Each call will update *start to new starting position.
BufferFragment split(char c, unsigned int *start)
{
while (*start < len) {
int end = indexOf(c, *start);
if (end == -1) {
end = len;
}
BufferFragment line(d + (*start), end - (*start));
*start = end + 1;
return line;
}
return BufferFragment();
}
bool isEmpty() const
{
return !len;
}
BufferFragment left(unsigned int size) const
{
return BufferFragment(d, qMin(size, len));
}
void truncateLeft(unsigned int size)
{
Q_ASSERT(size <= len);
d += size;
len -= size;
}
void truncate(unsigned int pos)
{
if (pos < len) {
len = pos;
}
}
bool isNull() const
{
return !d;
}
BufferFragment mid(unsigned int pos, int length = -1) const
{
Q_ASSERT(pos < len);
int size = length;
if (length == -1 || (pos + length) > len) {
size = len - pos;
}
return BufferFragment(d + pos, size);
}
bool operator==(const QByteArray &other) const
{
return (other.size() == (int)len && memcmp(d, other.constData(), len) == 0);
}
bool operator!=(const QByteArray &other) const
{
return (other.size() != (int)len || memcmp(d, other.constData(), len) != 0);
}
bool operator==(const BufferFragment other) const
{
return other.len == len && !memcmp(d, other.d, len);
}
int indexOf(char c, unsigned int from = 0) const
{
const char *cursor = d + from - 1;
const char *end = d + len;
while (++cursor < end)
if (*cursor == c) {
return cursor - d;
}
return -1;
}
int lastIndexOf(char c) const
{
int from = len - 1;
while (from >= 0)
if (d[from] == c) {
return from;
} else {
from--;
}
return -1;
}
QByteArray toByteArray() const
{
return QByteArray(d, len);
}
// this is faster than toByteArray, but returned QByteArray becomes invalid
// when buffer for this BufferFragment disappears
QByteArray toVolatileByteArray() const
{
return QByteArray::fromRawData(d, len);
}
private:
char *d;
unsigned int len;
};
uint qHash(const KConfigIniBackend::BufferFragment fragment)
{
const uchar *p = reinterpret_cast<const uchar*>(fragment.constData());
const int len = fragment.length();
// This algorithm is copied from qhash.cpp (Qt5 version).
// Sadly this code is not accessible from the outside without going through abstraction
// layers. Even QByteArray::fromRawData would do an allocation internally...
uint h = 0;
for (int i = 0; i < len; ++i) {
h = 31 * h + p[i];
}
return h;
}
#endif
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