mirror of
https://gitlab.com/gnuwget/wget2.git
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139 lines
3.1 KiB
C
139 lines
3.1 KiB
C
/*
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* Copyright (c) 2018-2024 Free Software Foundation, Inc.
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*
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* This file is part of libwget.
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*
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* Libwget is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Libwget is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with libwget. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <wget.h>
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#include "private.h"
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/**
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* \file
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* \brief Functions for bitmap
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* \defgroup libwget-bitmap Bitmap management functions
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*
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* @{
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*
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* Bitmap (bit array) implementation.
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*
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* This is useful when you need a bitmap with more than 64 bits. Up to 64 bits you can
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* use the C99 uint64_t as a standard C bitfield.
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*
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* As a usage example, Wget2 uses bitmaps for options with lists of HTTP status codes, which have values
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* of 100-699.
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*
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*/
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#define bitmap_type uint64_t
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#define bitmap_bits (sizeof(bitmap_type) * 8)
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#define bitmap_shift 6 // ln(bitmap_bits)/ln(2)
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#define map(n) (((wget_bitmap *)b)->map[(n) >> bitmap_shift])
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#define bit(n) (((bitmap_type) 1) << ((n) & (bitmap_bits - 1)))
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struct wget_bitmap_st {
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bitmap_type
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bits;
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bitmap_type
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map[];
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};
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/**
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* \param b Bitmap to act on
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* \param n Number of the bit to set (0-...)
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*
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* Set the bit \p n in the bitmap \p b.
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*/
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void wget_bitmap_set(wget_bitmap *b, unsigned n)
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{
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if (b && n < ((wget_bitmap *) b)->bits)
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map(n) |= bit(n);
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}
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/**
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* \param b Bitmap to act on
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* \param n Number of the bit to clear (0-...)
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*
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* Clear the bit \p n in the bitmap \p b.
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*/
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void wget_bitmap_clear(wget_bitmap *b, unsigned n)
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{
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if (b && n < ((wget_bitmap *) b)->bits)
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map(n) &= ~bit(n);
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}
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/**
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* \param[in] b Bitmap to read from
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* \param[in] n Number of the bit of interest (0-...)
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* \return
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* 0 if bit \p n is cleared or if \p n is out of range
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* 1 if bit \p is set
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*
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* Returns whether the bit \p n is set or not.
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*/
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bool wget_bitmap_get(const wget_bitmap *b, unsigned n)
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{
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if (b && n < ((wget_bitmap *) b)->bits)
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return (map(n) & bit(n)) != 0;
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return 0;
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}
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/**
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* \param[out] b Pointer to the allocated bitmap
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* \param[in] bits Number of bits
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* \return A \ref wget_error value
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*
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* Allocates a bitmap with a capacity of \p bits.
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* It must be freed by wget_bitmap_free() after usage.
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*/
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int wget_bitmap_init(wget_bitmap **b, unsigned bits)
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{
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if (!b)
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return WGET_E_INVALID;
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wget_bitmap *_b =
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wget_calloc((bits + sizeof(bitmap_type) - 1) / sizeof(bitmap_type) + 1, sizeof(bitmap_type));
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if (!_b)
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return WGET_E_MEMORY;
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_b->bits = bits;
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*b = _b;
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return WGET_E_SUCCESS;
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}
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/**
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* \param[in] b Pointer to bitmap to free
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*
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* Frees and clears the bitmap pointed to by \p b.
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*/
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void wget_bitmap_free(wget_bitmap **b)
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{
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if (b)
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xfree(*b);
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}
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/** @} */
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