ref: fb6fd61f3ec5bc98fab5ad8e0d6fec95c70d643a
dir: /src/ext4_bitmap.c/
/* * Copyright (c) 2013 Grzegorz Kostka ([email protected]) * All rights reserved. * * 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. * - The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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. */ /** @addtogroup lwext4 * @{ */ /** * @file ext4_bitmap.c * @brief Block/inode bitmap allocator. */ #include "ext4_config.h" #include "ext4_types.h" #include "ext4_misc.h" #include "ext4_errno.h" #include "ext4_debug.h" #include "ext4_bitmap.h" void ext4_bmap_bits_free(uint8_t *bmap, uint32_t sbit, uint32_t bcnt) { uint32_t i = sbit; while (i & 7) { if (!bcnt) return; ext4_bmap_bit_clr(bmap, i); bcnt--; i++; } sbit = i; bmap += (sbit >> 3); #if CONFIG_UNALIGNED_ACCESS while (bcnt >= 32) { *(uint32_t *)bmap = 0; bmap += 4; bcnt -= 32; sbit += 32; } while (bcnt >= 16) { *(uint16_t *)bmap = 0; bmap += 2; bcnt -= 16; sbit += 16; } #endif while (bcnt >= 8) { *bmap = 0; bmap += 1; bcnt -= 8; sbit += 8; } for (i = 0; i < bcnt; ++i) { ext4_bmap_bit_clr(bmap, i); } } int ext4_bmap_bit_find_clr(uint8_t *bmap, uint32_t sbit, uint32_t ebit, uint32_t *bit_id) { uint32_t i; uint32_t bcnt = ebit - sbit; i = sbit; while (i & 7) { if (!bcnt) return ENOSPC; if (ext4_bmap_is_bit_clr(bmap, i)) { *bit_id = sbit; return EOK; } i++; bcnt--; } sbit = i; bmap += (sbit >> 3); #if CONFIG_UNALIGNED_ACCESS while (bcnt >= 32) { if (*(uint32_t *)bmap != 0xFFFFFFFF) goto finish_it; bmap += 4; bcnt -= 32; sbit += 32; } while (bcnt >= 16) { if (*(uint16_t *)bmap != 0xFFFF) goto finish_it; bmap += 2; bcnt -= 16; sbit += 16; } finish_it: #endif while (bcnt >= 8) { if (*bmap != 0xFF) { for (i = 0; i < 8; ++i) { if (ext4_bmap_is_bit_clr(bmap, i)) { *bit_id = sbit + i; return EOK; } } } bmap += 1; bcnt -= 8; sbit += 8; } for (i = 0; i < bcnt; ++i) { if (ext4_bmap_is_bit_clr(bmap, i)) { *bit_id = sbit + i; return EOK; } } return ENOSPC; } /** * @} */