| /* |
| * Copyright (c) 2015 Damien Miller <djm@mindrot.org> |
| * |
| * Permission to use, copy, modify, and distribute this software for any |
| * purpose with or without fee is hereby granted, provided that the above |
| * copyright notice and this permission notice appear in all copies. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
| * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
| * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| */ |
| |
| #include "includes.h" |
| |
| #include <sys/types.h> |
| #include <string.h> |
| #include <stdlib.h> |
| |
| #include "bitmap.h" |
| |
| #define BITMAP_WTYPE u_int |
| #define BITMAP_MAX (1<<24) |
| #define BITMAP_BYTES (sizeof(BITMAP_WTYPE)) |
| #define BITMAP_BITS (sizeof(BITMAP_WTYPE) * 8) |
| #define BITMAP_WMASK ((BITMAP_WTYPE)BITMAP_BITS - 1) |
| struct bitmap { |
| BITMAP_WTYPE *d; |
| size_t len; /* number of words allocated */ |
| size_t top; /* index of top word allocated */ |
| }; |
| |
| struct bitmap * |
| bitmap_new(void) |
| { |
| struct bitmap *ret; |
| |
| if ((ret = calloc(1, sizeof(*ret))) == NULL) |
| return NULL; |
| if ((ret->d = calloc(1, BITMAP_BYTES)) == NULL) { |
| free(ret); |
| return NULL; |
| } |
| ret->len = 1; |
| ret->top = 0; |
| return ret; |
| } |
| |
| void |
| bitmap_free(struct bitmap *b) |
| { |
| if (b != NULL && b->d != NULL) { |
| bitmap_zero(b); |
| free(b->d); |
| b->d = NULL; |
| } |
| free(b); |
| } |
| |
| void |
| bitmap_zero(struct bitmap *b) |
| { |
| memset(b->d, 0, b->len * BITMAP_BYTES); |
| b->top = 0; |
| } |
| |
| int |
| bitmap_test_bit(struct bitmap *b, u_int n) |
| { |
| if (b->top >= b->len) |
| return 0; /* invalid */ |
| if (b->len == 0 || (n / BITMAP_BITS) > b->top) |
| return 0; |
| return (b->d[n / BITMAP_BITS] >> (n & BITMAP_WMASK)) & 1; |
| } |
| |
| static int |
| reserve(struct bitmap *b, u_int n) |
| { |
| BITMAP_WTYPE *tmp; |
| size_t nlen; |
| |
| if (b->top >= b->len || n > BITMAP_MAX) |
| return -1; /* invalid */ |
| nlen = (n / BITMAP_BITS) + 1; |
| if (b->len < nlen) { |
| if ((tmp = recallocarray(b->d, b->len, nlen, BITMAP_BYTES)) == NULL) |
| return -1; |
| b->d = tmp; |
| memset(b->d + b->len, 0, (nlen - b->len) * BITMAP_BYTES); |
| b->len = nlen; |
| } |
| return 0; |
| } |
| |
| int |
| bitmap_set_bit(struct bitmap *b, u_int n) |
| { |
| int r; |
| size_t offset; |
| |
| if ((r = reserve(b, n)) != 0) |
| return r; |
| offset = n / BITMAP_BITS; |
| if (offset > b->top) |
| b->top = offset; |
| b->d[offset] |= (BITMAP_WTYPE)1 << (n & BITMAP_WMASK); |
| return 0; |
| } |
| |
| /* Resets b->top to point to the most significant bit set in b->d */ |
| static void |
| retop(struct bitmap *b) |
| { |
| if (b->top >= b->len) |
| return; |
| while (b->top > 0 && b->d[b->top] == 0) |
| b->top--; |
| } |
| |
| void |
| bitmap_clear_bit(struct bitmap *b, u_int n) |
| { |
| size_t offset; |
| |
| if (b->top >= b->len || n > BITMAP_MAX) |
| return; /* invalid */ |
| offset = n / BITMAP_BITS; |
| if (offset > b->top) |
| return; |
| b->d[offset] &= ~((BITMAP_WTYPE)1 << (n & BITMAP_WMASK)); |
| /* The top may have changed as a result of the clear */ |
| retop(b); |
| } |
| |
| size_t |
| bitmap_nbits(struct bitmap *b) |
| { |
| size_t bits; |
| BITMAP_WTYPE w; |
| |
| retop(b); |
| if (b->top >= b->len) |
| return 0; /* invalid */ |
| if (b->len == 0 || (b->top == 0 && b->d[0] == 0)) |
| return 0; |
| /* Find MSB set */ |
| w = b->d[b->top]; |
| bits = (b->top + 1) * BITMAP_BITS; |
| while (!(w & ((BITMAP_WTYPE)1 << (BITMAP_BITS - 1)))) { |
| w <<= 1; |
| bits--; |
| } |
| return bits; |
| } |
| |
| size_t |
| bitmap_nbytes(struct bitmap *b) |
| { |
| return (bitmap_nbits(b) + 7) / 8; |
| } |
| |
| int |
| bitmap_to_string(struct bitmap *b, void *p, size_t l) |
| { |
| u_char *s = (u_char *)p; |
| size_t i, j, k, need = bitmap_nbytes(b); |
| |
| if (l < need || b->top >= b->len) |
| return -1; |
| if (l > need) |
| l = need; |
| /* Put the bytes from LSB backwards */ |
| for (i = k = 0; i < b->top + 1; i++) { |
| for (j = 0; j < BITMAP_BYTES; j++) { |
| if (k >= l) |
| break; |
| s[need - 1 - k++] = (b->d[i] >> (j * 8)) & 0xff; |
| } |
| } |
| return 0; |
| } |
| |
| int |
| bitmap_from_string(struct bitmap *b, const void *p, size_t l) |
| { |
| int r; |
| size_t i, offset, shift; |
| u_char *s = (u_char *)p; |
| |
| if (l > BITMAP_MAX / 8) |
| return -1; |
| if ((r = reserve(b, l * 8)) != 0) |
| return r; |
| bitmap_zero(b); |
| if (l == 0) |
| return 0; |
| b->top = offset = ((l + (BITMAP_BYTES - 1)) / BITMAP_BYTES) - 1; |
| shift = ((l + (BITMAP_BYTES - 1)) % BITMAP_BYTES) * 8; |
| for (i = 0; i < l; i++) { |
| b->d[offset] |= (BITMAP_WTYPE)s[i] << shift; |
| if (shift == 0) { |
| offset--; |
| shift = BITMAP_BITS - 8; |
| } else |
| shift -= 8; |
| } |
| retop(b); |
| return 0; |
| } |