diff --git a/bitmap.c b/bitmap.c new file mode 100644 index 000000000..cd9df8c77 --- /dev/null +++ b/bitmap.c @@ -0,0 +1,387 @@ +/* + * Copyright (c) 2015 Damien Miller + * + * 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 +#include +#include + +#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) { + memset(b->d, 0, b->len); + free(b->d); + } + 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 = reallocarray(b->d, 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; +} + +#ifdef BITMAP_TEST + +/* main() test against OpenSSL BN */ +#include +#include +#include +#include + +#define LIM 131 +#define FAIL(...) fail(__FILE__, __LINE__, __VA_ARGS__) + +void +bitmap_dump(struct bitmap *b, FILE *f) +{ + size_t i; + + fprintf(f, "bitmap %p len=%zu top=%zu d =", b, b->len, b->top); + for (i = 0; i < b->len; i++) { + fprintf(f, " %0*llx", (int)BITMAP_BITS / 4, + (unsigned long long)b->d[i]); + } + fputc('\n', f); +} + +static void +fail(char *file, int line, char *fmt, ...) +{ + va_list ap; + + fprintf(stderr, "%s:%d ", file, line); + va_start(ap, fmt); + vfprintf(stderr, fmt, ap); + va_end(ap); + fputc('\n', stdout); + /* abort(); */ + exit(1); +} + +static void +dump(const char *s, const u_char *buf, size_t l) +{ + size_t i; + + fprintf(stderr, "%s len %zu = ", s, l); + for (i = 0; i < l; i++) + fprintf(stderr, "%02x ", buf[i]); + fputc('\n', stderr); +} + +int main(void) { + struct bitmap *b = bitmap_new(); + BIGNUM *bn = BN_new(); + size_t len; + int i, j, k, n; + u_char bbuf[1024], bnbuf[1024]; + int r; + + for (i = -1; i < LIM; i++) { + fputc('i', stdout); + fflush(stdout); + for (j = -1; j < LIM; j++) { + for (k = -1; k < LIM; k++) { + bitmap_zero(b); + BN_clear(bn); + /* Test setting bits */ + if (i > 0 && bitmap_set_bit(b, i) != 0) + FAIL("bitmap_set_bit %d fail", i); + if (j > 0 && bitmap_set_bit(b, j) != 0) + FAIL("bitmap_set_bit %d fail", j); + if (k > 0 && bitmap_set_bit(b, k) != 0) + FAIL("bitmap_set_bit %d fail", k); + if ((i > 0 && BN_set_bit(bn, i) != 1) || + (j > 0 && BN_set_bit(bn, j) != 1) || + (k > 0 && BN_set_bit(bn, k) != 1)) + FAIL("BN_set_bit fail"); + for (n = 0; n < LIM; n++) { + if (BN_is_bit_set(bn, n) != + bitmap_test_bit(b, n)) { + FAIL("miss %d/%d/%d %d " + "%d %d", i, j, k, n, + BN_is_bit_set(bn, n), + bitmap_test_bit(b, n)); + } + } + /* Test length calculations */ + if (BN_num_bytes(bn) != (int)bitmap_nbytes(b)) { + FAIL("bytes %d/%d/%d %d != %zu", + i, j, k, BN_num_bytes(bn), + bitmap_nbytes(b)); + } + if (BN_num_bits(bn) != (int)bitmap_nbits(b)) { + FAIL("bits %d/%d/%d %d != %zu", + i, j, k, BN_num_bits(bn), + bitmap_nbits(b)); + } + /* Test serialisation */ + len = bitmap_nbytes(b); + memset(bbuf, 0xfc, sizeof(bbuf)); + if (bitmap_to_string(b, bbuf, + sizeof(bbuf)) != 0) + FAIL("bitmap_to_string %d/%d/%d", + i, j, k); + for (n = len; n < (int)sizeof(bbuf); n++) { + if (bbuf[n] != 0xfc) + FAIL("bad string " + "%d/%d/%d %d 0x%02x", + i, j, k, n, bbuf[n]); + } + if ((r = BN_bn2bin(bn, bnbuf)) < 0) + FAIL("BN_bn2bin %d/%d/%d", + i, j, k); + if ((size_t)r != len) + FAIL("len bad %d/%d/%d", i, j, k); + if (memcmp(bbuf, bnbuf, len) != 0) { + dump("bbuf", bbuf, sizeof(bbuf)); + dump("bnbuf", bnbuf, sizeof(bnbuf)); + FAIL("buf bad %d/%d/%d", i, j, k); + } + /* Test deserialisation */ + bitmap_zero(b); + if (bitmap_from_string(b, bnbuf, len) != 0) + FAIL("bitmap_to_string %d/%d/%d", + i, j, k); + for (n = 0; n < LIM; n++) { + if (BN_is_bit_set(bn, n) != + bitmap_test_bit(b, n)) { + FAIL("miss %d/%d/%d %d " + "%d %d", i, j, k, n, + BN_is_bit_set(bn, n), + bitmap_test_bit(b, n)); + } + } + /* Test clearing bits */ + for (n = 0; n < LIM; n++) { + if (bitmap_set_bit(b, n) != 0) { + bitmap_dump(b, stderr); + FAIL("bitmap_set_bit %d " + "fail", n); + } + if (BN_set_bit(bn, n) != 1) + FAIL("BN_set_bit fail"); + } + if (i > 0) { + bitmap_clear_bit(b, i); + BN_clear_bit(bn, i); + } + if (j > 0) { + bitmap_clear_bit(b, j); + BN_clear_bit(bn, j); + } + if (k > 0) { + bitmap_clear_bit(b, k); + BN_clear_bit(bn, k); + } + for (n = 0; n < LIM; n++) { + if (BN_is_bit_set(bn, n) != + bitmap_test_bit(b, n)) { + bitmap_dump(b, stderr); + FAIL("cmiss %d/%d/%d %d " + "%d %d", i, j, k, n, + BN_is_bit_set(bn, n), + bitmap_test_bit(b, n)); + } + } + } + } + } + fputc('\n', stdout); + bitmap_free(b); + BN_free(bn); + + return 0; +} +#endif diff --git a/bitmap.h b/bitmap.h new file mode 100644 index 000000000..c1bb1741a --- /dev/null +++ b/bitmap.h @@ -0,0 +1,56 @@ +/* + * Copyright (c) 2015 Damien Miller + * + * 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. + */ + +#ifndef _BITMAP_H +#define _BITMAP_H + +#include + +/* Simple bit vector routines */ + +struct bitmap; + +/* Allocate a new bitmap. Returns NULL on allocation failure. */ +struct bitmap *bitmap_new(void); + +/* Free a bitmap */ +void bitmap_free(struct bitmap *b); + +/* Zero an existing bitmap */ +void bitmap_zero(struct bitmap *b); + +/* Test whether a bit is set in a bitmap. */ +int bitmap_test_bit(struct bitmap *b, u_int n); + +/* Set a bit in a bitmap. Returns 0 on success or -1 on error */ +int bitmap_set_bit(struct bitmap *b, u_int n); + +/* Clear a bit in a bitmap */ +void bitmap_clear_bit(struct bitmap *b, u_int n); + +/* Return the number of bits in a bitmap (i.e. the position of the MSB) */ +size_t bitmap_nbits(struct bitmap *b); + +/* Return the number of bytes needed to represent a bitmap */ +size_t bitmap_nbytes(struct bitmap *b); + +/* Convert a bitmap to a big endian byte string */ +int bitmap_to_string(struct bitmap *b, void *p, size_t l); + +/* Convert a big endian byte string to a bitmap */ +int bitmap_from_string(struct bitmap *b, const void *p, size_t l); + +#endif /* _BITMAP_H */