From 7bf62e31a3c820852271768fafc04ba95c31a19f Mon Sep 17 00:00:00 2001 From: Havoc Pennington Date: Mon, 17 Jan 2005 03:53:40 +0000 Subject: 2005-01-16 Havoc Pennington This is about it on what can be disabled/deleted from libdbus easily, back below 150K anyhow. Deeper cuts are more work than just turning the code off as I've done here. * dbus/dbus-marshal-basic.c (_dbus_pack_int32): we don't need the signed int convenience funcs * dbus/dbus-internals.c (_dbus_verbose_real): omit when not in verbose mode * dbus/dbus-string-util.c, dbus/dbus-string.c: more breaking things out of libdbus * dbus/dbus-sysdeps.c, dbus/dbus-sysdeps-util.c: same * dbus/dbus-hash.c: purge the TWO_STRINGS crap (well, make it tests-enabled-only, though it should probably be deleted) * dbus/dbus-message-util.c: same stuff * dbus/dbus-auth-util.c: same stuff --- dbus/dbus-string-util.c | 727 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 727 insertions(+) create mode 100644 dbus/dbus-string-util.c (limited to 'dbus/dbus-string-util.c') diff --git a/dbus/dbus-string-util.c b/dbus/dbus-string-util.c new file mode 100644 index 00000000..1ff2ec67 --- /dev/null +++ b/dbus/dbus-string-util.c @@ -0,0 +1,727 @@ +/* -*- mode: C; c-file-style: "gnu" -*- */ +/* dbus-string-util.c Would be in dbus-string.c, but not used in libdbus + * + * Copyright (C) 2002, 2003, 2004, 2005 Red Hat, Inc. + * + * Licensed under the Academic Free License version 2.1 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + */ + +#include "dbus-internals.h" +#include "dbus-string.h" +#define DBUS_CAN_USE_DBUS_STRING_PRIVATE 1 +#include "dbus-string-private.h" + +/** + * @addtogroup DBusString + * @{ + */ + +/** + * Copies the contents of a DBusString into a different + * buffer. The resulting buffer will be nul-terminated. + * + * @param str a string + * @param buffer a C buffer to copy data to + * @param avail_len maximum length of C buffer + */ +void +_dbus_string_copy_to_buffer (const DBusString *str, + char *buffer, + int avail_len) +{ + int copy_len; + DBUS_CONST_STRING_PREAMBLE (str); + + _dbus_assert (avail_len >= 0); + + copy_len = MIN (avail_len, real->len+1); + memcpy (buffer, real->str, copy_len); + if (avail_len > 0 && avail_len == copy_len) + buffer[avail_len-1] = '\0'; +} + +/** + * Returns whether a string ends with the given suffix + * + * @todo memcmp might make this faster. + * + * @param a the string + * @param c_str the C-style string + * @returns #TRUE if the string ends with the suffix + */ +dbus_bool_t +_dbus_string_ends_with_c_str (const DBusString *a, + const char *c_str) +{ + const unsigned char *ap; + const unsigned char *bp; + const unsigned char *a_end; + unsigned long c_str_len; + const DBusRealString *real_a = (const DBusRealString*) a; + DBUS_GENERIC_STRING_PREAMBLE (real_a); + _dbus_assert (c_str != NULL); + + c_str_len = strlen (c_str); + if (((unsigned long)real_a->len) < c_str_len) + return FALSE; + + ap = real_a->str + (real_a->len - c_str_len); + bp = (const unsigned char*) c_str; + a_end = real_a->str + real_a->len; + while (ap != a_end) + { + if (*ap != *bp) + return FALSE; + + ++ap; + ++bp; + } + + _dbus_assert (*ap == '\0'); + _dbus_assert (*bp == '\0'); + + return TRUE; +} + +/** + * Find the given byte scanning backward from the given start. + * Sets *found to -1 if the byte is not found. + * + * @param str the string + * @param start the place to start scanning (will not find the byte at this point) + * @param byte the byte to find + * @param found return location for where it was found + * @returns #TRUE if found + */ +dbus_bool_t +_dbus_string_find_byte_backward (const DBusString *str, + int start, + unsigned char byte, + int *found) +{ + int i; + DBUS_CONST_STRING_PREAMBLE (str); + _dbus_assert (start <= real->len); + _dbus_assert (start >= 0); + _dbus_assert (found != NULL); + + i = start - 1; + while (i >= 0) + { + if (real->str[i] == byte) + break; + + --i; + } + + if (found) + *found = i; + + return i >= 0; +} + +/** + * Skips whitespace from start, storing the first non-whitespace in *end. + * (whitespace is space, tab, newline, CR). + * + * @param str the string + * @param start where to start + * @param end where to store the first non-whitespace byte index + */ +void +_dbus_string_skip_white (const DBusString *str, + int start, + int *end) +{ + int i; + DBUS_CONST_STRING_PREAMBLE (str); + _dbus_assert (start <= real->len); + _dbus_assert (start >= 0); + + i = start; + while (i < real->len) + { + if (!(real->str[i] == ' ' || + real->str[i] == '\n' || + real->str[i] == '\r' || + real->str[i] == '\t')) + break; + + ++i; + } + + _dbus_assert (i == real->len || !(real->str[i] == ' ' || + real->str[i] == '\t')); + + if (end) + *end = i; +} + +/** @} */ + +#ifdef DBUS_BUILD_TESTS +#include "dbus-test.h" +#include + +static void +test_max_len (DBusString *str, + int max_len) +{ + if (max_len > 0) + { + if (!_dbus_string_set_length (str, max_len - 1)) + _dbus_assert_not_reached ("setting len to one less than max should have worked"); + } + + if (!_dbus_string_set_length (str, max_len)) + _dbus_assert_not_reached ("setting len to max len should have worked"); + + if (_dbus_string_set_length (str, max_len + 1)) + _dbus_assert_not_reached ("setting len to one more than max len should not have worked"); + + if (!_dbus_string_set_length (str, 0)) + _dbus_assert_not_reached ("setting len to zero should have worked"); +} + +static void +test_hex_roundtrip (const unsigned char *data, + int len) +{ + DBusString orig; + DBusString encoded; + DBusString decoded; + int end; + + if (len < 0) + len = strlen (data); + + if (!_dbus_string_init (&orig)) + _dbus_assert_not_reached ("could not init string"); + + if (!_dbus_string_init (&encoded)) + _dbus_assert_not_reached ("could not init string"); + + if (!_dbus_string_init (&decoded)) + _dbus_assert_not_reached ("could not init string"); + + if (!_dbus_string_append_len (&orig, data, len)) + _dbus_assert_not_reached ("couldn't append orig data"); + + if (!_dbus_string_hex_encode (&orig, 0, &encoded, 0)) + _dbus_assert_not_reached ("could not encode"); + + if (!_dbus_string_hex_decode (&encoded, 0, &end, &decoded, 0)) + _dbus_assert_not_reached ("could not decode"); + + _dbus_assert (_dbus_string_get_length (&encoded) == end); + + if (!_dbus_string_equal (&orig, &decoded)) + { + const char *s; + + printf ("Original string %d bytes encoded %d bytes decoded %d bytes\n", + _dbus_string_get_length (&orig), + _dbus_string_get_length (&encoded), + _dbus_string_get_length (&decoded)); + printf ("Original: %s\n", data); + s = _dbus_string_get_const_data (&decoded); + printf ("Decoded: %s\n", s); + _dbus_assert_not_reached ("original string not the same as string decoded from hex"); + } + + _dbus_string_free (&orig); + _dbus_string_free (&encoded); + _dbus_string_free (&decoded); +} + +typedef void (* TestRoundtripFunc) (const unsigned char *data, + int len); +static void +test_roundtrips (TestRoundtripFunc func) +{ + (* func) ("Hello this is a string\n", -1); + (* func) ("Hello this is a string\n1", -1); + (* func) ("Hello this is a string\n12", -1); + (* func) ("Hello this is a string\n123", -1); + (* func) ("Hello this is a string\n1234", -1); + (* func) ("Hello this is a string\n12345", -1); + (* func) ("", 0); + (* func) ("1", 1); + (* func) ("12", 2); + (* func) ("123", 3); + (* func) ("1234", 4); + (* func) ("12345", 5); + (* func) ("", 1); + (* func) ("1", 2); + (* func) ("12", 3); + (* func) ("123", 4); + (* func) ("1234", 5); + (* func) ("12345", 6); + { + unsigned char buf[512]; + int i; + + i = 0; + while (i < _DBUS_N_ELEMENTS (buf)) + { + buf[i] = i; + ++i; + } + i = 0; + while (i < _DBUS_N_ELEMENTS (buf)) + { + (* func) (buf, i); + ++i; + } + } +} + +#ifdef DBUS_BUILD_TESTS +/* The max length thing is sort of a historical artifact + * from a feature that turned out to be dumb; perhaps + * we should purge it entirely. The problem with + * the feature is that it looks like memory allocation + * failure, but is not a transient or resolvable failure. + */ +static void +set_max_length (DBusString *str, + int max_length) +{ + DBusRealString *real; + + real = (DBusRealString*) str; + + real->max_length = max_length; +} +#endif /* DBUS_BUILD_TESTS */ + +/** + * @ingroup DBusStringInternals + * Unit test for DBusString. + * + * @todo Need to write tests for _dbus_string_copy() and + * _dbus_string_move() moving to/from each of start/middle/end of a + * string. Also need tests for _dbus_string_move_len () + * + * @returns #TRUE on success. + */ +dbus_bool_t +_dbus_string_test (void) +{ + DBusString str; + DBusString other; + int i, end; + long v; + double d; + int lens[] = { 0, 1, 2, 3, 4, 5, 10, 16, 17, 18, 25, 31, 32, 33, 34, 35, 63, 64, 65, 66, 67, 68, 69, 70, 71, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136 }; + char *s; + dbus_unichar_t ch; + + i = 0; + while (i < _DBUS_N_ELEMENTS (lens)) + { + if (!_dbus_string_init (&str)) + _dbus_assert_not_reached ("failed to init string"); + + set_max_length (&str, lens[i]); + + test_max_len (&str, lens[i]); + _dbus_string_free (&str); + + ++i; + } + + /* Test shortening and setting length */ + i = 0; + while (i < _DBUS_N_ELEMENTS (lens)) + { + int j; + + if (!_dbus_string_init (&str)) + _dbus_assert_not_reached ("failed to init string"); + + set_max_length (&str, lens[i]); + + if (!_dbus_string_set_length (&str, lens[i])) + _dbus_assert_not_reached ("failed to set string length"); + + j = lens[i]; + while (j > 0) + { + _dbus_assert (_dbus_string_get_length (&str) == j); + if (j > 0) + { + _dbus_string_shorten (&str, 1); + _dbus_assert (_dbus_string_get_length (&str) == (j - 1)); + } + --j; + } + + _dbus_string_free (&str); + + ++i; + } + + /* Test appending data */ + if (!_dbus_string_init (&str)) + _dbus_assert_not_reached ("failed to init string"); + + i = 0; + while (i < 10) + { + if (!_dbus_string_append (&str, "a")) + _dbus_assert_not_reached ("failed to append string to string\n"); + + _dbus_assert (_dbus_string_get_length (&str) == i * 2 + 1); + + if (!_dbus_string_append_byte (&str, 'b')) + _dbus_assert_not_reached ("failed to append byte to string\n"); + + _dbus_assert (_dbus_string_get_length (&str) == i * 2 + 2); + + ++i; + } + + _dbus_string_free (&str); + + /* Check steal_data */ + + if (!_dbus_string_init (&str)) + _dbus_assert_not_reached ("failed to init string"); + + if (!_dbus_string_append (&str, "Hello World")) + _dbus_assert_not_reached ("could not append to string"); + + i = _dbus_string_get_length (&str); + + if (!_dbus_string_steal_data (&str, &s)) + _dbus_assert_not_reached ("failed to steal data"); + + _dbus_assert (_dbus_string_get_length (&str) == 0); + _dbus_assert (((int)strlen (s)) == i); + + dbus_free (s); + + /* Check move */ + + if (!_dbus_string_append (&str, "Hello World")) + _dbus_assert_not_reached ("could not append to string"); + + i = _dbus_string_get_length (&str); + + if (!_dbus_string_init (&other)) + _dbus_assert_not_reached ("could not init string"); + + if (!_dbus_string_move (&str, 0, &other, 0)) + _dbus_assert_not_reached ("could not move"); + + _dbus_assert (_dbus_string_get_length (&str) == 0); + _dbus_assert (_dbus_string_get_length (&other) == i); + + if (!_dbus_string_append (&str, "Hello World")) + _dbus_assert_not_reached ("could not append to string"); + + if (!_dbus_string_move (&str, 0, &other, _dbus_string_get_length (&other))) + _dbus_assert_not_reached ("could not move"); + + _dbus_assert (_dbus_string_get_length (&str) == 0); + _dbus_assert (_dbus_string_get_length (&other) == i * 2); + + if (!_dbus_string_append (&str, "Hello World")) + _dbus_assert_not_reached ("could not append to string"); + + if (!_dbus_string_move (&str, 0, &other, _dbus_string_get_length (&other) / 2)) + _dbus_assert_not_reached ("could not move"); + + _dbus_assert (_dbus_string_get_length (&str) == 0); + _dbus_assert (_dbus_string_get_length (&other) == i * 3); + + _dbus_string_free (&other); + + /* Check copy */ + + if (!_dbus_string_append (&str, "Hello World")) + _dbus_assert_not_reached ("could not append to string"); + + i = _dbus_string_get_length (&str); + + if (!_dbus_string_init (&other)) + _dbus_assert_not_reached ("could not init string"); + + if (!_dbus_string_copy (&str, 0, &other, 0)) + _dbus_assert_not_reached ("could not copy"); + + _dbus_assert (_dbus_string_get_length (&str) == i); + _dbus_assert (_dbus_string_get_length (&other) == i); + + if (!_dbus_string_copy (&str, 0, &other, _dbus_string_get_length (&other))) + _dbus_assert_not_reached ("could not copy"); + + _dbus_assert (_dbus_string_get_length (&str) == i); + _dbus_assert (_dbus_string_get_length (&other) == i * 2); + _dbus_assert (_dbus_string_equal_c_str (&other, + "Hello WorldHello World")); + + if (!_dbus_string_copy (&str, 0, &other, _dbus_string_get_length (&other) / 2)) + _dbus_assert_not_reached ("could not copy"); + + _dbus_assert (_dbus_string_get_length (&str) == i); + _dbus_assert (_dbus_string_get_length (&other) == i * 3); + _dbus_assert (_dbus_string_equal_c_str (&other, + "Hello WorldHello WorldHello World")); + + _dbus_string_free (&str); + _dbus_string_free (&other); + + /* Check replace */ + + if (!_dbus_string_init (&str)) + _dbus_assert_not_reached ("failed to init string"); + + if (!_dbus_string_append (&str, "Hello World")) + _dbus_assert_not_reached ("could not append to string"); + + i = _dbus_string_get_length (&str); + + if (!_dbus_string_init (&other)) + _dbus_assert_not_reached ("could not init string"); + + if (!_dbus_string_replace_len (&str, 0, _dbus_string_get_length (&str), + &other, 0, _dbus_string_get_length (&other))) + _dbus_assert_not_reached ("could not replace"); + + _dbus_assert (_dbus_string_get_length (&str) == i); + _dbus_assert (_dbus_string_get_length (&other) == i); + _dbus_assert (_dbus_string_equal_c_str (&other, "Hello World")); + + if (!_dbus_string_replace_len (&str, 0, _dbus_string_get_length (&str), + &other, 5, 1)) + _dbus_assert_not_reached ("could not replace center space"); + + _dbus_assert (_dbus_string_get_length (&str) == i); + _dbus_assert (_dbus_string_get_length (&other) == i * 2 - 1); + _dbus_assert (_dbus_string_equal_c_str (&other, + "HelloHello WorldWorld")); + + + if (!_dbus_string_replace_len (&str, 1, 1, + &other, + _dbus_string_get_length (&other) - 1, + 1)) + _dbus_assert_not_reached ("could not replace end character"); + + _dbus_assert (_dbus_string_get_length (&str) == i); + _dbus_assert (_dbus_string_get_length (&other) == i * 2 - 1); + _dbus_assert (_dbus_string_equal_c_str (&other, + "HelloHello WorldWorle")); + + _dbus_string_free (&str); + _dbus_string_free (&other); + + /* Check append/get unichar */ + + if (!_dbus_string_init (&str)) + _dbus_assert_not_reached ("failed to init string"); + + ch = 0; + if (!_dbus_string_append_unichar (&str, 0xfffc)) + _dbus_assert_not_reached ("failed to append unichar"); + + _dbus_string_get_unichar (&str, 0, &ch, &i); + + _dbus_assert (ch == 0xfffc); + _dbus_assert (i == _dbus_string_get_length (&str)); + + _dbus_string_free (&str); + + /* Check insert/set/get byte */ + + if (!_dbus_string_init (&str)) + _dbus_assert_not_reached ("failed to init string"); + + if (!_dbus_string_append (&str, "Hello")) + _dbus_assert_not_reached ("failed to append Hello"); + + _dbus_assert (_dbus_string_get_byte (&str, 0) == 'H'); + _dbus_assert (_dbus_string_get_byte (&str, 1) == 'e'); + _dbus_assert (_dbus_string_get_byte (&str, 2) == 'l'); + _dbus_assert (_dbus_string_get_byte (&str, 3) == 'l'); + _dbus_assert (_dbus_string_get_byte (&str, 4) == 'o'); + + _dbus_string_set_byte (&str, 1, 'q'); + _dbus_assert (_dbus_string_get_byte (&str, 1) == 'q'); + + if (!_dbus_string_insert_bytes (&str, 0, 1, 255)) + _dbus_assert_not_reached ("can't insert byte"); + + if (!_dbus_string_insert_bytes (&str, 2, 4, 'Z')) + _dbus_assert_not_reached ("can't insert byte"); + + if (!_dbus_string_insert_bytes (&str, _dbus_string_get_length (&str), 1, 'W')) + _dbus_assert_not_reached ("can't insert byte"); + + _dbus_assert (_dbus_string_get_byte (&str, 0) == 255); + _dbus_assert (_dbus_string_get_byte (&str, 1) == 'H'); + _dbus_assert (_dbus_string_get_byte (&str, 2) == 'Z'); + _dbus_assert (_dbus_string_get_byte (&str, 3) == 'Z'); + _dbus_assert (_dbus_string_get_byte (&str, 4) == 'Z'); + _dbus_assert (_dbus_string_get_byte (&str, 5) == 'Z'); + _dbus_assert (_dbus_string_get_byte (&str, 6) == 'q'); + _dbus_assert (_dbus_string_get_byte (&str, 7) == 'l'); + _dbus_assert (_dbus_string_get_byte (&str, 8) == 'l'); + _dbus_assert (_dbus_string_get_byte (&str, 9) == 'o'); + _dbus_assert (_dbus_string_get_byte (&str, 10) == 'W'); + + _dbus_string_free (&str); + + /* Check append/parse int/double */ + + if (!_dbus_string_init (&str)) + _dbus_assert_not_reached ("failed to init string"); + + if (!_dbus_string_append_int (&str, 27)) + _dbus_assert_not_reached ("failed to append int"); + + i = _dbus_string_get_length (&str); + + if (!_dbus_string_parse_int (&str, 0, &v, &end)) + _dbus_assert_not_reached ("failed to parse int"); + + _dbus_assert (v == 27); + _dbus_assert (end == i); + + _dbus_string_free (&str); + + if (!_dbus_string_init (&str)) + _dbus_assert_not_reached ("failed to init string"); + + if (!_dbus_string_append_double (&str, 50.3)) + _dbus_assert_not_reached ("failed to append float"); + + i = _dbus_string_get_length (&str); + + if (!_dbus_string_parse_double (&str, 0, &d, &end)) + _dbus_assert_not_reached ("failed to parse float"); + + _dbus_assert (d > (50.3 - 1e-6) && d < (50.3 + 1e-6)); + _dbus_assert (end == i); + + _dbus_string_free (&str); + + /* Test find */ + if (!_dbus_string_init (&str)) + _dbus_assert_not_reached ("failed to init string"); + + if (!_dbus_string_append (&str, "Hello")) + _dbus_assert_not_reached ("couldn't append to string"); + + if (!_dbus_string_find (&str, 0, "He", &i)) + _dbus_assert_not_reached ("didn't find 'He'"); + _dbus_assert (i == 0); + + if (!_dbus_string_find (&str, 0, "Hello", &i)) + _dbus_assert_not_reached ("didn't find 'Hello'"); + _dbus_assert (i == 0); + + if (!_dbus_string_find (&str, 0, "ello", &i)) + _dbus_assert_not_reached ("didn't find 'ello'"); + _dbus_assert (i == 1); + + if (!_dbus_string_find (&str, 0, "lo", &i)) + _dbus_assert_not_reached ("didn't find 'lo'"); + _dbus_assert (i == 3); + + if (!_dbus_string_find (&str, 2, "lo", &i)) + _dbus_assert_not_reached ("didn't find 'lo'"); + _dbus_assert (i == 3); + + if (_dbus_string_find (&str, 4, "lo", &i)) + _dbus_assert_not_reached ("did find 'lo'"); + + if (!_dbus_string_find (&str, 0, "l", &i)) + _dbus_assert_not_reached ("didn't find 'l'"); + _dbus_assert (i == 2); + + if (!_dbus_string_find (&str, 0, "H", &i)) + _dbus_assert_not_reached ("didn't find 'H'"); + _dbus_assert (i == 0); + + if (!_dbus_string_find (&str, 0, "", &i)) + _dbus_assert_not_reached ("didn't find ''"); + _dbus_assert (i == 0); + + if (_dbus_string_find (&str, 0, "Hello!", NULL)) + _dbus_assert_not_reached ("Did find 'Hello!'"); + + if (_dbus_string_find (&str, 0, "Oh, Hello", NULL)) + _dbus_assert_not_reached ("Did find 'Oh, Hello'"); + + if (_dbus_string_find (&str, 0, "ill", NULL)) + _dbus_assert_not_reached ("Did find 'ill'"); + + if (_dbus_string_find (&str, 0, "q", NULL)) + _dbus_assert_not_reached ("Did find 'q'"); + + if (!_dbus_string_find_to (&str, 0, 2, "He", NULL)) + _dbus_assert_not_reached ("Didn't find 'He'"); + + if (_dbus_string_find_to (&str, 0, 2, "Hello", NULL)) + _dbus_assert_not_reached ("Did find 'Hello'"); + + if (!_dbus_string_find_byte_backward (&str, _dbus_string_get_length (&str), 'H', &i)) + _dbus_assert_not_reached ("Did not find 'H'"); + _dbus_assert (i == 0); + + if (!_dbus_string_find_byte_backward (&str, _dbus_string_get_length (&str), 'o', &i)) + _dbus_assert_not_reached ("Did not find 'o'"); + _dbus_assert (i == _dbus_string_get_length (&str) - 1); + + if (_dbus_string_find_byte_backward (&str, _dbus_string_get_length (&str) - 1, 'o', &i)) + _dbus_assert_not_reached ("Did find 'o'"); + _dbus_assert (i == -1); + + if (_dbus_string_find_byte_backward (&str, 1, 'e', &i)) + _dbus_assert_not_reached ("Did find 'e'"); + _dbus_assert (i == -1); + + if (!_dbus_string_find_byte_backward (&str, 2, 'e', &i)) + _dbus_assert_not_reached ("Didn't find 'e'"); + _dbus_assert (i == 1); + + _dbus_string_free (&str); + + /* Hex encoding */ + _dbus_string_init_const (&str, "cafebabe, this is a bogus hex string"); + if (!_dbus_string_init (&other)) + _dbus_assert_not_reached ("could not init string"); + + if (!_dbus_string_hex_decode (&str, 0, &end, &other, 0)) + _dbus_assert_not_reached ("deccoded bogus hex string with no error"); + + _dbus_assert (end == 8); + + _dbus_string_free (&other); + + test_roundtrips (test_hex_roundtrip); + + _dbus_string_free (&str); + + return TRUE; +} + +#endif /* DBUS_BUILD_TESTS */ -- cgit