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C++ dbuf_read函数代码示例

原作者: [db:作者] 来自: [db:来源] 收藏 邀请

本文整理汇总了C++中dbuf_read函数的典型用法代码示例。如果您正苦于以下问题：C++ dbuf_read函数的具体用法？C++ dbuf_read怎么用？C++ dbuf_read使用的例子？那么恭喜您, 这里精选的函数代码示例或许可以为您提供帮助。



在下文中一共展示了dbuf_read函数的20个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于我们的系统推荐出更棒的C++代码示例。

示例1: dmu_buf_hold

int
dmu_buf_hold(objset_t *os, uint64_t object, uint64_t offset,
    void *tag, dmu_buf_t **dbp, int flags)
{
	dnode_t *dn;
	uint64_t blkid;
	dmu_buf_impl_t *db;
	int err;
	int db_flags = DB_RF_CANFAIL;

	if (flags & DMU_READ_NO_PREFETCH)
		db_flags |= DB_RF_NOPREFETCH;

	err = dnode_hold(os, object, FTAG, &dn);
	if (err)
		return (err);
	blkid = dbuf_whichblock(dn, offset);
	rw_enter(&dn->dn_struct_rwlock, RW_READER);
	db = dbuf_hold(dn, blkid, tag);
	rw_exit(&dn->dn_struct_rwlock);
	if (db == NULL) {
		err = EIO;
	} else {
		err = dbuf_read(db, NULL, db_flags);
		if (err) {
			dbuf_rele(db, tag);
			db = NULL;
		}
	}

	dnode_rele(dn, FTAG);
	*dbp = &db->db; /* NULL db plus first field offset is NULL */
	return (err);
}
开发者ID:Acidburn0zzz，项目名称:osv，代码行数:34，代码来源:dmu.c


示例2: dmu_bonus_hold

/*
 * returns ENOENT, EIO, or 0.
 */
int
dmu_bonus_hold(objset_t *os, uint64_t object, void *tag, dmu_buf_t **dbp)
{
	dnode_t *dn;
	dmu_buf_impl_t *db;
	int error;

	error = dnode_hold(os->os, object, FTAG, &dn);
	if (error)
		return (error);

	rw_enter(&dn->dn_struct_rwlock, RW_READER);
	if (dn->dn_bonus == NULL) {
		rw_exit(&dn->dn_struct_rwlock);
		rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
		if (dn->dn_bonus == NULL)
			dbuf_create_bonus(dn);
	}
	db = dn->dn_bonus;
	rw_exit(&dn->dn_struct_rwlock);

	/* as long as the bonus buf is held, the dnode will be held */
	if (refcount_add(&db->db_holds, tag) == 1)
		VERIFY(dnode_add_ref(dn, db));

	dnode_rele(dn, FTAG);

	VERIFY(0 == dbuf_read(db, NULL, DB_RF_MUST_SUCCEED));

	*dbp = &db->db;
	return (0);
}
开发者ID:YaroslavLitvinov，项目名称:zfs-port，代码行数:35，代码来源:dmu.c


示例3: dbuf_getu32le_p

i64 dbuf_getu32le_p(dbuf *f, i64 *ppos)
{
	u8 m[4];
	dbuf_read(f, m, *ppos, 4);
	(*ppos) += 4;
	return de_getu32le_direct(m);
}
开发者ID:jsummers，项目名称:deark，代码行数:7，代码来源:deark-dbuf.c


示例4: dmu_buf_hold

int
dmu_buf_hold(objset_t *os, uint64_t object, uint64_t offset,
    void *tag, dmu_buf_t **dbp)
{
	dnode_t *dn;
	uint64_t blkid;
	dmu_buf_impl_t *db;
	int err;

	err = dnode_hold(os->os, object, FTAG, &dn);
	if (err)
		return (err);
	blkid = dbuf_whichblock(dn, offset);
	rw_enter(&dn->dn_struct_rwlock, RW_READER);
	db = dbuf_hold(dn, blkid, tag);
	rw_exit(&dn->dn_struct_rwlock);
	if (db == NULL) {
		err = EIO;
	} else {
		err = dbuf_read(db, NULL, DB_RF_CANFAIL);
		if (err) {
			dbuf_rele(db, tag);
			db = NULL;
		}
	}

	dnode_rele(dn, FTAG);
	*dbp = &db->db;
	return (err);
}
开发者ID:YaroslavLitvinov，项目名称:zfs-port，代码行数:30，代码来源:dmu.c


示例5: dbuf_getu16le_p

i64 dbuf_getu16le_p(dbuf *f, i64 *ppos)
{
	u8 m[2];
	dbuf_read(f, m, *ppos, 2);
	(*ppos) += 2;
	return de_getu16le_direct(m);
}
开发者ID:jsummers，项目名称:deark，代码行数:7，代码来源:deark-dbuf.c


示例6: dbuf_getRGB

u32 dbuf_getRGB(dbuf *f, i64 pos, unsigned int flags)
{
	u8 buf[3];
	dbuf_read(f, buf, pos, 3);
	if(flags&DE_GETRGBFLAG_BGR)
		return DE_MAKE_RGB(buf[2], buf[1], buf[0]);
	return DE_MAKE_RGB(buf[0], buf[1], buf[2]);
}
开发者ID:jsummers，项目名称:deark，代码行数:8，代码来源:deark-dbuf.c


示例7: dbuf_getint_ext_x

static i64 dbuf_getint_ext_x(dbuf *f, i64 pos, unsigned int nbytes, int is_le)
{
	u8 m[24];

	if(nbytes>(unsigned int)sizeof(m)) return 0;
	dbuf_read(f, m, pos, (i64)nbytes);
	if(is_le) {
		return 0; // TODO
	}
	return dbuf_getint_ext_be_direct(m, nbytes);
}
开发者ID:jsummers，项目名称:deark，代码行数:11，代码来源:deark-dbuf.c


示例8: dbuf_standard_read

// A function that works a little more like a standard read/fread function than
// does dbuf_read. It returns the number of bytes read, won't read past end of
// file, and helps track the file position.
i64 dbuf_standard_read(dbuf *f, u8 *buf, i64 n, i64 *fpos)
{
	i64 amt_to_read;

	if(*fpos < 0 || *fpos >= f->len) return 0;

	amt_to_read = n;
	if(*fpos + amt_to_read > f->len) amt_to_read = f->len - *fpos;
	dbuf_read(f, buf, *fpos, amt_to_read);
	*fpos += amt_to_read;
	return amt_to_read;
}
开发者ID:jsummers，项目名称:deark，代码行数:15，代码来源:deark-dbuf.c


示例9: dbuf_read_ascii_number

int dbuf_read_ascii_number(dbuf *f, i64 pos, i64 fieldsize,
	int base, i64 *value)
{
	char buf[32];

	*value = 0;
	if(fieldsize>(i64)(sizeof(buf)-1)) return 0;

	dbuf_read(f, (u8*)buf, pos, fieldsize);
	buf[fieldsize] = '\0';

	*value = de_strtoll(buf, NULL, base);
	return 1;
}
开发者ID:jsummers，项目名称:deark，代码行数:14，代码来源:deark-dbuf.c


示例10: dbuf_read_to_ucstring

// Read (up to) len bytes from f, translate them to characters, and append
// them to s.
void dbuf_read_to_ucstring(dbuf *f, i64 pos, i64 len,
	de_ucstring *s, unsigned int conv_flags, int encoding)
{
	u8 *buf = NULL;
	deark *c = f->c;

	if(conv_flags & DE_CONVFLAG_STOP_AT_NUL) {
		i64 foundpos = 0;
		if(dbuf_search_byte(f, 0x00, pos, len, &foundpos)) {
			len = foundpos - pos;
		}
	}

	buf = de_malloc(c, len);
	dbuf_read(f, buf, pos, len);
	ucstring_append_bytes(s, buf, len, 0, encoding);
	de_free(c, buf);
}
开发者ID:jsummers，项目名称:deark，代码行数:20，代码来源:deark-dbuf.c


示例11: de_linereader_readnextline

// TODO: Make the linereader more efficient and flexible, and make
// it a standard library function.
static int de_linereader_readnextline(deark *c, struct de_linereader *lr,
	char *buf, size_t buf_len, unsigned int flags)
{
	int ret;
	i64 content_len = 0;
	i64 total_len = 0;

	buf[0] = '\0';

	ret = dbuf_find_line(lr->f, lr->f_pos, &content_len, &total_len);
	if(!ret) return 0;
	if(content_len > (i64)buf_len-1) {
		lr->f_pos += total_len;
		return 0;
	}
	dbuf_read(lr->f, (u8*)buf, lr->f_pos, content_len);
	buf[content_len] = '\0';
	lr->f_pos += total_len;
	return 1;
}
开发者ID:jsummers，项目名称:deark，代码行数:22，代码来源:unifont.c


示例12: dbuf_copy

void dbuf_copy(dbuf *inf, i64 input_offset, i64 input_len, dbuf *outf)
{
	u8 tmpbuf[256];

	if(inf->btype==DBUF_TYPE_MEMBUF &&
		(input_offset>=0) && (input_offset+input_len<=inf->len))
	{
		// Fast path if the data to copy is all in memory
		dbuf_write(outf, &inf->membuf_buf[input_offset], input_len);
		return;
	}

	if(input_len<=(i64)sizeof(tmpbuf)) {
		// Fast path for small sizes
		dbuf_read(inf, tmpbuf, input_offset, input_len);
		dbuf_write(outf, tmpbuf, input_len);
		return;
	}

	dbuf_buffered_read(inf, input_offset, input_len, copy_cbfn, (void*)outf);
}
开发者ID:jsummers，项目名称:deark，代码行数:21，代码来源:deark-dbuf.c


示例13: dbuf_memcmp

int dbuf_memcmp(dbuf *f, i64 pos, const void *s, size_t n)
{
	u8 buf1[128];

	if(f->cache &&
		pos >= f->cache_start_pos &&
		pos + (i64)n <= f->cache_start_pos + f->cache_bytes_used)
	{
		// Fastest path: Compare directly to cache.
		return de_memcmp(s, &f->cache[pos - f->cache_start_pos], n);
	}

	if(n<=sizeof(buf1)) {
		// Use a stack buffer if small enough.
		dbuf_read(f, buf1, pos, n);
		return de_memcmp(buf1, s, n);
	}

	// Fallback method.
	return !dbuf_buffered_read(f, pos, n, dbufmemcmp_cbfn, (void*)s);
}
开发者ID:jsummers，项目名称:deark，代码行数:21，代码来源:deark-dbuf.c


示例14: dbuf_getbyte

u8 dbuf_getbyte(dbuf *f, i64 pos)
{
	switch(f->btype) {
	case DBUF_TYPE_MEMBUF:
		// Optimization for memory buffers
		if(pos>=0 && pos<f->len) {
			return f->membuf_buf[pos];
		}
		break;
	default:
		if(f->cache2_bytes_used>0 && pos==f->cache2_start_pos) {
			return f->cache2[0];
		}

		dbuf_read(f, &f->cache2[0], pos, 1);
		f->cache2_bytes_used = 1;
		f->cache2_start_pos = pos;
		return f->cache2[0];
	}
	return 0x00;
}
开发者ID:jsummers，项目名称:deark，代码行数:21，代码来源:deark-dbuf.c


示例15: dmu_bonus_hold

/*
 * returns ENOENT, EIO, or 0.
 */
int
dmu_bonus_hold(objset_t *os, uint64_t object, void *tag, dmu_buf_t **dbp)
{
	dnode_t *dn;
	dmu_buf_impl_t *db;
	int error;

	error = dnode_hold(os, object, FTAG, &dn);
	if (error)
		return (error);

	rw_enter(&dn->dn_struct_rwlock, RW_READER);
	if (dn->dn_bonus == NULL) {
		rw_exit(&dn->dn_struct_rwlock);
		rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
		if (dn->dn_bonus == NULL)
			dbuf_create_bonus(dn);
	}
	db = dn->dn_bonus;

	/* as long as the bonus buf is held, the dnode will be held */
	if (refcount_add(&db->db_holds, tag) == 1) {
		VERIFY(dnode_add_ref(dn, db));
		atomic_inc_32(&dn->dn_dbufs_count);
	}

	/*
	 * Wait to drop dn_struct_rwlock until after adding the bonus dbuf's
	 * hold and incrementing the dbuf count to ensure that dnode_move() sees
	 * a dnode hold for every dbuf.
	 */
	rw_exit(&dn->dn_struct_rwlock);

	dnode_rele(dn, FTAG);

	VERIFY(0 == dbuf_read(db, NULL, DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH));

	*dbp = &db->db;
	return (0);
}
开发者ID:yaoyutian，项目名称:freebsd，代码行数:43，代码来源:dmu.c


示例16: dmu_spill_hold_by_dnode

/*
 * returns ENOENT, EIO, or 0.
 *
 * This interface will allocate a blank spill dbuf when a spill blk
 * doesn't already exist on the dnode.
 *
 * if you only want to find an already existing spill db, then
 * dmu_spill_hold_existing() should be used.
 */
int
dmu_spill_hold_by_dnode(dnode_t *dn, uint32_t flags, void *tag, dmu_buf_t **dbp)
{
	dmu_buf_impl_t *db = NULL;
	int err;

	if ((flags & DB_RF_HAVESTRUCT) == 0)
		rw_enter(&dn->dn_struct_rwlock, RW_READER);

	db = dbuf_hold(dn, DMU_SPILL_BLKID, tag);

	if ((flags & DB_RF_HAVESTRUCT) == 0)
		rw_exit(&dn->dn_struct_rwlock);

	ASSERT(db != NULL);
	err = dbuf_read(db, NULL, flags);
	if (err == 0)
		*dbp = &db->db;
	else
		dbuf_rele(db, tag);
	return (err);
}
开发者ID:yaoyutian，项目名称:freebsd，代码行数:31，代码来源:dmu.c


示例17: dmu_buf_hold

int
dmu_buf_hold(objset_t *os, uint64_t object, uint64_t offset,
    void *tag, dmu_buf_t **dbp, int flags)
{
	int err;
	int db_flags = DB_RF_CANFAIL;

	if (flags & DMU_READ_NO_PREFETCH)
		db_flags |= DB_RF_NOPREFETCH;

	err = dmu_buf_hold_noread(os, object, offset, tag, dbp);
	if (err == 0) {
		dmu_buf_impl_t *db = (dmu_buf_impl_t *)(*dbp);
		err = dbuf_read(db, NULL, db_flags);
		if (err != 0) {
			dbuf_rele(db, tag);
			*dbp = NULL;
		}
	}

	return (err);
}
开发者ID:yaoyutian，项目名称:freebsd，代码行数:22，代码来源:dmu.c


示例18: dnode_increase_indirection

static void
dnode_increase_indirection(dnode_t *dn, dmu_tx_t *tx)
{
	dmu_buf_impl_t *db;
	int txgoff = tx->tx_txg & TXG_MASK;
	int nblkptr = dn->dn_phys->dn_nblkptr;
	int old_toplvl = dn->dn_phys->dn_nlevels - 1;
	int new_level = dn->dn_next_nlevels[txgoff];
	int i;

	rw_enter(&dn->dn_struct_rwlock, RW_WRITER);

	/* this dnode can't be paged out because it's dirty */
	ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);
	ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
	ASSERT(new_level > 1 && dn->dn_phys->dn_nlevels > 0);

	db = dbuf_hold_level(dn, dn->dn_phys->dn_nlevels, 0, FTAG);
	ASSERT(db != NULL);

	dn->dn_phys->dn_nlevels = new_level;
	dprintf("os=%p obj=%llu, increase to %d\n", dn->dn_objset,
	    dn->dn_object, dn->dn_phys->dn_nlevels);

	/* check for existing blkptrs in the dnode */
	for (i = 0; i < nblkptr; i++)
		if (!BP_IS_HOLE(&dn->dn_phys->dn_blkptr[i]))
			break;
	if (i != nblkptr) {
		/* transfer dnode's block pointers to new indirect block */
		(void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED|DB_RF_HAVESTRUCT);
		ASSERT(db->db.db_data);
		ASSERT(arc_released(db->db_buf));
		ASSERT3U(sizeof (blkptr_t) * nblkptr, <=, db->db.db_size);
		bcopy(dn->dn_phys->dn_blkptr, db->db.db_data,
		    sizeof (blkptr_t) * nblkptr);
		arc_buf_freeze(db->db_buf);
	}
开发者ID:Acidburn0zzz，项目名称:zfs，代码行数:38，代码来源:dnode_sync.c


示例19: dnode_increase_indirection

static void
dnode_increase_indirection(dnode_t *dn, dmu_tx_t *tx)
{
	dmu_buf_impl_t *db;
	int txgoff = tx->tx_txg & TXG_MASK;
	int nblkptr = dn->dn_phys->dn_nblkptr;
	int old_toplvl = dn->dn_phys->dn_nlevels - 1;
	int new_level = dn->dn_next_nlevels[txgoff];
	int i;

	rw_enter(&dn->dn_struct_rwlock, RW_WRITER);

	/* this dnode can't be paged out because it's dirty */
	ASSERT(dn->dn_phys->dn_type != DMU_OT_NONE);
	ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
	ASSERT(new_level > 1 && dn->dn_phys->dn_nlevels > 0);

	db = dbuf_hold_level(dn, dn->dn_phys->dn_nlevels, 0, FTAG);
	ASSERT(db != NULL);

	dn->dn_phys->dn_nlevels = new_level;
	dprintf("os=%p obj=%llu, increase to %d\n", dn->dn_objset,
	    dn->dn_object, dn->dn_phys->dn_nlevels);

	/* transfer dnode's block pointers to new indirect block */
	(void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED|DB_RF_HAVESTRUCT);
	ASSERT(db->db.db_data);
	ASSERT(arc_released(db->db_buf));
	ASSERT3U(sizeof (blkptr_t) * nblkptr, <=, db->db.db_size);
	bcopy(dn->dn_phys->dn_blkptr, db->db.db_data,
	    sizeof (blkptr_t) * nblkptr);
	arc_buf_freeze(db->db_buf);

	/* set dbuf's parent pointers to new indirect buf */
	for (i = 0; i < nblkptr; i++) {
		dmu_buf_impl_t *child =
		    dbuf_find(dn->dn_objset, dn->dn_object, old_toplvl, i);

		if (child == NULL)
			continue;
#ifdef	DEBUG
		DB_DNODE_ENTER(child);
		ASSERT3P(DB_DNODE(child), ==, dn);
		DB_DNODE_EXIT(child);
#endif	/* DEBUG */
		if (child->db_parent && child->db_parent != dn->dn_dbuf) {
			ASSERT(child->db_parent->db_level == db->db_level);
			ASSERT(child->db_blkptr !=
			    &dn->dn_phys->dn_blkptr[child->db_blkid]);
			mutex_exit(&child->db_mtx);
			continue;
		}
		ASSERT(child->db_parent == NULL ||
		    child->db_parent == dn->dn_dbuf);

		child->db_parent = db;
		dbuf_add_ref(db, child);
		if (db->db.db_data)
			child->db_blkptr = (blkptr_t *)db->db.db_data + i;
		else
			child->db_blkptr = NULL;
		dprintf_dbuf_bp(child, child->db_blkptr,
		    "changed db_blkptr to new indirect %s", "");

		mutex_exit(&child->db_mtx);
	}

	bzero(dn->dn_phys->dn_blkptr, sizeof (blkptr_t) * nblkptr);

	dbuf_rele(db, FTAG);

	rw_exit(&dn->dn_struct_rwlock);
}
开发者ID:64116278，项目名称:zfs，代码行数:73，代码来源:dnode_sync.c


示例20: dbuf_getu16le

i64 dbuf_getu16le(dbuf *f, i64 pos)
{
	u8 m[2];
	dbuf_read(f, m, pos, 2);
	return de_getu16le_direct(m);
}
开发者ID:jsummers，项目名称:deark，代码行数:6，代码来源:deark-dbuf.c



注：本文中的dbuf_read函数示例由纯净天空整理自Github/MSDocs等源码及文档管理平台，相关代码片段筛选自各路编程大神贡献的开源项目，源码版权归原作者所有，传播和使用请参考对应项目的License；未经允许，请勿转载。

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