U.S. patent application number 14/574137 was filed with the patent office on 2016-04-28 for deriving hardware acceleration of decoding from a declarative protocol description.
The applicant listed for this patent is TEKTRONIX, INC.. Invention is credited to JAMES FEIST, KEITH D. RULE, EDWARD F. TANOUS.
Application Number | 20160119218 14/574137 |
Document ID | / |
Family ID | 54364104 |
Filed Date | 2016-04-28 |
United States Patent
Application |
20160119218 |
Kind Code |
A1 |
TANOUS; EDWARD F. ; et
al. |
April 28, 2016 |
DERIVING HARDWARE ACCELERATION OF DECODING FROM A DECLARATIVE
PROTOCOL DESCRIPTION
Abstract
A test-and-measurement instrument is described. The
test-and-measurement instrument can store a state machine. As the
state machine is used to analyze a bit stream, breadcrumbs can be
saved from states in a memory of the state machine. The breadcrumbs
can then be used to analyze the operation of the state machine.
Inventors: |
TANOUS; EDWARD F.; (LAKE
OSWEGO, OR) ; RULE; KEITH D.; (BEAVERTON, OR)
; FEIST; JAMES; (PORTLAND, OR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TEKTRONIX, INC. |
Beaverton |
OR |
US |
|
|
Family ID: |
54364104 |
Appl. No.: |
14/574137 |
Filed: |
December 17, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62068384 |
Oct 24, 2014 |
|
|
|
Current U.S.
Class: |
375/224 |
Current CPC
Class: |
G01R 31/31903 20130101;
H04L 43/50 20130101; H04L 43/04 20130101; G11C 29/56 20130101; H04L
43/12 20130101 |
International
Class: |
H04L 12/26 20060101
H04L012/26 |
Claims
1. A system, comprising: a test-and-measurement instrument; a
memory on the test-and-measurement instrument; a receiver on the
test-and-measurement instrument operative to receive a regular
expression and a bit stream; a state machine generator to generate
a state machine from the regular expression; an analyzer operative
to analyze the bit stream using the state machine; and a breadcrumb
generator operative to generate and save in the memory a breadcrumb
whenever a state in the state machine is entered.
2. A system according to claim 1, wherein the breadcrumb generator
is operative to generate a breadcrumb including at least one of a
type of state, a state ID, and a time.
3. A system according to claim 1, wherein the breadcrumb generator
is operative to generate and save in the memory a breadcrumb when
an error state is entered on an unexpected input, the breadcrumb
including at least one of a type of state, a state ID, and a
time.
4. A system according to claim 1, further comprising a state
machine optimizer operative to optimize the state machine.
5. A system according to claim 1, further comprising a re-creator
to recreate the operation of the state machine using the saved
breadcrumbs.
6. A method, comprising: receiving a regular expression at a
test-and-measurement instrument; generating a state machine from
the regular expression; applying the state machine to a bit stream;
and for at least one state in the state machine, saving a
breadcrumb in a memory of the test-and-measurement instrument when
the at least one state is entered.
7. A method according to claim 6, wherein saving a breadcrumb in a
memory of the test-and-measurement instrument when the at least one
state is entered includes saving a breadcrumb in the memory of the
test-and-measurement instrument as each state in the state machine
is entered.
8. A method according to claim 6, wherein saving a breadcrumb in a
memory of the test-and-measurement instrument when the at least one
state is entered includes saving the breadcrumb in the memory of
the test-and-measurement instrument when the at least one state is
entered, the breadcrumb including at least one of a type of state,
a state ID, and a time.
9. A method according to claim 6, wherein saving a breadcrumb in a
memory of the test-and-measurement instrument when the at least one
state is entered includes saving an error breadcrumb in the memory
of the test-and-measurement instrument when an error state is
entered on an unexpected input, the breadcrumb including at least
one of a type of state, a state ID, and a time.
10. A method according to claim 6, wherein generating a state
machine from the regular expression includes optimizing the state
machine.
11. A method according to claim 6, further comprising using the
saved breadcrumbs to follow the application of the bit stream to
the state machine.
Description
RELATED APPLICATION DATA
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 62/068,384, filed Oct. 24, 2014, which
is incorporated herein for all purposes.
BACKGROUND
[0002] This invention relates to test-and-measurement instruments,
and more particularly to ways to recreate the analysis of a bit
stream in a test-and-measurement instrument.
[0003] Real time analysis of signals has its place. But sometimes,
it is useful to recreate the operation of a test-and-measurement
instrument on data after the fact, and more slowly, so that the
details can be checked. Currently, there is no way to do this
analysis recreation when analyzing data in a bit stream.
[0004] Embodiments of the invention address this and other problems
with the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1A shows an example of a protocol for matching a
particular packet
[0006] FIG. 1B shows a state machine that can match the packet of
FIG. 1A.
[0007] FIG. 1C shows a state machine that can trigger on a
condition involving the data of the packet of FIG. 1A.
[0008] FIG. 2A shows a second example of a protocol for matching
several packets.
[0009] FIG. 2B shows an un-optimized state machine to match the
packets of FIG. 2A.
[0010] FIG. 2C shows an optimized state machine to match the
packets of FIG. 2A.
[0011] FIG. 2D shows a state machine that can trigger on a
condition involving the data of the packets of FIG. 2A.
[0012] FIGS. 3A-3B show the state machine of FIG. 1B modified to
reflect compound trigger conditions.
[0013] FIG. 4 shows a test-and-measurement instrument that can
create and use the state machines of FIGS. 1B-1C and 2B-2D to
trigger the test-and-measurement instrument when various trigger
conditions are met, and to save breadcrumbs into memory reflecting
the operation of the state machines of FIGS. 1B-1C and 2B-2D,
according to an embodiment of the invention.
[0014] FIG. 5 shows more detail about the state machine modifier of
FIG. 4.
[0015] FIG. 6 shows more detail about the breadcrumbs of FIG.
4.
[0016] FIGS. 7A-7B show a flowchart of a procedure for creating a
trigger state machine from a protocol and user configuration using
the test-and-measurement instrument of FIG. 4, according to an
embodiment of the invention.
[0017] FIG. 8 shows a flowchart of a procedure for creating a
trigger state machine from a protocol and a compound trigger
condition using the test-and-measurement instrument of FIG. 4,
according to an embodiment of the invention.
[0018] FIG. 9 shows a flowchart of a procedure for optimizing a
state machine using the test-and-measurement instrument of FIG. 4,
according to an embodiment of the invention.
[0019] FIG. 10 shows a flowchart of a procedure for using creating
a state machine that can save breadcrumbs using the
test-and-measurement instrument of FIG. 4, according to an
embodiment of the invention.
DETAILED DESCRIPTION
[0020] Before explaining how the invention operates, it is useful
to understand the relationship between regular expressions and
state machines. Given a regular expression, a state machine can be
constructed that represents that regular expression. The state
machine can then be used to determine whether a particular input
matches the regular expression. If the state machine processes to
an acceptable end state, then the input matches the regular
expression; otherwise, the input does not match the regular
expression.
[0021] FIG. 1A shows an example of a protocol for a packet of data
named "dataPacket", expressed as a regular expression. Protocol 105
describes a packet of data. When a bit stream is compared against
this regular expression, the system can determine if the packet is
found within the bit stream.
[0022] FIG. 1B shows a state machine that corresponds to the
regular expression of FIG. 1A. State machine 110 includes states
115, 120, 125, 130, 135, 140, and 145, with transitions between
these states. Each state (which can also be called a node or
vertex) describes what data needs to be matched to enter the state
(the acceptance criterion). Each arrow is a path that can be
traversed provide the target acceptance criterion for the state is
met. Aside from start state 115 and success state 145, these states
correspond sequentially to the data expected by the packet. Thus,
state 120 matches a state S within the bit stream, state 125
matches three bits of data against the field labeled "begin", state
130 matches four bits of data against the field labeled "addr", and
so on. Assuming that all the data can be matched by the states of
state machine 110, when success state 145 is reached, the system
can declare that the packet "dataPacket" has been successfully
matched.
[0023] State machine 110 represents a simplified version of the
actual state machine. For example, state machine 110 does not label
the transitions between the various states, nor does state machine
110 show error states or transitions that are used when data does
not match what is expected. A person skilled in the art would
understand how state machine 110 operates, even without these
details.
[0024] Formally, in mathematical terms, a state machine can be
represented as a quintuple (.SIGMA., S, s.sub.0, .delta., F), where
.SIGMA. is the alphabet (the set of symbols recognized by the state
machine), S is the set of states in the state machine, s.sub.0 is
the initial state, .delta. is the transition function, which maps
from each state in S and each symbol in .SIGMA. to a state in S
(which could be the same state as the input state), and F is the
set of final states in S. Thus, state machine 110 could be more
formally represented as (.SIGMA., S, s.sub.0, .delta., F),
where:
[0025] .SIGMA.={S, 0, 1, . . . } (there could potentially be more
symbols recognized than just the state S and binary values 0 and 1,
even though these are the only symbols recognized by the state
machine)
[0026] S={110, 115, 120, 125, 130, 135, 140, 145}
[0027] s.sub.0=110
[0028] .delta. (.delta. is not expressed in more detail here
because expressing the complete transition function would be very
cumbersome and of little value)
[0029] F={145}
[0030] In fact, this expression of state machine 110 is not
necessarily complete. Transitions typically occur on individual
symbols, rather than groups of symbols. Thus, transitioning from
state 120 to 125 can actually involve three transitions (and
therefore some intermediate states): one for each bit recognized
for the field labeled "begin". But as a simplification, a person
skilled in the art would understand how state machine 110
operates.
[0031] A user might want to trigger some process if a particular
value is read for a given state in state machine 110. For example,
a user might want to trigger a process if the address field stores
the value 10 (in binary, 1010; in hexadecimal, A). FIG. 1C shows an
example of how state machine 110 can be modified to implement this
trigger. In FIG. 1C, instead of matching against any possible value
for the address field, state machine 150 compares the bit stream
with the specific value 1010 (in state 155). If that value is
found, then at state 160, the trigger is considered satisfied, and
the trigger causes the process to start (whatever that process
might be).
[0032] Note that states 115 and 120 are the same in state machine
150 as in state machine 110: state 115 is a state in which the
state machine starts, and state 120 matches state S from the bit
stream. But state 165 is different from state 125, in that state
165 does not care about the particular field being read. Put
another way, in state 165 all that matters is that three bits are
read from the bit stream. State 155 is also different from state
130, as state 155 is concerned only with matching the particular
bit pattern 1010, rather than matching the address field (as in
state 130). Finally, once the user condition has been matched, no
further matching needs to be done, so state machine 150 does not
include analogs to states 135 and 140: the trigger can be issued
immediately after the condition is met.
[0033] FIGS. 1A-1C show a fairly simple example of a regular
expression, state machine to match the regular expression, and
trigger state machine. (Trigger state machines are sometimes
referred to simply as "state machines", but from context a person
skilled in the art can determine if a particular state machine is a
trigger state machine or a state machine to match a regular
expression.) FIGS. 2A-2D show a more complicated example. In FIG.
2A, regular expressions for three different packets are shown.
These regular expressions can be converted into a state machine, as
shown in FIG. 2B. Note that state machine 205 in FIG. 2B uses a
single start state to cover all three possible protocols.
[0034] State machine 205 can be used as shown. But using state
machine 205 as shown would require look-ahead or backtracking,
which requires additional memory and can slow down processing of a
bit stream. For example, assume that where multiple states can be
reached given a particular input, the left-most (as FIG. 2B would
be read by a person, rather than how a processor might use state
machine 205). For example, note that states 210, 215, and 220 all
match Begin states, and states 225, 230, and 235 all match 4 bits
as a slaveAddress field. Using a left-most first approach, after
reading a Begin state and 4 bits as the slaveAddress field, the
system would be in state 225. But if the next bit read would be a
0, then the system would be following the wrong branch of state
machine 205, and would have to unwind the processing of state
machine 205 to attempt to find the correct branch. This is an
example of backtracking. It should be apparent that having to
reverse state machine 205 and process a different branch can slow
down processing of the bit stream. Avoiding backtracking using
state machine 205 would require look-ahead processing: the system
would have to somehow look at bits yet to come in the bit stream.
Look-ahead is also complicated and expensive.
[0035] To avoid both backtracking and look-ahead, state machine 205
can be optimized. State machine 240 in FIG. 2C shows an example of
an optimized state machine. With state machine 240, there is no
need to look ahead, and no concern about backtracking. Given any
prefix (up to and including the entire packet) of any of the
packets, there is only one possible path through state machine 240
that matches that prefix. Therefore, there is no need to perform
look-ahead, and no need to worry about backtracking: given a
particular state in state machine 240 and a particular input
symbol, there is only one possible state to transition to (this
state might be an error state, not shown in FIG. 2C for
simplicity).
[0036] Optimization can be accomplished using the following
procedure. Start by walking the tree from the start state and
combining the nodes (that is, merge the nodes into a single node)
that are equivalent and have the same parent. This process can be
repeated until there are no more like nodes to combine. Then find
the equivalent Success states, combine them, and then combine nodes
that are equivalent and have the same children (again, repeating
the process until there are no more like nodes to combine).
[0037] FIG. 2D shows an example of a particular trigger customized
by the user. In FIG. 2D, the user has selected to trigger when the
address field (not the slaveAddress field) of a packet in the
regular expression is set to the value 0. Since this field does not
appear in the packet Register0Write, this entire branch of the
state machine can be eliminated from trigger state machine 245. Any
value can be matched against the slaveAddress field, after which
the bits 0 and 1 must be matched. Any bit can occur after that
(although the actual bit would depend on the particular packet
being read, trigger state machine 245 does not care which value is
received), after which the bits for the address field are received,
and can be compared with the value 0. If the value 0 is matched for
the address field, then trigger state machine 245 has succeeded,
and the trigger can be initiated.
[0038] The above examples use a single trigger criterion, expressed
as an equality. But there is no reason to limit the trigger
condition to an equality. Aside from equality (==), examples of
other trigger conditions can be inequality (!=), less than (<),
less than or equal to (<=), greater than (>), or greater than
or equal to (>=). In addition, the trigger condition might
depend on only a subset of information from the field in the
regular expression. For example, in FIG. 2D, the user might only be
interested in whether the middle three bits of the address field
are equal to 001: the first and last bit in the address field
(which has a total of five bits) can match any value. It is also
possible to set a trigger condition that depends merely on reaching
a particular state. For example, the user might be interested in
knowing when the address field is reached, regardless of its actual
value.
[0039] In addition, trigger conditions do not have to be limited to
a single criterion (which can be termed a simple trigger
condition). The user can specify multiple criteria (compound
trigger conditions), combined using AND and OR operators, in any
desired combination. Thus, the state machine might be testing for
multiple conditions, any of which might involve a set of
sub-conditions, and so on. A person skilled in the art would know
how to simplify the user's provided condition into disjunctive
normal form or conjunctive normal form, as desired, which might
simplify the design of the state machine. (Disjunctive normal form
refers to a logical formula expressed as a disjunction of
conjunctive clauses: that is, an OR of ANDs. Conjunctive normal
form similarly describes an AND of ORs.)
[0040] FIGS. 3A-3B show examples of state machines with compound
trigger conditions. In FIG. 3A, the user has specified the trigger
condition of (addr==0xA && parity==1). Such a trigger
condition is a conjunction of the two conditions. Because the
trigger condition requires that two states both have specified
values, two states in the state machine are set to specific values
(as specified by the user); the values for other states are
generally not important, and can be combined into a single
state.
[0041] In FIG. 3B, the user has specified a trigger condition of
(addr==0xA II parity==1): a disjunctive trigger condition. Because
the trigger condition requires one of two states to have a
specified value, two state machines, with the separate conditions,
can be established and merged using the optimization techniques
described earlier. Note that even though the trigger condition
applies to a single state machine, because of the disjunction,
there are two possible paths to a successful trigger.
[0042] FIGS. 3A-3B give examples involving a single AND or OR
combining two possible trigger values. But it should be apparent
that the process can be generalized for more complicated trigger
conditions. For example, if the trigger condition involves two
values joined by an AND operation, or another value (an expression
of the form ((X AND Y) OR Z), then the state machine can be copied.
One copy can be modified to reflect the first value of the AND
operation; a second copy can be modified to reflect the second
value of the AND operation; and the third copy can be modified to
reflect the other value of the OR operation. The first two state
machines can then be combined and optimized as described above to
represent the AND operation, and that state machine can then be
combined and optimized with the third state machine to represent
the compound trigger condition.
[0043] Now that trigger state machines have been described, a
system that can use trigger state machines can be described. FIG. 4
shows a test-and-measurement instrument that can create and use the
state machines of FIGS. 1B-1C and 2B-2D to trigger the
test-and-measurement instrument when various trigger conditions are
met, according to an embodiment of the invention. The system can
include test-and-measurement instrument 405. Test-and-measurement
instrument can be any desired test-and-measurement instrument, such
as an oscilloscope, among other possibilities.
[0044] Test-and-measurement instrument 405 can include memory 410.
Memory 410 can store information, such as state machine 415. State
machine 415 can be a state machine used to match a regular
expression: in other words, a state machine such as state machines
110, 205, and 240 of FIGS. 1B, 2B, and 2C). State machine 415 can
also be a trigger state machine, such as state machines 150 and 245
of FIGS. 1C and 2D.
[0045] Test-and-measurement instrument 405 can also include
receiver 420, which can receive input into test-and-measurement
instrument 405. Input can be received in any number of ways. For
example, receiver 420 can include a user interface for a user to
input information, such as trigger condition 425, which itself can
include, for example, user-selected value 430 for a particular bit
field. Or, receiver 420 can include receive a signal that includes
a bit stream, such as bit stream 435, to be analyzed. Receiver 420
can also receive regular expression 440 (for example, through an
integrated development environment (IDE), which can identify the
data the system should expect to receive in bit stream 435, and
which can be used to construct state machine 415 (be it a state
machine to recognize regular expression 440 or a trigger state
machine).
[0046] Test-and-measurement instrument 405 can also include various
other units. State machine modifier 445 can take an existing state
machine (for example, one that matches data to regular expression
440) and modifies it to operate as a trigger state machine. As
discussed above, this can include eliminating states that occur
after the trigger condition is satisfied, and combining states
whose values are not considered as part of the trigger condition,
among other possibilities.
[0047] Processing engine 450 can process bit stream 435 using
various state machines (including, for example, a state machine
generated using regular expression 440 or a trigger state machine
produced using state machine modifier 445). This processing can
include updating the current state for each various state machine,
as bits are read from bit stream 435.
[0048] Trigger system 455 can send a trigger when the trigger
condition is met (that is, when the trigger state machine is
satisfied. Trigger system 455 can send the trigger to any desired
component of test-and-measurement instrument 405 to perform any
action as a result of the trigger, as would be understood by person
of ordinary skill in the art.
[0049] State machine generator 460 can generate a state machine
from regular expression 440. As discussed above, this can include
creating a sequential series of states that match fields in the
order presented in the regular expression. This can also include
combining various state machines that match different regular
expressions into a single state machine, and optimizing a state
machine to avoid look-ahead and backtracking problems.
[0050] Aside from generating and using trigger state machines,
test-and-measurement instrument 405 can also be used to generate
breadcrumbs. Breadcrumbs let a user recreate the operation of a
state machine, to see how data was processed. Breadcrumbs, such as
breadcrumb 465, are bits of data that can be stored in memory 410.
Essentially, whenever a state in a state machine is entered, a
breadcrumb can be saved. A breadcrumb can include data, such as the
type of state (e.g., error state, packet start, packet end, or
field), an ID for the state (that can identify the field or
packet), and a time, such as the start and/or stop time of the data
that caused the state entry. A person skilled in the art will
recognize that "time" does not have to refer to the literal concept
of time (as in seconds or fractions thereof since the start of the
signal), but rather can refer to an index into a signal, among
other possibilities. Breadcrumbs can also include additional data
pertinent to analysis, as appropriate. Therefore, the
identification of the data to be included in the breadcrumbs can be
user-customized.
[0051] Breadcrumbs are usually generated using a trigger state
machine. But a person skilled in the art will recognize that there
is no reason why any other state machine cannot be used to generate
breadcrumbs, and therefore breadcrumbs can be generated using any
state machine.
[0052] To support breadcrumb generation, test-and-measurement
instrument 405 can include analyzer 470. Analyzer 470 can analyze
bit stream 435 using a state machine. In operation, analyzer 470 is
similar to processing engine 450, but their objectives are
different. Whereas processing engine 450 is concerned with matching
bits from bit stream 435 to attempt to recognize regular
expressions, analyzer 470 is concerned with determining when to
save a breadcrumb to memory 410. Analyzer 470 and processing engine
450 also typically operate on different state machines: analyzer
470 usually uses (but does not have to use) a trigger state
machine, whereas processor 450 uses a full state machine to match a
regular expression.
[0053] Test-and-measurement instrument 405 can also include
breadcrumb generator 475. When it is time to generate a breadcrumb
(e.g., when a new state is entered as determined by analyzer 470),
breadcrumb generator 475 can save the breadcrumb to memory 410.
[0054] Finally, test-and-measurement instrument 405 can include
re-creator 480. Re-creator 480 permits a user to re-create the
operation of the state machine (as processed by analyzer 470) on
bit stream 435. This recreation enables the user to follow what
happened.
[0055] Test-and-measurement instrument 405 as described can process
either the trigger state machine or the breadcrumb generation, or
both. Some test-and-measurement instruments include the necessary
hardware and/or software to process multiple state machines. If a
test-and-measurement instrument is capable of processing multiple
state machines, then test-and-measurement instrument 405 can
perform both processing for trigger conditions and breadcrumbs.
[0056] FIG. 5 shows more detail about the state machine modifier of
FIG. 4. In FIG. 5, state machine modifier 445 is shown as including
state machine optimizer 505. State machine optimizer 505 can
optimize a state machine, as described above. Such optimization can
be either for a state machine designed to match a regular
expression or for a trigger state machine.
[0057] FIG. 6 shows more detail about the breadcrumbs of FIG. 4. In
FIG. 6, breadcrumb 465 is shown as including type 605, ID 610, and
time 615. As discussed above, type 605 can specify the type of
state which generated breadcrumb 465. ID 610 can specify the
specific state in the state machine that generated breadcrumb 465.
And time 615 can specify the time (or index) in the signal when the
state generated breadcrumb 465.
[0058] FIGS. 7A-7B show a flowchart of a procedure for creating a
trigger state machine from a protocol and user configuration using
the test-and-measurement instrument of FIG. 4, according to an
embodiment of the invention. In FIG. 7A, at block 705, the system
can receive a regular expression. At block 710, the system can
generate a state machine that corresponds to the regular
expression. At block 715, the system can optimize the state
machine.
[0059] At block 720, the system can identify the state machine
corresponding to a regular expression (which can be the same state
machine generated in blocks 705-715). At block 725, the system can
receive a trigger condition from the user. This can include, for
example, a user-specified value (or part of a value) for a
particular field in the regular expression, multiple such
user-specified values, or even just a field to be reached, among
other possibilities. At block 730, the system can identify a state
(or more than one state) in the state machine that can be modified
to implement the trigger condition.
[0060] At block 735 (FIG. 7B), the system can modify the identified
state(s) to compare with the user-selected value. At block 740, the
system can store the modified state machine. At block 745, the
system can receive a bit stream. At block 750, the system can
process the bit stream using the modified state machine. At block
710, the system can determine if the trigger condition was met. If
so, then at block 755 the system can apply a triggering system.
[0061] As discussed above, a trigger condition can be a compound
trigger condition. In that case, the flowchart of the procedure can
be modified to reflect the compound nature of the trigger
condition. FIG. 8 reflects this change. FIG. 8 modifies blocks 730
and 735 of FIGS. 7A-7B: the other blocks in FIGS. 7A-7B are
unmodified and therefore not shown in FIG. 8.
[0062] In FIG. 8, at block 805, the system identifies states that
are implicated by the compound trigger condition. The number of
implicated states might be less than the number of simple
conditions included in the compound trigger condition. For example,
a compound trigger condition for the state machine shown in FIG. 1B
might be (addr==0xA II addr==0xF). Note that the same state is used
in both sides of the compound trigger condition. At block 810, the
system replicates the state machine once for each simple trigger
condition in the compound trigger condition. Continuing the above
example, the compound trigger condition includes two simple trigger
conditions (addr==0xA and addr==0xF), so the system would generate
two replicas of the state machine. At block 815, within each
replicated state machine, an identified state is modified to
reflect the comparison with the user-specified value. Finally, at
block 820, the modified replicated state machines can be combined
to produce a single state machine that reflects the compound
trigger condition. At this point, processing can continue with
block 740 of FIG. 7B.
[0063] FIG. 9 shows a flowchart of a procedure for optimizing a
state machine using the test-and-measurement instrument of FIG. 4,
according to an embodiment of the invention. In FIG. 9, at block
905, the system can remove states that occur after the trigger
condition is met. At block 910, the system can merge adjacent
states that can be satisfied by any value into a single state.
[0064] FIG. 10 shows a flowchart of a procedure for using creating
a state machine that can save breadcrumbs using the
test-and-measurement instrument of FIG. 4, according to an
embodiment of the invention. At block 1005, the system can receive
a regular expression. At block 1010 the system can generate a state
machine from the regular expression. At block 1015, the system can
optimize the state machine. At block 1020, the system can apply the
state machine to a bit stream. At block 1025, the system can save a
breadcrumb whenever a state in the state machine is entered. At
block 1030, the system can use the saved breadcrumbs to recreate
the application of the state machine to the bit stream.
[0065] The above flowcharts show some possible embodiments of the
invention. But other embodiments of the invention can organize the
blocks in different arrangements, and can include or omit different
blocks as desired, or repeat a block (or multiple blocks) as
needed. Embodiments of the invention are intended to include all
such variations on the flowcharts.
[0066] Embodiments of the invention can extend to the following
statements, without limitation:
[0067] An embodiment of the invention includes a system,
comprising: a test-and-measurement instrument; a memory on the
test-and-measurement instrument; a receiver on the
test-and-measurement instrument operative to receive a regular
expression and a bit stream; a state machine generator to generate
a state machine from the regular expression; an analyzer operative
to analyze the bit stream using the state machine; and a breadcrumb
generator operative to generate and save in the memory a breadcrumb
whenever a state in the state machine is entered.
[0068] An embodiment of the invention includes a system,
comprising: a test-and-measurement instrument; a memory on the
test-and-measurement instrument; a receiver on the
test-and-measurement instrument operative to receive a regular
expression and a bit stream; a state machine generator to generate
a state machine from the regular expression; an analyzer operative
to analyze the bit stream using the state machine; and a breadcrumb
generator operative to generate and save in the memory a breadcrumb
whenever a state in the state machine is entered, wherein the
breadcrumb generator is operative to generate a breadcrumb
including at least one of a type, an ID, and a time.
[0069] An embodiment of the invention includes a system,
comprising: a test-and-measurement instrument; a memory on the
test-and-measurement instrument; a receiver on the
test-and-measurement instrument operative to receive a regular
expression and a bit stream; a state machine generator to generate
a state machine from the regular expression; an analyzer operative
to analyze the bit stream using the state machine; and a breadcrumb
generator operative to generate and save in the memory a breadcrumb
whenever a state in the state machine is entered, wherein the
breadcrumb generator is operative to generate and save in the
memory a breadcrumb when an error state is entered on an unexpected
input, the breadcrumb including at least one of a type, an ID, and
a time.
[0070] An embodiment of the invention includes a system,
comprising: a test-and-measurement instrument; a memory on the
test-and-measurement instrument; a receiver on the
test-and-measurement instrument operative to receive a regular
expression and a bit stream; a state machine generator to generate
a state machine from the regular expression; a state machine
optimizer operative to optimize the state machine; an analyzer
operative to analyze the bit stream using the optimized state
machine; and a breadcrumb generator operative to generate and save
in the memory a breadcrumb whenever a state in the optimized state
machine is entered.
[0071] An embodiment of the invention includes a system,
comprising: a test-and-measurement instrument; a memory on the
test-and-measurement instrument; a receiver on the
test-and-measurement instrument operative to receive a regular
expression and a bit stream; a state machine generator to generate
a state machine from the regular expression; an analyzer operative
to analyze the bit stream using the state machine; a breadcrumb
generator operative to generate and save in the memory a breadcrumb
whenever a state in the state machine is entered; and a re-creator
to recreate the operation of the state machine using the saved
breadcrumbs.
[0072] An embodiment of the invention includes a method,
comprising: receiving a regular expression at a
test-and-measurement instrument; generating a state machine from
the regular expression; applying the state machine to a bit stream;
and for at least one state in the state machine, saving a
breadcrumb in a memory of the test-and-measurement instrument when
the at least one state is entered.
[0073] An embodiment of the invention includes a method,
comprising: receiving a regular expression at a
test-and-measurement instrument; generating a state machine from
the regular expression; applying the state machine to a bit stream;
and for at least one state in the state machine, saving a
breadcrumb in a memory of the test-and-measurement instrument when
the at least one state is entered, including saving a breadcrumb in
the memory of the test-and-measurement instrument as each state in
the state machine is entered.
[0074] An embodiment of the invention includes a method,
comprising: receiving a regular expression at a
test-and-measurement instrument; generating a state machine from
the regular expression; applying the state machine to a bit stream;
and for at least one state in the state machine, saving a
breadcrumb in a memory of the test-and-measurement instrument when
the at least one state is entered, including saving the breadcrumb
in the memory of the test-and-measurement instrument when the at
least one state is entered, the breadcrumb including at least one
of a type, an ID, and a time.
[0075] An embodiment of the invention includes a method,
comprising: receiving a regular expression at a
test-and-measurement instrument; generating a state machine from
the regular expression; applying the state machine to a bit stream;
and for at least one state in the state machine, saving a
breadcrumb in a memory of the test-and-measurement instrument when
the at least one state is entered, including saving an error
breadcrumb in the memory of the test-and-measurement instrument
when an error state is entered on an unexpected input, the
breadcrumb including at least one of a type, an ID, and a time.
[0076] An embodiment of the invention includes a method,
comprising: receiving a regular expression at a
test-and-measurement instrument; generating a state machine from
the regular expression; optimizing the state machine; applying the
optimized state machine to a bit stream; and for at least one state
in the optimized state machine, saving a breadcrumb in a memory of
the test-and-measurement instrument when the at least one state is
entered.
[0077] An embodiment of the invention includes a method,
comprising: receiving a regular expression at a
test-and-measurement instrument; generating a state machine from
the regular expression; applying the state machine to a bit stream;
for at least one state in the state machine, saving a breadcrumb in
a memory of the test-and-measurement instrument when the at least
one state is entered; and using the saved breadcrumbs to follow the
application of the bit stream to the state machine.
[0078] The following discussion is intended to provide a brief,
general description of a suitable machine in which certain aspects
of the invention may be implemented. Typically, the machine
includes a system bus to which is attached processors, memory,
e.g., random access memory (RAM), read-only memory (ROM), or other
state preserving medium, storage devices, a video interface, and
input/output interface ports. The machine may be controlled, at
least in part, by input from conventional input devices, such as
keyboards, mice, etc., as well as by directives received from
another machine, interaction with a virtual reality (VR)
environment, biometric feedback, or other input signal. As used
herein, the term "machine" is intended to broadly encompass a
single machine, or a system of communicatively coupled machines or
devices operating together. Exemplary machines include computing
devices such as personal computers, workstations, servers, portable
computers, handheld devices, telephones, tablets, etc., as well as
transportation devices, such as private or public transportation,
e.g., automobiles, trains, cabs, etc.
[0079] The machine may include embedded controllers, such as
programmable or non-programmable logic devices or arrays,
Application Specific Integrated Circuits, embedded computers, smart
cards, and the like. The machine may utilize one or more
connections to one or more remote machines, such as through a
network interface, modem, or other communicative coupling. Machines
may be interconnected by way of a physical and/or logical network,
such as an intranet, the Internet, local area networks, wide area
networks, etc. One skilled in the art will appreciated that network
communication may utilize various wired and/or wireless short range
or long range carriers and protocols, including radio frequency
(RF), satellite, microwave, Institute of Electrical and Electronics
Engineers (IEEE) 810.11, Bluetooth, optical, infrared, cable,
laser, etc.
[0080] The invention may be described by reference to or in
conjunction with associated data including functions, procedures,
data structures, application programs, etc. which when accessed by
a machine results in the machine performing tasks or defining
abstract data types or low-level hardware contexts. Associated data
may be stored on tangible computer-readable media as non-transitory
computer-executable instructions. Associated data may be stored in,
for example, the volatile and/or non-volatile memory, e.g., RAM,
ROM, etc., or in other storage devices and their associated storage
media, including hard-drives, floppy-disks, optical storage, tapes,
flash memory, memory sticks, digital video disks, biological
storage, etc. Associated data may be delivered over transmission
environments, including the physical and/or logical network, in the
form of packets, serial data, parallel data, propagated signals,
etc., and may be used in a compressed or encrypted format.
Associated data may be used in a distributed environment, and
stored locally and/or remotely for machine access.
[0081] Having described and illustrated the principles of the
invention with reference to illustrated embodiments, it will be
recognized that the illustrated embodiments may be modified in
arrangement and detail without departing from such principles. And,
though the foregoing discussion has focused on particular
embodiments, other configurations are contemplated. In particular,
even though expressions such as "in one embodiment" or the like are
used herein, these phrases are meant to generally reference
embodiment possibilities, and are not intended to limit the
invention to particular embodiment configurations. As used herein,
these terms may reference the same or different embodiments that
are combinable into other embodiments.
* * * * *