grammar: Speed-up quoted string parsing

On the sysmoBTS (ARM7TDMI) the parsing of a simple response
with quoted string takes up to 200ms. Parsing the single
digest line takes 40ms itself. Create a custom parser to
speed things up to avoid the backtracking between three
optional parsers that are combined in a choice.

6 files changed, 173 insertions, 10 deletions

diff --git a/callagent/parser/SIPParser.st b/callagent/parser/SIPParser.st
index 5435f7e..9ffd4a4 100644
--- a/callagent/parser/SIPParser.st
+++ b/callagent/parser/SIPParser.st
@@ -138,14 +138,6 @@ SIPGrammar subclass: SIPParser [
         ^super EQUAL flatten
     ]
 
-    realm_value [
-        ^super realm_value => [:nodes | nodes third]
-    ]
-
-    nonce_value [
-        ^super nonce_value => [:nodes | nodes third]
-    ]
-
     stale [
         ^super stale => [:nodes |
             Array
@@ -191,7 +183,7 @@ SIPGrammar subclass: SIPParser [
                 Array
                     with: nodes first
                     with: nodes second
-                    with: nodes third third]
+                    with: nodes third]
     ]
 
     Authorization [
diff --git a/callagent/tests/SIPParserTest.st b/callagent/tests/SIPParserTest.st
index 13fcab3..6348f86 100644
--- a/callagent/tests/SIPParserTest.st
+++ b/callagent/tests/SIPParserTest.st
@@ -117,6 +117,7 @@ PP.PPCompositeParserTest subclass: SIPParserTest [
         self should: [((res parameter: 'To') valueAt: 'foo')] raise: SystemExceptions.NotFound.
         self assert: (res parameter: 'From') tag = 'MzQ4NTQ0MTg2NzIyNDEwNjkyNjY_'.
         self assert: (res parameter: 'From') address = 'sip:1000@on-waves.com'.
+        self assert: res asDatagram equals: self testResponseData.
     ]
 
     testSIPDialog [
@@ -182,6 +183,7 @@ PP.PPCompositeParserTest subclass: SIPParserTest [
         from := (res parameter: 'From' ifAbsent: []).
         self assert: from address equals: 'sip:1000@osmocom.org'.
         self assert: from tag equals: 'MzQ4ODYyNTkyODQxMDY0OTAxMzI_'.
+        self assert: res asDatagram equals: self statusResponseData.
     ]
 
     resultUnauthorized [
diff --git a/grammar/SIPGrammar.st b/grammar/SIPGrammar.st
index 570ca85..a570b60 100644
--- a/grammar/SIPGrammar.st
+++ b/grammar/SIPGrammar.st
@@ -346,7 +346,7 @@ PP.PPCompositeParser subclass: SIPGrammar [
 
     quoted_string [
         <category: 'generic'>
-        ^SWS, DQUOTE, (self qdtext / self quoted_pair) star flatten, DQUOTE
+        ^SIPQuotedStringParser new
     ]
 
     qdtext [
diff --git a/grammar/SIPQuotedStringParser.st b/grammar/SIPQuotedStringParser.st
new file mode 100644
index 0000000..b56bfc9
--- /dev/null
+++ b/grammar/SIPQuotedStringParser.st
@@ -0,0 +1,102 @@
+"
+ (C) 2011-2014 by Holger Hans Peter Freyther
+ All Rights Reserved
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as
+ published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"
+
+PP.PPParser subclass: SIPQuotedStringParser [
+    <category: 'OsmoSIP-Grammar'>
+    <comment: 'The simple rule for PetitParser is a performance
+    issue on ARMv5te and we can do better here.
+
+    From RFC3161:
+
+      quoted-string  =  SWS DQUOTE *(qdtext / quoted-pair ) DQUOTE
+      qdtext         =  LWS / %x21 / %x23-5B / %x5D-7E
+                        / UTF8-NONASCII
+
+      quoted-pair  =  "\" (%x00-09 / %x0B-0C
+                / %x0E-7F)
+
+      LWS  =  [*WSP CRLF] 1*WSP ; linear whitespace
+      SWS  =  [LWS] ; sep whitespace'>
+
+    skipWhitespace: aStream [
+        [aStream atEnd] whileFalse: [
+            | c |
+            c := aStream uncheckedPeek.
+            c = ##(Character tab) ifTrue: [aStream next].
+            c = ##(Character space) ifTrue: [aStream next].
+            ^self
+        ]
+    ]
+
+    parseToClosingQuote: aStream startingAt: aStartPointer [
+        | text inQuote finish parsed |
+        text := WriteStream on: String new.
+
+        inQuote := false.
+        parsed := false.
+        finish := aStream atEnd.
+        [finish] whileFalse: [
+            "Did we have an escape?"
+            inQuote
+                ifTrue: [
+                    "TODO: Check if that is a valid sequence"
+                    text nextPut: aStream next.
+                    inQuote := false.
+                    finish := aStream atEnd]
+                ifFalse: [
+                    | c |
+                    c := aStream uncheckedPeek.
+                    c = $"
+                        ifTrue: [
+                            aStream skip: 1.
+                            parsed := true.
+                            finish := true]
+                        ifFalse: [
+                            c = $\ ifTrue: [inQuote := true].
+                            text nextPut: c.
+                            aStream skip: 1.
+                            finish := aStream atEnd]]].
+
+        ^parsed
+            ifFalse: [
+                aStream pointer: aStartPointer.
+                PPFailure message: 'Expected closing quote' at: aStream position]
+            ifTrue: [
+                text contents].
+    ]
+
+    parseOn: aStream [
+        | startPtr |
+
+        startPtr := aStream pointer.
+
+        "Skip whitespace"
+        self skipWhitespace: aStream.
+
+        "Check for the opening space"
+        aStream atEnd ifTrue: [
+            aStream pointer: startPtr.
+            ^PPFailure message: 'No space for opening quote' at: aStream position].
+        aStream uncheckedPeek = $" ifFalse: [
+            aStream pointer: startPtr.
+            ^PPFailure message: 'No opening quote' at: aStream position].
+        aStream skip: 1.
+
+        ^self parseToClosingQuote: aStream startingAt: startPtr.
+    ]
+]
diff --git a/grammar/SIPQuotedStringParserTest.st b/grammar/SIPQuotedStringParserTest.st
new file mode 100644
index 0000000..1f767f9
--- /dev/null
+++ b/grammar/SIPQuotedStringParserTest.st
@@ -0,0 +1,64 @@
+"
+ (C) 2011-2014 by Holger Hans Peter Freyther
+ All Rights Reserved
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Affero General Public License as
+ published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"
+
+PP.PPCompositeParserTest subclass: SIPQuotedStringParserTest [
+    <category: 'OsmoSIP-Grammar'>
+
+    parserClass [
+        ^SIPQuotedStringParser
+    ]
+
+    testParseStrings [
+        | res beenHere stream |
+
+        beenHere := false.
+        stream := '' readStream asPetitStream.
+        self assert: stream position equals: 0.
+        res := self parserInstance parse: stream onError: [beenHere := true].
+        self assert: stream position equals: 0.
+        self assert: beenHere.
+
+        beenHere := false.
+        stream := '"' readStream asPetitStream.
+        self assert: stream position equals: 0.
+        res := self parserInstance parse: stream onError: [beenHere := true].
+        self assert: stream position equals: 0.
+        self assert: beenHere.
+
+        stream := '""' readStream asPetitStream.
+        res := self parse: stream.
+        self assert: stream atEnd.
+        self assert: res equals: ''.
+
+
+        stream := ' ""' readStream asPetitStream.
+        res := self parse: stream.
+        self assert: stream atEnd.
+        self assert: res equals: ''.
+
+        stream := '"abcdef0123-!"' readStream asPetitStream.
+        res := self parserInstance parse: stream.
+        self assert: stream atEnd.
+        self assert: res equals: 'abcdef0123-!'.
+
+        stream := '"\""' readStream asPetitStream.
+        res := self parserInstance parse: stream.
+        self assert: stream atEnd.
+        self assert: res equals: '\"'.
+    ]
+]
diff --git a/package.xml b/package.xml
index 0e6918d..e5d7a8c 100644
--- a/package.xml
+++ b/package.xml
@@ -8,6 +8,7 @@
     <prereq>PetitParser</prereq>
     <prereq>Digest</prereq>
 
+    <filein>grammar/SIPQuotedStringParser.st</filein>
     <filein>grammar/SIPGrammar.st</filein>
 
     <filein>callagent/Base64MimeConverter.st</filein>
@@ -63,6 +64,7 @@
 
     <test>
         <prereq>PetitParserTests</prereq>
+        <sunit>Osmo.SIPQuotedStringParserTest</sunit>
         <sunit>Osmo.SIPGrammarTest</sunit>
         <sunit>Osmo.SIPParserTest</sunit>
         <sunit>Osmo.SIPRequestTest</sunit>
@@ -73,6 +75,7 @@
         <sunit>Osmo.SIPInviteTest</sunit>
         <sunit>Osmo.SIPBase64Test</sunit>
         <filein>grammar/SIPGrammarTest.st</filein>
+        <filein>grammar/SIPQuotedStringParserTest.st</filein>
         <filein>callagent/tests/SIPParserTest.st</filein>
         <filein>callagent/tests/Tests.st</filein>
         <filein>callagent/tests/SIPCallAgentTest.st</filein>