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authorKevin Hart <khart@codeaurora.org>2016-02-11 12:04:26 -0800
committerSteve Kondik <steve@cyngn.com>2016-04-20 15:09:18 -0700
commit3a5c4a7f6a52c6e6f71616940920cb647aafff2b (patch)
tree787c15d6458b58a7468eb4ff4633d07b4625b259
parent45b2d5a055d63d261ec908e1dd35cf5589827384 (diff)
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XML Pull Parser optimizations
This patch includes three improvements to the pull parser. 1. readValue now only uses the stringPool for all-whitespace strings. Values are generally not repeated, and this function can thrash the string pool in some cases 2. Added a fast path for the normal, correct, end-tag case. This avoids a hash and lookup in the stringPool 3. While parsing an element (not attribute) name, the namespace and post-namespace strings are generated using the stringPool. This saves the cost of calling String.substring in adjustNsp. Change-Id: I69482a49bf52cb72d48bcbecd30fb56effe6a4ef
-rw-r--r--xml/src/main/java/org/kxml2/io/KXmlParser.java74
1 files changed, 66 insertions, 8 deletions
diff --git a/xml/src/main/java/org/kxml2/io/KXmlParser.java b/xml/src/main/java/org/kxml2/io/KXmlParser.java
index a90db3b..a75cc72 100644
--- a/xml/src/main/java/org/kxml2/io/KXmlParser.java
+++ b/xml/src/main/java/org/kxml2/io/KXmlParser.java
@@ -157,6 +157,8 @@ public class KXmlParser implements XmlPullParser, Closeable {
private boolean isWhitespace;
private String namespace;
private String prefix;
+ private String foundPrefix = null;
+ private String foundName = null;
private String name;
private String text;
@@ -268,15 +270,21 @@ public class KXmlParser implements XmlPullParser, Closeable {
}
}
- int cut = name.indexOf(':');
+ if (foundPrefix != null && foundName != null) {
+ prefix = foundPrefix;
+ name = foundName;
+ }
+ else {
+ int cut = name.indexOf(':');
if (cut == 0) {
checkRelaxed("illegal tag name: " + name);
}
- if (cut != -1) {
- prefix = name.substring(0, cut);
- name = name.substring(cut + 1);
+ if (cut != -1) {
+ prefix = name.substring(0, cut);
+ name = name.substring(cut + 1);
+ }
}
this.namespace = getNamespace(prefix);
@@ -961,13 +969,19 @@ public class KXmlParser implements XmlPullParser, Closeable {
}
private void readEndTag() throws IOException, XmlPullParserException {
+ int sp = (depth - 1) * 4;
read('<');
read('/');
- name = readName(); // TODO: pass the expected name in as a hint?
+ if (depth == 0) {
+ name = readName();
+ }
+ else {
+ // Pass the expected name in as a hint.
+ name = readExpectedName(elementStack[sp + 3]);
+ }
skip();
read('>');
- int sp = (depth - 1) * 4;
if (depth == 0) {
checkRelaxed("read end tag " + name + " with no tags open");
@@ -1055,7 +1069,7 @@ public class KXmlParser implements XmlPullParser, Closeable {
if (!xmldecl) {
read('<');
}
- name = readName();
+ name = readName(true);
attributeCount = 0;
while (true) {
@@ -1429,7 +1443,12 @@ public class KXmlParser implements XmlPullParser, Closeable {
}
if (result == null) {
- return stringPool.get(buffer, start, position - start);
+ if (isWhitespace) {
+ return stringPool.get(buffer, start, position - start);
+ }
+ else {
+ return new String(buffer, start, position - start);
+ }
} else {
result.append(buffer, start, position - start);
return result.toString();
@@ -1525,13 +1544,44 @@ public class KXmlParser implements XmlPullParser, Closeable {
* Returns an element or attribute name. This is always non-empty for
* non-relaxed parsers.
*/
+ private String readExpectedName(String expected) throws IOException, XmlPullParserException {
+ int length = expected.length();
+ int end = position + length;
+ if (end < limit) {
+ // Fast path for normal case.
+ boolean match = true;
+ for (int i = 0; i < length; i++) {
+ if (buffer[position+i] != expected.charAt(i)) {
+ match = false;
+ break;
+ }
+ }
+ if (match) {
+ position += length;
+ return expected;
+ }
+ }
+ return readName();
+ }
+
private String readName() throws IOException, XmlPullParserException {
+ return readName(false);
+ }
+
+ /**
+ * Returns an element or attribute name. This is always non-empty for
+ * non-relaxed parsers. findPrefix should only be true for element names
+ */
+ private String readName(boolean findPrefix) throws IOException, XmlPullParserException {
if (position >= limit && !fillBuffer(1)) {
checkRelaxed("name expected");
return "";
}
int start = position;
+ int nameStart = -1;
+ foundPrefix = null;
+ foundName = null;
StringBuilder result = null;
// read the first character
@@ -1575,12 +1625,20 @@ public class KXmlParser implements XmlPullParser, Closeable {
|| c == ':'
|| c == '.'
|| c >= '\u00b7') { // TODO: check the XML spec
+ // Fast path for common case
+ if (c == ':' && findPrefix && foundPrefix == null) {
+ foundPrefix = stringPool.get(buffer, start, position - start);
+ nameStart = position+1;
+ }
position++;
continue;
}
// we encountered a non-name character. done!
if (result == null) {
+ if (foundPrefix != null && position != nameStart) {
+ foundName = stringPool.get(buffer, nameStart, position - nameStart);
+ }
return stringPool.get(buffer, start, position - start);
} else {
result.append(buffer, start, position - start);