Misc perf fixes (toml, yaml)

toml/src/main/java/tools/jackson/dataformat/toml/TomlParser.java

@@ -327,10 +327,17 @@ private JsonNode parseInt(int nextState) throws IOException {
 
         for (int i = 0; i < length; i++) {
             if (buffer[start + i] == '_') {
-                // slow path to remove underscores
-                buffer = new String(buffer, start, length).replace("_", "").toCharArray();
-                start = 0;
-                length = buffer.length;
+                // slow path to remove underscores: compact into the already-owned
+                // buffer itself (chars before the first '_' are already in place),
+                // avoiding a second array allocation
+                int pos = start + i;
+                for (int j = pos + 1; j < start + length; j++) {
+                    char c = buffer[j];
+                    if (c != '_') {
+                        buffer[pos++] = c;
+                    }
+                }
+                length = pos - start;
                 break;
             }
         }
@@ -447,7 +454,8 @@ private ValueNode parseIntFromBuffer(char[] buffer, int start, int length) throw
     }
 
     private JsonNode parseFloat(int nextState) throws IOException {
-        final String text = lexer.yytext().replace("_", "");
+        String rawText = lexer.yytext();
+        final String text = rawText.indexOf('_') >= 0 ? rawText.replace("_", "") : rawText;
         pollExpected(TomlToken.FLOAT, nextState);
         if (text.endsWith("nan")) {
             return factory.numberNode(Double.NaN);

toml/src/test/java/tools/jackson/dataformat/toml/LongTokenTest.java

@@ -84,6 +84,27 @@ public void integerTooLongHex() throws IOException {
         assertRadixIntegerRejected("0xa");
     }
 
+    @Test
+    public void integerUnderscoreBufferGrowth() throws IOException {
+        // Digits interleaved with underscores, long enough to force the lexer's
+        // token buffer (initial size 4000) to grow while removing the underscores,
+        // followed by another key/value pair to prove later tokens are unaffected.
+        StringBuilder digits = new StringBuilder();
+        for (int i = 0; i < SCALE; i++) {
+            digits.append((char) ('0' + (i % 10)));
+            if (i % 3 == 2 && i != SCALE - 1) {
+                digits.append('_');
+            }
+        }
+        String toml = "foo = 1" + digits + "\nbar = 42";
+
+        ObjectNode node = (ObjectNode) NO_LIMITS_MAPPER.readTree(toml);
+
+        BigInteger expected = new BigInteger("1" + digits.toString().replace("_", ""));
+        assertEquals(expected, node.get("foo").bigIntegerValue());
+        assertEquals(42, node.get("bar").intValue());
+    }
+
     private void assertRadixIntegerRejected(String prefixAndFirstDigit) throws IOException {
         final ObjectMapper mapper = newTomlMapper();
         StringBuilder toml = new StringBuilder("foo = ").append(prefixAndFirstDigit);

yaml/src/main/java/tools/jackson/dataformat/yaml/YAMLGenerator.java

@@ -324,7 +324,7 @@ public JsonGenerator writeName(SerializableString name)
     @Override
     public JsonGenerator writePropertyId(long id) throws JacksonException {
         // 24-Jul-2019, tatu: Should not force construction of a String here...
-        String idStr = Long.valueOf(id).toString(); // since instances for small values cached
+        String idStr = Long.toString(id);
         if (!_streamWriteContext.writeName(idStr)) {
             _reportError("Cannot write a property id, expecting a value");
         }
@@ -684,7 +684,7 @@ public JsonGenerator writeNumber(BigInteger v) throws JacksonException
             return writeNull();
         }
         _verifyValueWrite("write number");
-        _writeScalar(String.valueOf(v.toString()), "java.math.BigInteger", STYLE_SCALAR);
+        _writeScalar(v.toString(), "java.math.BigInteger", STYLE_SCALAR);
         return this;
     }
 
@@ -792,7 +792,7 @@ public JsonGenerator writeObjectRef(Object id)
         throws JacksonException
     {
         _verifyValueWrite("write Object reference");
-        AliasEvent evt = new AliasEvent(Optional.of(String.valueOf(id)).map(s -> new Anchor(s)));
+        AliasEvent evt = new AliasEvent(id == null ? Optional.empty() : Optional.of(new Anchor(id.toString())));
         _emit(evt);
         return this;
     }