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Write numbers without using substring.
Another attempt to simplify how numbers are written to avoid object creation. Try to group related methods together to relate numberToString() with writeNumber(), and related.
1 parent c0e9764 commit 1483bb8

2 files changed

Lines changed: 137 additions & 66 deletions

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‎JSONObject.java‎

Lines changed: 93 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -451,20 +451,7 @@ public static String doubleToString(double d) {
451451
// Shave off trailing zeros and decimal point, if possible.
452452

453453
String string = Double.toString(d);
454-
if (string.indexOf('.') > 0 && string.indexOf('e') < 0
455-
&& string.indexOf('E') < 0) {
456-
int len = string.length();
457-
while ((len > 0) && (string.charAt(len - 1) == '0')) {
458-
len--;
459-
}
460-
if ((len > 0) && (string.charAt(len - 1) == '.')) {
461-
len--;
462-
}
463-
if (len < string.length()) {
464-
string = string.substring(0, len);
465-
}
466-
}
467-
return string;
454+
return stripNumberDigits(string);
468455
}
469456

470457
/**
@@ -852,6 +839,97 @@ public static String numberToString(Number number) throws JSONException {
852839
// Shave off trailing zeros and decimal point, if possible.
853840

854841
String string = number.toString();
842+
return stripNumberDigits(string);
843+
}
844+
845+
/**
846+
* Write the given double to the given Appendable.
847+
*
848+
* @param writer
849+
* The Appendable to which the double value is written
850+
* @param d
851+
* A double
852+
* @param <T> subtype of Appendable, returned to the caller
853+
* @return the given Appendable
854+
* @throws JSONException there was a problem writing the double
855+
*/
856+
public static <T extends Appendable> T writeDouble(T writer, double d) throws JSONException {
857+
if (Double.isInfinite(d) || Double.isNaN(d)) {
858+
try {
859+
writer.append("null");
860+
return writer;
861+
} catch (IOException e) {
862+
throw new JSONException(e);
863+
}
864+
}
865+
866+
String string = Double.toString(d);
867+
writeNumberDigits(writer, string);
868+
return writer;
869+
}
870+
871+
/**
872+
* Write the given number to the given Appendable.
873+
*
874+
* @param writer
875+
* The Appendable to which the number value is written
876+
* @param number
877+
* A Number
878+
* @param <T> subtype of Appendable, returned to the caller
879+
* @return the given Appendable
880+
* @throws JSONException there was a problem writing the number
881+
*/
882+
public static <T extends Appendable> T writeNumber(T writer, Number number) throws JSONException {
883+
if (number == null) {
884+
throw new JSONException("Null pointer");
885+
}
886+
testValidity(number);
887+
888+
// Shave off trailing zeros and decimal point, if possible.
889+
890+
String string = number.toString();
891+
writeNumberDigits(writer, string);
892+
return writer;
893+
}
894+
895+
/**
896+
* Write a number value, trimming any trailing zero digits from a real number.
897+
* If all zeros appear immediately after a decimal, the decimal is omitted
898+
* as well.
899+
*
900+
* @param writer the Appendable to which the digits will be written
901+
* @param string the string of digits
902+
*/
903+
private static void writeNumberDigits(Appendable writer, String string) throws JSONException {
904+
try {
905+
if (string.indexOf('.') > 0 && string.indexOf('e') < 0
906+
&& string.indexOf('E') < 0) {
907+
int len = string.length();
908+
while ((len > 0) && (string.charAt(len - 1) == '0')) {
909+
len--;
910+
}
911+
if ((len > 0) && (string.charAt(len - 1) == '.')) {
912+
len--;
913+
}
914+
if (len < string.length()) {
915+
writer.append(string, 0, len);
916+
return;
917+
}
918+
}
919+
writer.append(string);
920+
} catch (IOException e) {
921+
throw new JSONException(e);
922+
}
923+
}
924+
925+
/**
926+
* Trim any trailing zero digits from a real number. If all zeros appear
927+
* immediately after a decimal, omit the decimal as well.
928+
*
929+
* @param string the string of digits
930+
* @return the string, with trailing digits stripped if possible
931+
*/
932+
private static String stripNumberDigits(String string) {
855933
if (string.indexOf('.') > 0 && string.indexOf('e') < 0
856934
&& string.indexOf('E') < 0) {
857935
int len = string.length();
@@ -1900,7 +1978,7 @@ static final <T extends Appendable> T writeValue(T writer, Object value,
19001978
} else if (value.getClass().isArray()) {
19011979
new JSONArray(value).write(writer, indentFactor, indent);
19021980
} else if (value instanceof Number) {
1903-
writer.append(numberToString((Number) value));
1981+
writeNumber(writer, (Number) value);
19041982
} else if (value instanceof Boolean) {
19051983
writer.append(value.toString());
19061984
} else if (value instanceof JSONString) {

‎JSONWriter.java‎

Lines changed: 44 additions & 51 deletions
Original file line numberDiff line numberDiff line change
@@ -4,7 +4,6 @@
44

55
import java.io.Closeable;
66
import java.io.IOException;
7-
import java.util.Map;
87
import java.util.HashSet;
98
import java.util.Map.Entry;
109
import java.util.Set;
@@ -106,15 +105,10 @@ public JSONWriter(Appendable w) {
106105
}
107106

108107
/**
109-
* Append a JSON-encoded value.
110-
* @param string A string value.
111-
* @return this
112-
* @throws JSONException If the value is out of sequence.
108+
* Prepare for the next value to be written. Append a comma if required,
109+
* assert and advance the mode as needed.
113110
*/
114-
private JSONWriter append(String string) throws JSONException {
115-
if (string == null) {
116-
throw new JSONException("Null pointer");
117-
}
111+
private void prepValue() throws JSONException {
118112
try {
119113
switch (this.mode) {
120114
case 'a':
@@ -128,38 +122,7 @@ private JSONWriter append(String string) throws JSONException {
128122
default:
129123
throw new JSONException("Value out of sequence.");
130124
}
131-
this.writer.append(string);
132125
this.comma = true;
133-
return this;
134-
} catch (IOException e) {
135-
throw new JSONException(e);
136-
}
137-
}
138-
139-
/**
140-
* Append a value, converting it into a JSON string.
141-
*
142-
* @param val A value.
143-
* @return this
144-
* @throws JSONException If the value is out of sequence.
145-
*/
146-
private JSONWriter appendValue(Object val) throws JSONException {
147-
try {
148-
switch (this.mode) {
149-
case 'a':
150-
if (this.comma) {
151-
this.writer.append(',');
152-
}
153-
break;
154-
case 'o':
155-
this.mode = 'k';
156-
break;
157-
default:
158-
throw new JSONException("Value out of sequence.");
159-
}
160-
JSONObject.writeValue(this.writer, val);
161-
this.comma = true;
162-
return this;
163126
} catch (IOException e) {
164127
throw new JSONException(e);
165128
}
@@ -177,7 +140,12 @@ private JSONWriter appendValue(Object val) throws JSONException {
177140
public JSONWriter array() throws JSONException {
178141
if (this.mode == 'i' || this.mode == 'o' || this.mode == 'a') {
179142
this.push(false);
180-
this.append("[");
143+
try {
144+
this.prepValue();
145+
this.writer.append('[');
146+
} catch (IOException e) {
147+
throw new JSONException(e);
148+
}
181149
this.comma = false;
182150
return this;
183151
}
@@ -274,7 +242,12 @@ public JSONWriter object() throws JSONException {
274242
this.mode = 'o';
275243
}
276244
if (this.mode == 'o' || this.mode == 'a') {
277-
this.append("{");
245+
try {
246+
this.prepValue();
247+
this.writer.append('{');
248+
} catch (IOException e) {
249+
throw new JSONException(e);
250+
}
278251
this.push(true);
279252
this.comma = false;
280253
return this;
@@ -324,7 +297,14 @@ private void push(boolean obj) throws JSONException {
324297
* @throws JSONException
325298
*/
326299
public JSONWriter value(boolean b) throws JSONException {
327-
return this.append(Boolean.toString(b));
300+
String string = Boolean.toString(b);
301+
try {
302+
this.prepValue();
303+
this.writer.append(string);
304+
return this;
305+
} catch (IOException e) {
306+
throw new JSONException(e);
307+
}
328308
}
329309

330310
/**
@@ -334,7 +314,9 @@ public JSONWriter value(boolean b) throws JSONException {
334314
* @throws JSONException If the number is not finite.
335315
*/
336316
public JSONWriter value(double d) throws JSONException {
337-
return this.append(JSONObject.numberToString(d));
317+
this.prepValue();
318+
JSONObject.writeDouble(this.writer, d);
319+
return this;
338320
}
339321

340322
/**
@@ -344,33 +326,43 @@ public JSONWriter value(double d) throws JSONException {
344326
* @throws JSONException
345327
*/
346328
public JSONWriter value(long l) throws JSONException {
347-
return this.append(Long.toString(l));
329+
String string = Long.toString(l);
330+
try {
331+
this.prepValue();
332+
this.writer.append(string);
333+
return this;
334+
} catch (IOException e) {
335+
throw new JSONException(e);
336+
}
348337
}
349338

350339

351340
/**
352341
* Append an object value.
353-
* @param object The object to append. It can be null, or a Boolean, Number,
342+
* @param object The object to appendString. It can be null, or a Boolean, Number,
354343
* String, JSONObject, or JSONArray, or an object that implements JSONString.
355344
* @return this
356345
* @throws JSONException If the value is out of sequence.
357346
*/
358347
public JSONWriter value(Object object) throws JSONException {
359-
return this.appendValue(object);
348+
this.prepValue();
349+
JSONObject.writeValue(this.writer, object);
350+
return this;
360351
}
361352

362353
/**
363354
* Append a sequence of values into an array.
364355
*
365-
* @param values The objects to append. They can be null, or a Boolean, Number,
356+
* @param values The objects to appendString. They can be null, or a Boolean, Number,
366357
* String, JSONObject, or JSONArray, or an object that implements JSONString.
367358
* @return this
368359
* @throws JSONException If a value is out of place. For example, a value
369360
* occurs where a key is expected.
370361
*/
371362
public JSONWriter values(Iterable<?> values) throws JSONException {
372363
for(Object obj : values) {
373-
this.appendValue(obj);
364+
this.prepValue();
365+
JSONObject.writeValue(this.writer, obj);
374366
}
375367
return this;
376368
}
@@ -380,7 +372,7 @@ public JSONWriter values(Iterable<?> values) throws JSONException {
380372
* The key will be associated with the corresponding value. In an
381373
* object, every value must be associated with a key.
382374
*
383-
* @param kvPairs The objects to append. The values can be null, or a Boolean,
375+
* @param kvPairs The objects to appendString. The values can be null, or a Boolean,
384376
* Number, String, JSONObject, or JSONArray, or an object that implements
385377
* JSONString.
386378
* @return this
@@ -390,7 +382,8 @@ public JSONWriter values(Iterable<?> values) throws JSONException {
390382
public JSONWriter entries(Iterable<Entry<String, ?>> kvPairs) throws JSONException {
391383
for(Entry<String, ?> entry : kvPairs) {
392384
this.key(entry.getKey());
393-
this.appendValue(entry.getValue());
385+
this.prepValue();
386+
JSONObject.writeValue(this.writer, entry.getValue());
394387
}
395388
return this;
396389
}

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