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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// http://code.google.com/p/protobuf/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
package com.google.protobuf;
import com.google.protobuf.Descriptors.Descriptor;
import com.google.protobuf.Descriptors.EnumDescriptor;
import com.google.protobuf.Descriptors.EnumValueDescriptor;
import com.google.protobuf.Descriptors.FieldDescriptor;
import java.io.IOException;
import java.math.BigInteger;
import java.nio.CharBuffer;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Provide ascii text parsing and formatting support for proto2 instances.
* The implementation largely follows google/protobuf/text_format.cc.
*
* @author [email protected] Wenbo Zhu
* @author [email protected] Kenton Varda
*/
public final class TextFormat {
private static final int BUFFER_SIZE = 4096;
private TextFormat() {
}
/**
* Outputs a textual representation of the Protocol Message supplied into
* the parameter output. (This representation is the new version of the
* classic "ProtocolPrinter" output from the original Protocol Buffer system)
*/
public static void print(final Message message, final Appendable output)
throws IOException {
final TextGenerator generator = new TextGenerator(output);
print(message, generator);
}
/**
* Outputs a textual representation of {@code fields} to {@code output}.
*/
public static void print(final UnknownFieldSet fields,
final Appendable output)
throws IOException {
final TextGenerator generator = new TextGenerator(output);
printUnknownFields(fields, generator);
}
/**
* Like {@code print()}, but writes directly to a {@code String} and
* returns it.
*/
public static String printToString(final Message message) {
try {
final StringBuilder text = new StringBuilder();
print(message, text);
return text.toString();
} catch (IOException e) {
throw new RuntimeException(
"Writing to a StringBuilder threw an IOException (should never " +
"happen).", e);
}
}
/**
* Like {@code print()}, but writes directly to a {@code String} and
* returns it.
*/
public static String printToString(final UnknownFieldSet fields) {
try {
final StringBuilder text = new StringBuilder();
print(fields, text);
return text.toString();
} catch (IOException e) {
throw new RuntimeException(
"Writing to a StringBuilder threw an IOException (should never " +
"happen).", e);
}
}
private static void print(final Message message,
final TextGenerator generator)
throws IOException {
for (final Map.Entry field :
message.getAllFields().entrySet()) {
printField(field.getKey(), field.getValue(), generator);
}
printUnknownFields(message.getUnknownFields(), generator);
}
public static void printField(final FieldDescriptor field,
final Object value,
final Appendable output)
throws IOException {
final TextGenerator generator = new TextGenerator(output);
printField(field, value, generator);
}
public static String printFieldToString(final FieldDescriptor field,
final Object value) {
try {
final StringBuilder text = new StringBuilder();
printField(field, value, text);
return text.toString();
} catch (IOException e) {
throw new RuntimeException(
"Writing to a StringBuilder threw an IOException (should never " +
"happen).", e);
}
}
private static void printField(final FieldDescriptor field,
final Object value,
final TextGenerator generator)
throws IOException {
if (field.isRepeated()) {
// Repeated field. Print each element.
for (final Object element : (List) value) {
printSingleField(field, element, generator);
}
} else {
printSingleField(field, value, generator);
}
}
private static void printSingleField(final FieldDescriptor field,
final Object value,
final TextGenerator generator)
throws IOException {
if (field.isExtension()) {
generator.print("[");
// We special-case MessageSet elements for compatibility with proto1.
if (field.getContainingType().getOptions().getMessageSetWireFormat()
&& (field.getType() == FieldDescriptor.Type.MESSAGE)
&& (field.isOptional())
// object equality
&& (field.getExtensionScope() == field.getMessageType())) {
generator.print(field.getMessageType().getFullName());
} else {
generator.print(field.getFullName());
}
generator.print("]");
} else {
if (field.getType() == FieldDescriptor.Type.GROUP) {
// Groups must be serialized with their original capitalization.
generator.print(field.getMessageType().getName());
} else {
generator.print(field.getName());
}
}
if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
generator.print(" {\n");
generator.indent();
} else {
generator.print(": ");
}
printFieldValue(field, value, generator);
if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
generator.outdent();
generator.print("}");
}
generator.print("\n");
}
private static void printFieldValue(final FieldDescriptor field,
final Object value,
final TextGenerator generator)
throws IOException {
switch (field.getType()) {
case INT32:
case INT64:
case SINT32:
case SINT64:
case SFIXED32:
case SFIXED64:
case FLOAT:
case DOUBLE:
case BOOL:
// Good old toString() does what we want for these types.
generator.print(value.toString());
break;
case UINT32:
case FIXED32:
generator.print(unsignedToString((Integer) value));
break;
case UINT64:
case FIXED64:
generator.print(unsignedToString((Long) value));
break;
case STRING:
generator.print("\"");
generator.print(escapeText((String) value));
generator.print("\"");
break;
case BYTES:
generator.print("\"");
generator.print(escapeBytes((ByteString) value));
generator.print("\"");
break;
case ENUM:
generator.print(((EnumValueDescriptor) value).getName());
break;
case MESSAGE:
case GROUP:
print((Message) value, generator);
break;
}
}
private static void printUnknownFields(final UnknownFieldSet unknownFields,
final TextGenerator generator)
throws IOException {
for (final Map.Entry entry :
unknownFields.asMap().entrySet()) {
final String prefix = entry.getKey().toString() + ": ";
final UnknownFieldSet.Field field = entry.getValue();
for (final long value : field.getVarintList()) {
generator.print(entry.getKey().toString());
generator.print(": ");
generator.print(unsignedToString(value));
generator.print("\n");
}
for (final int value : field.getFixed32List()) {
generator.print(entry.getKey().toString());
generator.print(": ");
generator.print(String.format((Locale) null, "0x%08x", value));
generator.print("\n");
}
for (final long value : field.getFixed64List()) {
generator.print(entry.getKey().toString());
generator.print(": ");
generator.print(String.format((Locale) null, "0x%016x", value));
generator.print("\n");
}
for (final ByteString value : field.getLengthDelimitedList()) {
generator.print(entry.getKey().toString());
generator.print(": \"");
generator.print(escapeBytes(value));
generator.print("\"\n");
}
for (final UnknownFieldSet value : field.getGroupList()) {
generator.print(entry.getKey().toString());
generator.print(" {\n");
generator.indent();
printUnknownFields(value, generator);
generator.outdent();
generator.print("}\n");
}
}
}
/**
* Convert an unsigned 32-bit integer to a string.
*/
private static String unsignedToString(final int value) {
if (value >= 0) {
return Integer.toString(value);
} else {
return Long.toString(((long) value) & 0x00000000FFFFFFFFL);
}
}
/**
* Convert an unsigned 64-bit integer to a string.
*/
private static String unsignedToString(final long value) {
if (value >= 0) {
return Long.toString(value);
} else {
// Pull off the most-significant bit so that BigInteger doesn't think
// the number is negative, then set it again using setBit().
return BigInteger.valueOf(value & 0x7FFFFFFFFFFFFFFFL)
.setBit(63).toString();
}
}
// =================================================================
// Parsing
/**
* Parse a text-format message from {@code input} and merge the contents
* into {@code builder}.
*/
public static void merge(final Readable input,
final Message.Builder builder)
throws IOException {
merge(input, ExtensionRegistry.getEmptyRegistry(), builder);
}
/**
* Parse a text-format message from {@code input} and merge the contents
* into {@code builder}.
*/
public static void merge(final CharSequence input,
final Message.Builder builder)
throws ParseException {
merge(input, ExtensionRegistry.getEmptyRegistry(), builder);
}
/**
* Parse a text-format message from {@code input} and merge the contents
* into {@code builder}. Extensions will be recognized if they are
* registered in {@code extensionRegistry}.
*/
public static void merge(final Readable input,
final ExtensionRegistry extensionRegistry,
final Message.Builder builder)
throws IOException {
// Read the entire input to a String then parse that.
// If StreamTokenizer were not quite so crippled, or if there were a kind
// of Reader that could read in chunks that match some particular regex,
// or if we wanted to write a custom Reader to tokenize our stream, then
// we would not have to read to one big String. Alas, none of these is
// the case. Oh well.
merge(toStringBuilder(input), extensionRegistry, builder);
}
// TODO(chrisn): See if working around java.io.Reader#read(CharBuffer)
// overhead is worthwhile
private static StringBuilder toStringBuilder(final Readable input)
throws IOException {
final StringBuilder text = new StringBuilder();
final CharBuffer buffer = CharBuffer.allocate(BUFFER_SIZE);
while (true) {
final int n = input.read(buffer);
if (n == -1) {
break;
}
buffer.flip();
text.append(buffer, 0, n);
}
return text;
}
/**
* Parse a text-format message from {@code input} and merge the contents
* into {@code builder}. Extensions will be recognized if they are
* registered in {@code extensionRegistry}.
*/
public static void merge(final CharSequence input,
final ExtensionRegistry extensionRegistry,
final Message.Builder builder)
throws ParseException {
final Tokenizer tokenizer = new Tokenizer(input);
while (!tokenizer.atEnd()) {
mergeField(tokenizer, extensionRegistry, builder);
}
}
/**
* Parse a single field from {@code tokenizer} and merge it into
* {@code builder}.
*/
private static void mergeField(final Tokenizer tokenizer,
final ExtensionRegistry extensionRegistry,
final Message.Builder builder)
throws ParseException {
FieldDescriptor field;
final Descriptor type = builder.getDescriptorForType();
ExtensionRegistry.ExtensionInfo extension = null;
if (tokenizer.tryConsume("[")) {
// An extension.
final StringBuilder name =
new StringBuilder(tokenizer.consumeIdentifier());
while (tokenizer.tryConsume(".")) {
name.append('.');
name.append(tokenizer.consumeIdentifier());
}
extension = extensionRegistry.findExtensionByName(name.toString());
if (extension == null) {
throw tokenizer.parseExceptionPreviousToken(
"Extension \"" + name + "\" not found in the ExtensionRegistry.");
} else if (extension.descriptor.getContainingType() != type) {
throw tokenizer.parseExceptionPreviousToken(
"Extension \"" + name + "\" does not extend message type \"" +
type.getFullName() + "\".");
}
tokenizer.consume("]");
field = extension.descriptor;
} else {
final String name = tokenizer.consumeIdentifier();
field = type.findFieldByName(name);
// Group names are expected to be capitalized as they appear in the
// .proto file, which actually matches their type names, not their field
// names.
if (field == null) {
// Explicitly specify US locale so that this code does not break when
// executing in Turkey.
final String lowerName = name.toLowerCase(Locale.US);
field = type.findFieldByName(lowerName);
// If the case-insensitive match worked but the field is NOT a group,
if (field != null && field.getType() != FieldDescriptor.Type.GROUP) {
field = null;
}
}
// Again, special-case group names as described above.
if (field != null && field.getType() == FieldDescriptor.Type.GROUP &&
!field.getMessageType().getName().equals(name)) {
field = null;
}
if (field == null) {
throw tokenizer.parseExceptionPreviousToken(
"Message type \"" + type.getFullName() +
"\" has no field named \"" + name + "\".");
}
}
Object value = null;
if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
tokenizer.tryConsume(":"); // optional
final String endToken;
if (tokenizer.tryConsume("<")) {
endToken = ">";
} else {
tokenizer.consume("{");
endToken = "}";
}
final Message.Builder subBuilder;
if (extension == null) {
subBuilder = builder.newBuilderForField(field);
} else {
subBuilder = extension.defaultInstance.newBuilderForType();
}
while (!tokenizer.tryConsume(endToken)) {
if (tokenizer.atEnd()) {
throw tokenizer.parseException(
"Expected \"" + endToken + "\".");
}
mergeField(tokenizer, extensionRegistry, subBuilder);
}
value = subBuilder.build();
} else {
tokenizer.consume(":");
switch (field.getType()) {
case INT32:
case SINT32:
case SFIXED32:
value = tokenizer.consumeInt32();
break;
case INT64:
case SINT64:
case SFIXED64:
value = tokenizer.consumeInt64();
break;
case UINT32:
case FIXED32:
value = tokenizer.consumeUInt32();
break;
case UINT64:
case FIXED64:
value = tokenizer.consumeUInt64();
break;
case FLOAT:
value = tokenizer.consumeFloat();
break;
case DOUBLE:
value = tokenizer.consumeDouble();
break;
case BOOL:
value = tokenizer.consumeBoolean();
break;
case STRING:
value = tokenizer.consumeString();
break;
case BYTES:
value = tokenizer.consumeByteString();
break;
case ENUM:
final EnumDescriptor enumType = field.getEnumType();
if (tokenizer.lookingAtInteger()) {
final int number = tokenizer.consumeInt32();
value = enumType.findValueByNumber(number);
if (value == null) {
throw tokenizer.parseExceptionPreviousToken(
"Enum type \"" + enumType.getFullName() +
"\" has no value with number " + number + '.');
}
} else {
final String id = tokenizer.consumeIdentifier();
value = enumType.findValueByName(id);
if (value == null) {
throw tokenizer.parseExceptionPreviousToken(
"Enum type \"" + enumType.getFullName() +
"\" has no value named \"" + id + "\".");
}
}
break;
case MESSAGE:
case GROUP:
throw new RuntimeException("Can't get here.");
}
}
if (field.isRepeated()) {
builder.addRepeatedField(field, value);
} else {
builder.setField(field, value);
}
}
/**
* Escapes bytes in the format used in protocol buffer text format, which
* is the same as the format used for C string literals. All bytes
* that are not printable 7-bit ASCII characters are escaped, as well as
* backslash, single-quote, and double-quote characters. Characters for
* which no defined short-hand escape sequence is defined will be escaped
* using 3-digit octal sequences.
*/
static String escapeBytes(final ByteString input) {
final StringBuilder builder = new StringBuilder(input.size());
for (int i = 0; i < input.size(); i++) {
final byte b = input.byteAt(i);
switch (b) {
// Java does not recognize \a or \v, apparently.
case 0x07:
builder.append("\\a");
break;
case '\b':
builder.append("\\b");
break;
case '\f':
builder.append("\\f");
break;
case '\n':
builder.append("\\n");
break;
case '\r':
builder.append("\\r");
break;
case '\t':
builder.append("\\t");
break;
case 0x0b:
builder.append("\\v");
break;
case '\\':
builder.append("\\\\");
break;
case '\'':
builder.append("\\\'");
break;
case '"':
builder.append("\\\"");
break;
default:
if (b >= 0x20) {
builder.append((char) b);
} else {
builder.append('\\');
builder.append((char) ('0' + ((b >>> 6) & 3)));
builder.append((char) ('0' + ((b >>> 3) & 7)));
builder.append((char) ('0' + (b & 7)));
}
break;
}
}
return builder.toString();
}
/**
* Un-escape a byte sequence as escaped using
* {@link #escapeBytes(ByteString)}. Two-digit hex escapes (starting with
* "\x") are also recognized.
*/
static ByteString unescapeBytes(final CharSequence input)
throws InvalidEscapeSequenceException {
final byte[] result = new byte[input.length()];
int pos = 0;
for (int i = 0; i < input.length(); i++) {
char c = input.charAt(i);
if (c == '\\') {
if (i + 1 < input.length()) {
++i;
c = input.charAt(i);
if (isOctal(c)) {
// Octal escape.
int code = digitValue(c);
if (i + 1 < input.length() && isOctal(input.charAt(i + 1))) {
++i;
code = code * 8 + digitValue(input.charAt(i));
}
if (i + 1 < input.length() && isOctal(input.charAt(i + 1))) {
++i;
code = code * 8 + digitValue(input.charAt(i));
}
result[pos++] = (byte) code;
} else {
switch (c) {
case 'a':
result[pos++] = 0x07;
break;
case 'b':
result[pos++] = '\b';
break;
case 'f':
result[pos++] = '\f';
break;
case 'n':
result[pos++] = '\n';
break;
case 'r':
result[pos++] = '\r';
break;
case 't':
result[pos++] = '\t';
break;
case 'v':
result[pos++] = 0x0b;
break;
case '\\':
result[pos++] = '\\';
break;
case '\'':
result[pos++] = '\'';
break;
case '"':
result[pos++] = '\"';
break;
case 'x':
// hex escape
int code = 0;
if (i + 1 < input.length() && isHex(input.charAt(i + 1))) {
++i;
code = digitValue(input.charAt(i));
} else {
throw new InvalidEscapeSequenceException(
"Invalid escape sequence: '\\x' with no digits");
}
if (i + 1 < input.length() && isHex(input.charAt(i + 1))) {
++i;
code = code * 16 + digitValue(input.charAt(i));
}
result[pos++] = (byte) code;
break;
default:
throw new InvalidEscapeSequenceException(
"Invalid escape sequence: '\\" + c + '\'');
}
}
} else {
throw new InvalidEscapeSequenceException(
"Invalid escape sequence: '\\' at end of string.");
}
} else {
result[pos++] = (byte) c;
}
}
return ByteString.copyFrom(result, 0, pos);
}
/**
* Like {@link #escapeBytes(ByteString)}, but escapes a text string.
* Non-ASCII characters are first encoded as UTF-8, then each byte is escaped
* individually as a 3-digit octal escape. Yes, it's weird.
*/
static String escapeText(final String input) {
return escapeBytes(ByteString.copyFromUtf8(input));
}
// =================================================================
// Utility functions
//
// Some of these methods are package-private because Descriptors.java uses
// them.
/**
* Un-escape a text string as escaped using {@link #escapeText(String)}.
* Two-digit hex escapes (starting with "\x") are also recognized.
*/
static String unescapeText(final String input)
throws InvalidEscapeSequenceException {
return unescapeBytes(input).toStringUtf8();
}
/**
* Is this an octal digit?
*/
private static boolean isOctal(final char c) {
return '0' <= c && c <= '7';
}
/**
* Is this a hex digit?
*/
private static boolean isHex(final char c) {
return ('0' <= c && c <= '9') ||
('a' <= c && c <= 'f') ||
('A' <= c && c <= 'F');
}
/**
* Interpret a character as a digit (in any base up to 36) and return the
* numeric value. This is like {@code Character.digit()} but we don't accept
* non-ASCII digits.
*/
private static int digitValue(final char c) {
if ('0' <= c && c <= '9') {
return c - '0';
} else if ('a' <= c && c <= 'z') {
return c - 'a' + 10;
} else {
return c - 'A' + 10;
}
}
/**
* Parse a 32-bit signed integer from the text. Unlike the Java standard
* {@code Integer.parseInt()}, this function recognizes the prefixes "0x"
* and "0" to signify hexidecimal and octal numbers, respectively.
*/
static int parseInt32(final String text) throws NumberFormatException {
return (int) parseInteger(text, true, false);
}
/**
* Parse a 32-bit unsigned integer from the text. Unlike the Java standard
* {@code Integer.parseInt()}, this function recognizes the prefixes "0x"
* and "0" to signify hexidecimal and octal numbers, respectively. The
* result is coerced to a (signed) {@code int} when returned since Java has
* no unsigned integer type.
*/
static int parseUInt32(final String text) throws NumberFormatException {
return (int) parseInteger(text, false, false);
}
/**
* Parse a 64-bit signed integer from the text. Unlike the Java standard
* {@code Integer.parseInt()}, this function recognizes the prefixes "0x"
* and "0" to signify hexidecimal and octal numbers, respectively.
*/
static long parseInt64(final String text) throws NumberFormatException {
return parseInteger(text, true, true);
}
/**
* Parse a 64-bit unsigned integer from the text. Unlike the Java standard
* {@code Integer.parseInt()}, this function recognizes the prefixes "0x"
* and "0" to signify hexidecimal and octal numbers, respectively. The
* result is coerced to a (signed) {@code long} when returned since Java has
* no unsigned long type.
*/
static long parseUInt64(final String text) throws NumberFormatException {
return parseInteger(text, false, true);
}
private static long parseInteger(final String text,
final boolean isSigned,
final boolean isLong)
throws NumberFormatException {
int pos = 0;
boolean negative = false;
if (text.startsWith("-", pos)) {
if (!isSigned) {
throw new NumberFormatException("Number must be positive: " + text);
}
++pos;
negative = true;
}
int radix = 10;
if (text.startsWith("0x", pos)) {
pos += 2;
radix = 16;
} else if (text.startsWith("0", pos)) {
radix = 8;
}
final String numberText = text.substring(pos);
long result = 0;
if (numberText.length() < 16) {
// Can safely assume no overflow.
result = Long.parseLong(numberText, radix);
if (negative) {
result = -result;
}
// Check bounds.
// No need to check for 64-bit numbers since they'd have to be 16 chars
// or longer to overflow.
if (!isLong) {
if (isSigned) {
if (result > Integer.MAX_VALUE || result < Integer.MIN_VALUE) {
throw new NumberFormatException(
"Number out of range for 32-bit signed integer: " + text);
}
} else {
if (result >= (1L << 32) || result < 0) {
throw new NumberFormatException(
"Number out of range for 32-bit unsigned integer: " + text);
}
}
}
} else {
BigInteger bigValue = new BigInteger(numberText, radix);
if (negative) {
bigValue = bigValue.negate();
}
// Check bounds.
if (!isLong) {
if (isSigned) {
if (bigValue.bitLength() > 31) {
throw new NumberFormatException(
"Number out of range for 32-bit signed integer: " + text);
}
} else {
if (bigValue.bitLength() > 32) {
throw new NumberFormatException(
"Number out of range for 32-bit unsigned integer: " + text);
}
}
} else {
if (isSigned) {
if (bigValue.bitLength() > 63) {
throw new NumberFormatException(
"Number out of range for 64-bit signed integer: " + text);
}
} else {
if (bigValue.bitLength() > 64) {
throw new NumberFormatException(
"Number out of range for 64-bit unsigned integer: " + text);
}
}
}
result = bigValue.longValue();
}
return result;
}
/**
* An inner class for writing text to the output stream.
*/
private static final class TextGenerator {
private final StringBuilder indent = new StringBuilder();
private Appendable output;
private boolean atStartOfLine = true;
private TextGenerator(final Appendable output) {
this.output = output;
}
/**
* Indent text by two spaces. After calling Indent(), two spaces will be
* inserted at the beginning of each line of text. Indent() may be called
* multiple times to produce deeper indents.
*/
public void indent() {
indent.append(" ");
}
/**
* Reduces the current indent level by two spaces, or crashes if the indent
* level is zero.
*/
public void outdent() {
final int length = indent.length();
if (length == 0) {
throw new IllegalArgumentException(
" Outdent() without matching Indent().");
}
indent.delete(length - 2, length);
}
/**
* Print text to the output stream.
*/
public void print(final CharSequence text) throws IOException {
final int size = text.length();
int pos = 0;
for (int i = 0; i < size; i++) {
if (text.charAt(i) == '\n') {
write(text.subSequence(pos, size), i - pos + 1);
pos = i + 1;
atStartOfLine = true;
}
}
write(text.subSequence(pos, size), size - pos);
}
private void write(final CharSequence data, final int size)
throws IOException {
if (size == 0) {
return;
}
if (atStartOfLine) {
atStartOfLine = false;
output.append(indent);
}
output.append(data);
}
}
/**
* Represents a stream of tokens parsed from a {@code String}.
*
* The Java standard library provides many classes that you might think
* would be useful for implementing this, but aren't. For example:
*
*
* - {@code java.io.StreamTokenizer}: This almost does what we want -- or,
* at least, something that would get us close to what we want -- except
* for one fatal flaw: It automatically un-escapes strings using Java
* escape sequences, which do not include all the escape sequences we
* need to support (e.g. '\x').
*
- {@code java.util.Scanner}: This seems like a great way at least to
* parse regular expressions out of a stream (so we wouldn't have to load
* the entire input into a single string before parsing). Sadly,
* {@code Scanner} requires that tokens be delimited with some delimiter.
* Thus, although the text "foo:" should parse to two tokens ("foo" and
* ":"), {@code Scanner} would recognize it only as a single token.
* Furthermore, {@code Scanner} provides no way to inspect the contents
* of delimiters, making it impossible to keep track of line and column
* numbers.
*
*
* Luckily, Java's regular expression support does manage to be useful to
* us. (Barely: We need {@code Matcher.usePattern()}, which is new in
* Java 1.5.) So, we can use that, at least. Unfortunately, this implies
* that we need to have the entire input in one contiguous string.
*/
private static final class Tokenizer {
// We use possesive quantifiers (*+ and ++) because otherwise the Java
// regex matcher has stack overflows on large inputs.
private static final Pattern WHITESPACE =
Pattern.compile("(\\s|(#.*$))++", Pattern.MULTILINE);
private static final Pattern TOKEN = Pattern.compile(
"[a-zA-Z_][0-9a-zA-Z_+-]*+|" + // an identifier
"[.]?[0-9+-][0-9a-zA-Z_.+-]*+|" + // a number
"\"([^\"\n\\\\]|\\\\.)*+(\"|\\\\?$)|" + // a double-quoted string
"\'([^\'\n\\\\]|\\\\.)*+(\'|\\\\?$)", // a single-quoted string
Pattern.MULTILINE);
private static final Pattern DOUBLE_INFINITY = Pattern.compile(
"-?inf(inity)?",
Pattern.CASE_INSENSITIVE);
private static final Pattern FLOAT_INFINITY = Pattern.compile(
"-?inf(inity)?f?",
Pattern.CASE_INSENSITIVE);
private static final Pattern FLOAT_NAN = Pattern.compile(
"nanf?",
Pattern.CASE_INSENSITIVE);
private final CharSequence text;
private final Matcher matcher;
private String currentToken;
// The character index within this.text at which the current token begins.
private int pos = 0;
// The line and column numbers of the current token.
private int line = 0;
private int column = 0;
// The line and column numbers of the previous token (allows throwing
// errors *after* consuming).
private int previousLine = 0;
private int previousColumn = 0;
/**
* Construct a tokenizer that parses tokens from the given text.
*/
private Tokenizer(final CharSequence text) {
this.text = text;
this.matcher = WHITESPACE.matcher(text);
skipWhitespace();
nextToken();
}
/**
* Are we at the end of the input?
*/
public boolean atEnd() {
return currentToken.length() == 0;
}
/**
* Advance to the next token.
*/
public void nextToken() {
previousLine = line;
previousColumn = column;
// Advance the line counter to the current position.
while (pos < matcher.regionStart()) {
if (text.charAt(pos) == '\n') {
++line;
column = 0;
} else {
++column;
}
++pos;
}
// Match the next token.
if (matcher.regionStart() == matcher.regionEnd()) {
// EOF
currentToken = "";
} else {
matcher.usePattern(TOKEN);
if (matcher.lookingAt()) {
currentToken = matcher.group();
matcher.region(matcher.end(), matcher.regionEnd());
} else {
// Take one character.
currentToken = String.valueOf(text.charAt(pos));
matcher.region(pos + 1, matcher.regionEnd());
}
skipWhitespace();
}
}
/**
* Skip over any whitespace so that the matcher region starts at the next
* token.
*/
private void skipWhitespace() {
matcher.usePattern(WHITESPACE);
if (matcher.lookingAt()) {
matcher.region(matcher.end(), matcher.regionEnd());
}
}
/**
* If the next token exactly matches {@code token}, consume it and return
* {@code true}. Otherwise, return {@code false} without doing anything.
*/
public boolean tryConsume(final String token) {
if (currentToken.equals(token)) {
nextToken();
return true;
} else {
return false;
}
}
/**
* If the next token exactly matches {@code token}, consume it. Otherwise,
* throw a {@link ParseException}.
*/
public void consume(final String token) throws ParseException {
if (!tryConsume(token)) {
throw parseException("Expected \"" + token + "\".");
}
}
/**
* Returns {@code true} if the next token is an integer, but does
* not consume it.
*/
public boolean lookingAtInteger() {
if (currentToken.length() == 0) {
return false;
}
final char c = currentToken.charAt(0);
return ('0' <= c && c <= '9') ||
c == '-' || c == '+';
}
/**
* If the next token is an identifier, consume it and return its value.
* Otherwise, throw a {@link ParseException}.
*/
public String consumeIdentifier() throws ParseException {
for (int i = 0; i < currentToken.length(); i++) {
final char c = currentToken.charAt(i);
if (('a' <= c && c <= 'z') ||
('A' <= c && c <= 'Z') ||
('0' <= c && c <= '9') ||
(c == '_') || (c == '.')) {
// OK
} else {
throw parseException("Expected identifier.");
}
}
final String result = currentToken;
nextToken();
return result;
}
/**
* If the next token is a 32-bit signed integer, consume it and return its
* value. Otherwise, throw a {@link ParseException}.
*/
public int consumeInt32() throws ParseException {
try {
final int result = parseInt32(currentToken);
nextToken();
return result;
} catch (NumberFormatException e) {
throw integerParseException(e);
}
}
/**
* If the next token is a 32-bit unsigned integer, consume it and return its
* value. Otherwise, throw a {@link ParseException}.
*/
public int consumeUInt32() throws ParseException {
try {
final int result = parseUInt32(currentToken);
nextToken();
return result;
} catch (NumberFormatException e) {
throw integerParseException(e);
}
}
/**
* If the next token is a 64-bit signed integer, consume it and return its
* value. Otherwise, throw a {@link ParseException}.
*/
public long consumeInt64() throws ParseException {
try {
final long result = parseInt64(currentToken);
nextToken();
return result;
} catch (NumberFormatException e) {
throw integerParseException(e);
}
}
/**
* If the next token is a 64-bit unsigned integer, consume it and return its
* value. Otherwise, throw a {@link ParseException}.
*/
public long consumeUInt64() throws ParseException {
try {
final long result = parseUInt64(currentToken);
nextToken();
return result;
} catch (NumberFormatException e) {
throw integerParseException(e);
}
}
/**
* If the next token is a double, consume it and return its value.
* Otherwise, throw a {@link ParseException}.
*/
public double consumeDouble() throws ParseException {
// We need to parse infinity and nan separately because
// Double.parseDouble() does not accept "inf", "infinity", or "nan".
if (DOUBLE_INFINITY.matcher(currentToken).matches()) {
final boolean negative = currentToken.startsWith("-");
nextToken();
return negative ? Double.NEGATIVE_INFINITY : Double.POSITIVE_INFINITY;
}
if (currentToken.equalsIgnoreCase("nan")) {
nextToken();
return Double.NaN;
}
try {
final double result = Double.parseDouble(currentToken);
nextToken();
return result;
} catch (NumberFormatException e) {
throw floatParseException(e);
}
}
/**
* If the next token is a float, consume it and return its value.
* Otherwise, throw a {@link ParseException}.
*/
public float consumeFloat() throws ParseException {
// We need to parse infinity and nan separately because
// Float.parseFloat() does not accept "inf", "infinity", or "nan".
if (FLOAT_INFINITY.matcher(currentToken).matches()) {
final boolean negative = currentToken.startsWith("-");
nextToken();
return negative ? Float.NEGATIVE_INFINITY : Float.POSITIVE_INFINITY;
}
if (FLOAT_NAN.matcher(currentToken).matches()) {
nextToken();
return Float.NaN;
}
try {
final float result = Float.parseFloat(currentToken);
nextToken();
return result;
} catch (NumberFormatException e) {
throw floatParseException(e);
}
}
/**
* If the next token is a boolean, consume it and return its value.
* Otherwise, throw a {@link ParseException}.
*/
public boolean consumeBoolean() throws ParseException {
if (currentToken.equals("true")) {
nextToken();
return true;
} else if (currentToken.equals("false")) {
nextToken();
return false;
} else {
throw parseException("Expected \"true\" or \"false\".");
}
}
/**
* If the next token is a string, consume it and return its (unescaped)
* value. Otherwise, throw a {@link ParseException}.
*/
public String consumeString() throws ParseException {
return consumeByteString().toStringUtf8();
}
/**
* If the next token is a string, consume it, unescape it as a
* {@link ByteString}, and return it. Otherwise, throw a
* {@link ParseException}.
*/
public ByteString consumeByteString() throws ParseException {
List list = new ArrayList();
consumeByteString(list);
while (currentToken.startsWith("'") || currentToken.startsWith("\"")) {
consumeByteString(list);
}
return ByteString.copyFrom(list);
}
/**
* Like {@link #consumeByteString()} but adds each token of the string to
* the given list. String literals (whether bytes or text) may come in
* multiple adjacent tokens which are automatically concatenated, like in
* C or Python.
*/
private void consumeByteString(List list) throws ParseException {
final char quote = currentToken.length() > 0 ? currentToken.charAt(0)
: '\0';
if (quote != '\"' && quote != '\'') {
throw parseException("Expected string.");
}
if (currentToken.length() < 2 ||
currentToken.charAt(currentToken.length() - 1) != quote) {
throw parseException("String missing ending quote.");
}
try {
final String escaped =
currentToken.substring(1, currentToken.length() - 1);
final ByteString result = unescapeBytes(escaped);
nextToken();
list.add(result);
} catch (InvalidEscapeSequenceException e) {
throw parseException(e.getMessage());
}
}
/**
* Returns a {@link ParseException} with the current line and column
* numbers in the description, suitable for throwing.
*/
public ParseException parseException(final String description) {
// Note: People generally prefer one-based line and column numbers.
return new ParseException(
(line + 1) + ":" + (column + 1) + ": " + description);
}
/**
* Returns a {@link ParseException} with the line and column numbers of
* the previous token in the description, suitable for throwing.
*/
public ParseException parseExceptionPreviousToken(
final String description) {
// Note: People generally prefer one-based line and column numbers.
return new ParseException(
(previousLine + 1) + ":" + (previousColumn + 1) + ": " + description);
}
/**
* Constructs an appropriate {@link ParseException} for the given
* {@code NumberFormatException} when trying to parse an integer.
*/
private ParseException integerParseException(
final NumberFormatException e) {
return parseException("Couldn't parse integer: " + e.getMessage());
}
/**
* Constructs an appropriate {@link ParseException} for the given
* {@code NumberFormatException} when trying to parse a float or double.
*/
private ParseException floatParseException(final NumberFormatException e) {
return parseException("Couldn't parse number: " + e.getMessage());
}
}
/**
* Thrown when parsing an invalid text format message.
*/
public static class ParseException extends IOException {
private static final long serialVersionUID = 3196188060225107702L;
public ParseException(final String message) {
super(message);
}
}
/**
* Thrown by {@link TextFormat#unescapeBytes} and
* {@link TextFormat#unescapeText} when an invalid escape sequence is seen.
*/
static class InvalidEscapeSequenceException extends IOException {
private static final long serialVersionUID = -8164033650142593304L;
InvalidEscapeSequenceException(final String description) {
super(description);
}
}
}