/*
* Copyright (C) 2008-2009, Google Inc.
* Copyright (C) 2006-2008, Shawn O. Pearce <spearce@spearce.org>
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* 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 the Eclipse Foundation, 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 org.eclipse.jgit.util;
import static org.eclipse.jgit.lib.ObjectChecker.author;
import static org.eclipse.jgit.lib.ObjectChecker.committer;
import static org.eclipse.jgit.lib.ObjectChecker.encoding;
import static org.eclipse.jgit.lib.ObjectChecker.tagger;
import java.nio.ByteBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CodingErrorAction;
import java.util.Arrays;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.PersonIdent;
/** Handy utility functions to parse raw object contents. */
public final class RawParseUtils {
private static final byte[] digits10;
private static final byte[] digits16;
private static final byte[] footerLineKeyChars;
static {
digits10 = new byte['9' + 1];
Arrays.fill(digits10, (byte) -1);
for (char i = '0'; i <= '9'; i++)
digits10[i] = (byte) (i - '0');
digits16 = new byte['f' + 1];
Arrays.fill(digits16, (byte) -1);
for (char i = '0'; i <= '9'; i++)
digits16[i] = (byte) (i - '0');
for (char i = 'a'; i <= 'f'; i++)
digits16[i] = (byte) ((i - 'a') + 10);
for (char i = 'A'; i <= 'F'; i++)
digits16[i] = (byte) ((i - 'A') + 10);
footerLineKeyChars = new byte['z' + 1];
footerLineKeyChars['-'] = 1;
for (char i = '0'; i <= '9'; i++)
footerLineKeyChars[i] = 1;
for (char i = 'A'; i <= 'Z'; i++)
footerLineKeyChars[i] = 1;
for (char i = 'a'; i <= 'z'; i++)
footerLineKeyChars[i] = 1;
}
/**
* Determine if b[ptr] matches src.
*
* @param b
* the buffer to scan.
* @param ptr
* first position within b, this should match src[0].
* @param src
* the buffer to test for equality with b.
* @return ptr + src.length if b[ptr..src.length] == src; else -1.
*/
public static final int match(final byte[] b, int ptr, final byte[] src) {
if (ptr + src.length > b.length)
return -1;
for (int i = 0; i < src.length; i++, ptr++)
if (b[ptr] != src[i])
return -1;
return ptr;
}
private static final byte[] base10byte = { '0', '1', '2', '3', '4', '5',
'6', '7', '8', '9' };
/**
* Format a base 10 numeric into a temporary buffer.
* <p>
* Formatting is performed backwards. The method starts at offset
* <code>o-1</code> and ends at <code>o-1-digits</code>, where
* <code>digits</code> is the number of positions necessary to store the
* base 10 value.
* <p>
* The argument and return values from this method make it easy to chain
* writing, for example:
* </p>
*
* <pre>
* final byte[] tmp = new byte[64];
* int ptr = tmp.length;
* tmp[--ptr] = '\n';
* ptr = RawParseUtils.formatBase10(tmp, ptr, 32);
* tmp[--ptr] = ' ';
* ptr = RawParseUtils.formatBase10(tmp, ptr, 18);
* tmp[--ptr] = 0;
* final String str = new String(tmp, ptr, tmp.length - ptr);
* </pre>
*
* @param b
* buffer to write into.
* @param o
* one offset past the location where writing will begin; writing
* proceeds towards lower index values.
* @param value
* the value to store.
* @return the new offset value <code>o</code>. This is the position of
* the last byte written. Additional writing should start at one
* position earlier.
*/
public static int formatBase10(final byte[] b, int o, int value) {
if (value == 0) {
b[--o] = '0';
return o;
}
final boolean isneg = value < 0;
while (value != 0) {
b[--o] = base10byte[value % 10];
value /= 10;
}
if (isneg)
b[--o] = '-';
return o;
}
/**
* Parse a base 10 numeric from a sequence of ASCII digits into an int.
* <p>
* Digit sequences can begin with an optional run of spaces before the
* sequence, and may start with a '+' or a '-' to indicate sign position.
* Any other characters will cause the method to stop and return the current
* result to the caller.
*
* @param b
* buffer to scan.
* @param ptr
* position within buffer to start parsing digits at.
* @param ptrResult
* optional location to return the new ptr value through. If null
* the ptr value will be discarded.
* @return the value at this location; 0 if the location is not a valid
* numeric.
*/
public static final int parseBase10(final byte[] b, int ptr,
final MutableInteger ptrResult) {
int r = 0;
int sign = 0;
try {
final int sz = b.length;
while (ptr < sz && b[ptr] == ' ')
ptr++;
if (ptr >= sz)
return 0;
switch (b[ptr]) {
case '-':
sign = -1;
ptr++;
break;
case '+':
ptr++;
break;
}
while (ptr < sz) {
final byte v = digits10[b[ptr]];
if (v < 0)
break;
r = (r * 10) + v;
ptr++;
}
} catch (ArrayIndexOutOfBoundsException e) {
// Not a valid digit.
}
if (ptrResult != null)
ptrResult.value = ptr;
return sign < 0 ? -r : r;
}
/**
* Parse a base 10 numeric from a sequence of ASCII digits into a long.
* <p>
* Digit sequences can begin with an optional run of spaces before the
* sequence, and may start with a '+' or a '-' to indicate sign position.
* Any other characters will cause the method to stop and return the current
* result to the caller.
*
* @param b
* buffer to scan.
* @param ptr
* position within buffer to start parsing digits at.
* @param ptrResult
* optional location to return the new ptr value through. If null
* the ptr value will be discarded.
* @return the value at this location; 0 if the location is not a valid
* numeric.
*/
public static final long parseLongBase10(final byte[] b, int ptr,
final MutableInteger ptrResult) {
long r = 0;
int sign = 0;
try {
final int sz = b.length;
while (ptr < sz && b[ptr] == ' ')
ptr++;
if (ptr >= sz)
return 0;
switch (b[ptr]) {
case '-':
sign = -1;
ptr++;
break;
case '+':
ptr++;
break;
}
while (ptr < sz) {
final byte v = digits10[b[ptr]];
if (v < 0)
break;
r = (r * 10) + v;
ptr++;
}
} catch (ArrayIndexOutOfBoundsException e) {
// Not a valid digit.
}
if (ptrResult != null)
ptrResult.value = ptr;
return sign < 0 ? -r : r;
}
/**
* Parse 4 character base 16 (hex) formatted string to unsigned integer.
* <p>
* The number is read in network byte order, that is, most significant
* nybble first.
*
* @param bs
* buffer to parse digits from; positions {@code [p, p+4)} will
* be parsed.
* @param p
* first position within the buffer to parse.
* @return the integer value.
* @throws ArrayIndexOutOfBoundsException
* if the string is not hex formatted.
*/
public static final int parseHexInt16(final byte[] bs, final int p) {
int r = digits16[bs[p]] << 4;
r |= digits16[bs[p + 1]];
r <<= 4;
r |= digits16[bs[p + 2]];
r <<= 4;
r |= digits16[bs[p + 3]];
if (r < 0)
throw new ArrayIndexOutOfBoundsException();
return r;
}
/**
* Parse 8 character base 16 (hex) formatted string to unsigned integer.
* <p>
* The number is read in network byte order, that is, most significant
* nybble first.
*
* @param bs
* buffer to parse digits from; positions {@code [p, p+8)} will
* be parsed.
* @param p
* first position within the buffer to parse.
* @return the integer value.
* @throws ArrayIndexOutOfBoundsException
* if the string is not hex formatted.
*/
public static final int parseHexInt32(final byte[] bs, final int p) {
int r = digits16[bs[p]] << 4;
r |= digits16[bs[p + 1]];
r <<= 4;
r |= digits16[bs[p + 2]];
r <<= 4;
r |= digits16[bs[p + 3]];
r <<= 4;
r |= digits16[bs[p + 4]];
r <<= 4;
r |= digits16[bs[p + 5]];
r <<= 4;
r |= digits16[bs[p + 6]];
final int last = digits16[bs[p + 7]];
if (r < 0 || last < 0)
throw new ArrayIndexOutOfBoundsException();
return (r << 4) | last;
}
/**
* Parse a single hex digit to its numeric value (0-15).
*
* @param digit
* hex character to parse.
* @return numeric value, in the range 0-15.
* @throws ArrayIndexOutOfBoundsException
* if the input digit is not a valid hex digit.
*/
public static final int parseHexInt4(final byte digit) {
final byte r = digits16[digit];
if (r < 0)
throw new ArrayIndexOutOfBoundsException();
return r;
}
/**
* Parse a Git style timezone string.
* <p>
* The sequence "-0315" will be parsed as the numeric value -195, as the
* lower two positions count minutes, not 100ths of an hour.
*
* @param b
* buffer to scan.
* @param ptr
* position within buffer to start parsing digits at.
* @return the timezone at this location, expressed in minutes.
*/
public static final int parseTimeZoneOffset(final byte[] b, int ptr) {
final int v = parseBase10(b, ptr, null);
final int tzMins = v % 100;
final int tzHours = v / 100;
return tzHours * 60 + tzMins;
}
/**
* Locate the first position after a given character.
*
* @param b
* buffer to scan.
* @param ptr
* position within buffer to start looking for chrA at.
* @param chrA
* character to find.
* @return new position just after chrA.
*/
public static final int next(final byte[] b, int ptr, final char chrA) {
final int sz = b.length;
while (ptr < sz) {
if (b[ptr++] == chrA)
return ptr;
}
return ptr;
}
/**
* Locate the first position after the next LF.
* <p>
* This method stops on the first '\n' it finds.
*
* @param b
* buffer to scan.
* @param ptr
* position within buffer to start looking for LF at.
* @return new position just after the first LF found.
*/
public static final int nextLF(final byte[] b, int ptr) {
return next(b, ptr, '\n');
}
/**
* Locate the first position after either the given character or LF.
* <p>
* This method stops on the first match it finds from either chrA or '\n'.
*
* @param b
* buffer to scan.
* @param ptr
* position within buffer to start looking for chrA or LF at.
* @param chrA
* character to find.
* @return new position just after the first chrA or LF to be found.
*/
public static final int nextLF(final byte[] b, int ptr, final char chrA) {
final int sz = b.length;
while (ptr < sz) {
final byte c = b[ptr++];
if (c == chrA || c == '\n')
return ptr;
}
return ptr;
}
/**
* Locate the first position before a given character.
*
* @param b
* buffer to scan.
* @param ptr
* position within buffer to start looking for chrA at.
* @param chrA
* character to find.
* @return new position just before chrA, -1 for not found
*/
public static final int prev(final byte[] b, int ptr, final char chrA) {
if (ptr == b.length)
--ptr;
while (ptr >= 0) {
if (b[ptr--] == chrA)
return ptr;
}
return ptr;
}
/**
* Locate the first position before the previous LF.
* <p>
* This method stops on the first '\n' it finds.
*
* @param b
* buffer to scan.
* @param ptr
* position within buffer to start looking for LF at.
* @return new position just before the first LF found, -1 for not found
*/
public static final int prevLF(final byte[] b, int ptr) {
return prev(b, ptr, '\n');
}
/**
* Locate the previous position before either the given character or LF.
* <p>
* This method stops on the first match it finds from either chrA or '\n'.
*
* @param b
* buffer to scan.
* @param ptr
* position within buffer to start looking for chrA or LF at.
* @param chrA
* character to find.
* @return new position just before the first chrA or LF to be found, -1 for
* not found
*/
public static final int prevLF(final byte[] b, int ptr, final char chrA) {
if (ptr == b.length)
--ptr;
while (ptr >= 0) {
final byte c = b[ptr--];
if (c == chrA || c == '\n')
return ptr;
}
return ptr;
}
/**
* Index the region between <code>[ptr, end)</code> to find line starts.
* <p>
* The returned list is 1 indexed. Index 0 contains
* {@link Integer#MIN_VALUE} to pad the list out.
* <p>
* Using a 1 indexed list means that line numbers can be directly accessed
* from the list, so <code>list.get(1)</code> (aka get line 1) returns
* <code>ptr</code>.
* <p>
* The last element (index <code>map.size()-1</code>) always contains
* <code>end</code>.
*
* @param buf
* buffer to scan.
* @param ptr
* position within the buffer corresponding to the first byte of
* line 1.
* @param end
* 1 past the end of the content within <code>buf</code>.
* @return a line map indexing the start position of each line.
*/
public static final IntList lineMap(final byte[] buf, int ptr, int end) {
// Experimentally derived from multiple source repositories
// the average number of bytes/line is 36. Its a rough guess
// to initially size our map close to the target.
//
final IntList map = new IntList((end - ptr) / 36);
map.fillTo(1, Integer.MIN_VALUE);
for (; ptr < end; ptr = nextLF(buf, ptr))
map.add(ptr);
map.add(end);
return map;
}
/**
* Locate the "author " header line data.
*
* @param b
* buffer to scan.
* @param ptr
* position in buffer to start the scan at. Most callers should
* pass 0 to ensure the scan starts from the beginning of the
* commit buffer and does not accidentally look at message body.
* @return position just after the space in "author ", so the first
* character of the author's name. If no author header can be
* located -1 is returned.
*/
public static final int author(final byte[] b, int ptr) {
final int sz = b.length;
if (ptr == 0)
ptr += 46; // skip the "tree ..." line.
while (ptr < sz && b[ptr] == 'p')
ptr += 48; // skip this parent.
return match(b, ptr, author);
}
/**
* Locate the "committer " header line data.
*
* @param b
* buffer to scan.
* @param ptr
* position in buffer to start the scan at. Most callers should
* pass 0 to ensure the scan starts from the beginning of the
* commit buffer and does not accidentally look at message body.
* @return position just after the space in "committer ", so the first
* character of the committer's name. If no committer header can be
* located -1 is returned.
*/
public static final int committer(final byte[] b, int ptr) {
final int sz = b.length;
if (ptr == 0)
ptr += 46; // skip the "tree ..." line.
while (ptr < sz && b[ptr] == 'p')
ptr += 48; // skip this parent.
if (ptr < sz && b[ptr] == 'a')
ptr = nextLF(b, ptr);
return match(b, ptr, committer);
}
/**
* Locate the "tagger " header line data.
*
* @param b
* buffer to scan.
* @param ptr
* position in buffer to start the scan at. Most callers should
* pass 0 to ensure the scan starts from the beginning of the tag
* buffer and does not accidentally look at message body.
* @return position just after the space in "tagger ", so the first
* character of the tagger's name. If no tagger header can be
* located -1 is returned.
*/
public static final int tagger(final byte[] b, int ptr) {
final int sz = b.length;
if (ptr == 0)
ptr += 48; // skip the "object ..." line.
while (ptr < sz) {
if (b[ptr] == '\n')
return -1;
final int m = match(b, ptr, tagger);
if (m >= 0)
return m;
ptr = nextLF(b, ptr);
}
return -1;
}
/**
* Locate the "encoding " header line.
*
* @param b
* buffer to scan.
* @param ptr
* position in buffer to start the scan at. Most callers should
* pass 0 to ensure the scan starts from the beginning of the
* buffer and does not accidentally look at the message body.
* @return position just after the space in "encoding ", so the first
* character of the encoding's name. If no encoding header can be
* located -1 is returned (and UTF-8 should be assumed).
*/
public static final int encoding(final byte[] b, int ptr) {
final int sz = b.length;
while (ptr < sz) {
if (b[ptr] == '\n')
return -1;
if (b[ptr] == 'e')
break;
ptr = nextLF(b, ptr);
}
return match(b, ptr, encoding);
}
/**
* Parse the "encoding " header into a character set reference.
* <p>
* Locates the "encoding " header (if present) by first calling
* {@link #encoding(byte[], int)} and then returns the proper character set
* to apply to this buffer to evaluate its contents as character data.
* <p>
* If no encoding header is present, {@link Constants#CHARSET} is assumed.
*
* @param b
* buffer to scan.
* @return the Java character set representation. Never null.
*/
public static Charset parseEncoding(final byte[] b) {
final int enc = encoding(b, 0);
if (enc < 0)
return Constants.CHARSET;
final int lf = nextLF(b, enc);
return Charset.forName(decode(Constants.CHARSET, b, enc, lf - 1));
}
/**
* Parse a name line (e.g. author, committer, tagger) into a PersonIdent.
* <p>
* When passing in a value for <code>nameB</code> callers should use the
* return value of {@link #author(byte[], int)} or
* {@link #committer(byte[], int)}, as these methods provide the proper
* position within the buffer.
*
* @param raw
* the buffer to parse character data from.
* @param nameB
* first position of the identity information. This should be the
* first position after the space which delimits the header field
* name (e.g. "author" or "committer") from the rest of the
* identity line.
* @return the parsed identity. Never null.
*/
public static PersonIdent parsePersonIdent(final byte[] raw, final int nameB) {
final Charset cs = parseEncoding(raw);
final int emailB = nextLF(raw, nameB, '<');
final int emailE = nextLF(raw, emailB, '>');
if (emailB <= nameB + 1 || // No name
emailB >= raw.length || // No email start
raw[emailB] == '\n' ||
emailE >= raw.length - 1 || // No email end at all or no trailing date
raw[emailE] == '\n') {
return null;
}
final String name = decode(cs, raw, nameB, emailB - 2);
final String email = decode(cs, raw, emailB, emailE - 1);
final MutableInteger ptrout = new MutableInteger();
final long when = parseLongBase10(raw, emailE + 1, ptrout);
final int whenE = ptrout.value;
if (whenE >= raw.length || // No trailing timezone
raw[whenE] == '\n') {
return null;
}
final int tz = parseTimeZoneOffset(raw, whenE);
return new PersonIdent(name, email, when * 1000L, tz);
}
/**
* Parse a name data (e.g. as within a reflog) into a PersonIdent.
* <p>
* When passing in a value for <code>nameB</code> callers should use the
* return value of {@link #author(byte[], int)} or
* {@link #committer(byte[], int)}, as these methods provide the proper
* position within the buffer.
*
* @param raw
* the buffer to parse character data from.
* @param nameB
* first position of the identity information. This should be the
* first position after the space which delimits the header field
* name (e.g. "author" or "committer") from the rest of the
* identity line.
* @return the parsed identity. Never null.
*/
public static PersonIdent parsePersonIdentOnly(final byte[] raw, final int nameB) {
int stop = nextLF(raw, nameB);
int emailB = nextLF(raw, nameB, '<');
int emailE = nextLF(raw, emailB, '>');
final String name;
final String email;
if (emailE < stop) {
email = decode(raw, emailB, emailE - 1);
} else {
email = "invalid";
}
if (emailB < stop)
name = decode(raw, nameB, emailB - 2);
else
name = decode(raw, nameB, stop);
final MutableInteger ptrout = new MutableInteger();
long when;
int tz;
if (emailE < stop) {
when = parseLongBase10(raw, emailE + 1, ptrout);
tz = parseTimeZoneOffset(raw, ptrout.value);
} else {
when = 0;
tz = 0;
}
return new PersonIdent(name, email, when * 1000L, tz);
}
/**
* Locate the end of a footer line key string.
* <p>
* If the region at {@code raw[ptr]} matches {@code ^[A-Za-z0-9-]+:} (e.g.
* "Signed-off-by: A. U. Thor\n") then this method returns the position of
* the first ':'.
* <p>
* If the region at {@code raw[ptr]} does not match {@code ^[A-Za-z0-9-]+:}
* then this method returns -1.
*
* @param raw
* buffer to scan.
* @param ptr
* first position within raw to consider as a footer line key.
* @return position of the ':' which terminates the footer line key if this
* is otherwise a valid footer line key; otherwise -1.
*/
public static int endOfFooterLineKey(final byte[] raw, int ptr) {
try {
for (;;) {
final byte c = raw[ptr];
if (footerLineKeyChars[c] == 0) {
if (c == ':')
return ptr;
return -1;
}
ptr++;
}
} catch (ArrayIndexOutOfBoundsException e) {
return -1;
}
}
/**
* Decode a buffer under UTF-8, if possible.
*
* If the byte stream cannot be decoded that way, the platform default is tried
* and if that too fails, the fail-safe ISO-8859-1 encoding is tried.
*
* @param buffer
* buffer to pull raw bytes from.
* @return a string representation of the range <code>[start,end)</code>,
* after decoding the region through the specified character set.
*/
public static String decode(final byte[] buffer) {
return decode(buffer, 0, buffer.length);
}
/**
* Decode a buffer under UTF-8, if possible.
*
* If the byte stream cannot be decoded that way, the platform default is
* tried and if that too fails, the fail-safe ISO-8859-1 encoding is tried.
*
* @param buffer
* buffer to pull raw bytes from.
* @param start
* start position in buffer
* @param end
* one position past the last location within the buffer to take
* data from.
* @return a string representation of the range <code>[start,end)</code>,
* after decoding the region through the specified character set.
*/
public static String decode(final byte[] buffer, final int start,
final int end) {
return decode(Constants.CHARSET, buffer, start, end);
}
/**
* Decode a buffer under the specified character set if possible.
*
* If the byte stream cannot be decoded that way, the platform default is tried
* and if that too fails, the fail-safe ISO-8859-1 encoding is tried.
*
* @param cs
* character set to use when decoding the buffer.
* @param buffer
* buffer to pull raw bytes from.
* @return a string representation of the range <code>[start,end)</code>,
* after decoding the region through the specified character set.
*/
public static String decode(final Charset cs, final byte[] buffer) {
return decode(cs, buffer, 0, buffer.length);
}
/**
* Decode a region of the buffer under the specified character set if possible.
*
* If the byte stream cannot be decoded that way, the platform default is tried
* and if that too fails, the fail-safe ISO-8859-1 encoding is tried.
*
* @param cs
* character set to use when decoding the buffer.
* @param buffer
* buffer to pull raw bytes from.
* @param start
* first position within the buffer to take data from.
* @param end
* one position past the last location within the buffer to take
* data from.
* @return a string representation of the range <code>[start,end)</code>,
* after decoding the region through the specified character set.
*/
public static String decode(final Charset cs, final byte[] buffer,
final int start, final int end) {
try {
return decodeNoFallback(cs, buffer, start, end);
} catch (CharacterCodingException e) {
// Fall back to an ISO-8859-1 style encoding. At least all of
// the bytes will be present in the output.
//
return extractBinaryString(buffer, start, end);
}
}
/**
* Decode a region of the buffer under the specified character set if
* possible.
*
* If the byte stream cannot be decoded that way, the platform default is
* tried and if that too fails, an exception is thrown.
*
* @param cs
* character set to use when decoding the buffer.
* @param buffer
* buffer to pull raw bytes from.
* @param start
* first position within the buffer to take data from.
* @param end
* one position past the last location within the buffer to take
* data from.
* @return a string representation of the range <code>[start,end)</code>,
* after decoding the region through the specified character set.
* @throws CharacterCodingException
* the input is not in any of the tested character sets.
*/
public static String decodeNoFallback(final Charset cs,
final byte[] buffer, final int start, final int end)
throws CharacterCodingException {
final ByteBuffer b = ByteBuffer.wrap(buffer, start, end - start);
b.mark();
// Try our built-in favorite. The assumption here is that
// decoding will fail if the data is not actually encoded
// using that encoder.
//
try {
return decode(b, Constants.CHARSET);
} catch (CharacterCodingException e) {
b.reset();
}
if (!cs.equals(Constants.CHARSET)) {
// Try the suggested encoding, it might be right since it was
// provided by the caller.
//
try {
return decode(b, cs);
} catch (CharacterCodingException e) {
b.reset();
}
}
// Try the default character set. A small group of people
// might actually use the same (or very similar) locale.
//
final Charset defcs = Charset.defaultCharset();
if (!defcs.equals(cs) && !defcs.equals(Constants.CHARSET)) {
try {
return decode(b, defcs);
} catch (CharacterCodingException e) {
b.reset();
}
}
throw new CharacterCodingException();
}
/**
* Decode a region of the buffer under the ISO-8859-1 encoding.
*
* Each byte is treated as a single character in the 8859-1 character
* encoding, performing a raw binary->char conversion.
*
* @param buffer
* buffer to pull raw bytes from.
* @param start
* first position within the buffer to take data from.
* @param end
* one position past the last location within the buffer to take
* data from.
* @return a string representation of the range <code>[start,end)</code>.
*/
public static String extractBinaryString(final byte[] buffer,
final int start, final int end) {
final StringBuilder r = new StringBuilder(end - start);
for (int i = start; i < end; i++)
r.append((char) (buffer[i] & 0xff));
return r.toString();
}
private static String decode(final ByteBuffer b, final Charset charset)
throws CharacterCodingException {
final CharsetDecoder d = charset.newDecoder();
d.onMalformedInput(CodingErrorAction.REPORT);
d.onUnmappableCharacter(CodingErrorAction.REPORT);
return d.decode(b).toString();
}
/**
* Locate the position of the commit message body.
*
* @param b
* buffer to scan.
* @param ptr
* position in buffer to start the scan at. Most callers should
* pass 0 to ensure the scan starts from the beginning of the
* commit buffer.
* @return position of the user's message buffer.
*/
public static final int commitMessage(final byte[] b, int ptr) {
final int sz = b.length;
if (ptr == 0)
ptr += 46; // skip the "tree ..." line.
while (ptr < sz && b[ptr] == 'p')
ptr += 48; // skip this parent.
// Skip any remaining header lines, ignoring what their actual
// header line type is. This is identical to the logic for a tag.
//
return tagMessage(b, ptr);
}
/**
* Locate the position of the tag message body.
*
* @param b
* buffer to scan.
* @param ptr
* position in buffer to start the scan at. Most callers should
* pass 0 to ensure the scan starts from the beginning of the tag
* buffer.
* @return position of the user's message buffer.
*/
public static final int tagMessage(final byte[] b, int ptr) {
final int sz = b.length;
if (ptr == 0)
ptr += 48; // skip the "object ..." line.
while (ptr < sz && b[ptr] != '\n')
ptr = nextLF(b, ptr);
if (ptr < sz && b[ptr] == '\n')
return ptr + 1;
return -1;
}
/**
* Locate the end of a paragraph.
* <p>
* A paragraph is ended by two consecutive LF bytes.
*
* @param b
* buffer to scan.
* @param start
* position in buffer to start the scan at. Most callers will
* want to pass the first position of the commit message (as
* found by {@link #commitMessage(byte[], int)}.
* @return position of the LF at the end of the paragraph;
* <code>b.length</code> if no paragraph end could be located.
*/
public static final int endOfParagraph(final byte[] b, final int start) {
int ptr = start;
final int sz = b.length;
while (ptr < sz && b[ptr] != '\n')
ptr = nextLF(b, ptr);
while (0 < ptr && start < ptr && b[ptr - 1] == '\n')
ptr--;
return ptr;
}
private RawParseUtils() {
// Don't create instances of a static only utility.
}
}