java/src/main/java/com/jsoniter/IterImplString.java at master · akan/java · GitHub

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package com.jsoniter;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import static java.lang.Character.MIN_HIGH_SURROGATE;

import static java.lang.Character.MIN_LOW_SURROGATE;

import static java.lang.Character.MIN_SUPPLEMENTARY_CODE_POINT;

class IterImplString {

static int[] base64Tbl = {

-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

-1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54,

55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2,

3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,

20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30,

31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,

48, 49, 50, 51, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1};

public static final String readString(JsonIterator iter) throws IOException {

byte c = iter.nextToken();

if (c == 'n') {

IterImplSkip.skipUntilBreak(iter);

return null;

}

if (c != '"') {

throw iter.reportError("readString", "expect n or \"");

}

// try fast path first

for (int i = iter.head, j = 0; i < iter.tail && j < iter.reusableChars.length; i++, j++) {

c = iter.buf[i];

if (c == '"') {

iter.head = i + 1;

return new String(iter.reusableChars, 0, j);

}

// If we encounter a backslash, which is a beginning of an escape sequence

// or a high bit was set - indicating an UTF-8 encoded multibyte character,

// there is no chance that we can decode the string without instantiating

// a temporary buffer, so quit this loop

if ((c ^ '\\') < 1) break;

iter.reusableChars[j] = (char) c;

}

return readStringSlowPath(iter);

}

final static String readStringSlowPath(JsonIterator iter) throws IOException {

// http://grepcode.com/file_/repository.grepcode.com/java/root/jdk/openjdk/8u40-b25/sun/nio/cs/UTF_8.java/?v=source

// byte => char with support of escape in one pass

int j = 0;

int minimumCapacity = iter.reusableChars.length - 2;

for (; ; ) {

if (j == minimumCapacity) {

char[] newBuf = new char[iter.reusableChars.length * 2];

System.arraycopy(iter.reusableChars, 0, newBuf, 0, iter.reusableChars.length);

iter.reusableChars = newBuf;

minimumCapacity = iter.reusableChars.length - 2;

}

int b1 = iter.readByte();

if (b1 >= 0) {

if (b1 == '"') {

return new String(iter.reusableChars, 0, j);

} else if (b1 == '\\') {

int b2 = iter.readByte();

switch (b2) {

case '"':

iter.reusableChars[j++] = '"';

break;

case '\\':

iter.reusableChars[j++] = '\\';

break;

case '/':

iter.reusableChars[j++] = '/';

break;

case 'b':

iter.reusableChars[j++] = '\b';

break;

case 'f':

iter.reusableChars[j++] = '\f';

break;

case 'n':

iter.reusableChars[j++] = '\n';

break;

case 'r':

iter.reusableChars[j++] = '\r';

break;

case 't':

iter.reusableChars[j++] = '\t';

break;

case 'u':

iter.reusableChars[j++] = IterImplNumber.readU4(iter);

break;

default:

throw iter.reportError("readStringSlowPath", "unexpected escape char: " + b2);

}

} else {

// 1 byte, 7 bits: 0xxxxxxx

iter.reusableChars[j++] = (char) b1;

}

} else if ((b1 >> 5) == -2 && (b1 & 0x1e) != 0) {

// 2 bytes, 11 bits: 110xxxxx 10xxxxxx

int b2 = iter.readByte();

iter.reusableChars[j++] = (char) (((b1 << 6) ^ b2)

(((byte) 0xC0 << 6) ^

((byte) 0x80 << 0)));

} else if ((b1 >> 4) == -2) {

// 3 bytes, 16 bits: 1110xxxx 10xxxxxx 10xxxxxx

int b2 = iter.readByte();

int b3 = iter.readByte();

char c = (char)

((b1 << 12) ^

(b2 << 6) ^

(b3 ^

(((byte) 0xE0 << 12) ^

((byte) 0x80 << 6) ^

((byte) 0x80 << 0))));

iter.reusableChars[j++] = c;

} else if ((b1 >> 3) == -2) {

// 4 bytes, 21 bits: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx

int b2 = iter.readByte();

int b3 = iter.readByte();

int b4 = iter.readByte();

int uc = ((b1 << 18) ^

(b2 << 12) ^

(b3 << 6) ^

(b4 ^

(((byte) 0xF0 << 18) ^

((byte) 0x80 << 12) ^

((byte) 0x80 << 6) ^

((byte) 0x80 << 0))));

iter.reusableChars[j++] = highSurrogate(uc);

iter.reusableChars[j++] = lowSurrogate(uc);

} else {

throw iter.reportError("readStringSlowPath", "unexpected input");

}

private static char highSurrogate(int codePoint) {

return (char) ((codePoint >>> 10)

+ (MIN_HIGH_SURROGATE - (MIN_SUPPLEMENTARY_CODE_POINT >>> 10)));

}

private static char lowSurrogate(int codePoint) {

return (char) ((codePoint & 0x3ff) + MIN_LOW_SURROGATE);

}

public static final byte[] readBase64(JsonIterator iter) throws IOException {

// from https://gist.github.com/EmilHernvall/953733

if (iter.nextToken() != '"') {

throw iter.reportError("readBase64", "expect \" for base64");

}

Slice slice = readSlice(iter);

if (slice == null) {

return null;

}

ByteArrayOutputStream buffer = new ByteArrayOutputStream();

int end = slice.head + slice.len;

for (int i = slice.head; i < end; i++) {

int b = 0;

if (base64Tbl[slice.data[i]] != -1) {

b = (base64Tbl[slice.data[i]] & 0xFF) << 18;

}

// skip unknown characters

else {

i++;

continue;

}

int num = 0;

if (i + 1 < end && base64Tbl[slice.data[i + 1]] != -1) {

b = b | ((base64Tbl[slice.data[i + 1]] & 0xFF) << 12);

num++;

}

if (i + 2 < end && base64Tbl[slice.data[i + 2]] != -1) {

b = b | ((base64Tbl[slice.data[i + 2]] & 0xFF) << 6);

num++;

}

if (i + 3 < end && base64Tbl[slice.data[i + 3]] != -1) {

b = b | (base64Tbl[slice.data[i + 3]] & 0xFF);

num++;

}

while (num > 0) {

int c = (b & 0xFF0000) >> 16;

buffer.write((char) c);

b <<= 8;

num--;

}

i += 4;

}

return buffer.toByteArray();

}

// read the bytes between " "

final static Slice readSlice(JsonIterator iter) throws IOException {

int end = findSliceEnd(iter);

if (end != -1) {

// reuse current buffer

iter.reusableSlice.data = iter.buf;

iter.reusableSlice.head = iter.head;

iter.reusableSlice.len = end - iter.head - 1;

iter.head = end;

return iter.reusableSlice;

}

byte[] part1 = new byte[iter.tail - iter.head];

System.arraycopy(iter.buf, iter.head, part1, 0, part1.length);

for (; ; ) {

if (!iter.loadMore()) {

throw iter.reportError("readSlice", "unmatched quote");

}

end = findSliceEnd(iter);

if (end == -1) {

byte[] part2 = new byte[part1.length + iter.buf.length];

System.arraycopy(part1, 0, part2, 0, part1.length);

System.arraycopy(iter.buf, 0, part2, part1.length, iter.buf.length);

part1 = part2;

} else {

byte[] part2 = new byte[part1.length + end - 1];

System.arraycopy(part1, 0, part2, 0, part1.length);

System.arraycopy(iter.buf, 0, part2, part1.length, end - 1);

iter.head = end;

iter.reusableSlice.data = part2;

iter.reusableSlice.head = 0;

iter.reusableSlice.len = part2.length;

return iter.reusableSlice;

}

// slice does not allow escape

final static int findSliceEnd(JsonIterator iter) {

for (int i = iter.head; i < iter.tail; i++) {

byte c = iter.buf[i];

if (c == '"') {

return i + 1;

} else if (c == '\\') {

throw iter.reportError("findSliceEnd", "slice does not support escape char");

}

return -1;

}

java/src/main/java/com/jsoniter/IterImplString.java at master · akan/java · GitHub

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