| /* |
| ******************************************************************************* |
| * Copyright (C) 1996-2005, International Business Machines Corporation and * |
| * others. All Rights Reserved. * |
| ******************************************************************************* |
| * |
| */ |
| |
| package com.ibm.icu.text; |
| |
| /** |
| * This class matches UTF-16 and UTF-32, both big- and little-endian. The |
| * BOM will be used if it is present. |
| * |
| * @internal |
| */ |
| abstract class CharsetRecog_Unicode extends CharsetRecognizer { |
| |
| /* (non-Javadoc) |
| * @see com.ibm.icu.text.CharsetRecognizer#getName() |
| */ |
| abstract String getName(); |
| |
| /* (non-Javadoc) |
| * @see com.ibm.icu.text.CharsetRecognizer#match(com.ibm.icu.text.CharsetDetector) |
| */ |
| abstract int match(CharsetDetector det); |
| |
| static class CharsetRecog_UTF_16_BE extends CharsetRecog_Unicode |
| { |
| String getName() |
| { |
| return "UTF-16BE"; |
| } |
| |
| int match(CharsetDetector det) |
| { |
| byte[] input = det.fRawInput; |
| |
| if ((input[0] & 0xFF) == 0xFE && (input[1] & 0xFF) == 0xFF) { |
| return 100; |
| } |
| |
| // TODO: Do some statastics to check for unsigned UTF-16BE |
| return 0; |
| } |
| } |
| |
| static class CharsetRecog_UTF_16_LE extends CharsetRecog_Unicode |
| { |
| String getName() |
| { |
| return "UTF-16LE"; |
| } |
| |
| int match(CharsetDetector det) |
| { |
| byte[] input = det.fRawInput; |
| |
| if ((input[0] & 0xFF) == 0xFF && (input[1] & 0xFF) == 0xFE && (input[2] != 0x00 || input[3] != 0x00)) { |
| return 100; |
| } |
| |
| // TODO: Do some statastics to check for unsigned UTF-16LE |
| return 0; |
| } |
| } |
| |
| static abstract class CharsetRecog_UTF_32 extends CharsetRecog_Unicode |
| { |
| abstract int getChar(byte[] input, int index); |
| |
| abstract String getName(); |
| |
| int match(CharsetDetector det) |
| { |
| byte[] input = det.fRawInput; |
| int limit = (det.fRawLength / 4) * 4; |
| int numValid = 0; |
| int numInvalid = 0; |
| boolean hasBOM = false; |
| int confidence = 0; |
| |
| if (input[0] == 0x00 && input[1] == 0x00 && (input[2] & 0xFF) == 0xFE && (input[3] & 0xFF) == 0xFF) { |
| hasBOM = true; |
| } |
| |
| for(int i = 0; i < limit; i += 4) { |
| int ch = getChar(input, i); |
| |
| if (ch < 0 || ch >= 0x10FFFF || (ch >= 0xD800 && ch <= 0xDFFF)) { |
| numInvalid += 1; |
| } else { |
| numValid += 1; |
| } |
| } |
| |
| |
| // Cook up some sort of confidence score, based on presense of a BOM |
| // and the existence of valid and/or invalid multi-byte sequences. |
| if (hasBOM && numInvalid==0) { |
| confidence = 100; |
| } else if (hasBOM && numValid > numInvalid*10) { |
| confidence = 80; |
| } else if (numValid > 3 && numInvalid == 0) { |
| confidence = 100; |
| } else if (numValid > 0 && numInvalid == 0) { |
| confidence = 80; |
| } else if (numValid > numInvalid*10) { |
| // Probably corruput UTF-32BE data. Valid sequences aren't likely by chance. |
| confidence = 25; |
| } |
| |
| return confidence; |
| } |
| } |
| |
| static class CharsetRecog_UTF_32_BE extends CharsetRecog_UTF_32 |
| { |
| int getChar(byte[] input, int index) |
| { |
| return (input[index + 0] & 0xFF) << 24 | (input[index + 1] & 0xFF) << 16 | |
| (input[index + 2] & 0xFF) << 8 | (input[index + 3] & 0xFF); |
| } |
| |
| String getName() |
| { |
| return "UTF-32BE"; |
| } |
| } |
| |
| |
| static class CharsetRecog_UTF_32_LE extends CharsetRecog_UTF_32 |
| { |
| int getChar(byte[] input, int index) |
| { |
| return (input[index + 3] & 0xFF) << 24 | (input[index + 2] & 0xFF) << 16 | |
| (input[index + 1] & 0xFF) << 8 | (input[index + 0] & 0xFF); |
| } |
| |
| String getName() |
| { |
| return "UTF-32LE"; |
| } |
| } |
| } |