Added TagLib (with AUTORS and COPYING files)
[someplayer] / src / taglib / toolkit / unicode.cpp
diff --git a/src/taglib/toolkit/unicode.cpp b/src/taglib/toolkit/unicode.cpp
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+/*******************************************************************************
+ *                                                                             *
+ * THIS FILE IS INCLUDED IN TAGLIB, BUT IS NOT COPYRIGHTED BY THE TAGLIB       *
+ * AUTHORS, NOT PART OF THE TAGLIB API AND COULD GO AWAY AT ANY POINT IN TIME. *
+ * AS SUCH IT SHOULD BE CONSIERED FOR INTERNAL USE ONLY.                       *
+ *                                                                             *
+ *******************************************************************************/
+
+/*
+ * Copyright 2001 Unicode, Inc.
+ * 
+ * Disclaimer
+ * 
+ * This source code is provided as is by Unicode, Inc. No claims are
+ * made as to fitness for any particular purpose. No warranties of any
+ * kind are expressed or implied. The recipient agrees to determine
+ * applicability of information provided. If this file has been
+ * purchased on magnetic or optical media from Unicode, Inc., the
+ * sole remedy for any claim will be exchange of defective media
+ * within 90 days of receipt.
+ * 
+ * Limitations on Rights to Redistribute This Code
+ * 
+ * Unicode, Inc. hereby grants the right to freely use the information
+ * supplied in this file in the creation of products supporting the
+ * Unicode Standard, and to make copies of this file in any form
+ * for internal or external distribution as long as this notice
+ * remains attached.
+ */
+
+/*
+ * This file has been modified by Scott Wheeler <wheeler@kde.org> to remove
+ * the UTF32 conversion functions and to place the appropriate functions
+ * in their own C++ namespace.
+ */
+
+/* ---------------------------------------------------------------------
+
+    Conversions between UTF32, UTF-16, and UTF-8. Source code file.
+       Author: Mark E. Davis, 1994.
+       Rev History: Rick McGowan, fixes & updates May 2001.
+       Sept 2001: fixed const & error conditions per
+               mods suggested by S. Parent & A. Lillich.
+
+    See the header file "ConvertUTF.h" for complete documentation.
+
+------------------------------------------------------------------------ */
+
+
+#include "unicode.h"
+#include <stdio.h>
+
+#define UNI_SUR_HIGH_START     (UTF32)0xD800
+#define UNI_SUR_HIGH_END       (UTF32)0xDBFF
+#define UNI_SUR_LOW_START      (UTF32)0xDC00
+#define UNI_SUR_LOW_END                (UTF32)0xDFFF
+#define false                  0
+#define true                   1
+
+namespace Unicode {
+
+static const int halfShift     = 10; /* used for shifting by 10 bits */
+
+static const UTF32 halfBase    = 0x0010000UL;
+static const UTF32 halfMask    = 0x3FFUL;
+
+/*
+ * Index into the table below with the first byte of a UTF-8 sequence to
+ * get the number of trailing bytes that are supposed to follow it.
+ */
+static const char trailingBytesForUTF8[256] = {
+       0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+       0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+       0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+       0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+       0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+       0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+       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,
+       2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, 3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5
+};
+
+/*
+ * Magic values subtracted from a buffer value during UTF8 conversion.
+ * This table contains as many values as there might be trailing bytes
+ * in a UTF-8 sequence.
+ */
+static const UTF32 offsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL, 
+                                        0x03C82080UL, 0xFA082080UL, 0x82082080UL };
+
+/*
+ * Once the bits are split out into bytes of UTF-8, this is a mask OR-ed
+ * into the first byte, depending on how many bytes follow.  There are
+ * as many entries in this table as there are UTF-8 sequence types.
+ * (I.e., one byte sequence, two byte... six byte sequence.)
+ */
+static const UTF8 firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
+
+/* --------------------------------------------------------------------- */
+
+/* The interface converts a whole buffer to avoid function-call overhead.
+ * Constants have been gathered. Loops & conditionals have been removed as
+ * much as possible for efficiency, in favor of drop-through switches.
+ * (See "Note A" at the bottom of the file for equivalent code.)
+ * If your compiler supports it, the "isLegalUTF8" call can be turned
+ * into an inline function.
+ */
+
+/* --------------------------------------------------------------------- */
+
+ConversionResult ConvertUTF16toUTF8 (
+               const UTF16** sourceStart, const UTF16* sourceEnd, 
+               UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) {
+       ConversionResult result = conversionOK;
+       const UTF16* source = *sourceStart;
+       UTF8* target = *targetStart;
+       while (source < sourceEnd) {
+               UTF32 ch;
+               unsigned short bytesToWrite = 0;
+               const UTF32 byteMask = 0xBF;
+               const UTF32 byteMark = 0x80; 
+               const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */
+               ch = *source++;
+               /* If we have a surrogate pair, convert to UTF32 first. */
+               if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END && source < sourceEnd) {
+                       UTF32 ch2 = *source;
+                       if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) {
+                               ch = ((ch - UNI_SUR_HIGH_START) << halfShift)
+                                       + (ch2 - UNI_SUR_LOW_START) + halfBase;
+                               ++source;
+                       } else if (flags == strictConversion) { /* it's an unpaired high surrogate */
+                               --source; /* return to the illegal value itself */
+                               result = sourceIllegal;
+                               break;
+                       }
+               } else if ((flags == strictConversion) && (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END)) {
+                       --source; /* return to the illegal value itself */
+                       result = sourceIllegal;
+                       break;
+               }
+               /* Figure out how many bytes the result will require */
+               if (ch < (UTF32)0x80) {                 bytesToWrite = 1;
+               } else if (ch < (UTF32)0x800) {         bytesToWrite = 2;
+               } else if (ch < (UTF32)0x10000) {       bytesToWrite = 3;
+               } else if (ch < (UTF32)0x200000) {      bytesToWrite = 4;
+               } else {                                bytesToWrite = 2;
+                                                       ch = UNI_REPLACEMENT_CHAR;
+               }
+               // printf("bytes to write = %i\n", bytesToWrite);
+               target += bytesToWrite;
+               if (target > targetEnd) {
+                       source = oldSource; /* Back up source pointer! */
+                       target -= bytesToWrite; result = targetExhausted; break;
+               }
+               switch (bytesToWrite) { /* note: everything falls through. */
+                       case 4: *--target = (ch | byteMark) & byteMask; ch >>= 6;
+                       case 3: *--target = (ch | byteMark) & byteMask; ch >>= 6;
+                       case 2: *--target = (ch | byteMark) & byteMask; ch >>= 6;
+                       case 1: *--target =  ch | firstByteMark[bytesToWrite];
+               }
+               target += bytesToWrite;
+       }
+       *sourceStart = source;
+       *targetStart = target;
+       return result;
+}
+
+/* --------------------------------------------------------------------- */
+
+/*
+ * Utility routine to tell whether a sequence of bytes is legal UTF-8.
+ * This must be called with the length pre-determined by the first byte.
+ * If not calling this from ConvertUTF8to*, then the length can be set by:
+ *     length = trailingBytesForUTF8[*source]+1;
+ * and the sequence is illegal right away if there aren't that many bytes
+ * available.
+ * If presented with a length > 4, this returns false.  The Unicode
+ * definition of UTF-8 goes up to 4-byte sequences.
+ */
+
+static Boolean isLegalUTF8(const UTF8 *source, int length) {
+       UTF8 a;
+       const UTF8 *srcptr = source+length;
+       switch (length) {
+       default: return false;
+               /* Everything else falls through when "true"... */
+       case 4: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
+       case 3: if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
+       case 2: if ((a = (*--srcptr)) > 0xBF) return false;
+               switch (*source) {
+                   /* no fall-through in this inner switch */
+                   case 0xE0: if (a < 0xA0) return false; break;
+                   case 0xF0: if (a < 0x90) return false; break;
+                   case 0xF4: if (a > 0x8F) return false; break;
+                   default:  if (a < 0x80) return false;
+               }
+       case 1: if (*source >= 0x80 && *source < 0xC2) return false;
+               if (*source > 0xF4) return false;
+       }
+       return true;
+}
+
+/* --------------------------------------------------------------------- */
+
+/*
+ * Exported function to return whether a UTF-8 sequence is legal or not.
+ * This is not used here; it's just exported.
+ */
+Boolean isLegalUTF8Sequence(const UTF8 *source, const UTF8 *sourceEnd) {
+       int length = trailingBytesForUTF8[*source]+1;
+       if (source+length > sourceEnd) {
+           return false;
+       }
+       return isLegalUTF8(source, length);
+}
+
+/* --------------------------------------------------------------------- */
+
+ConversionResult ConvertUTF8toUTF16 (
+               const UTF8** sourceStart, const UTF8* sourceEnd, 
+               UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) {
+       ConversionResult result = conversionOK;
+       const UTF8* source = *sourceStart;
+       UTF16* target = *targetStart;
+       while (source < sourceEnd) {
+               UTF32 ch = 0;
+               unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
+               if (source + extraBytesToRead >= sourceEnd) {
+                       result = sourceExhausted; break;
+               }
+               /* Do this check whether lenient or strict */
+               if (! isLegalUTF8(source, extraBytesToRead+1)) {
+                       result = sourceIllegal;
+                       break;
+               }
+               /*
+                * The cases all fall through. See "Note A" below.
+                */
+               switch (extraBytesToRead) {
+                       case 3: ch += *source++; ch <<= 6;
+                       case 2: ch += *source++; ch <<= 6;
+                       case 1: ch += *source++; ch <<= 6;
+                       case 0: ch += *source++;
+               }
+               ch -= offsetsFromUTF8[extraBytesToRead];
+
+               if (target >= targetEnd) {
+                       source -= (extraBytesToRead+1); /* Back up source pointer! */
+                       result = targetExhausted; break;
+               }
+               if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */
+                       if ((flags == strictConversion) && (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END)) {
+                               source -= (extraBytesToRead+1); /* return to the illegal value itself */
+                               result = sourceIllegal;
+                               break;
+                       } else {
+                           *target++ = ch;     /* normal case */
+                       }
+               } else if (ch > UNI_MAX_UTF16) {
+                       if (flags == strictConversion) {
+                               result = sourceIllegal;
+                               source -= (extraBytesToRead+1); /* return to the start */
+                               break; /* Bail out; shouldn't continue */
+                       } else {
+                               *target++ = UNI_REPLACEMENT_CHAR;
+                       }
+               } else {
+                       /* target is a character in range 0xFFFF - 0x10FFFF. */
+                       if (target + 1 >= targetEnd) {
+                               source -= (extraBytesToRead+1); /* Back up source pointer! */
+                               result = targetExhausted; break;
+                       }
+                       ch -= halfBase;
+                       *target++ = (ch >> halfShift) + UNI_SUR_HIGH_START;
+                       *target++ = (ch & halfMask) + UNI_SUR_LOW_START;
+               }
+       }
+       *sourceStart = source;
+       *targetStart = target;
+       return result;
+}
+
+}
+
+/* ---------------------------------------------------------------------
+
+       Note A.
+       The fall-through switches in UTF-8 reading code save a
+       temp variable, some decrements & conditionals.  The switches
+       are equivalent to the following loop:
+               {
+                       int tmpBytesToRead = extraBytesToRead+1;
+                       do {
+                               ch += *source++;
+                               --tmpBytesToRead;
+                               if (tmpBytesToRead) ch <<= 6;
+                       } while (tmpBytesToRead > 0);
+               }
+       In UTF-8 writing code, the switches on "bytesToWrite" are
+       similarly unrolled loops.
+
+   --------------------------------------------------------------------- */
+
+