Add unicode.org UTF-8/16/32 conversion code.

Add wrapper functions to make things more convenient. git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@88 4c0a9323-5329-0410-9bdc-e9ce6186880e
2024-11-28 00:34:16 +01:00 · 2006-12-15 00:03:27 +00:00 · 2006-12-15 00:03:27 +00:00 · eee138c2f3
commit eee138c2f3
parent b7b89b3b01
4 changed files with 895 additions and 0 deletions
--- a/src/common/convert_UTF.c
+++ b/src/common/convert_UTF.c
@ -0,0 +1,533 @@
+/*
+ * Copyright 2001-2004 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.
+ */
+
+/* ---------------------------------------------------------------------
+
+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.
+June 2002: Tim Dodd added detection and handling of incomplete
+source sequences, enhanced error detection, added casts
+to eliminate compiler warnings.
+July 2003: slight mods to back out aggressive FFFE detection.
+Jan 2004: updated switches in from-UTF8 conversions.
+Oct 2004: updated to use UNI_MAX_LEGAL_UTF32 in UTF-32 conversions.
+
+See the header file "ConvertUTF.h" for complete documentation.
+
+------------------------------------------------------------------------ */
+
+
+#include "convert_UTF.h"
+#ifdef CVTUTF_DEBUG
+#include <stdio.h>
+#endif
+
+static const int halfShift  = 10; /* used for shifting by 10 bits */
+
+static const UTF32 halfBase = 0x0010000UL;
+static const UTF32 halfMask = 0x3FFUL;
+
+#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
+
+/* --------------------------------------------------------------------- */
+
+ConversionResult ConvertUTF32toUTF16 (const UTF32** sourceStart, const UTF32* sourceEnd,
+                                      UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) {
+  ConversionResult result = conversionOK;
+  const UTF32* source = *sourceStart;
+  UTF16* target = *targetStart;
+  while (source < sourceEnd) {
+    UTF32 ch;
+    if (target >= targetEnd) {
+	    result = targetExhausted; break;
+    }
+    ch = *source++;
+    if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */
+	    /* UTF-16 surrogate values are illegal in UTF-32; 0xffff or 0xfffe are both reserved values */
+	    if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
+        if (flags == strictConversion) {
+          --source; /* return to the illegal value itself */
+          result = sourceIllegal;
+          break;
+        } else {
+          *target++ = UNI_REPLACEMENT_CHAR;
+        }
+	    } else {
+        *target++ = (UTF16)ch; /* normal case */
+	    }
+    } else if (ch > UNI_MAX_LEGAL_UTF32) {
+	    if (flags == strictConversion) {
+        result = sourceIllegal;
+	    } else {
+        *target++ = UNI_REPLACEMENT_CHAR;
+	    }
+    } else {
+	    /* target is a character in range 0xFFFF - 0x10FFFF. */
+	    if (target + 1 >= targetEnd) {
+        --source; /* Back up source pointer! */
+        result = targetExhausted; break;
+	    }
+	    ch -= halfBase;
+	    *target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START);
+	    *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START);
+    }
+  }
+*sourceStart = source;
+*targetStart = target;
+return result;
+}
+
+/* --------------------------------------------------------------------- */
+
+ConversionResult ConvertUTF16toUTF32 (const UTF16** sourceStart, const UTF16* sourceEnd,
+                                      UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) {
+  ConversionResult result = conversionOK;
+  const UTF16* source = *sourceStart;
+  UTF32* target = *targetStart;
+  UTF32 ch, ch2;
+  while (source < sourceEnd) {
+    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) {
+	    /* If the 16 bits following the high surrogate are in the source buffer... */
+	    if (source < sourceEnd) {
+        ch2 = *source;
+        /* If it's a low surrogate, convert to UTF32. */
+        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 { /* We don't have the 16 bits following the high surrogate. */
+        --source; /* return to the high surrogate */
+        result = sourceExhausted;
+        break;
+	    }
+    } else if (flags == strictConversion) {
+	    /* UTF-16 surrogate values are illegal in UTF-32 */
+	    if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
+        --source; /* return to the illegal value itself */
+        result = sourceIllegal;
+        break;
+	    }
+    }
+    if (target >= targetEnd) {
+	    source = oldSource; /* Back up source pointer! */
+	    result = targetExhausted; break;
+    }
+    *target++ = ch;
+  }
+  *sourceStart = source;
+  *targetStart = target;
+#ifdef CVTUTF_DEBUG
+  if (result == sourceIllegal) {
+    fprintf(stderr, "ConvertUTF16toUTF32 illegal seq 0x%04x,%04x\n", ch, ch2);
+    fflush(stderr);
+  }
+#endif
+  return result;
+}
+
+/* --------------------------------------------------------------------- */
+
+/*
+ * 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.
+ * Note that *legal* UTF-8 values can't have 4 or 5-bytes. The table is
+ * left as-is for anyone who may want to do such conversion, which was
+ * allowed in earlier algorithms.
+ */
+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... etc.). Remember that sequencs
+ * for *legal* UTF-8 will be 4 or fewer bytes total.
+ */
+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) {
+	    /* If the 16 bits following the high surrogate are in the source buffer... */
+	    if (source < sourceEnd) {
+        UTF32 ch2 = *source;
+        /* If it's a low surrogate, convert to UTF32. */
+        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 { /* We don't have the 16 bits following the high surrogate. */
+        --source; /* return to the high surrogate */
+        result = sourceExhausted;
+        break;
+	    }
+    } else if (flags == strictConversion) {
+	    /* UTF-16 surrogate values are illegal in UTF-32 */
+	    if (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)0x110000) {  bytesToWrite = 4;
+    } else {			    bytesToWrite = 3;
+      ch = UNI_REPLACEMENT_CHAR;
+    }
+
+    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 = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
+	    case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
+	    case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
+	    case 1: *--target =  (UTF8)(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 0xED: if (a > 0x9F) 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 5: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */
+	    case 4: ch += *source++; ch <<= 6; /* remember, illegal UTF-8 */
+	    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 */
+	    /* UTF-16 surrogate values are illegal in UTF-32 */
+	    if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
+        if (flags == strictConversion) {
+          source -= (extraBytesToRead+1); /* return to the illegal value itself */
+          result = sourceIllegal;
+          break;
+        } else {
+          *target++ = UNI_REPLACEMENT_CHAR;
+        }
+	    } else {
+        *target++ = (UTF16)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++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START);
+	    *target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START);
+    }
+  }
+*sourceStart = source;
+*targetStart = target;
+return result;
+}
+
+/* --------------------------------------------------------------------- */
+
+ConversionResult ConvertUTF32toUTF8 (const UTF32** sourceStart, const UTF32* sourceEnd,
+                                     UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags) {
+  ConversionResult result = conversionOK;
+  const UTF32* source = *sourceStart;
+  UTF8* target = *targetStart;
+  while (source < sourceEnd) {
+    UTF32 ch;
+    unsigned short bytesToWrite = 0;
+    const UTF32 byteMask = 0xBF;
+    const UTF32 byteMark = 0x80;
+    ch = *source++;
+    if (flags == strictConversion ) {
+	    /* UTF-16 surrogate values are illegal in UTF-32 */
+	    if (ch >= UNI_SUR_HIGH_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. Turn any
+     * illegally large UTF32 things (> Plane 17) into replacement chars.
+     */
+    if (ch < (UTF32)0x80) {	     bytesToWrite = 1;
+    } else if (ch < (UTF32)0x800) {     bytesToWrite = 2;
+    } else if (ch < (UTF32)0x10000) {   bytesToWrite = 3;
+    } else if (ch <= UNI_MAX_LEGAL_UTF32) {  bytesToWrite = 4;
+    } else {			    bytesToWrite = 3;
+      ch = UNI_REPLACEMENT_CHAR;
+      result = sourceIllegal;
+    }
+
+    target += bytesToWrite;
+    if (target > targetEnd) {
+	    --source; /* Back up source pointer! */
+	    target -= bytesToWrite; result = targetExhausted; break;
+    }
+    switch (bytesToWrite) { /* note: everything falls through. */
+	    case 4: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
+	    case 3: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
+	    case 2: *--target = (UTF8)((ch | byteMark) & byteMask); ch >>= 6;
+	    case 1: *--target = (UTF8) (ch | firstByteMark[bytesToWrite]);
+    }
+    target += bytesToWrite;
+  }
+*sourceStart = source;
+*targetStart = target;
+return result;
+}
+
+/* --------------------------------------------------------------------- */
+
+ConversionResult ConvertUTF8toUTF32 (const UTF8** sourceStart, const UTF8* sourceEnd,
+                                     UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags) {
+  ConversionResult result = conversionOK;
+  const UTF8* source = *sourceStart;
+  UTF32* 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 5: ch += *source++; ch <<= 6;
+	    case 4: ch += *source++; ch <<= 6;
+	    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 the source pointer! */
+	    result = targetExhausted; break;
+    }
+    if (ch <= UNI_MAX_LEGAL_UTF32) {
+	    /*
+	     * UTF-16 surrogate values are illegal in UTF-32, and anything
+	     * over Plane 17 (> 0x10FFFF) is illegal.
+	     */
+	    if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
+        if (flags == strictConversion) {
+          source -= (extraBytesToRead+1); /* return to the illegal value itself */
+          result = sourceIllegal;
+          break;
+        } else {
+          *target++ = UNI_REPLACEMENT_CHAR;
+        }
+	    } else {
+        *target++ = ch;
+	    }
+    } else { /* i.e., ch > UNI_MAX_LEGAL_UTF32 */
+	    result = sourceIllegal;
+	    *target++ = UNI_REPLACEMENT_CHAR;
+    }
+  }
+  *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.
+
+--------------------------------------------------------------------- */
--- a/src/common/convert_UTF.h
+++ b/src/common/convert_UTF.h
@ -0,0 +1,143 @@
+/*
+ * Copyright 2001-2004 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.
+ */
+
+/* ---------------------------------------------------------------------
+
+Conversions between UTF32, UTF-16, and UTF-8.  Header file.
+
+Several funtions are included here, forming a complete set of
+conversions between the three formats.  UTF-7 is not included
+here, but is handled in a separate source file.
+
+Each of these routines takes pointers to input buffers and output
+buffers.  The input buffers are const.
+
+Each routine converts the text between *sourceStart and sourceEnd,
+putting the result into the buffer between *targetStart and
+targetEnd. Note: the end pointers are *after* the last item: e.g.
+*(sourceEnd - 1) is the last item.
+
+The return result indicates whether the conversion was successful,
+and if not, whether the problem was in the source or target buffers.
+(Only the first encountered problem is indicated.)
+
+After the conversion, *sourceStart and *targetStart are both
+updated to point to the end of last text successfully converted in
+the respective buffers.
+
+Input parameters:
+sourceStart - pointer to a pointer to the source buffer.
+The contents of this are modified on return so that
+it points at the next thing to be converted.
+targetStart - similarly, pointer to pointer to the target buffer.
+sourceEnd, targetEnd - respectively pointers to the ends of the
+two buffers, for overflow checking only.
+
+These conversion functions take a ConversionFlags argument. When this
+flag is set to strict, both irregular sequences and isolated surrogates
+will cause an error.  When the flag is set to lenient, both irregular
+sequences and isolated surrogates are converted.
+
+Whether the flag is strict or lenient, all illegal sequences will cause
+an error return. This includes sequences such as: <F4 90 80 80>, <C0 80>,
+or <A0> in UTF-8, and values above 0x10FFFF in UTF-32. Conformant code
+must check for illegal sequences.
+
+When the flag is set to lenient, characters over 0x10FFFF are converted
+to the replacement character; otherwise (when the flag is set to strict)
+they constitute an error.
+
+Output parameters:
+The value "sourceIllegal" is returned from some routines if the input
+sequence is malformed.  When "sourceIllegal" is returned, the source
+value will point to the illegal value that caused the problem. E.g.,
+in UTF-8 when a sequence is malformed, it points to the start of the
+malformed sequence.
+
+Author: Mark E. Davis, 1994.
+Rev History: Rick McGowan, fixes & updates May 2001.
+Fixes & updates, Sept 2001.
+
+------------------------------------------------------------------------ */
+
+/* ---------------------------------------------------------------------
+The following 4 definitions are compiler-specific.
+The C standard does not guarantee that wchar_t has at least
+16 bits, so wchar_t is no less portable than unsigned short!
+All should be unsigned values to avoid sign extension during
+bit mask & shift operations.
+------------------------------------------------------------------------ */
+
+typedef unsigned long	UTF32;	/* at least 32 bits */
+typedef unsigned short	UTF16;	/* at least 16 bits */
+typedef unsigned char	UTF8;	/* typically 8 bits */
+typedef unsigned char	Boolean; /* 0 or 1 */
+
+/* Some fundamental constants */
+#define UNI_REPLACEMENT_CHAR (UTF32)0x0000FFFD
+#define UNI_MAX_BMP (UTF32)0x0000FFFF
+#define UNI_MAX_UTF16 (UTF32)0x0010FFFF
+#define UNI_MAX_UTF32 (UTF32)0x7FFFFFFF
+#define UNI_MAX_LEGAL_UTF32 (UTF32)0x0010FFFF
+
+typedef enum {
+	conversionOK, 		/* conversion successful */
+	sourceExhausted,	/* partial character in source, but hit end */
+	targetExhausted,	/* insuff. room in target for conversion */
+	sourceIllegal		/* source sequence is illegal/malformed */
+} ConversionResult;
+
+typedef enum {
+	strictConversion = 0,
+	lenientConversion
+} ConversionFlags;
+
+/* This is for C++ and does no harm in C */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+ConversionResult ConvertUTF8toUTF16 (const UTF8** sourceStart, const UTF8* sourceEnd,
+                                     UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags);
+
+ConversionResult ConvertUTF16toUTF8 (const UTF16** sourceStart, const UTF16* sourceEnd,
+                                     UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags);
+
+ConversionResult ConvertUTF8toUTF32 (const UTF8** sourceStart, const UTF8* sourceEnd,
+                                     UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags);
+
+ConversionResult ConvertUTF32toUTF8 (const UTF32** sourceStart, const UTF32* sourceEnd,
+                                     UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags);
+
+ConversionResult ConvertUTF16toUTF32 (const UTF16** sourceStart, const UTF16* sourceEnd,
+                                      UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags);
+
+ConversionResult ConvertUTF32toUTF16 (const UTF32** sourceStart, const UTF32* sourceEnd,
+                                      UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags);
+
+Boolean isLegalUTF8Sequence(const UTF8 *source, const UTF8 *sourceEnd);
+
+#ifdef __cplusplus
+}
+#endif
+
+/* --------------------------------------------------------------------- */
--- a/src/common/string_conversion.cc
+++ b/src/common/string_conversion.cc
@ -0,0 +1,154 @@
+// Copyright (c) 2006, Google Inc.
+// 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 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.
+
+#include "common/convert_UTF.h"
+#include "processor/scoped_ptr.h"
+#include "common/string_conversion.h"
+
+using std::string;
+using std::vector;
+
+namespace google_airbag {
+
+void UTF8ToUTF16(const char *in, vector<u_int16_t> &out) {
+  size_t source_length = strlen(in);
+  const UTF8 *source_ptr = reinterpret_cast<const UTF8 *>(in);
+  const UTF8 *source_end_ptr = source_ptr + source_length;
+  // Erase the contents and zero fill to the expected size
+  out.empty();
+  out.insert(out.begin(), source_length, 0);
+  u_int16_t *target_ptr = &out[0];
+  u_int16_t *target_end_ptr = target_ptr + out.capacity() * sizeof(u_int16_t);
+  ConversionResult result = ConvertUTF8toUTF16(&source_ptr, source_end_ptr,
+                                               &target_ptr, target_end_ptr,
+                                               strictConversion);
+
+  // Resize to be the size of the # of converted characters + NULL
+  out.resize(result == conversionOK ? target_ptr - &out[0] + 1: 0);
+}
+
+int UTF8ToUTF16Char(const char *in, int in_length, u_int16_t out[2]) {
+  const UTF8 *source_ptr = reinterpret_cast<const UTF8 *>(in);
+  const UTF8 *source_end_ptr = source_ptr + sizeof(char);
+  u_int16_t *target_ptr = out;
+  u_int16_t *target_end_ptr = target_ptr + 2 * sizeof(u_int16_t);
+  out[0] = out[1] = 0;
+
+  // Process one character at a time
+  while (1) {
+    ConversionResult result = ConvertUTF8toUTF16(&source_ptr, source_end_ptr,
+                                                 &target_ptr, target_end_ptr,
+                                                 strictConversion);
+
+    if (result == conversionOK)
+      return source_ptr - reinterpret_cast<const UTF8 *>(in);
+
+    // Add another character to the input stream and try again
+    source_ptr = reinterpret_cast<const UTF8 *>(in);
+    ++source_end_ptr;
+
+    if (source_end_ptr > reinterpret_cast<const UTF8 *>(in) + in_length)
+      break;
+  }
+
+  return 0;
+}
+
+void UTF32ToUTF16(const wchar_t *in, vector<u_int16_t> &out) {
+  size_t source_length = wcslen(in);
+  const UTF32 *source_ptr = reinterpret_cast<const UTF32 *>(in);
+  const UTF32 *source_end_ptr = source_ptr + source_length;
+  // Erase the contents and zero fill to the expected size
+  out.empty();
+  out.insert(out.begin(), source_length, 0);
+  u_int16_t *target_ptr = &out[0];
+  u_int16_t *target_end_ptr = target_ptr + out.capacity() * sizeof(u_int16_t);
+  ConversionResult result = ConvertUTF32toUTF16(&source_ptr, source_end_ptr,
+                                                &target_ptr, target_end_ptr,
+                                                strictConversion);
+
+  // Resize to be the size of the # of converted characters + NULL
+  out.resize(result == conversionOK ? target_ptr - &out[0] + 1: 0);
+}
+
+void UTF32ToUTF16Char(wchar_t in, u_int16_t out[2]) {
+  const UTF32 *source_ptr = reinterpret_cast<const UTF32 *>(in);
+  const UTF32 *source_end_ptr = source_ptr + sizeof(wchar_t);
+  u_int16_t *target_ptr = out;
+  u_int16_t *target_end_ptr = target_ptr + 2 * sizeof(u_int16_t);
+  out[0] = out[1] = 0;
+  ConversionResult result = ConvertUTF32toUTF16(&source_ptr, source_end_ptr,
+                                                &target_ptr, target_end_ptr,
+                                                strictConversion);
+
+  if (result != conversionOK) {
+    out[0] = out[1] = 0;
+  }
+}
+
+static inline u_int16_t Swap(u_int16_t value) {
+  return (value >> 8) | (value << 8);
+}
+
+string UTF16ToUTF8(const vector<u_int16_t> &in, bool swap) {
+  const UTF16 *source_ptr = &in[0];
+  scoped_ptr<u_int16_t> source_buffer;
+
+  // If we're to swap, we need to make a local copy and swap each byte pair
+  if (swap) {
+    int idx = 0;
+    source_buffer.reset(new u_int16_t[in.size()]);
+    UTF16 *source_buffer_ptr = source_buffer.get();
+    for (vector<u_int16_t>::const_iterator it = in.begin();
+         it != in.end(); ++it, ++idx)
+      source_buffer_ptr[idx] = Swap(*it);
+
+    source_ptr = source_buffer.get();
+  }
+
+  // The maximum expansion would be 4x the size of the input string.
+  const UTF16 *source_end_ptr = source_ptr + in.size();
+  int target_capacity = in.size() * 4;
+  scoped_array<UTF8> target_buffer(new UTF8[target_capacity]);
+  UTF8 *target_ptr = target_buffer.get();
+  UTF8 *target_end_ptr = target_ptr + target_capacity;
+  ConversionResult result = ConvertUTF16toUTF8(&source_ptr, source_end_ptr, 
+                                               &target_ptr, target_end_ptr,
+                                               strictConversion);
+
+  if (result == conversionOK) {
+    const char *targetPtr = reinterpret_cast<const char *>(target_buffer.get());
+    string result(targetPtr);
+    return result;
+  }
+
+  return "";
+}
+
+}  // namespace google_airbag
--- a/src/common/string_conversion.h
+++ b/src/common/string_conversion.h
@ -0,0 +1,65 @@
+// Copyright (c) 2006, Google Inc.
+// 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 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.
+
+// string_conversion.h: Conversion between different UTF-8/16/32 encodings.
+
+#ifndef COMMON_STRING_CONVERSION_H__
+#define COMMON_STRING_CONVERSION_H__
+
+#include <string>
+#include <vector>
+
+namespace google_airbag {
+  
+using std::vector;
+
+// Convert |in| to UTF-16 into |out|.  Use platform byte ordering.  If the
+// conversion failed, |out| will be zero length.
+void UTF8ToUTF16(const char *in, vector<u_int16_t> *out);
+
+// Convert at least one character (up to a maximum of |in_length|) from |in|
+// to UTF-16 into |out|.  Return the number of characters consumed from |in|.
+// Any unused characters in |out| will be initialized to 0.  No memory will
+// be allocated by this routine.
+int UTF8ToUTF16Char(const char *in, int in_length, u_int16_t out[2]);
+
+// Convert |in| to UTF-16 into |out|.  Use platform byte ordering.  If the
+// conversion failed, |out| will be zero length.
+void UTF32ToUTF16(const wchar_t *in, vector<u_int16_t> *out);
+
+// Convert |in| to UTF-16 into |out|.  Any unused characters in |out| will be
+// initialized to 0.  No memory will be allocated by this routine.
+void UTF32ToUTF16Char(wchar_t in, u_int16_t out[2]);
+
+// Convert |in| to UTF-8.  If |swap| is true, swap bytes before converting.
+std::string UTF16ToUTF8(const vector<u_int16_t> &in, bool swap);
+
+}  // namespace google_airbag
+
+#endif  // COMMON_STRING_CONVERSION_H__