1 files changed, 370 insertions, 0 deletions
diff --git a/intl/uconv/nsUTF8ToUnicode.cpp b/intl/uconv/nsUTF8ToUnicode.cpp
new file mode 100644
index 000000000..d4e28b04d
--- /dev/null
+++ b/intl/uconv/nsUTF8ToUnicode.cpp
@@ -0,0 +1,370 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsUCSupport.h"
+#include "nsUTF8ToUnicode.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/SSE.h"
+#include "nsCharTraits.h"
+#include <algorithm>
+
+#define UNICODE_BYTE_ORDER_MARK    0xFEFF
+
+static char16_t* EmitSurrogatePair(uint32_t ucs4, char16_t* aDest)
+{
+  NS_ASSERTION(ucs4 > 0xFFFF, "Should be a supplementary character");
+  ucs4 -= 0x00010000;
+  *aDest++ = 0xD800 | (0x000003FF & (ucs4 >> 10));
+  *aDest++ = 0xDC00 | (0x000003FF & ucs4);
+  return aDest;
+}
+
+//----------------------------------------------------------------------
+// Class nsUTF8ToUnicode [implementation]
+
+nsUTF8ToUnicode::nsUTF8ToUnicode()
+: nsBasicDecoderSupport()
+{
+  Reset();
+}
+
+//----------------------------------------------------------------------
+// Subclassing of nsTableDecoderSupport class [implementation]
+
+/**
+ * Normally the maximum length of the output of the UTF8 decoder in UTF16
+ *  code units is the same as the length of the input in UTF8 code units,
+ *  since 1-byte, 2-byte and 3-byte UTF-8 sequences decode to a single
+ *  UTF-16 character, and 4-byte UTF-8 sequences decode to a surrogate pair.
+ *
+ * However, there is an edge case where the output can be longer than the
+ *  input: if the previous buffer ended with an incomplete multi-byte
+ *  sequence and this buffer does not begin with a valid continuation
+ *  byte, we will return NS_ERROR_ILLEGAL_INPUT and the caller may insert a
+ *  replacement character in the output buffer which corresponds to no
+ *  character in the input buffer. So in the worst case the destination
+ *  will need to be one code unit longer than the source.
+ *  See bug 301797.
+ */
+NS_IMETHODIMP nsUTF8ToUnicode::GetMaxLength(const char * aSrc,
+                                            int32_t aSrcLength,
+                                            int32_t * aDestLength)
+{
+  mozilla::CheckedInt32 length = aSrcLength;
+  length += 1;
+
+  if (!length.isValid()) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  *aDestLength = length.value();
+  return NS_OK;
+}
+
+
+//----------------------------------------------------------------------
+// Subclassing of nsBasicDecoderSupport class [implementation]
+
+NS_IMETHODIMP nsUTF8ToUnicode::Reset()
+{
+
+  mUcs4  = 0;     // cached Unicode character
+  mState = 0;     // cached expected number of octets after the current octet
+                  // until the beginning of the next UTF8 character sequence
+  mBytes = 1;     // cached expected number of octets in the current sequence
+  mFirst = true;
+
+  return NS_OK;
+
+}
+
+//----------------------------------------------------------------------
+// Subclassing of nsBasicDecoderSupport class [implementation]
+
+// Fast ASCII -> UTF16 inner loop implementations
+//
+// Convert_ascii_run will update src and dst to the new values, and
+// len must be the maximum number ascii chars that it would be valid
+// to take from src and place into dst.  (That is, the minimum of the
+// number of bytes left in src and the number of unichars available in
+// dst.)
+
+#if defined(__arm__) || defined(_M_ARM)
+
+// on ARM, do extra work to avoid byte/halfword reads/writes by
+// reading/writing a word at a time for as long as we can
+static inline void
+Convert_ascii_run (const char *&src,
+                   char16_t *&dst,
+                   int32_t len)
+{
+  const uint32_t *src32;
+  uint32_t *dst32;
+
+  // with some alignments, we'd never actually break out of the slow loop, so
+  // check and do the faster slow loop
+  if ((((NS_PTR_TO_UINT32(dst) & 3) == 0) && ((NS_PTR_TO_UINT32(src) & 1) == 0)) ||
+      (((NS_PTR_TO_UINT32(dst) & 3) == 2) && ((NS_PTR_TO_UINT32(src) & 1) == 1)))
+  {
+    while (((NS_PTR_TO_UINT32(src) & 3) ||
+            (NS_PTR_TO_UINT32(dst) & 3)) &&
+           len > 0)
+    {
+      if (*src & 0x80U)
+        return;
+      *dst++ = (char16_t) *src++;
+      len--;
+    }
+  } else {
+    goto finish;
+  }
+
+  // then go 4 bytes at a time
+  src32 = (const uint32_t*) src;
+  dst32 = (uint32_t*) dst;
+
+  while (len > 4) {
+    uint32_t in = *src32++;
+
+    if (in & 0x80808080U) {
+      src32--;
+      break;
+    }
+
+    *dst32++ = ((in & 0x000000ff) >>  0) | ((in & 0x0000ff00) << 8);
+    *dst32++ = ((in & 0x00ff0000) >> 16) | ((in & 0xff000000) >> 8);
+
+    len -= 4;
+  }
+
+  src = (const char *) src32;
+  dst = (char16_t *) dst32;
+
+finish:
+  while (len-- > 0 && (*src & 0x80U) == 0) {
+    *dst++ = (char16_t) *src++;
+  }
+}
+
+#else
+
+#ifdef MOZILLA_MAY_SUPPORT_SSE2
+namespace mozilla {
+namespace SSE2 {
+
+void Convert_ascii_run(const char *&src, char16_t *&dst, int32_t len);
+
+} // namespace SSE2
+} // namespace mozilla
+#endif
+
+static inline void
+Convert_ascii_run (const char *&src,
+                   char16_t *&dst,
+                   int32_t len)
+{
+#ifdef MOZILLA_MAY_SUPPORT_SSE2
+  if (mozilla::supports_sse2()) {
+    mozilla::SSE2::Convert_ascii_run(src, dst, len);
+    return;
+  }
+#endif
+
+  while (len-- > 0 && (*src & 0x80U) == 0) {
+    *dst++ = (char16_t) *src++;
+  }
+}
+
+#endif
+
+NS_IMETHODIMP nsUTF8ToUnicode::Convert(const char * aSrc,
+                                       int32_t * aSrcLength,
+                                       char16_t * aDest,
+                                       int32_t * aDestLength)
+{
+  uint32_t aSrcLen   = (uint32_t) (*aSrcLength);
+  uint32_t aDestLen = (uint32_t) (*aDestLength);
+
+  const char *in, *inend;
+  inend = aSrc + aSrcLen;
+
+  char16_t *out, *outend;
+  outend = aDest + aDestLen;
+
+  nsresult res = NS_OK; // conversion result
+
+  out = aDest;
+  if (mState == 0xFF) {
+    // Emit supplementary character left over from previous iteration. It is
+    // caller's responsibility to keep a sufficient buffer.
+    if (aDestLen < 2) {
+      *aSrcLength = *aDestLength = 0;
+      return NS_OK_UDEC_MOREOUTPUT;
+    }
+    out = EmitSurrogatePair(mUcs4, out);
+    mUcs4 = 0;
+    mState = 0;
+    mBytes = 1;
+    mFirst = false;
+  }
+
+  // alias these locally for speed
+  int32_t mUcs4 = this->mUcs4;
+  uint8_t mState = this->mState;
+  uint8_t mBytes = this->mBytes;
+  bool mFirst = this->mFirst;
+
+  // Set mFirst to false now so we don't have to every time through the ASCII
+  // branch within the loop.
+  if (mFirst && aSrcLen && (0 == (0x80 & (*aSrc))))
+    mFirst = false;
+
+  for (in = aSrc; ((in < inend) && (out < outend)); ++in) {
+    uint8_t c = *in;
+    if (0 == mState) {
+      // When mState is zero we expect either a US-ASCII character or a
+      // multi-octet sequence.
+      if (c < 0x80) {  // 00..7F
+        int32_t max_loops = std::min(inend - in, outend - out);
+        Convert_ascii_run(in, out, max_loops);
+        --in; // match the rest of the cases
+        mBytes = 1;
+      } else if (c < 0xC2) {  // C0/C1
+        // Overlong 2 octet sequence
+        if (mErrBehavior == kOnError_Signal) {
+          res = NS_ERROR_ILLEGAL_INPUT;
+          break;
+        }
+        *out++ = UCS2_REPLACEMENT_CHAR;
+        mFirst = false;
+      } else if (c < 0xE0) {  // C2..DF
+        // First octet of 2 octet sequence
+        mUcs4 = c;
+        mUcs4 = (mUcs4 & 0x1F) << 6;
+        mState = 1;
+        mBytes = 2;
+      } else if (c < 0xF0) {  // E0..EF
+        // First octet of 3 octet sequence
+        mUcs4 = c;
+        mUcs4 = (mUcs4 & 0x0F) << 12;
+        mState = 2;
+        mBytes = 3;
+      } else if (c < 0xF5) {  // F0..F4
+        // First octet of 4 octet sequence
+        mUcs4 = c;
+        mUcs4 = (mUcs4 & 0x07) << 18;
+        mState = 3;
+        mBytes = 4;
+      } else {  // F5..FF
+        /* Current octet is neither in the US-ASCII range nor a legal first
+         * octet of a multi-octet sequence.
+         */
+        if (mErrBehavior == kOnError_Signal) {
+          /* Return an error condition. Caller is responsible for flushing and
+           * refilling the buffer and resetting state.
+           */
+          res = NS_ERROR_ILLEGAL_INPUT;
+          break;
+        }
+        *out++ = UCS2_REPLACEMENT_CHAR;
+        mFirst = false;
+      }
+    } else {
+      // When mState is non-zero, we expect a continuation of the multi-octet
+      // sequence
+      if (0x80 == (0xC0 & c)) {
+        if (mState > 1) {
+          // If we are here, all possibilities are:
+          // mState == 2 && mBytes == 3 ||
+          // mState == 2 && mBytes == 4 ||
+          // mState == 3 && mBytes == 4
+          if ((mBytes == 3 && ((!mUcs4 && c < 0xA0) ||             // E0 80..9F
+                               (mUcs4 == 0xD000 && c > 0x9F))) ||  // ED A0..BF
+              (mState == 3 && ((!mUcs4 && c < 0x90) ||             // F0 80..8F
+                               (mUcs4 == 0x100000 && c > 0x8F)))) {// F4 90..BF
+            // illegal sequences or sequences converted into illegal ranges.
+            in--;
+            if (mErrBehavior == kOnError_Signal) {
+              res = NS_ERROR_ILLEGAL_INPUT;
+              break;
+            }
+            *out++ = UCS2_REPLACEMENT_CHAR;
+            mState = 0;
+            mFirst = false;
+            continue;
+          }
+        }
+
+        // Legal continuation.
+        uint32_t shift = (mState - 1) * 6;
+        uint32_t tmp = c;
+        tmp = (tmp & 0x0000003FL) << shift;
+        mUcs4 |= tmp;
+
+        if (0 == --mState) {
+          /* End of the multi-octet sequence. mUcs4 now contains the final
+           * Unicode codepoint to be output
+           */
+
+          if (mUcs4 > 0xFFFF) {
+            // mUcs4 is in the range 0x10000 - 0x10FFFF. Output a UTF-16 pair
+            if (out + 2 > outend) {
+              // insufficient space left in the buffer. Keep mUcs4 for the
+              // next iteration.
+              mState = 0xFF;
+              ++in;
+              res = NS_OK_UDEC_MOREOUTPUT;
+              break;
+            }
+            out = EmitSurrogatePair(mUcs4, out);
+          } else if (UNICODE_BYTE_ORDER_MARK != mUcs4 || !mFirst) {
+            // Don't output the BOM only if it is the first character
+            *out++ = mUcs4;
+          }
+          //initialize UTF8 cache
+          mUcs4  = 0;
+          mState = 0;
+          mBytes = 1;
+          mFirst = false;
+        }
+      } else {
+        /* ((0xC0 & c != 0x80) && (mState != 0))
+         *
+         * Incomplete multi-octet sequence. Unconsume this
+         * octet and return an error condition. Caller is responsible
+         * for flushing and refilling the buffer and resetting state.
+         */
+        in--;
+        if (mErrBehavior == kOnError_Signal) {
+          res = NS_ERROR_ILLEGAL_INPUT;
+          break;
+        }
+        *out++ = UCS2_REPLACEMENT_CHAR;
+        mState = 0;
+        mFirst = false;
+      }
+    }
+  }
+
+  // output not finished, output buffer too short
+  if ((NS_OK == res) && (in < inend) && (out >= outend))
+    res = NS_OK_UDEC_MOREOUTPUT;
+
+  // last UCS4 is incomplete, make sure the caller
+  // returns with properly aligned continuation of the buffer
+  if ((NS_OK == res) && (mState != 0))
+    res = NS_OK_UDEC_MOREINPUT;
+
+  *aSrcLength = in - aSrc;
+  *aDestLength = out - aDest;
+
+  this->mUcs4 = mUcs4;
+  this->mState = mState;
+  this->mBytes = mBytes;
+  this->mFirst = mFirst;
+
+  return(res);
+}