Add Basilisk

1 files changed, 1369 insertions, 0 deletions

diff --git a/application/basilisk/components/translation/cld2/internal/utf8statetable.cc b/application/basilisk/components/translation/cld2/internal/utf8statetable.cc
new file mode 100644
index 000000000..8c97123d8
--- /dev/null
+++ b/application/basilisk/components/translation/cld2/internal/utf8statetable.cc
@@ -0,0 +1,1369 @@
+// Copyright 2013 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//
+// State Table follower for scanning UTF-8 strings without converting to
+// 32- or 16-bit Unicode values.
+//
+
+#ifdef COMPILER_MSVC
+// MSVC warns: warning C4309: 'initializing' : truncation of constant value
+// But the value is in fact not truncated.  0xFF still comes out 0xFF at
+// runtime.
+#pragma warning ( disable : 4309 )
+#endif
+
+#include "utf8statetable.h"
+
+#include <stdint.h>                     // for uintptr_t
+#include <string.h>                     // for NULL, memcpy, memmove
+
+#include "integral_types.h"        // for uint8, uint32, int8
+#include "stringpiece.h"
+#include "offsetmap.h"
+
+
+namespace CLD2 {
+
+static const int kReplaceAndResumeFlag = 0x80; // Bit in del byte to distinguish
+                                               // optional next-state field
+                                               // after replacement text
+static const int kHtmlPlaintextFlag = 0x80;    // Bit in add byte to distinguish
+                                               // HTML replacement vs. plaintext
+
+
+/**
+ * This code implements a little interpreter for UTF8 state
+ * tables. There are three kinds of quite-similar state tables,
+ * property, scanning, and replacement. Each state in one of
+ * these tables consists of an array of 256 or 64 one-byte
+ * entries. The state is subscripted by an incoming source byte,
+ * and the entry either specifies the next state or specifies an
+ * action. Space-optimized tables have full 256-entry states for
+ * the first byte of a UTF-8 character, but only 64-entry states
+ * for continuation bytes. Space-optimized tables may only be
+ * used with source input that has been checked to be
+ * structurally- (or stronger interchange-) valid.
+ *
+ * A property state table has an unsigned one-byte property for
+ * each possible UTF-8 character. One-byte character properties
+ * are in the state[0] array, while for other lengths the
+ * state[0] array gives the next state, which contains the
+ * property value for two-byte characters or yet another state
+ * for longer ones. The code simply loads the right number of
+ * next-state values, then returns the final byte as property
+ * value. There are no actions specified in property tables.
+ * States are typically shared for multi-byte UTF-8 characters
+ * that all have the same property value.
+ *
+ * A scanning state table has entries that are either a
+ * next-state specifier for bytes that are accepted by the
+ * scanner, or an exit action for the last byte of each
+ * character that is rejected by the scanner.
+ *
+ * Scanning long strings involves a tight loop that picks up one
+ * byte at a time and follows next-state value back to state[0]
+ * for each accepted UTF-8 character. Scanning stops at the end
+ * of the string or at the first character encountered that has
+ * an exit action such as "reject". Timing information is given
+ * below.
+ *
+ * Since so much of Google's text is 7-bit-ASCII values
+ * (approximately 94% of the bytes of web documents), the
+ * scanning interpreter has two speed optimizations. One checks
+ * 8 bytes at a time to see if they are all in the range lo..hi,
+ * as specified in constants in the overall statetable object.
+ * The check involves ORing together four 4-byte values that
+ * overflow into the high bit of some byte when a byte is out of
+ * range. For seven-bit-ASCII, lo is 0x20 and hi is 0x7E. This
+ * loop is about 8x faster than the one-byte-at-a-time loop.
+ *
+ * If checking for exit bytes in the 0x00-0x1F and 7F range is
+ * unneeded, an even faster loop just looks at the high bits of
+ * 8 bytes at once, and is about 1.33x faster than the lo..hi
+ * loop.
+ *
+ * Exit from the scanning routines backs up to the first byte of
+ * the rejected character, so the text spanned is always a
+ * complete number of UTF-8 characters. The normal scanning exit
+ * is at the first rejected character, or at the end of the
+ * input text. Scanning also exits on any detected ill-formed
+ * character or at a special do-again action built into some
+ * exit-optimized tables. The do-again action gets back to the
+ * top of the scanning loop to retry eight-byte ASCII scans. It
+ * is typically put into state tables after four seven-bit-ASCII
+ * characters in a row are seen, to allow restarting the fast
+ * scan after some slower processing of multi-byte characters.
+ *
+ * A replacement state table is similar to a scanning state
+ * table but has more extensive actions. The default
+ * byte-at-a-time loop copies one byte from source to
+ * destination and goes to the next state. The replacement
+ * actions overwrite 1-3 bytes of the destination with different
+ * bytes, possibly shortening the output by 1 or 2 bytes. The
+ * replacement bytes come from within the state table, from
+ * dummy states inserted just after any state that contains a
+ * replacement action. This gives a quick address calculation for
+ * the replacement byte(s) and gives some cache locality.
+ *
+ * Additional replacement actions use one or two bytes from
+ * within dummy states to index a side table of more-extensive
+ * replacements. The side table specifies a length of 0..15
+ * destination bytes to overwrite and a length of 0..127 bytes
+ * to overwrite them with, plus the actual replacement bytes.
+ *
+ * This side table uses one extra bit to specify a pair of
+ * replacements, the first to be used in an HTML context and the
+ * second to be used in a plaintext context. This allows
+ * replacements that are spelled with "&lt;" in the former
+ * context and "<" in the latter.
+ *
+ * The side table also uses an extra bit to specify a non-zero
+ * next state after a replacement. This allows a combination
+ * replacement and state change, used to implement a limited
+ * version of the Boyer-Moore algorithm for multi-character
+ * replacement without backtracking. This is useful when there
+ * are overlapping replacements, such as ch => x and also c =>
+ * y, the latter to be used only if the character after c is not
+ * h. in this case, the state[0] table's entry for c would
+ * change c to y and also have a next-state of say n, and the
+ * state[n] entry for h would specify a replacement of the two
+ * bytes yh by x. No backtracking is needed.
+ *
+ * A replacement table may also include the exit actions of a
+ * scanning state table, so some character sequences can
+ * terminate early.
+ *
+ * During replacement, an optional data structure called an
+ * offset map can be updated to reflect each change in length
+ * between source and destination. This offset map can later be
+ * used to map destination-string offsets to corresponding
+ * source-string offsets or vice versa.
+ *
+ * The routines below also have variants in which state-table
+ * entries are all two bytes instead of one byte. This allows
+ * tables with more than 240 total states, but takes up twice as
+ * much space per state.
+ *
+**/
+
+// Return true if current Tbl pointer is within state0 range
+// Note that unsigned compare checks both ends of range simultaneously
+static inline bool InStateZero(const UTF8ScanObj* st, const uint8* Tbl) {
+  const uint8* Tbl0 = &st->state_table[st->state0];
+  return (static_cast<uint32>(Tbl - Tbl0) < st->state0_size);
+}
+
+static inline bool InStateZero_2(const UTF8ReplaceObj_2* st,
+                                 const unsigned short int* Tbl) {
+  const unsigned short int* Tbl0 =  &st->state_table[st->state0];
+  // Word difference, not byte difference
+  return (static_cast<uint32>(Tbl - Tbl0) < st->state0_size);
+}
+
+// UTF8PropObj, UTF8ScanObj, UTF8ReplaceObj are all typedefs of
+// UTF8MachineObj.
+
+static bool IsPropObj(const UTF8StateMachineObj& obj) {
+  return obj.fast_state == NULL
+      && obj.max_expand == 0;
+}
+
+static bool IsPropObj_2(const UTF8StateMachineObj_2& obj) {
+  return obj.fast_state == NULL
+      && obj.max_expand == 0;
+}
+
+static bool IsScanObj(const UTF8StateMachineObj& obj) {
+  return obj.fast_state != NULL
+      && obj.max_expand == 0;
+}
+
+static bool IsReplaceObj(const UTF8StateMachineObj& obj) {
+  // Normally, obj.fast_state != NULL, but the handwritten tables
+  // in utf8statetable_unittest don't handle fast_states.
+  return obj.max_expand > 0;
+}
+
+static bool IsReplaceObj_2(const UTF8StateMachineObj_2& obj) {
+  return obj.max_expand > 0;
+}
+
+// Look up property of one UTF-8 character and advance over it
+// Return 0 if input length is zero
+// Return 0 and advance one byte if input is ill-formed
+uint8 UTF8GenericProperty(const UTF8PropObj* st,
+                          const uint8** src,
+                          int* srclen) {
+  if (*srclen <= 0) {
+    return 0;
+  }
+
+  const uint8* lsrc = *src;
+  const uint8* Tbl_0 = &st->state_table[st->state0];
+  const uint8* Tbl = Tbl_0;
+  int e;
+  int eshift = st->entry_shift;
+
+  // Short series of tests faster than switch, optimizes 7-bit ASCII
+  unsigned char c = lsrc[0];
+  if (static_cast<signed char>(c) >= 0) {           // one byte
+    e = Tbl[c];
+    *src += 1;
+    *srclen -= 1;
+  } else if (((c & 0xe0) == 0xc0) && (*srclen >= 2)) {     // two bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+    *src += 2;
+    *srclen -= 2;
+  } else if (((c & 0xf0) == 0xe0) && (*srclen >= 3)) {     // three bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[2]];
+    *src += 3;
+    *srclen -= 3;
+  }else if (((c & 0xf8) == 0xf0) && (*srclen >= 4)) {     // four bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[2]];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[3]];
+    *src += 4;
+    *srclen -= 4;
+  } else {                                                // Ill-formed
+    e = 0;
+    *src += 1;
+    *srclen -= 1;
+  }
+  return e;
+}
+
+bool UTF8HasGenericProperty(const UTF8PropObj& st, const char* src) {
+  const uint8* lsrc = reinterpret_cast<const uint8*>(src);
+  const uint8* Tbl_0 = &st.state_table[st.state0];
+  const uint8* Tbl = Tbl_0;
+  int e;
+  int eshift = st.entry_shift;
+
+  // Short series of tests faster than switch, optimizes 7-bit ASCII
+  unsigned char c = lsrc[0];
+  if (static_cast<signed char>(c) >= 0) {           // one byte
+    e = Tbl[c];
+  } else if ((c & 0xe0) == 0xc0) {     // two bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+  } else if ((c & 0xf0) == 0xe0) {     // three bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[2]];
+  } else {                             // four bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[2]];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[3]];
+  }
+  return e;
+}
+
+
+// BigOneByte versions are needed for tables > 240 states, but most
+// won't need the TwoByte versions.
+// Internally, to next-to-last offset is multiplied by 16 and the last
+// offset is relative instead of absolute.
+// Look up property of one UTF-8 character and advance over it
+// Return 0 if input length is zero
+// Return 0 and advance one byte if input is ill-formed
+uint8 UTF8GenericPropertyBigOneByte(const UTF8PropObj* st,
+                          const uint8** src,
+                          int* srclen) {
+  if (*srclen <= 0) {
+    return 0;
+  }
+
+  const uint8* lsrc = *src;
+  const uint8* Tbl_0 = &st->state_table[st->state0];
+  const uint8* Tbl = Tbl_0;
+  int e;
+  int eshift = st->entry_shift;
+
+  // Short series of tests faster than switch, optimizes 7-bit ASCII
+  unsigned char c = lsrc[0];
+  if (static_cast<signed char>(c) >= 0) {           // one byte
+    e = Tbl[c];
+    *src += 1;
+    *srclen -= 1;
+  } else if (((c & 0xe0) == 0xc0) && (*srclen >= 2)) {     // two bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+    *src += 2;
+    *srclen -= 2;
+  } else if (((c & 0xf0) == 0xe0) && (*srclen >= 3)) {     // three bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << (eshift + 4)];  // 16x the range
+    e = (reinterpret_cast<const int8*>(Tbl))[lsrc[1]];
+    Tbl = &Tbl[e << eshift];          // Relative +/-
+    e = Tbl[lsrc[2]];
+    *src += 3;
+    *srclen -= 3;
+  }else if (((c & 0xf8) == 0xf0) && (*srclen >= 4)) {     // four bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+    Tbl = &Tbl_0[e << (eshift + 4)];  // 16x the range
+    e = (reinterpret_cast<const int8*>(Tbl))[lsrc[2]];
+    Tbl = &Tbl[e << eshift];          // Relative +/-
+    e = Tbl[lsrc[3]];
+    *src += 4;
+    *srclen -= 4;
+  } else {                                                // Ill-formed
+    e = 0;
+    *src += 1;
+    *srclen -= 1;
+  }
+  return e;
+}
+
+// BigOneByte versions are needed for tables > 240 states, but most
+// won't need the TwoByte versions.
+bool UTF8HasGenericPropertyBigOneByte(const UTF8PropObj& st, const char* src) {
+  const uint8* lsrc = reinterpret_cast<const uint8*>(src);
+  const uint8* Tbl_0 = &st.state_table[st.state0];
+  const uint8* Tbl = Tbl_0;
+  int e;
+  int eshift = st.entry_shift;
+
+  // Short series of tests faster than switch, optimizes 7-bit ASCII
+  unsigned char c = lsrc[0];
+  if (static_cast<signed char>(c) >= 0) {           // one byte
+    e = Tbl[c];
+  } else if ((c & 0xe0) == 0xc0) {    // two bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+  } else if ((c & 0xf0) == 0xe0) {    // three bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << (eshift + 4)];  // 16x the range
+    e = (reinterpret_cast<const int8*>(Tbl))[lsrc[1]];
+    Tbl = &Tbl[e << eshift];          // Relative +/-
+    e = Tbl[lsrc[2]];
+  } else {                            // four bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+    Tbl = &Tbl_0[e << (eshift + 4)];  // 16x the range
+    e = (reinterpret_cast<const int8*>(Tbl))[lsrc[2]];
+    Tbl = &Tbl[e << eshift];          // Relative +/-
+    e = Tbl[lsrc[3]];
+  }
+  return e;
+}
+
+
+// TwoByte versions are needed for tables > 240 states
+// Look up property of one UTF-8 character and advance over it
+// Return 0 if input length is zero
+// Return 0 and advance one byte if input is ill-formed
+uint8 UTF8GenericPropertyTwoByte(const UTF8PropObj_2* st,
+                          const uint8** src,
+                          int* srclen) {
+  if (*srclen <= 0) {
+    return 0;
+  }
+
+  const uint8* lsrc = *src;
+  const unsigned short* Tbl_0 = &st->state_table[st->state0];
+  const unsigned short* Tbl = Tbl_0;
+  int e;
+  int eshift = st->entry_shift;
+
+  // Short series of tests faster than switch, optimizes 7-bit ASCII
+  unsigned char c = lsrc[0];
+  if (static_cast<signed char>(c) >= 0) {           // one byte
+    e = Tbl[c];
+    *src += 1;
+    *srclen -= 1;
+  } else if (((c & 0xe0) == 0xc0) && (*srclen >= 2)) {     // two bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+    *src += 2;
+    *srclen -= 2;
+  } else if (((c & 0xf0) == 0xe0) && (*srclen >= 3)) {     // three bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[2]];
+    *src += 3;
+    *srclen -= 3;
+  }else if (((c & 0xf8) == 0xf0) && (*srclen >= 4)) {     // four bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[2]];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[3]];
+    *src += 4;
+    *srclen -= 4;
+  } else {                                                // Ill-formed
+    e = 0;
+    *src += 1;
+    *srclen -= 1;
+  }
+  return e;
+}
+
+// TwoByte versions are needed for tables > 240 states
+bool UTF8HasGenericPropertyTwoByte(const UTF8PropObj_2& st, const char* src) {
+  const uint8* lsrc = reinterpret_cast<const uint8*>(src);
+  const unsigned short* Tbl_0 = &st.state_table[st.state0];
+  const unsigned short* Tbl = Tbl_0;
+  int e;
+  int eshift = st.entry_shift;
+
+  // Short series of tests faster than switch, optimizes 7-bit ASCII
+  unsigned char c = lsrc[0];
+  if (static_cast<signed char>(c) >= 0) {           // one byte
+    e = Tbl[c];
+  } else if ((c & 0xe0) == 0xc0) {     // two bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+  } else if ((c & 0xf0) == 0xe0) {     // three bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[2]];
+  } else {                             // four bytes
+    e = Tbl[c];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[1]];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[2]];
+    Tbl = &Tbl_0[e << eshift];
+    e = Tbl[lsrc[3]];
+  }
+  return e;
+}
+
+
+// Approximate speeds on 2.8 GHz Pentium 4:
+//   GenericScan 1-byte loop           300 MB/sec *
+//   GenericScan 4-byte loop          1200 MB/sec
+//   GenericScan 8-byte loop          2400 MB/sec *
+//   GenericScanFastAscii 4-byte loop 3000 MB/sec
+//   GenericScanFastAscii 8-byte loop 3200 MB/sec *
+//
+// * Implemented below. FastAscii loop is memory-bandwidth constrained.
+
+// Scan a UTF-8 stringpiece based on state table.
+// Always scan complete UTF-8 characters
+// Set number of bytes scanned. Return reason for exiting
+int UTF8GenericScan(const UTF8ScanObj* st,
+                    const StringPiece& str,
+                    int* bytes_consumed) {
+  int eshift = st->entry_shift;       // 6 (space optimized) or 8
+  // int nEntries = (1 << eshift);       // 64 or 256 entries per state
+
+  const uint8* isrc =
+    reinterpret_cast<const uint8*>(str.data());
+  const uint8* src = isrc;
+  const int len = str.length();
+  const uint8* srclimit = isrc + len;
+  const uint8* srclimit8 = srclimit - 7;
+  *bytes_consumed = 0;
+  if (len == 0) return kExitOK;
+
+  const uint8* Tbl_0 = &st->state_table[st->state0];
+
+DoAgain:
+  // Do state-table scan
+  int e = 0;
+  uint8 c;
+
+  // Do fast for groups of 8 identity bytes.
+  // This covers a lot of 7-bit ASCII ~8x faster than the 1-byte loop,
+  // including slowing slightly on cr/lf/ht
+  //----------------------------
+  const uint8* Tbl2 = &st->fast_state[0];
+  uint32 losub = st->losub;
+  uint32 hiadd = st->hiadd;
+  while (src < srclimit8) {
+    uint32 s0123 = (reinterpret_cast<const uint32 *>(src))[0];
+    uint32 s4567 = (reinterpret_cast<const uint32 *>(src))[1];
+    src += 8;
+    // This is a fast range check for all bytes in [lowsub..0x80-hiadd)
+    uint32 temp = (s0123 - losub) | (s0123 + hiadd) |
+                  (s4567 - losub) | (s4567 + hiadd);
+    if ((temp & 0x80808080) != 0) {
+      // We typically end up here on cr/lf/ht; src was incremented
+      int e0123 = (Tbl2[src[-8]] | Tbl2[src[-7]]) |
+                  (Tbl2[src[-6]] | Tbl2[src[-5]]);
+      if (e0123 != 0) {src -= 8; break;}    // Exit on Non-interchange
+      e0123 = (Tbl2[src[-4]] | Tbl2[src[-3]]) |
+              (Tbl2[src[-2]] | Tbl2[src[-1]]);
+      if (e0123 != 0) {src -= 4; break;}    // Exit on Non-interchange
+      // Else OK, go around again
+    }
+  }
+  //----------------------------
+
+  // Byte-at-a-time scan
+  //----------------------------
+  const uint8* Tbl = Tbl_0;
+  while (src < srclimit) {
+    c = *src;
+    e = Tbl[c];
+    src++;
+    if (e >= kExitIllegalStructure) {break;}
+    Tbl = &Tbl_0[e << eshift];
+  }
+  //----------------------------
+
+
+  // Exit possibilities:
+  //  Some exit code, !state0, back up over last char
+  //  Some exit code, state0, back up one byte exactly
+  //  source consumed, !state0, back up over partial char
+  //  source consumed, state0, exit OK
+  // For illegal byte in state0, avoid backup up over PREVIOUS char
+  // For truncated last char, back up to beginning of it
+
+  if (e >= kExitIllegalStructure) {
+    // Back up over exactly one byte of rejected/illegal UTF-8 character
+    src--;
+    // Back up more if needed
+    if (!InStateZero(st, Tbl)) {
+      do {src--;} while ((src > isrc) && ((src[0] & 0xc0) == 0x80));
+    }
+  } else if (!InStateZero(st, Tbl)) {
+    // Back up over truncated UTF-8 character
+    e = kExitIllegalStructure;
+    do {src--;} while ((src > isrc) && ((src[0] & 0xc0) == 0x80));
+  } else {
+    // Normal termination, source fully consumed
+    e = kExitOK;
+  }
+
+  if (e == kExitDoAgain) {
+    // Loop back up to the fast scan
+    goto DoAgain;
+  }
+
+  *bytes_consumed = src - isrc;
+  return e;
+}
+
+// Scan a UTF-8 stringpiece based on state table.
+// Always scan complete UTF-8 characters
+// Set number of bytes scanned. Return reason for exiting
+// OPTIMIZED for case of 7-bit ASCII 0000..007f all valid
+int UTF8GenericScanFastAscii(const UTF8ScanObj* st,
+                    const StringPiece& str,
+                    int* bytes_consumed) {
+  const uint8* isrc =
+    reinterpret_cast<const uint8*>(str.data());
+  const uint8* src = isrc;
+  const int len = str.length();
+  const uint8* srclimit = isrc + len;
+  const uint8* srclimit8 = srclimit - 7;
+  *bytes_consumed = 0;
+  if (len == 0) return kExitOK;
+
+  int n;
+  int rest_consumed;
+  int exit_reason;
+  do {
+    // Skip 8 bytes of ASCII at a whack; no endianness issue
+    while ((src < srclimit8) &&
+           (((reinterpret_cast<const uint32*>(src)[0] |
+              reinterpret_cast<const uint32*>(src)[1]) & 0x80808080) == 0)) {
+      src += 8;
+    }
+    // Run state table on the rest
+    n = src - isrc;
+    StringPiece str2(str.data() + n, str.length() - n);
+    exit_reason = UTF8GenericScan(st, str2, &rest_consumed);
+    src += rest_consumed;
+  } while ( exit_reason == kExitDoAgain );
+
+  *bytes_consumed = src - isrc;
+  return exit_reason;
+}
+
+// Hack to change halfwidth katakana to match an old UTF8CharToLower()
+
+// Return number of src bytes skipped
+static int DoSpecialFixup(const unsigned char c,
+                    const unsigned char** srcp, const unsigned char* srclimit,
+                    unsigned char** dstp, unsigned char* dstlimit) {
+  return 0;
+}
+
+
+// Scan a UTF-8 stringpiece based on state table, copying to output stringpiece
+//   and doing text replacements.
+// DO NOT CALL DIRECTLY. Use UTF8GenericReplace() below
+//   Needs caller to loop on kExitDoAgain
+static int UTF8GenericReplaceInternal(const UTF8ReplaceObj* st,
+                    const StringPiece& istr,
+                    StringPiece& ostr,
+                    bool is_plain_text,
+                    int* bytes_consumed,
+                    int* bytes_filled,
+                    int* chars_changed,
+                    OffsetMap* offsetmap) {
+  int eshift = st->entry_shift;
+  int nEntries = (1 << eshift);       // 64 or 256 entries per state
+  const uint8* isrc = reinterpret_cast<const uint8*>(istr.data());
+  const int ilen = istr.length();
+  const uint8* copystart = isrc;
+  const uint8* src = isrc;
+  const uint8* srclimit = src + ilen;
+  *bytes_consumed = 0;
+  *bytes_filled = 0;
+  *chars_changed = 0;
+
+  const uint8* odst = reinterpret_cast<const uint8*>(ostr.data());
+  const int olen = ostr.length();
+  uint8* dst = const_cast<uint8*>(odst);
+  uint8* dstlimit = dst + olen;
+
+  int total_changed = 0;
+
+  // Invariant condition during replacements:
+  //  remaining dst size >= remaining src size
+  if ((dstlimit - dst) < (srclimit - src)) {
+    if (offsetmap != NULL) {
+      offsetmap->Copy(src - copystart);
+      copystart = src;
+    }
+    return kExitDstSpaceFull;
+  }
+  const uint8* Tbl_0 = &st->state_table[st->state0];
+
+ Do_state_table:
+  // Do state-table scan, copying as we go
+  const uint8* Tbl = Tbl_0;
+  int e = 0;
+  uint8 c = 0;
+
+ Do_state_table_newe:
+
+  //----------------------------
+  while (src < srclimit) {
+    c = *src;
+    e = Tbl[c];
+    *dst = c;
+    src++;
+    dst++;
+    if (e >= kExitIllegalStructure) {break;}
+    Tbl = &Tbl_0[e << eshift];
+  }
+  //----------------------------
+
+  // Exit possibilities:
+  //  Replacement code, do the replacement and loop
+  //  Some other exit code, state0, back up one byte exactly
+  //  Some other exit code, !state0, back up over last char
+  //  source consumed, state0, exit OK
+  //  source consumed, !state0, back up over partial char
+  // For illegal byte in state0, avoid backup up over PREVIOUS char
+  // For truncated last char, back up to beginning of it
+
+  if (e >= kExitIllegalStructure) {
+    // Switch on exit code; most loop back to top
+    int offset = 0;
+    switch (e) {
+    // These all make the output string the same size or shorter
+    // No checking needed
+    case kExitReplace31:    // del 2, add 1 bytes to change
+      dst -= 2;
+      if (offsetmap != NULL) {
+        offsetmap->Copy(src - copystart - 2);
+        offsetmap->Delete(2);
+        copystart = src;
+      }
+      dst[-1] = (unsigned char)Tbl[c + (nEntries * 1)];
+      total_changed++;
+      goto Do_state_table;
+    case kExitReplace32:    // del 3, add 2 bytes to change
+      dst--;
+      if (offsetmap != NULL) {
+        offsetmap->Copy(src - copystart - 1);
+        offsetmap->Delete(1);
+        copystart = src;
+      }
+      dst[-2] = (unsigned char)Tbl[c + (nEntries * 2)];
+      dst[-1] = (unsigned char)Tbl[c + (nEntries * 1)];
+      total_changed++;
+      goto Do_state_table;
+    case kExitReplace21:    // del 2, add 1 bytes to change
+      dst--;
+      if (offsetmap != NULL) {
+        offsetmap->Copy(src - copystart - 1);
+        offsetmap->Delete(1);
+        copystart = src;
+      }
+      dst[-1] = (unsigned char)Tbl[c + (nEntries * 1)];
+      total_changed++;
+      goto Do_state_table;
+    case kExitReplace3:    // update 3 bytes to change
+      dst[-3] = (unsigned char)Tbl[c + (nEntries * 3)];
+      // Fall into next case
+    case kExitReplace2:    // update 2 bytes to change
+      dst[-2] = (unsigned char)Tbl[c + (nEntries * 2)];
+      // Fall into next case
+    case kExitReplace1:    // update 1 byte to change
+      dst[-1] = (unsigned char)Tbl[c + (nEntries * 1)];
+      total_changed++;
+      goto Do_state_table;
+    case kExitReplace1S0:     // update 1 byte to change, 256-entry state
+      dst[-1] = (unsigned char)Tbl[c + (256 * 1)];
+      total_changed++;
+      goto Do_state_table;
+    // These can make the output string longer than the input
+    case kExitReplaceOffset2:
+      if ((nEntries != 256) && InStateZero(st, Tbl)) {
+        // For space-optimized table, we need multiples of 256 bytes
+        // in state0 and multiples of nEntries in other states
+        offset += ((unsigned char)Tbl[c + (256 * 2)] << 8);
+      } else {
+        offset += ((unsigned char)Tbl[c + (nEntries * 2)] << 8);
+      }
+      // Fall into next case
+    case kExitSpecial:      // Apply special fixups [read: hacks]
+    case kExitReplaceOffset1:
+      if ((nEntries != 256) && InStateZero(st, Tbl)) {
+        // For space-optimized table, we need multiples of 256 bytes
+        // in state0 and multiples of nEntries in other states
+        offset += (unsigned char)Tbl[c + (256 * 1)];
+      } else {
+        offset += (unsigned char)Tbl[c + (nEntries * 1)];
+      }
+      {
+        const RemapEntry* re = &st->remap_base[offset];
+        int del_len = re->delete_bytes & ~kReplaceAndResumeFlag;
+        int add_len = re->add_bytes & ~kHtmlPlaintextFlag;
+
+        // Special-case non-HTML replacement of five sensitive entities
+        //   &quot; &amp; &apos; &lt; &gt;
+        //   0022   0026  0027   003c 003e
+        // A replacement creating one of these is expressed as a pair of
+        // entries, one for HTML output and one for plaintext output.
+        // The first of the pair has the high bit of add_bytes set.
+        if (re->add_bytes & kHtmlPlaintextFlag) {
+          // Use this entry for plain text
+          if (!is_plain_text) {
+            // Use very next entry for HTML text (same back/delete length)
+            re = &st->remap_base[offset + 1];
+            add_len = re->add_bytes & ~kHtmlPlaintextFlag;
+          }
+        }
+
+        int string_offset = re->bytes_offset;
+        // After the replacement, need (dstlimit - newdst) >= (srclimit - src)
+        uint8* newdst = dst - del_len + add_len;
+        if ((dstlimit - newdst) < (srclimit - src)) {
+          // Won't fit; don't do the replacement. Caller may realloc and retry
+          e = kExitDstSpaceFull;
+          break;    // exit, backing up over this char for later retry
+        }
+        dst -= del_len;
+        memcpy(dst, &st->remap_string[string_offset], add_len);
+        dst += add_len;
+        total_changed++;
+        if (offsetmap != NULL) {
+          if (add_len > del_len) {
+            offsetmap->Copy(src - copystart);
+            offsetmap->Insert(add_len - del_len);
+            copystart = src;
+          } else if (add_len < del_len) {
+            offsetmap->Copy(src - copystart + add_len - del_len);
+            offsetmap->Delete(del_len - add_len);
+            copystart = src;
+          }
+        }
+        if (re->delete_bytes & kReplaceAndResumeFlag) {
+          // There is a non-zero  target state at the end of the
+          // replacement string
+          e = st->remap_string[string_offset + add_len];
+          Tbl = &Tbl_0[e << eshift];
+          goto Do_state_table_newe;
+        }
+      }
+      if (e == kExitRejectAlt) {break;}
+      if (e != kExitSpecial) {goto Do_state_table;}
+
+    // case kExitSpecial:      // Apply special fixups [read: hacks]
+      // In this routine, do either UTF8CharToLower()
+      //   fullwidth/halfwidth mapping or
+      //   voiced mapping or
+      //   semi-voiced mapping
+
+      // First, do EXIT_REPLACE_OFFSET1 action (above)
+      // Second: do additional code fixup
+      {
+        int srcdel = DoSpecialFixup(c, &src, srclimit, &dst, dstlimit);
+        if (offsetmap != NULL) {
+          if (srcdel != 0) {
+            offsetmap->Copy(src - copystart - srcdel);
+            offsetmap->Delete(srcdel);
+            copystart = src;
+          }
+        }
+      }
+      goto Do_state_table;
+
+    case kExitIllegalStructure:   // structurally illegal byte; quit
+    case kExitReject:             // NUL or illegal code encountered; quit
+    case kExitRejectAlt:          // Apply replacement, then exit
+    default:                      // and all other exits
+      break;
+    }   // End switch (e)
+
+    // Exit possibilities:
+    //  Some other exit code, state0, back up one byte exactly
+    //  Some other exit code, !state0, back up over last char
+
+    // Back up over exactly one byte of rejected/illegal UTF-8 character
+    src--;
+    dst--;
+    // Back up more if needed
+    if (!InStateZero(st, Tbl)) {
+      do {src--;dst--;} while ((src > isrc) && ((src[0] & 0xc0) == 0x80));
+    }
+  } else if (!InStateZero(st, Tbl)) {
+    // src >= srclimit, !state0
+    // Back up over truncated UTF-8 character
+    e = kExitIllegalStructure;
+    do {src--; dst--;} while ((src > isrc) && ((src[0] & 0xc0) == 0x80));
+  } else {
+    // src >= srclimit, state0
+    // Normal termination, source fully consumed
+    e = kExitOK;
+  }
+
+  if (offsetmap != NULL) {
+    if (src > copystart) {
+      offsetmap->Copy(src - copystart);
+      copystart = src;
+    }
+  }
+
+  // Possible return values here:
+  //  kExitDstSpaceFull         caller may realloc and retry from middle
+  //  kExitIllegalStructure     caller my overwrite/truncate
+  //  kExitOK                   all done and happy
+  //  kExitReject               caller may overwrite/truncate
+  //  kExitDoAgain              LOOP NOT DONE; caller must retry from middle
+  //                            (may do fast ASCII loop first)
+  //  kExitPlaceholder          -unused-
+  //  kExitNone                 -unused-
+  *bytes_consumed = src - isrc;
+  *bytes_filled = dst - odst;
+  *chars_changed = total_changed;
+  return e;
+}
+
+// TwoByte versions are needed for tables > 240 states, such
+// as the table for full Unicode 4.1 canonical + compatibility mapping
+
+// Scan a UTF-8 stringpiece based on state table with two-byte entries,
+//   copying to output stringpiece
+//   and doing text replacements.
+// DO NOT CALL DIRECTLY. Use UTF8GenericReplace() below
+//   Needs caller to loop on kExitDoAgain
+static int UTF8GenericReplaceInternalTwoByte(const UTF8ReplaceObj_2* st,
+                    const StringPiece& istr,
+                    StringPiece& ostr,
+                    bool is_plain_text,
+                    int* bytes_consumed,
+                    int* bytes_filled,
+                    int* chars_changed,
+                    OffsetMap* offsetmap) {
+  int eshift = st->entry_shift;
+  int nEntries = (1 << eshift);       // 64 or 256 entries per state
+  const uint8* isrc = reinterpret_cast<const uint8*>(istr.data());
+  const int ilen = istr.length();
+  const uint8* copystart = isrc;
+  const uint8* src = isrc;
+  const uint8* srclimit = src + ilen;
+  *bytes_consumed = 0;
+  *bytes_filled = 0;
+  *chars_changed = 0;
+
+  const uint8* odst = reinterpret_cast<const uint8*>(ostr.data());
+  const int olen = ostr.length();
+  uint8* dst = const_cast<uint8*>(odst);
+  uint8* dstlimit = dst + olen;
+
+  *chars_changed = 0;
+
+  int total_changed = 0;
+
+  int src_lll = srclimit - src;
+  int dst_lll = dstlimit - dst;
+
+
+  // Invariant condition during replacements:
+  //  remaining dst size >= remaining src size
+  if ((dstlimit - dst) < (srclimit - src)) {
+    if (offsetmap != NULL) {
+      offsetmap->Copy(src - copystart);
+      copystart = src;
+    }
+    return kExitDstSpaceFull_2;
+  }
+  const unsigned short* Tbl_0 = &st->state_table[st->state0];
+
+ Do_state_table_2:
+  // Do state-table scan, copying as we go
+  const unsigned short* Tbl = Tbl_0;
+  int e = 0;
+  uint8 c = 0;
+
+ Do_state_table_newe_2:
+
+  //----------------------------
+  while (src < srclimit) {
+    c = *src;
+    e = Tbl[c];
+    *dst = c;
+    src++;
+    dst++;
+    if (e >= kExitIllegalStructure_2) {break;}
+    Tbl = &Tbl_0[e << eshift];
+  }
+  //----------------------------
+  src_lll = src - isrc;
+  dst_lll = dst - odst;
+
+  // Exit possibilities:
+  //  Replacement code, do the replacement and loop
+  //  Some other exit code, state0, back up one byte exactly
+  //  Some other exit code, !state0, back up over last char
+  //  source consumed, state0, exit OK
+  //  source consumed, !state0, back up over partial char
+  // For illegal byte in state0, avoid backup up over PREVIOUS char
+  // For truncated last char, back up to beginning of it
+
+  if (e >= kExitIllegalStructure_2) {
+    // Switch on exit code; most loop back to top
+    int offset = 0;
+    switch (e) {
+    // These all make the output string the same size or shorter
+    // No checking needed
+    case kExitReplace31_2:    // del 2, add 1 bytes to change
+      dst -= 2;
+      if (offsetmap != NULL) {
+        offsetmap->Copy(src - copystart - 2);
+        offsetmap->Delete(2);
+        copystart = src;
+      }
+      dst[-1] = (unsigned char)(Tbl[c + (nEntries * 1)] & 0xff);
+      total_changed++;
+      goto Do_state_table_2;
+    case kExitReplace32_2:    // del 3, add 2 bytes to change
+      dst--;
+      if (offsetmap != NULL) {
+        offsetmap->Copy(src - copystart - 1);
+        offsetmap->Delete(1);
+        copystart = src;
+      }
+      dst[-2] = (unsigned char)(Tbl[c + (nEntries * 1)] >> 8 & 0xff);
+      dst[-1] = (unsigned char)(Tbl[c + (nEntries * 1)] & 0xff);
+      total_changed++;
+      goto Do_state_table_2;
+    case kExitReplace21_2:    // del 2, add 1 bytes to change
+      dst--;
+      if (offsetmap != NULL) {
+        offsetmap->Copy(src - copystart - 1);
+        offsetmap->Delete(1);
+        copystart = src;
+      }
+      dst[-1] = (unsigned char)(Tbl[c + (nEntries * 1)] & 0xff);
+      total_changed++;
+      goto Do_state_table_2;
+    case kExitReplace3_2:    // update 3 bytes to change
+      dst[-3] = (unsigned char)(Tbl[c + (nEntries * 2)] & 0xff);
+      // Fall into next case
+    case kExitReplace2_2:    // update 2 bytes to change
+      dst[-2] = (unsigned char)(Tbl[c + (nEntries * 1)] >> 8 & 0xff);
+      // Fall into next case
+    case kExitReplace1_2:    // update 1 byte to change
+      dst[-1] = (unsigned char)(Tbl[c + (nEntries * 1)] & 0xff);
+      total_changed++;
+      goto Do_state_table_2;
+    case kExitReplace1S0_2:     // update 1 byte to change, 256-entry state
+      dst[-1] = (unsigned char)(Tbl[c + (256 * 1)] & 0xff);
+      total_changed++;
+      goto Do_state_table_2;
+    // These can make the output string longer than the input
+    case kExitReplaceOffset2_2:
+      if ((nEntries != 256) && InStateZero_2(st, Tbl)) {
+        // For space-optimized table, we need multiples of 256 bytes
+        // in state0 and multiples of nEntries in other states
+        offset += ((unsigned char)(Tbl[c + (256 * 1)] >> 8 & 0xff) << 8);
+      } else {
+        offset += ((unsigned char)(Tbl[c + (nEntries * 1)] >> 8 & 0xff) << 8);
+      }
+      // Fall into next case
+    case kExitReplaceOffset1_2:
+      if ((nEntries != 256) && InStateZero_2(st, Tbl)) {
+        // For space-optimized table, we need multiples of 256 bytes
+        // in state0 and multiples of nEntries in other states
+        offset += (unsigned char)(Tbl[c + (256 * 1)] & 0xff);
+      } else {
+        offset += (unsigned char)(Tbl[c + (nEntries * 1)] & 0xff);
+      }
+      {
+        const RemapEntry* re = &st->remap_base[offset];
+        int del_len = re->delete_bytes & ~kReplaceAndResumeFlag;
+        int add_len = re->add_bytes & ~kHtmlPlaintextFlag;
+        // Special-case non-HTML replacement of five sensitive entities
+        //   &quot; &amp; &apos; &lt; &gt;
+        //   0022   0026  0027   003c 003e
+        // A replacement creating one of these is expressed as a pair of
+        // entries, one for HTML output and one for plaintext output.
+        // The first of the pair has the high bit of add_bytes set.
+        if (re->add_bytes & kHtmlPlaintextFlag) {
+          // Use this entry for plain text
+          if (!is_plain_text) {
+            // Use very next entry for HTML text (same back/delete length)
+            re = &st->remap_base[offset + 1];
+            add_len = re->add_bytes & ~kHtmlPlaintextFlag;
+          }
+        }
+
+        // After the replacement, need (dstlimit - dst) >= (srclimit - src)
+        int string_offset = re->bytes_offset;
+        // After the replacement, need (dstlimit - newdst) >= (srclimit - src)
+        uint8* newdst = dst - del_len + add_len;
+        if ((dstlimit - newdst) < (srclimit - src)) {
+          // Won't fit; don't do the replacement. Caller may realloc and retry
+          e = kExitDstSpaceFull_2;
+          break;    // exit, backing up over this char for later retry
+        }
+        dst -= del_len;
+        memcpy(dst, &st->remap_string[string_offset], add_len);
+        dst += add_len;
+        if (offsetmap != NULL) {
+          if (add_len > del_len) {
+            offsetmap->Copy(src - copystart);
+            offsetmap->Insert(add_len - del_len);
+            copystart = src;
+          } else if (add_len < del_len) {
+            offsetmap->Copy(src - copystart + add_len - del_len);
+            offsetmap->Delete(del_len - add_len);
+            copystart = src;
+          }
+        }
+        if (re->delete_bytes & kReplaceAndResumeFlag) {
+          // There is a two-byte non-zero target state at the end of the
+          // replacement string
+          uint8 c1 = st->remap_string[string_offset + add_len];
+          uint8 c2 = st->remap_string[string_offset + add_len + 1];
+          e = (c1 << 8) | c2;
+          Tbl = &Tbl_0[e << eshift];
+          total_changed++;
+          goto Do_state_table_newe_2;
+        }
+      }
+      total_changed++;
+      if (e == kExitRejectAlt_2) {break;}
+      goto Do_state_table_2;
+
+    case kExitSpecial_2:           // NO special fixups [read: hacks]
+    case kExitIllegalStructure_2:  // structurally illegal byte; quit
+    case kExitReject_2:            // NUL or illegal code encountered; quit
+                                   // and all other exits
+    default:
+      break;
+    }   // End switch (e)
+
+    // Exit possibilities:
+    //  Some other exit code, state0, back up one byte exactly
+    //  Some other exit code, !state0, back up over last char
+
+    // Back up over exactly one byte of rejected/illegal UTF-8 character
+    src--;
+    dst--;
+    // Back up more if needed
+    if (!InStateZero_2(st, Tbl)) {
+      do {src--;dst--;} while ((src > isrc) && ((src[0] & 0xc0) == 0x80));
+    }
+  } else if (!InStateZero_2(st, Tbl)) {
+    // src >= srclimit, !state0
+    // Back up over truncated UTF-8 character
+    e = kExitIllegalStructure_2;
+
+    do {src--; dst--;} while ((src > isrc) && ((src[0] & 0xc0) == 0x80));
+  } else {
+    // src >= srclimit, state0
+    // Normal termination, source fully consumed
+    e = kExitOK_2;
+  }
+
+  if (offsetmap != NULL) {
+    if (src > copystart) {
+      offsetmap->Copy(src - copystart);
+      copystart = src;
+    }
+  }
+
+
+  // Possible return values here:
+  //  kExitDstSpaceFull_2         caller may realloc and retry from middle
+  //  kExitIllegalStructure_2     caller my overwrite/truncate
+  //  kExitOK_2                   all done and happy
+  //  kExitReject_2               caller may overwrite/truncate
+  //  kExitDoAgain_2              LOOP NOT DONE; caller must retry from middle
+  //                            (may do fast ASCII loop first)
+  //  kExitPlaceholder_2          -unused-
+  //  kExitNone_2                 -unused-
+  *bytes_consumed = src - isrc;
+  *bytes_filled = dst - odst;
+  *chars_changed = total_changed;
+  return e;
+}
+
+
+// Scan a UTF-8 stringpiece based on state table, copying to output stringpiece
+//   and doing text replacements.
+// Also writes an optional OffsetMap. Pass NULL to skip writing one.
+// Always scan complete UTF-8 characters
+// Set number of bytes consumed from input, number filled to output.
+// Return reason for exiting
+int UTF8GenericReplace(const UTF8ReplaceObj* st,
+                    const StringPiece& istr,
+                    StringPiece& ostr,
+                    bool is_plain_text,
+                    int* bytes_consumed,
+                    int* bytes_filled,
+                    int* chars_changed,
+                    OffsetMap* offsetmap) {
+  StringPiece local_istr(istr.data(), istr.length());
+  StringPiece local_ostr(ostr.data(), ostr.length());
+  int total_consumed = 0;
+  int total_filled = 0;
+  int total_changed = 0;
+  int local_bytes_consumed, local_bytes_filled, local_chars_changed;
+  int e;
+  do {
+    e = UTF8GenericReplaceInternal(st,
+                    local_istr, local_ostr, is_plain_text,
+                    &local_bytes_consumed, &local_bytes_filled,
+                    &local_chars_changed,
+                    offsetmap);
+    local_istr.remove_prefix(local_bytes_consumed);
+    local_ostr.remove_prefix(local_bytes_filled);
+    total_consumed += local_bytes_consumed;
+    total_filled += local_bytes_filled;
+    total_changed += local_chars_changed;
+  } while ( e == kExitDoAgain );
+  *bytes_consumed = total_consumed;
+  *bytes_filled = total_filled;
+  *chars_changed = total_changed;
+  return e;
+}
+
+// Older version without offsetmap
+int UTF8GenericReplace(const UTF8ReplaceObj* st,
+                    const StringPiece& istr,
+                    StringPiece& ostr,
+                    bool is_plain_text,
+                    int* bytes_consumed,
+                    int* bytes_filled,
+                    int* chars_changed) {
+  return UTF8GenericReplace(st,
+                    istr,
+                    ostr,
+                    is_plain_text,
+                    bytes_consumed,
+                    bytes_filled,
+                    chars_changed,
+                    NULL);
+}
+
+// Older version without is_plain_text or offsetmap
+int UTF8GenericReplace(const UTF8ReplaceObj* st,
+                    const StringPiece& istr,
+                    StringPiece& ostr,
+                    int* bytes_consumed,
+                    int* bytes_filled,
+                    int* chars_changed) {
+  bool is_plain_text = false;
+  return UTF8GenericReplace(st,
+                    istr,
+                    ostr,
+                    is_plain_text,
+                    bytes_consumed,
+                    bytes_filled,
+                    chars_changed,
+                    NULL);
+}
+
+// Scan a UTF-8 stringpiece based on state table with two-byte entries,
+//   copying to output stringpiece
+//   and doing text replacements.
+// Also writes an optional OffsetMap. Pass NULL to skip writing one.
+// Always scan complete UTF-8 characters
+// Set number of bytes consumed from input, number filled to output.
+// Return reason for exiting
+int UTF8GenericReplaceTwoByte(const UTF8ReplaceObj_2* st,
+                    const StringPiece& istr,
+                    StringPiece& ostr,
+                    bool is_plain_text,
+                    int* bytes_consumed,
+                    int* bytes_filled,
+                    int* chars_changed,
+                    OffsetMap* offsetmap) {
+  StringPiece local_istr(istr.data(), istr.length());
+  StringPiece local_ostr(ostr.data(), ostr.length());
+  int total_consumed = 0;
+  int total_filled = 0;
+  int total_changed = 0;
+  int local_bytes_consumed, local_bytes_filled, local_chars_changed;
+  int e;
+  do {
+    e = UTF8GenericReplaceInternalTwoByte(st,
+                    local_istr, local_ostr, is_plain_text,
+                    &local_bytes_consumed,
+                    &local_bytes_filled,
+                    &local_chars_changed,
+                    offsetmap);
+    local_istr.remove_prefix(local_bytes_consumed);
+    local_ostr.remove_prefix(local_bytes_filled);
+    total_consumed += local_bytes_consumed;
+    total_filled += local_bytes_filled;
+    total_changed += local_chars_changed;
+  } while ( e == kExitDoAgain_2 );
+  *bytes_consumed = total_consumed;
+  *bytes_filled = total_filled;
+  *chars_changed = total_changed;
+
+  return e - kExitOK_2 + kExitOK;
+}
+
+// Older version without offsetmap
+int UTF8GenericReplaceTwoByte(const UTF8ReplaceObj_2* st,
+                    const StringPiece& istr,
+                    StringPiece& ostr,
+                    bool is_plain_text,
+                    int* bytes_consumed,
+                    int* bytes_filled,
+                    int* chars_changed) {
+  return UTF8GenericReplaceTwoByte(st,
+                    istr,
+                    ostr,
+                    is_plain_text,
+                    bytes_consumed,
+                    bytes_filled,
+                    chars_changed,
+                    NULL);
+}
+
+// Older version without is_plain_text or offsetmap
+int UTF8GenericReplaceTwoByte(const UTF8ReplaceObj_2* st,
+                    const StringPiece& istr,
+                    StringPiece& ostr,
+                    int* bytes_consumed,
+                    int* bytes_filled,
+                    int* chars_changed) {
+  bool is_plain_text = false;
+  return UTF8GenericReplaceTwoByte(st,
+                    istr,
+                    ostr,
+                    is_plain_text,
+                    bytes_consumed,
+                    bytes_filled,
+                    chars_changed,
+                    NULL);
+}
+
+
+
+// Adjust a stringpiece to encompass complete UTF-8 characters.
+// The data pointer will be increased by 0..3 bytes to get to a character
+// boundary, and the length will then be decreased by 0..3 bytes
+// to encompass the last complete character.
+void UTF8TrimToChars(StringPiece* istr) {
+  const char* src = istr->data();
+  int len = istr->length();
+  // Exit if empty string
+  if (len == 0) {
+    return;
+  }
+
+  // Exit on simple, common case
+  if ( ((src[0] & 0xc0) != 0x80) &&
+       (static_cast<signed char>(src[len - 1]) >= 0) ) {
+    // First byte is not a continuation and last byte is 7-bit ASCII -- done
+    return;
+  }
+
+  // Adjust the back end, len > 0
+  const char* srclimit = src + len;
+  // Backscan over any ending continuation bytes to find last char start
+  const char* s = srclimit - 1;         // Last byte of the string
+  while ((src <= s) && ((*s & 0xc0) == 0x80)) {
+    s--;
+  }
+  // Include entire last char if it fits
+  if (src <= s) {
+    int last_char_len = UTF8OneCharLen(s);
+    if (s + last_char_len <= srclimit) {
+      // Last char fits, so include it, else exclude it
+      s += last_char_len;
+    }
+  }
+  if (s != srclimit) {
+    // s is one byte beyond the last full character, if any
+    istr->remove_suffix(srclimit - s);
+    // Exit if now empty string
+    if (istr->length() == 0) {
+      return;
+    }
+  }
+
+  // Adjust the front end, len > 0
+  len = istr->length();
+  srclimit = src + len;
+  s = src;                            // First byte of the string
+  // Scan over any beginning continuation bytes to find first char start
+  while ((s < srclimit) && ((*s & 0xc0) == 0x80)) {
+    s++;
+  }
+  if (s != src) {
+    // s is at the first full character, if any
+    istr->remove_prefix(s - src);
+  }
+}
+
+}       // End namespace CLD2