The Tor Browser: browser/components/translation/cld2/internal/utf8statetable.cc@6474c204b198 (annotated)

browser/components/translation/cld2/internal/utf8statetable.cc@6474c204b198 (annotated)

browser/components/translation/cld2/internal/utf8statetable.cc

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 // 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

The Tor Browser / annotate

browser/components/translation/cld2/internal/utf8statetable.cc@6474c204b198 (annotated)

browser/components/translation/cld2/internal/utf8statetable.cc