Replace RE2 import with a dependency

third_party/re2/util/strutil.cc

-// Copyright 1999-2005 The RE2 Authors.  All Rights Reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-#include "util/util.h"
-#include "re2/stringpiece.h"
-
-namespace re2 {
-
-// ----------------------------------------------------------------------
-// CEscapeString()
-//    Copies 'src' to 'dest', escaping dangerous characters using
-//    C-style escape sequences.  'src' and 'dest' should not overlap.
-//    Returns the number of bytes written to 'dest' (not including the \0)
-//    or -1 if there was insufficient space.
-// ----------------------------------------------------------------------
-int CEscapeString(const char* src, int src_len, char* dest,
-                  int dest_len) {
-  const char* src_end = src + src_len;
-  int used = 0;
-
-  for (; src < src_end; src++) {
-    if (dest_len - used < 2)   // space for two-character escape
-      return -1;
-
-    unsigned char c = *src;
-    switch (c) {
-      case '\n': dest[used++] = '\\'; dest[used++] = 'n';  break;
-      case '\r': dest[used++] = '\\'; dest[used++] = 'r';  break;
-      case '\t': dest[used++] = '\\'; dest[used++] = 't';  break;
-      case '\"': dest[used++] = '\\'; dest[used++] = '\"'; break;
-      case '\'': dest[used++] = '\\'; dest[used++] = '\''; break;
-      case '\\': dest[used++] = '\\'; dest[used++] = '\\'; break;
-      default:
-        // Note that if we emit \xNN and the src character after that is a hex
-        // digit then that digit must be escaped too to prevent it being
-        // interpreted as part of the character code by C.
-        if (c < ' ' || c > '~') {
-          if (dest_len - used < 5)   // space for four-character escape + \0
-            return -1;
-#if !defined(_WIN32)
-          snprintf(dest + used, 5, "\\%03o", c);
-#else
-          // On Windows, the function takes 4+VA arguments, not 3+VA. With an
-          // array, the buffer size will be inferred, but not with a pointer.
-          snprintf(dest + used, 5, _TRUNCATE, "\\%03o", c);
-#endif
-          used += 4;
-        } else {
-          dest[used++] = c; break;
-        }
-    }
-  }
-
-  if (dest_len - used < 1)   // make sure that there is room for \0
-    return -1;
-
-  dest[used] = '\0';   // doesn't count towards return value though
-  return used;
-}
-
-
-// ----------------------------------------------------------------------
-// CEscape()
-//    Copies 'src' to result, escaping dangerous characters using
-//    C-style escape sequences.  'src' and 'dest' should not overlap.
-// ----------------------------------------------------------------------
-string CEscape(const StringPiece& src) {
-  const int dest_length = src.size() * 4 + 1; // Maximum possible expansion
-  char* dest = new char[dest_length];
-  const int len = CEscapeString(src.data(), src.size(),
-                                dest, dest_length);
-  string s = string(dest, len);
-  delete[] dest;
-  return s;
-}
-
-string PrefixSuccessor(const StringPiece& prefix) {
-  // We can increment the last character in the string and be done
-  // unless that character is 255, in which case we have to erase the
-  // last character and increment the previous character, unless that
-  // is 255, etc. If the string is empty or consists entirely of
-  // 255's, we just return the empty string.
-  bool done = false;
-  string limit(prefix.data(), prefix.size());
-  int index = static_cast<int>(limit.size()) - 1;
-  while (!done && index >= 0) {
-    if ((limit[index]&255) == 255) {
-      limit.erase(index);
-      index--;
-    } else {
-      limit[index]++;
-      done = true;
-    }
-  }
-  if (!done) {
-    return "";
-  } else {
-    return limit;
-  }
-}
-
-}  // namespace re2