Initial Commit

absl/strings/strip.cc

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+// Copyright 2017 The Abseil Authors.
+//
+// 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.
+
+// This file contains functions that remove a defined part from the std::string,
+// i.e., strip the std::string.
+
+#include "absl/strings/strip.h"
+
+#include <algorithm>
+#include <cassert>
+#include <cstring>
+#include <string>
+
+#include "absl/strings/ascii.h"
+#include "absl/strings/string_view.h"
+
+// ----------------------------------------------------------------------
+// ReplaceCharacters
+//    Replaces any occurrence of the character 'remove' (or the characters
+//    in 'remove') with the character 'replace_with'.
+// ----------------------------------------------------------------------
+void ReplaceCharacters(char* str, size_t len, absl::string_view remove,
+                       char replace_with) {
+  for (char* end = str + len; str != end; ++str) {
+    if (remove.find(*str) != absl::string_view::npos) {
+      *str = replace_with;
+    }
+  }
+}
+
+void ReplaceCharacters(std::string* s, absl::string_view remove, char replace_with) {
+  for (char& ch : *s) {
+    if (remove.find(ch) != absl::string_view::npos) {
+      ch = replace_with;
+    }
+  }
+}
+
+bool StripTrailingNewline(std::string* s) {
+  if (!s->empty() && (*s)[s->size() - 1] == '\n') {
+    if (s->size() > 1 && (*s)[s->size() - 2] == '\r')
+      s->resize(s->size() - 2);
+    else
+      s->resize(s->size() - 1);
+    return true;
+  }
+  return false;
+}
+
+// ----------------------------------------------------------------------
+// Misc. stripping routines
+// ----------------------------------------------------------------------
+void StripCurlyBraces(std::string* s) {
+  return StripBrackets('{', '}', s);
+}
+
+void StripBrackets(char left, char right, std::string* s) {
+  std::string::iterator opencurly = std::find(s->begin(), s->end(), left);
+  while (opencurly != s->end()) {
+    std::string::iterator closecurly = std::find(opencurly, s->end(), right);
+    if (closecurly == s->end()) return;
+    opencurly = s->erase(opencurly, closecurly + 1);
+    opencurly = std::find(opencurly, s->end(), left);
+  }
+}
+
+void StripMarkupTags(std::string* s) {
+  std::string::iterator output = std::find(s->begin(), s->end(), '<');
+  std::string::iterator input = output;
+  while (input != s->end()) {
+    if (*input == '<') {
+      input = std::find(input, s->end(), '>');
+      if (input == s->end()) break;
+      ++input;
+    } else {
+      *output++ = *input++;
+    }
+  }
+  s->resize(output - s->begin());
+}
+
+std::string OutputWithMarkupTagsStripped(const std::string& s) {
+  std::string result(s);
+  StripMarkupTags(&result);
+  return result;
+}
+
+ptrdiff_t TrimStringLeft(std::string* s, absl::string_view remove) {
+  size_t i = 0;
+  while (i < s->size() && memchr(remove.data(), (*s)[i], remove.size())) {
+    ++i;
+  }
+  if (i > 0) s->erase(0, i);
+  return i;
+}
+
+ptrdiff_t TrimStringRight(std::string* s, absl::string_view remove) {
+  size_t i = s->size(), trimmed = 0;
+  while (i > 0 && memchr(remove.data(), (*s)[i - 1], remove.size())) {
+    --i;
+  }
+  if (i < s->size()) {
+    trimmed = s->size() - i;
+    s->erase(i);
+  }
+  return trimmed;
+}
+
+// Unfortunately, absl::string_view does not have erase, so we've to replicate
+// the implementation with remove_prefix()/remove_suffix()
+ptrdiff_t TrimStringLeft(absl::string_view* s, absl::string_view remove) {
+  size_t i = 0;
+  while (i < s->size() && memchr(remove.data(), (*s)[i], remove.size())) {
+    ++i;
+  }
+  if (i > 0) s->remove_prefix(i);
+  return i;
+}
+
+ptrdiff_t TrimStringRight(absl::string_view* s, absl::string_view remove) {
+  size_t i = s->size(), trimmed = 0;
+  while (i > 0 && memchr(remove.data(), (*s)[i - 1], remove.size())) {
+    --i;
+  }
+  if (i < s->size()) {
+    trimmed = s->size() - i;
+    s->remove_suffix(trimmed);
+  }
+  return trimmed;
+}
+
+// ----------------------------------------------------------------------
+// Various removal routines
+// ----------------------------------------------------------------------
+ptrdiff_t strrm(char* str, char c) {
+  char* src;
+  char* dest;
+  for (src = dest = str; *src != '\0'; ++src)
+    if (*src != c) *(dest++) = *src;
+  *dest = '\0';
+  return dest - str;
+}
+
+ptrdiff_t memrm(char* str, ptrdiff_t strlen, char c) {
+  char* src;
+  char* dest;
+  for (src = dest = str; strlen-- > 0; ++src)
+    if (*src != c) *(dest++) = *src;
+  return dest - str;
+}
+
+ptrdiff_t strrmm(char* str, const char* chars) {
+  char* src;
+  char* dest;
+  for (src = dest = str; *src != '\0'; ++src) {
+    bool skip = false;
+    for (const char* c = chars; *c != '\0'; c++) {
+      if (*src == *c) {
+        skip = true;
+        break;
+      }
+    }
+    if (!skip) *(dest++) = *src;
+  }
+  *dest = '\0';
+  return dest - str;
+}
+
+ptrdiff_t strrmm(std::string* str, const std::string& chars) {
+  size_t str_len = str->length();
+  size_t in_index = str->find_first_of(chars);
+  if (in_index == std::string::npos) return str_len;
+
+  size_t out_index = in_index++;
+
+  while (in_index < str_len) {
+    char c = (*str)[in_index++];
+    if (chars.find(c) == std::string::npos) (*str)[out_index++] = c;
+  }
+
+  str->resize(out_index);
+  return out_index;
+}
+
+// ----------------------------------------------------------------------
+// StripDupCharacters
+//    Replaces any repeated occurrence of the character 'dup_char'
+//    with single occurrence.  e.g.,
+//       StripDupCharacters("a//b/c//d", '/', 0) => "a/b/c/d"
+//    Return the number of characters removed
+// ----------------------------------------------------------------------
+ptrdiff_t StripDupCharacters(std::string* s, char dup_char, ptrdiff_t start_pos) {
+  if (start_pos < 0) start_pos = 0;
+
+  // remove dups by compaction in-place
+  ptrdiff_t input_pos = start_pos;   // current reader position
+  ptrdiff_t output_pos = start_pos;  // current writer position
+  const ptrdiff_t input_end = s->size();
+  while (input_pos < input_end) {
+    // keep current character
+    const char curr_char = (*s)[input_pos];
+    if (output_pos != input_pos)  // must copy
+      (*s)[output_pos] = curr_char;
+    ++input_pos;
+    ++output_pos;
+
+    if (curr_char == dup_char) {  // skip subsequent dups
+      while ((input_pos < input_end) && ((*s)[input_pos] == dup_char))
+        ++input_pos;
+    }
+  }
+  const ptrdiff_t num_deleted = input_pos - output_pos;
+  s->resize(s->size() - num_deleted);
+  return num_deleted;
+}
+
+// ----------------------------------------------------------------------
+// TrimRunsInString
+//    Removes leading and trailing runs, and collapses middle
+//    runs of a set of characters into a single character (the
+//    first one specified in 'remove').  Useful for collapsing
+//    runs of repeated delimiters, whitespace, etc.  E.g.,
+//    TrimRunsInString(&s, " :,()") removes leading and trailing
+//    delimiter chars and collapses and converts internal runs
+//    of delimiters to single ' ' characters, so, for example,
+//    "  a:(b):c  " -> "a b c"
+//    "first,last::(area)phone, ::zip" -> "first last area phone zip"
+// ----------------------------------------------------------------------
+void TrimRunsInString(std::string* s, absl::string_view remove) {
+  std::string::iterator dest = s->begin();
+  std::string::iterator src_end = s->end();
+  for (std::string::iterator src = s->begin(); src != src_end;) {
+    if (remove.find(*src) == absl::string_view::npos) {
+      *(dest++) = *(src++);
+    } else {
+      // Skip to the end of this run of chars that are in 'remove'.
+      for (++src; src != src_end; ++src) {
+        if (remove.find(*src) == absl::string_view::npos) {
+          if (dest != s->begin()) {
+            // This is an internal run; collapse it.
+            *(dest++) = remove[0];
+          }
+          *(dest++) = *(src++);
+          break;
+        }
+      }
+    }
+  }
+  s->erase(dest, src_end);
+}
+
+// ----------------------------------------------------------------------
+// RemoveNullsInString
+//    Removes any internal \0 characters from the std::string.
+// ----------------------------------------------------------------------
+void RemoveNullsInString(std::string* s) {
+  s->erase(std::remove(s->begin(), s->end(), '\0'), s->end());
+}