1//
2// Copyright 2017 The Abseil Authors.
3//
4// Licensed under the Apache License, Version 2.0 (the "License");
5// you may not use this file except in compliance with the License.
6// You may obtain a copy of the License at
7//
8// https://www.apache.org/licenses/LICENSE-2.0
9//
10// Unless required by applicable law or agreed to in writing, software
11// distributed under the License is distributed on an "AS IS" BASIS,
12// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13// See the License for the specific language governing permissions and
14// limitations under the License.
15//
16// -----------------------------------------------------------------------------
17// File: strip.h
18// -----------------------------------------------------------------------------
19//
20// This file contains various functions for stripping substrings from a string.
21#ifndef ABSL_STRINGS_STRIP_H_
22#define ABSL_STRINGS_STRIP_H_
23
24#include <cstddef>
25#include <string>
26
27#include "absl/base/macros.h"
28#include "absl/strings/ascii.h"
29#include "absl/strings/match.h"
30#include "absl/strings/string_view.h"
31
32namespace absl {
33
34// ConsumePrefix()
35//
36// Strips the `expected` prefix from the start of the given string, returning
37// `true` if the strip operation succeeded or false otherwise.
38//
39// Example:
40//
41// absl::string_view input("abc");
42// EXPECT_TRUE(absl::ConsumePrefix(&input, "a"));
43// EXPECT_EQ(input, "bc");
44inline bool ConsumePrefix(absl::string_view* str, absl::string_view expected) {
45 if (!absl::StartsWith(*str, expected)) return false;
46 str->remove_prefix(expected.size());
47 return true;
48}
49// ConsumeSuffix()
50//
51// Strips the `expected` suffix from the end of the given string, returning
52// `true` if the strip operation succeeded or false otherwise.
53//
54// Example:
55//
56// absl::string_view input("abcdef");
57// EXPECT_TRUE(absl::ConsumeSuffix(&input, "def"));
58// EXPECT_EQ(input, "abc");
59inline bool ConsumeSuffix(absl::string_view* str, absl::string_view expected) {
60 if (!absl::EndsWith(*str, expected)) return false;
61 str->remove_suffix(expected.size());
62 return true;
63}
64
65// StripPrefix()
66//
67// Returns a view into the input string 'str' with the given 'prefix' removed,
68// but leaving the original string intact. If the prefix does not match at the
69// start of the string, returns the original string instead.
70ABSL_MUST_USE_RESULT inline absl::string_view StripPrefix(
71 absl::string_view str, absl::string_view prefix) {
72 if (absl::StartsWith(str, prefix)) str.remove_prefix(prefix.size());
73 return str;
74}
75
76// StripSuffix()
77//
78// Returns a view into the input string 'str' with the given 'suffix' removed,
79// but leaving the original string intact. If the suffix does not match at the
80// end of the string, returns the original string instead.
81ABSL_MUST_USE_RESULT inline absl::string_view StripSuffix(
82 absl::string_view str, absl::string_view suffix) {
83 if (absl::EndsWith(str, suffix)) str.remove_suffix(suffix.size());
84 return str;
85}
86
87} // namespace absl
88
89#endif // ABSL_STRINGS_STRIP_H_
90