1 // Copyright 2017 The Abseil Authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 #include "absl/strings/substitute.h"
16
17 #include <algorithm>
18 #include <cassert>
19 #include <cstddef>
20 #include <cstdint>
21 #include <limits>
22 #include <string>
23
24 #include "absl/base/config.h"
25 #include "absl/base/internal/raw_logging.h"
26 #include "absl/base/nullability.h"
27 #include "absl/strings/ascii.h"
28 #include "absl/strings/escaping.h"
29 #include "absl/strings/internal/resize_uninitialized.h"
30 #include "absl/strings/numbers.h"
31 #include "absl/strings/str_cat.h"
32 #include "absl/strings/string_view.h"
33
34 namespace absl {
35 ABSL_NAMESPACE_BEGIN
36 namespace substitute_internal {
37
SubstituteAndAppendArray(absl::Nonnull<std::string * > output,absl::string_view format,absl::Nullable<const absl::string_view * > args_array,size_t num_args)38 void SubstituteAndAppendArray(
39 absl::Nonnull<std::string*> output, absl::string_view format,
40 absl::Nullable<const absl::string_view*> args_array, size_t num_args) {
41 // Determine total size needed.
42 size_t size = 0;
43 for (size_t i = 0; i < format.size(); i++) {
44 if (format[i] == '$') {
45 if (i + 1 >= format.size()) {
46 #ifndef NDEBUG
47 ABSL_RAW_LOG(FATAL,
48 "Invalid absl::Substitute() format string: \"%s\".",
49 absl::CEscape(format).c_str());
50 #endif
51 return;
52 } else if (absl::ascii_isdigit(
53 static_cast<unsigned char>(format[i + 1]))) {
54 int index = format[i + 1] - '0';
55 if (static_cast<size_t>(index) >= num_args) {
56 #ifndef NDEBUG
57 ABSL_RAW_LOG(
58 FATAL,
59 "Invalid absl::Substitute() format string: asked for \"$"
60 "%d\", but only %d args were given. Full format string was: "
61 "\"%s\".",
62 index, static_cast<int>(num_args), absl::CEscape(format).c_str());
63 #endif
64 return;
65 }
66 size += args_array[index].size();
67 ++i; // Skip next char.
68 } else if (format[i + 1] == '$') {
69 ++size;
70 ++i; // Skip next char.
71 } else {
72 #ifndef NDEBUG
73 ABSL_RAW_LOG(FATAL,
74 "Invalid absl::Substitute() format string: \"%s\".",
75 absl::CEscape(format).c_str());
76 #endif
77 return;
78 }
79 } else {
80 ++size;
81 }
82 }
83
84 if (size == 0) return;
85
86 // Build the string.
87 size_t original_size = output->size();
88 ABSL_INTERNAL_CHECK(
89 size <= std::numeric_limits<size_t>::max() - original_size,
90 "size_t overflow");
91 strings_internal::STLStringResizeUninitializedAmortized(output,
92 original_size + size);
93 char* target = &(*output)[original_size];
94 for (size_t i = 0; i < format.size(); i++) {
95 if (format[i] == '$') {
96 if (absl::ascii_isdigit(static_cast<unsigned char>(format[i + 1]))) {
97 const absl::string_view src = args_array[format[i + 1] - '0'];
98 target = std::copy(src.begin(), src.end(), target);
99 ++i; // Skip next char.
100 } else if (format[i + 1] == '$') {
101 *target++ = '$';
102 ++i; // Skip next char.
103 }
104 } else {
105 *target++ = format[i];
106 }
107 }
108
109 assert(target == output->data() + output->size());
110 }
111
Arg(absl::Nullable<const void * > value)112 Arg::Arg(absl::Nullable<const void*> value) {
113 static_assert(sizeof(scratch_) >= sizeof(value) * 2 + 2,
114 "fix sizeof(scratch_)");
115 if (value == nullptr) {
116 piece_ = "NULL";
117 } else {
118 char* ptr = scratch_ + sizeof(scratch_);
119 uintptr_t num = reinterpret_cast<uintptr_t>(value);
120 do {
121 *--ptr = absl::numbers_internal::kHexChar[num & 0xf];
122 num >>= 4;
123 } while (num != 0);
124 *--ptr = 'x';
125 *--ptr = '0';
126 piece_ = absl::string_view(
127 ptr, static_cast<size_t>(scratch_ + sizeof(scratch_) - ptr));
128 }
129 }
130
131 // TODO(jorg): Don't duplicate so much code between here and str_cat.cc
Arg(Hex hex)132 Arg::Arg(Hex hex) {
133 char* const end = &scratch_[numbers_internal::kFastToBufferSize];
134 char* writer = end;
135 uint64_t value = hex.value;
136 do {
137 *--writer = absl::numbers_internal::kHexChar[value & 0xF];
138 value >>= 4;
139 } while (value != 0);
140
141 char* beg;
142 if (end - writer < hex.width) {
143 beg = end - hex.width;
144 std::fill_n(beg, writer - beg, hex.fill);
145 } else {
146 beg = writer;
147 }
148
149 piece_ = absl::string_view(beg, static_cast<size_t>(end - beg));
150 }
151
152 // TODO(jorg): Don't duplicate so much code between here and str_cat.cc
Arg(Dec dec)153 Arg::Arg(Dec dec) {
154 assert(dec.width <= numbers_internal::kFastToBufferSize);
155 char* const end = &scratch_[numbers_internal::kFastToBufferSize];
156 char* const minfill = end - dec.width;
157 char* writer = end;
158 uint64_t value = dec.value;
159 bool neg = dec.neg;
160 while (value > 9) {
161 *--writer = '0' + (value % 10);
162 value /= 10;
163 }
164 *--writer = '0' + static_cast<char>(value);
165 if (neg) *--writer = '-';
166
167 ptrdiff_t fillers = writer - minfill;
168 if (fillers > 0) {
169 // Tricky: if the fill character is ' ', then it's <fill><+/-><digits>
170 // But...: if the fill character is '0', then it's <+/-><fill><digits>
171 bool add_sign_again = false;
172 if (neg && dec.fill == '0') { // If filling with '0',
173 ++writer; // ignore the sign we just added
174 add_sign_again = true; // and re-add the sign later.
175 }
176 writer -= fillers;
177 std::fill_n(writer, fillers, dec.fill);
178 if (add_sign_again) *--writer = '-';
179 }
180
181 piece_ = absl::string_view(writer, static_cast<size_t>(end - writer));
182 }
183
184 } // namespace substitute_internal
185 ABSL_NAMESPACE_END
186 } // namespace absl
187