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-rw-r--r--absl/strings/BUILD.bazel2
-rw-r--r--absl/strings/CMakeLists.txt2
-rw-r--r--absl/strings/escaping.cc188
-rw-r--r--absl/strings/internal/escaping.cc180
-rw-r--r--absl/strings/internal/escaping.h58
-rw-r--r--absl/strings/string_view.h4
-rw-r--r--absl/strings/string_view_test.cc25
7 files changed, 282 insertions, 177 deletions
diff --git a/absl/strings/BUILD.bazel b/absl/strings/BUILD.bazel
index 8d0a6b6..dc7e1bf 100644
--- a/absl/strings/BUILD.bazel
+++ b/absl/strings/BUILD.bazel
@@ -37,6 +37,7 @@ cc_library(
"internal/charconv_bigint.h",
"internal/charconv_parse.cc",
"internal/charconv_parse.h",
+ "internal/escaping.cc",
"internal/memutil.cc",
"internal/memutil.h",
"internal/stl_type_traits.h",
@@ -54,6 +55,7 @@ cc_library(
"ascii.h",
"charconv.h",
"escaping.h",
+ "internal/escaping.h",
"match.h",
"numbers.h",
"str_cat.h",
diff --git a/absl/strings/CMakeLists.txt b/absl/strings/CMakeLists.txt
index 9810157..36702f7 100644
--- a/absl/strings/CMakeLists.txt
+++ b/absl/strings/CMakeLists.txt
@@ -38,6 +38,8 @@ absl_cc_library(
"internal/charconv_bigint.h"
"internal/charconv_parse.cc"
"internal/charconv_parse.h"
+ "internal/escaping.cc"
+ "internal/escaping.h"
"internal/memutil.cc"
"internal/memutil.h"
"internal/stl_type_traits.h"
diff --git a/absl/strings/escaping.cc b/absl/strings/escaping.cc
index d2fcd9c..7adc1b6 100644
--- a/absl/strings/escaping.cc
+++ b/absl/strings/escaping.cc
@@ -26,6 +26,7 @@
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/unaligned_access.h"
#include "absl/strings/internal/char_map.h"
+#include "absl/strings/internal/escaping.h"
#include "absl/strings/internal/resize_uninitialized.h"
#include "absl/strings/internal/utf8.h"
#include "absl/strings/str_cat.h"
@@ -764,177 +765,10 @@ constexpr signed char kUnWebSafeBase64[] = {
};
/* clang-format on */
-size_t CalculateBase64EscapedLenInternal(size_t input_len, bool do_padding) {
- // Base64 encodes three bytes of input at a time. If the input is not
- // divisible by three, we pad as appropriate.
- //
- // (from https://tools.ietf.org/html/rfc3548)
- // Special processing is performed if fewer than 24 bits are available
- // at the end of the data being encoded. A full encoding quantum is
- // always completed at the end of a quantity. When fewer than 24 input
- // bits are available in an input group, zero bits are added (on the
- // right) to form an integral number of 6-bit groups. Padding at the
- // end of the data is performed using the '=' character. Since all base
- // 64 input is an integral number of octets, only the following cases
- // can arise:
-
- // Base64 encodes each three bytes of input into four bytes of output.
- size_t len = (input_len / 3) * 4;
-
- if (input_len % 3 == 0) {
- // (from https://tools.ietf.org/html/rfc3548)
- // (1) the final quantum of encoding input is an integral multiple of 24
- // bits; here, the final unit of encoded output will be an integral
- // multiple of 4 characters with no "=" padding,
- } else if (input_len % 3 == 1) {
- // (from https://tools.ietf.org/html/rfc3548)
- // (2) the final quantum of encoding input is exactly 8 bits; here, the
- // final unit of encoded output will be two characters followed by two
- // "=" padding characters, or
- len += 2;
- if (do_padding) {
- len += 2;
- }
- } else { // (input_len % 3 == 2)
- // (from https://tools.ietf.org/html/rfc3548)
- // (3) the final quantum of encoding input is exactly 16 bits; here, the
- // final unit of encoded output will be three characters followed by one
- // "=" padding character.
- len += 3;
- if (do_padding) {
- len += 1;
- }
- }
-
- assert(len >= input_len); // make sure we didn't overflow
- return len;
-}
-
-size_t Base64EscapeInternal(const unsigned char* src, size_t szsrc, char* dest,
- size_t szdest, const char* base64,
- bool do_padding) {
- static const char kPad64 = '=';
-
- if (szsrc * 4 > szdest * 3) return 0;
-
- char* cur_dest = dest;
- const unsigned char* cur_src = src;
-
- char* const limit_dest = dest + szdest;
- const unsigned char* const limit_src = src + szsrc;
-
- // Three bytes of data encodes to four characters of cyphertext.
- // So we can pump through three-byte chunks atomically.
- if (szsrc >= 3) { // "limit_src - 3" is UB if szsrc < 3.
- while (cur_src < limit_src - 3) { // While we have >= 32 bits.
- uint32_t in = absl::big_endian::Load32(cur_src) >> 8;
-
- cur_dest[0] = base64[in >> 18];
- in &= 0x3FFFF;
- cur_dest[1] = base64[in >> 12];
- in &= 0xFFF;
- cur_dest[2] = base64[in >> 6];
- in &= 0x3F;
- cur_dest[3] = base64[in];
-
- cur_dest += 4;
- cur_src += 3;
- }
- }
- // To save time, we didn't update szdest or szsrc in the loop. So do it now.
- szdest = limit_dest - cur_dest;
- szsrc = limit_src - cur_src;
-
- /* now deal with the tail (<=3 bytes) */
- switch (szsrc) {
- case 0:
- // Nothing left; nothing more to do.
- break;
- case 1: {
- // One byte left: this encodes to two characters, and (optionally)
- // two pad characters to round out the four-character cypherblock.
- if (szdest < 2) return 0;
- uint32_t in = cur_src[0];
- cur_dest[0] = base64[in >> 2];
- in &= 0x3;
- cur_dest[1] = base64[in << 4];
- cur_dest += 2;
- szdest -= 2;
- if (do_padding) {
- if (szdest < 2) return 0;
- cur_dest[0] = kPad64;
- cur_dest[1] = kPad64;
- cur_dest += 2;
- szdest -= 2;
- }
- break;
- }
- case 2: {
- // Two bytes left: this encodes to three characters, and (optionally)
- // one pad character to round out the four-character cypherblock.
- if (szdest < 3) return 0;
- uint32_t in = absl::big_endian::Load16(cur_src);
- cur_dest[0] = base64[in >> 10];
- in &= 0x3FF;
- cur_dest[1] = base64[in >> 4];
- in &= 0x00F;
- cur_dest[2] = base64[in << 2];
- cur_dest += 3;
- szdest -= 3;
- if (do_padding) {
- if (szdest < 1) return 0;
- cur_dest[0] = kPad64;
- cur_dest += 1;
- szdest -= 1;
- }
- break;
- }
- case 3: {
- // Three bytes left: same as in the big loop above. We can't do this in
- // the loop because the loop above always reads 4 bytes, and the fourth
- // byte is past the end of the input.
- if (szdest < 4) return 0;
- uint32_t in = (cur_src[0] << 16) + absl::big_endian::Load16(cur_src + 1);
- cur_dest[0] = base64[in >> 18];
- in &= 0x3FFFF;
- cur_dest[1] = base64[in >> 12];
- in &= 0xFFF;
- cur_dest[2] = base64[in >> 6];
- in &= 0x3F;
- cur_dest[3] = base64[in];
- cur_dest += 4;
- szdest -= 4;
- break;
- }
- default:
- // Should not be reached: blocks of 4 bytes are handled
- // in the while loop before this switch statement.
- ABSL_RAW_LOG(FATAL, "Logic problem? szsrc = %zu", szsrc);
- break;
- }
- return (cur_dest - dest);
-}
-
-constexpr char kBase64Chars[] =
- "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
-
constexpr char kWebSafeBase64Chars[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
template <typename String>
-void Base64EscapeInternal(const unsigned char* src, size_t szsrc, String* dest,
- bool do_padding, const char* base64_chars) {
- const size_t calc_escaped_size =
- CalculateBase64EscapedLenInternal(szsrc, do_padding);
- strings_internal::STLStringResizeUninitialized(dest, calc_escaped_size);
-
- const size_t escaped_len = Base64EscapeInternal(
- src, szsrc, &(*dest)[0], dest->size(), base64_chars, do_padding);
- assert(calc_escaped_size == escaped_len);
- dest->erase(escaped_len);
-}
-
-template <typename String>
bool Base64UnescapeInternal(const char* src, size_t slen, String* dest,
const signed char* unbase64) {
// Determine the size of the output std::string. Base64 encodes every 3 bytes into
@@ -1068,26 +902,30 @@ bool WebSafeBase64Unescape(absl::string_view src, std::string* dest) {
}
void Base64Escape(absl::string_view src, std::string* dest) {
- Base64EscapeInternal(reinterpret_cast<const unsigned char*>(src.data()),
- src.size(), dest, true, kBase64Chars);
+ strings_internal::Base64EscapeInternal(
+ reinterpret_cast<const unsigned char*>(src.data()), src.size(), dest,
+ true, strings_internal::kBase64Chars);
}
void WebSafeBase64Escape(absl::string_view src, std::string* dest) {
- Base64EscapeInternal(reinterpret_cast<const unsigned char*>(src.data()),
- src.size(), dest, false, kWebSafeBase64Chars);
+ strings_internal::Base64EscapeInternal(
+ reinterpret_cast<const unsigned char*>(src.data()), src.size(), dest,
+ false, kWebSafeBase64Chars);
}
std::string Base64Escape(absl::string_view src) {
std::string dest;
- Base64EscapeInternal(reinterpret_cast<const unsigned char*>(src.data()),
- src.size(), &dest, true, kBase64Chars);
+ strings_internal::Base64EscapeInternal(
+ reinterpret_cast<const unsigned char*>(src.data()), src.size(), &dest,
+ true, strings_internal::kBase64Chars);
return dest;
}
std::string WebSafeBase64Escape(absl::string_view src) {
std::string dest;
- Base64EscapeInternal(reinterpret_cast<const unsigned char*>(src.data()),
- src.size(), &dest, false, kWebSafeBase64Chars);
+ strings_internal::Base64EscapeInternal(
+ reinterpret_cast<const unsigned char*>(src.data()), src.size(), &dest,
+ false, kWebSafeBase64Chars);
return dest;
}
diff --git a/absl/strings/internal/escaping.cc b/absl/strings/internal/escaping.cc
new file mode 100644
index 0000000..c527128
--- /dev/null
+++ b/absl/strings/internal/escaping.cc
@@ -0,0 +1,180 @@
+// Copyright 2020 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
+//
+// https://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.
+
+#include "absl/strings/internal/escaping.h"
+
+#include "absl/base/internal/endian.h"
+#include "absl/base/internal/raw_logging.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace strings_internal {
+
+const char kBase64Chars[] =
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+size_t CalculateBase64EscapedLenInternal(size_t input_len, bool do_padding) {
+ // Base64 encodes three bytes of input at a time. If the input is not
+ // divisible by three, we pad as appropriate.
+ //
+ // (from https://tools.ietf.org/html/rfc3548)
+ // Special processing is performed if fewer than 24 bits are available
+ // at the end of the data being encoded. A full encoding quantum is
+ // always completed at the end of a quantity. When fewer than 24 input
+ // bits are available in an input group, zero bits are added (on the
+ // right) to form an integral number of 6-bit groups. Padding at the
+ // end of the data is performed using the '=' character. Since all base
+ // 64 input is an integral number of octets, only the following cases
+ // can arise:
+
+ // Base64 encodes each three bytes of input into four bytes of output.
+ size_t len = (input_len / 3) * 4;
+
+ if (input_len % 3 == 0) {
+ // (from https://tools.ietf.org/html/rfc3548)
+ // (1) the final quantum of encoding input is an integral multiple of 24
+ // bits; here, the final unit of encoded output will be an integral
+ // multiple of 4 characters with no "=" padding,
+ } else if (input_len % 3 == 1) {
+ // (from https://tools.ietf.org/html/rfc3548)
+ // (2) the final quantum of encoding input is exactly 8 bits; here, the
+ // final unit of encoded output will be two characters followed by two
+ // "=" padding characters, or
+ len += 2;
+ if (do_padding) {
+ len += 2;
+ }
+ } else { // (input_len % 3 == 2)
+ // (from https://tools.ietf.org/html/rfc3548)
+ // (3) the final quantum of encoding input is exactly 16 bits; here, the
+ // final unit of encoded output will be three characters followed by one
+ // "=" padding character.
+ len += 3;
+ if (do_padding) {
+ len += 1;
+ }
+ }
+
+ assert(len >= input_len); // make sure we didn't overflow
+ return len;
+}
+
+size_t Base64EscapeInternal(const unsigned char* src, size_t szsrc, char* dest,
+ size_t szdest, const char* base64,
+ bool do_padding) {
+ static const char kPad64 = '=';
+
+ if (szsrc * 4 > szdest * 3) return 0;
+
+ char* cur_dest = dest;
+ const unsigned char* cur_src = src;
+
+ char* const limit_dest = dest + szdest;
+ const unsigned char* const limit_src = src + szsrc;
+
+ // Three bytes of data encodes to four characters of cyphertext.
+ // So we can pump through three-byte chunks atomically.
+ if (szsrc >= 3) { // "limit_src - 3" is UB if szsrc < 3.
+ while (cur_src < limit_src - 3) { // While we have >= 32 bits.
+ uint32_t in = absl::big_endian::Load32(cur_src) >> 8;
+
+ cur_dest[0] = base64[in >> 18];
+ in &= 0x3FFFF;
+ cur_dest[1] = base64[in >> 12];
+ in &= 0xFFF;
+ cur_dest[2] = base64[in >> 6];
+ in &= 0x3F;
+ cur_dest[3] = base64[in];
+
+ cur_dest += 4;
+ cur_src += 3;
+ }
+ }
+ // To save time, we didn't update szdest or szsrc in the loop. So do it now.
+ szdest = limit_dest - cur_dest;
+ szsrc = limit_src - cur_src;
+
+ /* now deal with the tail (<=3 bytes) */
+ switch (szsrc) {
+ case 0:
+ // Nothing left; nothing more to do.
+ break;
+ case 1: {
+ // One byte left: this encodes to two characters, and (optionally)
+ // two pad characters to round out the four-character cypherblock.
+ if (szdest < 2) return 0;
+ uint32_t in = cur_src[0];
+ cur_dest[0] = base64[in >> 2];
+ in &= 0x3;
+ cur_dest[1] = base64[in << 4];
+ cur_dest += 2;
+ szdest -= 2;
+ if (do_padding) {
+ if (szdest < 2) return 0;
+ cur_dest[0] = kPad64;
+ cur_dest[1] = kPad64;
+ cur_dest += 2;
+ szdest -= 2;
+ }
+ break;
+ }
+ case 2: {
+ // Two bytes left: this encodes to three characters, and (optionally)
+ // one pad character to round out the four-character cypherblock.
+ if (szdest < 3) return 0;
+ uint32_t in = absl::big_endian::Load16(cur_src);
+ cur_dest[0] = base64[in >> 10];
+ in &= 0x3FF;
+ cur_dest[1] = base64[in >> 4];
+ in &= 0x00F;
+ cur_dest[2] = base64[in << 2];
+ cur_dest += 3;
+ szdest -= 3;
+ if (do_padding) {
+ if (szdest < 1) return 0;
+ cur_dest[0] = kPad64;
+ cur_dest += 1;
+ szdest -= 1;
+ }
+ break;
+ }
+ case 3: {
+ // Three bytes left: same as in the big loop above. We can't do this in
+ // the loop because the loop above always reads 4 bytes, and the fourth
+ // byte is past the end of the input.
+ if (szdest < 4) return 0;
+ uint32_t in = (cur_src[0] << 16) + absl::big_endian::Load16(cur_src + 1);
+ cur_dest[0] = base64[in >> 18];
+ in &= 0x3FFFF;
+ cur_dest[1] = base64[in >> 12];
+ in &= 0xFFF;
+ cur_dest[2] = base64[in >> 6];
+ in &= 0x3F;
+ cur_dest[3] = base64[in];
+ cur_dest += 4;
+ szdest -= 4;
+ break;
+ }
+ default:
+ // Should not be reached: blocks of 4 bytes are handled
+ // in the while loop before this switch statement.
+ ABSL_RAW_LOG(FATAL, "Logic problem? szsrc = %zu", szsrc);
+ break;
+ }
+ return (cur_dest - dest);
+}
+
+} // namespace strings_internal
+ABSL_NAMESPACE_END
+} // namespace absl
diff --git a/absl/strings/internal/escaping.h b/absl/strings/internal/escaping.h
new file mode 100644
index 0000000..6a9ce60
--- /dev/null
+++ b/absl/strings/internal/escaping.h
@@ -0,0 +1,58 @@
+// Copyright 2020 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
+//
+// https://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.
+
+#ifndef ABSL_STRINGS_INTERNAL_ESCAPING_H_
+#define ABSL_STRINGS_INTERNAL_ESCAPING_H_
+
+#include <cassert>
+
+#include "absl/strings/internal/resize_uninitialized.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace strings_internal {
+
+ABSL_CONST_INIT extern const char kBase64Chars[];
+
+// Calculates how long a string will be when it is base64 encoded given its
+// length and whether or not the result should be padded.
+size_t CalculateBase64EscapedLenInternal(size_t input_len, bool do_padding);
+
+// Base64-encodes `src` using the alphabet provided in `base64` and writes the
+// result to `dest`. If `do_padding` is true, `dest` is padded with '=' chars
+// until its length is a multiple of 3. Returns the length of `dest`.
+size_t Base64EscapeInternal(const unsigned char* src, size_t szsrc, char* dest,
+ size_t szdest, const char* base64, bool do_padding);
+
+// Base64-encodes `src` using the alphabet provided in `base64` and writes the
+// result to `dest`. If `do_padding` is true, `dest` is padded with '=' chars
+// until its length is a multiple of 3.
+template <typename String>
+void Base64EscapeInternal(const unsigned char* src, size_t szsrc, String* dest,
+ bool do_padding, const char* base64_chars) {
+ const size_t calc_escaped_size =
+ CalculateBase64EscapedLenInternal(szsrc, do_padding);
+ STLStringResizeUninitialized(dest, calc_escaped_size);
+
+ const size_t escaped_len = Base64EscapeInternal(
+ src, szsrc, &(*dest)[0], dest->size(), base64_chars, do_padding);
+ assert(calc_escaped_size == escaped_len);
+ dest->erase(escaped_len);
+}
+
+} // namespace strings_internal
+ABSL_NAMESPACE_END
+} // namespace absl
+
+#endif // ABSL_STRINGS_INTERNAL_ESCAPING_H_
diff --git a/absl/strings/string_view.h b/absl/strings/string_view.h
index 4b34e56..4f7dd6b 100644
--- a/absl/strings/string_view.h
+++ b/absl/strings/string_view.h
@@ -122,7 +122,7 @@ ABSL_NAMESPACE_BEGIN
//
// You may create a null `string_view` in two ways:
//
-// absl::string_view sv();
+// absl::string_view sv;
// absl::string_view sv(nullptr, 0);
//
// For the above, `sv.data() == nullptr`, `sv.length() == 0`, and
@@ -605,7 +605,7 @@ inline string_view ClippedSubstr(string_view s, size_t pos,
// Creates an `absl::string_view` from a pointer `p` even if it's null-valued.
// This function should be used where an `absl::string_view` can be created from
// a possibly-null pointer.
-inline string_view NullSafeStringView(const char* p) {
+constexpr string_view NullSafeStringView(const char* p) {
return p ? string_view(p) : string_view();
}
diff --git a/absl/strings/string_view_test.cc b/absl/strings/string_view_test.cc
index 96dacdf..c4fbd16 100644
--- a/absl/strings/string_view_test.cc
+++ b/absl/strings/string_view_test.cc
@@ -931,6 +931,31 @@ TEST(StringViewTest, NullSafeStringView) {
}
}
+TEST(StringViewTest, ConstexprNullSafeStringView) {
+ {
+ constexpr absl::string_view s = absl::NullSafeStringView(nullptr);
+ EXPECT_EQ(nullptr, s.data());
+ EXPECT_EQ(0, s.size());
+ EXPECT_EQ(absl::string_view(), s);
+ }
+#if !defined(_MSC_VER) || _MSC_VER >= 1910
+ // MSVC 2017+ is required for good constexpr string_view support.
+ // See the implementation of `absl::string_view::StrlenInternal()`.
+ {
+ static constexpr char kHi[] = "hi";
+ absl::string_view s = absl::NullSafeStringView(kHi);
+ EXPECT_EQ(kHi, s.data());
+ EXPECT_EQ(strlen(kHi), s.size());
+ EXPECT_EQ(absl::string_view("hi"), s);
+ }
+ {
+ constexpr absl::string_view s = absl::NullSafeStringView("hello");
+ EXPECT_EQ(s.size(), 5);
+ EXPECT_EQ("hello", s);
+ }
+#endif
+}
+
TEST(StringViewTest, ConstexprCompiles) {
constexpr absl::string_view sp;
#ifdef ABSL_HAVE_STRING_VIEW_FROM_NULLPTR
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