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-rw-r--r--Userland/Libraries/LibWeb/CMakeLists.txt1
-rw-r--r--Userland/Libraries/LibWeb/HTML/Window.cpp3
-rw-r--r--Userland/Libraries/LibWeb/Infra/Base64.cpp115
-rw-r--r--Userland/Libraries/LibWeb/Infra/Base64.h15
4 files changed, 133 insertions, 1 deletions
diff --git a/Userland/Libraries/LibWeb/CMakeLists.txt b/Userland/Libraries/LibWeb/CMakeLists.txt
index 12c274163a..1dd2502731 100644
--- a/Userland/Libraries/LibWeb/CMakeLists.txt
+++ b/Userland/Libraries/LibWeb/CMakeLists.txt
@@ -302,6 +302,7 @@ set(SOURCES
HTML/WorkerNavigator.cpp
HighResolutionTime/Performance.cpp
HighResolutionTime/TimeOrigin.cpp
+ Infra/Base64.cpp
Infra/ByteSequences.cpp
Infra/JSON.cpp
Infra/Strings.cpp
diff --git a/Userland/Libraries/LibWeb/HTML/Window.cpp b/Userland/Libraries/LibWeb/HTML/Window.cpp
index 661b92b887..5b24f477cf 100644
--- a/Userland/Libraries/LibWeb/HTML/Window.cpp
+++ b/Userland/Libraries/LibWeb/HTML/Window.cpp
@@ -50,6 +50,7 @@
#include <LibWeb/HTML/WindowProxy.h>
#include <LibWeb/HighResolutionTime/Performance.h>
#include <LibWeb/HighResolutionTime/TimeOrigin.h>
+#include <LibWeb/Infra/Base64.h>
#include <LibWeb/Infra/CharacterTypes.h>
#include <LibWeb/Layout/InitialContainingBlock.h>
#include <LibWeb/Page/Page.h>
@@ -1410,7 +1411,7 @@ JS_DEFINE_NATIVE_FUNCTION(Window::atob)
// Otherwise, the user agent must convert data to a byte sequence whose nth byte is the eight-bit representation of the nth code point of data
// and then must apply forgiving-base64 encode to that byte sequence and return the result.
- auto decoded = AK::decode_forgiving_base64(StringView(deprecated_string));
+ auto decoded = Infra::decode_forgiving_base64(StringView(deprecated_string));
if (decoded.is_error())
return vm.throw_completion<JS::TypeError>(JS::ErrorType::InvalidFormat, "Base64");
diff --git a/Userland/Libraries/LibWeb/Infra/Base64.cpp b/Userland/Libraries/LibWeb/Infra/Base64.cpp
new file mode 100644
index 0000000000..7944b5e427
--- /dev/null
+++ b/Userland/Libraries/LibWeb/Infra/Base64.cpp
@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2022-2023, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/Base64.h>
+#include <AK/ByteBuffer.h>
+#include <AK/CharacterTypes.h>
+#include <AK/Error.h>
+#include <AK/StringView.h>
+#include <AK/Vector.h>
+#include <LibWeb/Infra/Base64.h>
+
+namespace Web::Infra {
+
+// https://infra.spec.whatwg.org/#forgiving-base64
+ErrorOr<ByteBuffer> decode_forgiving_base64(StringView input)
+{
+ // 1. Remove all ASCII whitespace from data.
+ auto data = input.trim_whitespace();
+
+ // 2. If data’s code point length divides by 4 leaving no remainder, then:
+ if (data.length() % 4 == 0) {
+ // If data ends with one or two U+003D (=) code points, then remove them from data.
+ if (data.ends_with("=="sv))
+ data = data.substring_view(0, data.length() - 2);
+ else if (data.ends_with('='))
+ data = data.substring_view(0, data.length() - 1);
+ }
+
+ // 3. If data’s code point length divides by 4 leaving a remainder of 1, then return failure.
+ if (data.length() % 4 == 1)
+ return Error::from_string_literal("Invalid input length in forgiving base64 decode");
+
+ // 4. If data contains a code point that is not one of
+ // U+002B (+), U+002F (/), ASCII alphanumeric
+ // then return failure.
+ for (auto point : data) {
+ if (point != '+' && point != '/' && !is_ascii_alphanumeric(point))
+ return Error::from_string_literal("Invalid character in forgiving base64 decode");
+ }
+
+ // 5. Let output be an empty byte sequence.
+ // 6. Let buffer be an empty buffer that can have bits appended to it.
+ Vector<u8> output;
+ u32 buffer = 0;
+ auto accumulated_bits = 0;
+
+ auto add_to_buffer = [&](u8 number) {
+ VERIFY(number < 64);
+ u32 buffer_mask = number;
+
+ if (accumulated_bits == 0)
+ buffer_mask <<= 18;
+ else if (accumulated_bits == 6)
+ buffer_mask <<= 12;
+ else if (accumulated_bits == 12)
+ buffer_mask <<= 6;
+ else if (accumulated_bits == 18)
+ buffer_mask <<= 0;
+
+ buffer |= buffer_mask;
+
+ accumulated_bits += 6;
+ };
+
+ auto append_bytes = [&]() {
+ output.append(static_cast<u8>((buffer & 0xff0000) >> 16));
+ output.append(static_cast<u8>((buffer & 0xff00) >> 8));
+ output.append(static_cast<u8>(buffer & 0xff));
+
+ buffer = 0;
+ accumulated_bits = 0;
+ };
+
+ auto alphabet_lookup_table = AK::base64_lookup_table();
+
+ // 7. Let position be a position variable for data, initially pointing at the start of data.
+ // 8. While position does not point past the end of data:
+ for (auto point : data) {
+ // 1. Find the code point pointed to by position in the second column of Table 1: The Base 64 Alphabet of RFC 4648.
+ // Let n be the number given in the first cell of the same row. [RFC4648]
+ auto n = alphabet_lookup_table[point];
+ VERIFY(n >= 0);
+
+ // 2. Append the six bits corresponding to n, most significant bit first, to buffer.
+ add_to_buffer(static_cast<u8>(n));
+
+ // 3. buffer has accumulated 24 bits,
+ if (accumulated_bits == 24) {
+ // interpret them as three 8-bit big-endian numbers.
+ // Append three bytes with values equal to those numbers to output, in the same order, and then empty buffer
+ append_bytes();
+ }
+ }
+
+ // 9. If buffer is not empty, it contains either 12 or 18 bits.
+ VERIFY(accumulated_bits == 0 || accumulated_bits == 12 || accumulated_bits == 18);
+
+ // If it contains 12 bits, then discard the last four and interpret the remaining eight as an 8-bit big-endian number.
+ if (accumulated_bits == 12)
+ output.append(static_cast<u8>((buffer & 0xff0000) >> 16));
+
+ // If it contains 18 bits, then discard the last two and interpret the remaining 16 as two 8-bit big-endian numbers.
+ // Append the one or two bytes with values equal to those one or two numbers to output, in the same order.
+ if (accumulated_bits == 18) {
+ output.append(static_cast<u8>((buffer & 0xff0000) >> 16));
+ output.append(static_cast<u8>((buffer & 0xff00) >> 8));
+ }
+
+ return ByteBuffer::copy(output);
+}
+
+}
diff --git a/Userland/Libraries/LibWeb/Infra/Base64.h b/Userland/Libraries/LibWeb/Infra/Base64.h
new file mode 100644
index 0000000000..381fbebb75
--- /dev/null
+++ b/Userland/Libraries/LibWeb/Infra/Base64.h
@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2022-2023, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Forward.h>
+
+namespace Web::Infra {
+
+[[nodiscard]] ErrorOr<ByteBuffer> decode_forgiving_base64(StringView);
+
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-18 01:27:32 +0000