LadybirdBrowser/ladybird
1
1
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2024-10-26 06:49:12 +03:00
Code Issues Packages Projects Releases Wiki Activity

AK+LibWeb: Move decode forgiving base64 under Web::Infra namespace

Browse Source 
Since the forgiving base64 is part of the web infra standard
This commit is contained in:
Arda Cinar 2023-01-10 11:49:06 +03:00 committed by Linus Groh
parent 4ab2954210
commit 283187afc5
Notes: sideshowbarker 2024-07-17 01:50:45 +09:00 
Author: https://github.com/kuzux
Commit: https://github.com/SerenityOS/serenity/commit/283187afc5
Pull-request: https://github.com/SerenityOS/serenity/pull/16711
Issue: https://github.com/SerenityOS/serenity/issues/16638
Reviewed-by: https://github.com/linusg
Reviewed-by: https://github.com/nico
Reviewed-by: https://github.com/trflynn89
6 changed files with 133 additions and 101 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

98
AK/Base64.cpp
View File

@ -121,102 +121,4 @@ ErrorOr<String> encode_base64(ReadonlyBytes input)
return output.to_string();
}
// 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 = 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);
}
}

2
AK/Base64.h
View File

@ -40,8 +40,6 @@ consteval auto base64_lookup_table()
[[nodiscard]] ErrorOr<ByteBuffer> decode_base64(StringView);
[[nodiscard]] ErrorOr<ByteBuffer> decode_forgiving_base64(StringView);
[[nodiscard]] ErrorOr<String> encode_base64(ReadonlyBytes);
}

1
Userland/Libraries/LibWeb/CMakeLists.txt
View File

@ -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

3
Userland/Libraries/LibWeb/HTML/Window.cpp
View File

@ -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");

115
Userland/Libraries/LibWeb/Infra/Base64.cpp Normal file
View File

@ -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);
}
}

15
Userland/Libraries/LibWeb/Infra/Base64.h Normal file
View File

@ -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);
}