// Copyright 2020 The Wuffs 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.

pub status "#bad C0 control code"
pub status "#bad UTF-8"
pub status "#bad backslash-escape"
pub status "#bad input"
pub status "#unsupported number length"
pub status "#unsupported recursion depth"

pri status "#internal error: inconsistent I/O"

pub const decoder_workbuf_len_max_incl_worst_case base.u64 = 0

// decoder_depth_max_incl is the maximum supported recursion depth: how deeply
// nested [] arrays and {} objects can be.
//
// The JSON spec itself does not define a limit, but allows implementations to
// set their own limits.
pub const decoder_depth_max_incl base.u64 = 1024

// decoder_dst_token_buffer_length_min_incl is the minimum length of the dst
// wuffs_base__token_buffer passed to the decoder.
pub const decoder_dst_token_buffer_length_min_incl base.u64 = 1

// decoder_src_io_buffer_length_min_incl is the minimum length of the src
// wuffs_base__io_buffer passed to the decoder.
//
// This constrains the src.data.len field and it is the io_buffer capacity (the
// maximum possible src.meta.ri and src.meta.wi values). It is a property of
// the backing array's length, not the length of the JSON-formatted input per
// se. It is perfectly valid to decode "[1,2]" (of length 5) as JSON, as long
// as that content is placed in an io_buffer whose data.len is at least 100.
pub const decoder_src_io_buffer_length_min_incl base.u64 = 100

// decoder_number_length_max_incl is the longest supported byte length for a
// JSON number. Unlike JSON strings, this package's tokenizer never splits a
// single JSON number into multiple tokens, as this simplifies the callers.
// They can then call e.g. wuffs_base__parse_number_i64 without having to
// reconstitute a contiguous string representation.
//
// The JSON spec itself does not define a limit, but allows implementations to
// set their own limits.
pri const decoder_number_length_max_incl base.u64 = 99

// --------

// Look-Up Tables (LUTs).

// lut_backslashes[i] helps decode "\i", for various 'i's.
//
// If the element's 0x80 bit is set then "\i" is unconditionally a valid
// single-output-byte backslash-escape. The low 7 bits are the unescaped value.
// For example, lut_backslashes['n'] is (0x80 | 0x0A), because "\n" is U+000A.
//
// If the element is non-zero (but the 0x80 bit is not set) then "\i"'s
// validity depends on the relevant quirk. The element's value is an enum:
//  - 1: "\a", U+0007, quirk_allow_backslash_a.
//  - 2: "\e", U+001B, quirk_allow_backslash_e.
//  - 3: "\?", U+003F, quirk_allow_backslash_question_mark.
//  - 4: "\'", U+0027, quirk_allow_backslash_single_quote.
//  - 5: "\v", U+000B, quirk_allow_backslash_v.
//  - 6: "\0", U+0000, quirk_allow_backslash_zero.
// The U+1234 values are held in lut_quirky_backslashes, below.
//
// If the element is zero then "\i" is invalid, or it is a special case, the
// start of "\x12", "\u1234" or "\U12345678".
pri const lut_backslashes array[256] base.u8 = [
	// 0     1     2     3     4     5     6     7
	// 8     9     A     B     C     D     E     F
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x00 ..= 0x07.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x08 ..= 0x0F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x10 ..= 0x17.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x18 ..= 0x1F.
	0x00, 0x00, 0xA2, 0x00, 0x00, 0x00, 0x00, 0x04,  // 0x20 ..= 0x27. '"', '\''.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xAF,  // 0x28 ..= 0x2F. '/'.
	0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x30 ..= 0x37. '0'.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03,  // 0x38 ..= 0x3F. '?'

	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x40 ..= 0x47.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x48 ..= 0x4F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x50 ..= 0x57.
	0x00, 0x00, 0x00, 0x00, 0xDC, 0x00, 0x00, 0x00,  // 0x58 ..= 0x5F. '\\'.
	0x00, 0x01, 0x88, 0x00, 0x00, 0x02, 0x8C, 0x00,  // 0x60 ..= 0x67. 'a', 'b', 'e', 'f'.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x8A, 0x00,  // 0x68 ..= 0x6F. 'n'.
	0x00, 0x00, 0x8D, 0x00, 0x89, 0x00, 0x05, 0x00,  // 0x70 ..= 0x77. 'r', 't', 'v'.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x78 ..= 0x7F.

	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x80 ..= 0x87.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x88 ..= 0x8F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x90 ..= 0x97.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x98 ..= 0x9F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xA0 ..= 0xA7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xA8 ..= 0xAF.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xB0 ..= 0xB7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xB8 ..= 0xBF.

	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xC0 ..= 0xC7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xC8 ..= 0xCF.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xD0 ..= 0xD7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xD8 ..= 0xDF.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xE0 ..= 0xE7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xE8 ..= 0xEF.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xF0 ..= 0xF7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xF8 ..= 0xFF.
	// 0     1     2     3     4     5     6     7
	// 8     9     A     B     C     D     E     F
]

// lut_quirky_backslashes is discussed in the lut_backslashes comment. The
// first and last elements (indexes 0 and 7) are not used, but 8 is a round
// power of 2, so enforcing index-in-bounds is a simple "&7" operation.
pri const lut_quirky_backslashes array[8] base.u8 = [
	0x00, 0x07, 0x1B, 0x3F, 0x27, 0x0B, 0x00, 0x00,
]

// lut_chars helps decode bytes within a string:
//  - 0x00 is 1-byte UTF-8 (ASCII) but not '"', '\\' or a C0 control code.
//  - 0x01 is '"'.
//  - 0x02 is '\\'.
//  - 0x03 is the start of 2-byte UTF-8.
//  - 0x04 is the start of 3-byte UTF-8.
//  - 0x05 is the start of 4-byte UTF-8.
//  - 0x10 is a UTF-8 tail byte.
//  - 0x80 is invalid JSON (C0 control codes).
//  - 0x81 is invalid UTF-8.
//
// RFC 3629 (UTF-8) gives this grammar for valid UTF-8:
//    UTF8-1      = %x00-7F
//    UTF8-2      = %xC2-DF UTF8-tail
//    UTF8-3      = %xE0 %xA0-BF UTF8-tail / %xE1-EC 2( UTF8-tail ) /
//                  %xED %x80-9F UTF8-tail / %xEE-EF 2( UTF8-tail )
//    UTF8-4      = %xF0 %x90-BF 2( UTF8-tail ) / %xF1-F3 3( UTF8-tail ) /
//                  %xF4 %x80-8F 2( UTF8-tail )
//    UTF8-tail   = %x80-BF
pri const lut_chars array[256] base.u8 = [
	// 0     1     2     3     4     5     6     7
	// 8     9     A     B     C     D     E     F
	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,  // 0x00 ..= 0x07. C0 control codes.
	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,  // 0x08 ..= 0x0F. C0 control codes.
	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,  // 0x10 ..= 0x17. C0 control codes.
	0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80,  // 0x18 ..= 0x1F. C0 control codes.
	0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x20 ..= 0x27. UTF-8-1; '"'.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x28 ..= 0x2F. UTF-8-1.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x30 ..= 0x37. UTF-8-1.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x38 ..= 0x3F. UTF-8-1.

	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x40 ..= 0x47. UTF-8-1.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x48 ..= 0x4F. UTF-8-1.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x50 ..= 0x57. UTF-8-1.
	0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00,  // 0x58 ..= 0x5F. UTF-8-1; '\\'.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x60 ..= 0x67. UTF-8-1.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x68 ..= 0x6F. UTF-8-1.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x70 ..= 0x77. UTF-8-1.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x78 ..= 0x7F. UTF-8-1.

	0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,  // 0x80 ..= 0x87. UTF-8 tail.
	0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,  // 0x88 ..= 0x8F. UTF-8 tail.
	0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,  // 0x90 ..= 0x97. UTF-8 tail.
	0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,  // 0x98 ..= 0x9F. UTF-8 tail.
	0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,  // 0xA0 ..= 0xA7. UTF-8 tail.
	0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,  // 0xA8 ..= 0xAF. UTF-8 tail.
	0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,  // 0xB0 ..= 0xB7. UTF-8 tail.
	0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10, 0x10,  // 0xB8 ..= 0xBF. UTF-8 tail.

	0x81, 0x81, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,  // 0xC0 ..= 0xC7. Invalid UTF-8; UTF-8-2.
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,  // 0xC8 ..= 0xCF. UTF-8-2.
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,  // 0xD0 ..= 0xD7. UTF-8-2.
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,  // 0xD8 ..= 0xDF. UTF-8-2.
	0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,  // 0xE0 ..= 0xE7. UTF-8-3.
	0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,  // 0xE8 ..= 0xEF. UTF-8-3.
	0x05, 0x05, 0x05, 0x05, 0x05, 0x81, 0x81, 0x81,  // 0xF0 ..= 0xF7. UTF-8-4; Invalid UTF-8.
	0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81, 0x81,  // 0xF8 ..= 0xFF. Invalid UTF-8.
	// 0     1     2     3     4     5     6     7
	// 8     9     A     B     C     D     E     F
]

// lut_classes is:
//  - 0x00 (bitmask 0x0001) is CLASS_WHITESPACE.
//  - 0x01 (bitmask 0x0002) is CLASS_STRING.
//  - 0x02 (bitmask 0x0004) is CLASS_COMMA.
//  - 0x03 (bitmask 0x0008) is CLASS_COLON.
//  - 0x04 (bitmask 0x0010) is CLASS_NUMBER.
//  - 0x05 (bitmask 0x0020) is CLASS_OPEN_CURLY_BRACE.
//  - 0x06 (bitmask 0x0040) is CLASS_CLOSE_CURLY_BRACE.
//  - 0x07 (bitmask 0x0080) is CLASS_OPEN_SQUARE_BRACKET.
//  - 0x08 (bitmask 0x0100) is CLASS_CLOSE_SQUARE_BRACKET.
//  - 0x09 (bitmask 0x0200) is CLASS_FALSE.
//  - 0x0A (bitmask 0x0400) is CLASS_TRUE.
//  - 0x0B (bitmask 0x0800) is CLASS_NULL_NAN_INF.
//  - 0x0C (bitmask 0x1000) is CLASS_COMMENT.
//  - 0x0D (bitmask 0x2000) is reserved.
//  - 0x0E (bitmask 0x4000) is reserved.
//  - 0x0F (bitmask 0x8000) is CLASS_BAD_INPUT.
//
// The bitmasks are used by the "expect" variable: what the next character
// class can be.
//
//  - 0x1002 is EXPECT_STRING.
//  - 0x1EB0 is EXPECT_NON_STRING_VALUE.
//  - 0x1004 is EXPECT_COMMA.
//  - 0x1008 is EXPECT_COLON.
//  - 0x1040 is EXPECT_CLOSE_CURLY_BRACE.
//  - 0x1100 is EXPECT_CLOSE_SQUARE_BRACKET.
//
// Bitwise or'ing these together gives 0x0FFE. Whitespace is never expected, as
// it is handled separately.
//
// EXPECT_VALUE is also defined to be 0x1EB2, equivalent to (EXPECT_STRING |
// EXPECT_NON_STRING_VALUE).
//
// EXPECT_NUMBER is also defined to be 0x1010. Testing for EXPECT_NUMBER's
// presence is equivalent to testing for EXPECT_NON_STRING_VALUE.
//
// "Non-string value" includes literals (false, true, null), numbers, arrays
// and objects.
//
// "String value" includes "this" and "th\u0061t".
//
// Comments are always expected. Whether the relevant quirks are enabled are
// checked elsewhere.
pri const lut_classes array[256] base.u8[..= 0x0F] = [
	// 0     1     2     3     4     5     6     7
	// 8     9     A     B     C     D     E     F
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0x00 ..= 0x07.
	0x0F, 0x00, 0x00, 0x0F, 0x0F, 0x00, 0x0F, 0x0F,  // 0x08 ..= 0x0F. '\t', '\n', '\r'.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0x10 ..= 0x17.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0x18 ..= 0x1F.
	0x00, 0x0F, 0x01, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0x20 ..= 0x27. ' ', '"'.
	0x0F, 0x0F, 0x0F, 0x0B, 0x02, 0x04, 0x0F, 0x0C,  // 0x28 ..= 0x2F. '+', ',', '-', '/'.
	0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,  // 0x30 ..= 0x37. '0'-'7'.
	0x04, 0x04, 0x03, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0x38 ..= 0x3F. '8'-'9', ':'.

	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0x40 ..= 0x47.
	0x0F, 0x0B, 0x0F, 0x0F, 0x0F, 0x0F, 0x0B, 0x0F,  // 0x48 ..= 0x4F. 'I', 'N'.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0x50 ..= 0x57.
	0x0F, 0x0F, 0x0F, 0x07, 0x0F, 0x08, 0x0F, 0x0F,  // 0x58 ..= 0x5F. '[', ']'.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x09, 0x0F,  // 0x60 ..= 0x67. 'f'.
	0x0F, 0x0B, 0x0F, 0x0F, 0x0F, 0x0F, 0x0B, 0x0F,  // 0x68 ..= 0x6F. 'i', 'n'.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0A, 0x0F, 0x0F, 0x0F,  // 0x70 ..= 0x77. 't'.
	0x0F, 0x0F, 0x0F, 0x05, 0x0F, 0x06, 0x0F, 0x0F,  // 0x78 ..= 0x7F. '{', '}'.

	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0x80 ..= 0x87.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0x88 ..= 0x8F.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0x90 ..= 0x97.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0x98 ..= 0x9F.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0xA0 ..= 0xA7.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0xA8 ..= 0xAF.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0xB0 ..= 0xB7.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0xB8 ..= 0xBF.

	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0xC0 ..= 0xC7.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0xC8 ..= 0xCF.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0xD0 ..= 0xD7.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0xD8 ..= 0xDF.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0xE0 ..= 0xE7.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0xE8 ..= 0xEF.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0xF0 ..= 0xF7.
	0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F, 0x0F,  // 0xF8 ..= 0xFF.
	// 0     1     2     3     4     5     6     7
	// 8     9     A     B     C     D     E     F
]

pri const lut_decimal_digits array[256] base.u8 = [
	// 0     1     2     3     4     5     6     7
	// 8     9     A     B     C     D     E     F
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x00 ..= 0x07.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x08 ..= 0x0F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x10 ..= 0x17.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x18 ..= 0x1F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x20 ..= 0x27.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x28 ..= 0x2F.
	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,  // 0x30 ..= 0x37. '0'-'7'.
	0x88, 0x89, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x38 ..= 0x3F. '8'-'9'.

	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x40 ..= 0x47.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x48 ..= 0x4F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x50 ..= 0x57.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x58 ..= 0x5F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x60 ..= 0x67.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x68 ..= 0x6F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x70 ..= 0x77.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x78 ..= 0x7F.

	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x80 ..= 0x87.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x88 ..= 0x8F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x90 ..= 0x97.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x98 ..= 0x9F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xA0 ..= 0xA7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xA8 ..= 0xAF.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xB0 ..= 0xB7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xB8 ..= 0xBF.

	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xC0 ..= 0xC7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xC8 ..= 0xCF.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xD0 ..= 0xD7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xD8 ..= 0xDF.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xE0 ..= 0xE7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xE8 ..= 0xEF.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xF0 ..= 0xF7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xF8 ..= 0xFF.
	// 0     1     2     3     4     5     6     7
	// 8     9     A     B     C     D     E     F
]

pri const lut_hexadecimal_digits array[256] base.u8 = [
	// 0     1     2     3     4     5     6     7
	// 8     9     A     B     C     D     E     F
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x00 ..= 0x07.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x08 ..= 0x0F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x10 ..= 0x17.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x18 ..= 0x1F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x20 ..= 0x27.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x28 ..= 0x2F.
	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,  // 0x30 ..= 0x37. '0'-'7'.
	0x88, 0x89, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x38 ..= 0x3F. '8'-'9'.

	0x00, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x00,  // 0x40 ..= 0x47. 'A'-'F'.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x48 ..= 0x4F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x50 ..= 0x57.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x58 ..= 0x5F.
	0x00, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x00,  // 0x60 ..= 0x67. 'a'-'f'.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x68 ..= 0x6F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x70 ..= 0x77.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x78 ..= 0x7F.

	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x80 ..= 0x87.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x88 ..= 0x8F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x90 ..= 0x97.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x98 ..= 0x9F.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xA0 ..= 0xA7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xA8 ..= 0xAF.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xB0 ..= 0xB7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xB8 ..= 0xBF.

	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xC0 ..= 0xC7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xC8 ..= 0xCF.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xD0 ..= 0xD7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xD8 ..= 0xDF.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xE0 ..= 0xE7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xE8 ..= 0xEF.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xF0 ..= 0xF7.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0xF8 ..= 0xFF.
	// 0     1     2     3     4     5     6     7
	// 8     9     A     B     C     D     E     F
]