// 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 "#bad new-line in a string"
pub status "#bad quirk combination"
pub status "#unsupported number length"
pub status "#unsupported recursion depth"

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

// --------

// DECODER_WORKBUF_LEN_MAX_INCL_WORST_CASE is the largest workbuf length that a
// decoder will request.
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: "backslash new_line(not_n)", U+000A, QUIRK_ALLOW_BACKSLASH_NEW_LINE.
//  - 4: "\?", U+003F, QUIRK_ALLOW_BACKSLASH_QUESTION_MARK.
//  - 5: "\'", U+0027, QUIRK_ALLOW_BACKSLASH_SINGLE_QUOTE.
//  - 6: "\v", U+000B, QUIRK_ALLOW_BACKSLASH_V.
//  - 7: "\0", U+0000, QUIRK_ALLOW_BACKSLASH_ZERO.
// The quirk and U+1234 values are held in LUT_QUIRKY_BACKSLASHES_QUIRKS and
// LUT_QUIRKY_BACKSLASHES_CHARS, 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, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x08 ..= 0x0F. '\n'.
	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, 0x05,  // 0x20 ..= 0x27. '"', '\''.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xAF,  // 0x28 ..= 0x2F. '/'.
	0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  // 0x30 ..= 0x37. '0'.
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04,  // 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, 0x06, 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_QUIRKS is discussed in the LUT_BACKSLASHES comment.
// The first element (index 0) is 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_QUIRKS : array[8] base.u8[..= 0x0A] = [
	0,
	// Uncommenting the following lines requires being able to define consts in
	// terms of other consts, which could be non-trivial to specify and
	// implement (to avoid infinite loops).
	0x01,  // (QUIRK_ALLOW_BACKSLASH_A - QUIRKS_BASE) as base.u8,
	0x03,  // (QUIRK_ALLOW_BACKSLASH_E - QUIRKS_BASE) as base.u8,
	0x04,  // (QUIRK_ALLOW_BACKSLASH_NEW_LINE - QUIRKS_BASE) as base.u8,
	0x05,  // (QUIRK_ALLOW_BACKSLASH_QUESTION_MARK - QUIRKS_BASE) as base.u8,
	0x06,  // (QUIRK_ALLOW_BACKSLASH_SINGLE_QUOTE - QUIRKS_BASE) as base.u8,
	0x07,  // (QUIRK_ALLOW_BACKSLASH_V - QUIRKS_BASE) as base.u8,
	0x0A,  // (QUIRK_ALLOW_BACKSLASH_ZERO - QUIRKS_BASE) as base.u8,
]

// LUT_QUIRKY_BACKSLASHES_CHARS is discussed in the LUT_BACKSLASHES comment.
// The first element (index 0) is 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_CHARS : array[8] base.u8 = [
	0x00, 0x07, 0x1B, 0x0A, 0x3F, 0x27, 0x0B, 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.
//  - 0x20 is invalid UTF-8.
//  - 0x80 and above is invalid JSON (C0 control codes).
//
// 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, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,  // 0x00 ..= 0x07. C0 control codes.
	0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F,  // 0x08 ..= 0x0F. C0 control codes.
	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,  // 0x10 ..= 0x17. C0 control codes.
	0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D, 0x9E, 0x9F,  // 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.

	0x20, 0x20, 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, 0x20, 0x20, 0x20,  // 0xF0 ..= 0xF7. UTF-8-4; Invalid UTF-8.
	0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,  // 0xF8 ..= 0xFF. Invalid UTF-8.
	// 0     1     2     3     4     5     6     7
	// 8     9     A     B     C     D     E     F
]

pri const CLASS_WHITESPACE           : base.u8 = 0x00
pri const CLASS_STRING               : base.u8 = 0x01
pri const CLASS_COMMA                : base.u8 = 0x02
pri const CLASS_COLON                : base.u8 = 0x03
pri const CLASS_NUMBER               : base.u8 = 0x04
pri const CLASS_OPEN_CURLY_BRACE     : base.u8 = 0x05
pri const CLASS_CLOSE_CURLY_BRACE    : base.u8 = 0x06
pri const CLASS_OPEN_SQUARE_BRACKET  : base.u8 = 0x07
pri const CLASS_CLOSE_SQUARE_BRACKET : base.u8 = 0x08
pri const CLASS_FALSE                : base.u8 = 0x09
pri const CLASS_TRUE                 : base.u8 = 0x0A
pri const CLASS_NULL_NAN_INF         : base.u8 = 0x0B
pri const CLASS_COMMENT              : base.u8 = 0x0C

// EXPECT_ETC are unions of LUT_CLASSES bitmasks. See LUT_CLASSES below.
//
// Bitwise or'ing these together gives 0x1FFE. 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).
//
// "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 EXPECT_VALUE                : base.u32 = 0x1EB2
pri const EXPECT_NON_STRING_VALUE     : base.u32 = 0x1EB0
pri const EXPECT_STRING               : base.u32 = 0x1002
pri const EXPECT_COMMA                : base.u32 = 0x1004
pri const EXPECT_COLON                : base.u32 = 0x1008
pri const EXPECT_NUMBER               : base.u32 = 0x1010
pri const EXPECT_CLOSE_CURLY_BRACE    : base.u32 = 0x1040
pri const EXPECT_CLOSE_SQUARE_BRACKET : base.u32 = 0x1100

// 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. See EXPECT_ETC above.
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
]