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author | Wim <wim@42.be> | 2022-03-20 02:20:54 +0100 |
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committer | Wim <wim@42.be> | 2022-03-20 14:57:48 +0100 |
commit | 496d5b4ec7f5f4afae6199f928675d14d18de015 (patch) | |
tree | 3a649c80a76f0ffc33e6b3a63c0e65e892169cde /vendor/github.com/skip2/go-qrcode/encoder.go | |
parent | 2623a412c42a81104b97ae8c81a5f66760fee4b6 (diff) | |
download | matterbridge-msglm-496d5b4ec7f5f4afae6199f928675d14d18de015.tar.gz matterbridge-msglm-496d5b4ec7f5f4afae6199f928675d14d18de015.tar.bz2 matterbridge-msglm-496d5b4ec7f5f4afae6199f928675d14d18de015.zip |
Add whatsappmulti buildflag for whatsapp with multidevice support (whatsapp)
Diffstat (limited to 'vendor/github.com/skip2/go-qrcode/encoder.go')
-rw-r--r-- | vendor/github.com/skip2/go-qrcode/encoder.go | 455 |
1 files changed, 455 insertions, 0 deletions
diff --git a/vendor/github.com/skip2/go-qrcode/encoder.go b/vendor/github.com/skip2/go-qrcode/encoder.go new file mode 100644 index 00000000..713378c0 --- /dev/null +++ b/vendor/github.com/skip2/go-qrcode/encoder.go @@ -0,0 +1,455 @@ +// go-qrcode +// Copyright 2014 Tom Harwood + +package qrcode + +import ( + "errors" + "log" + + bitset "github.com/skip2/go-qrcode/bitset" +) + +// Data encoding. +// +// The main data portion of a QR Code consists of one or more segments of data. +// A segment consists of: +// +// - The segment Data Mode: numeric, alphanumeric, or byte. +// - The length of segment in bits. +// - Encoded data. +// +// For example, the string "123ZZ#!#!" may be represented as: +// +// [numeric, 3, "123"] [alphanumeric, 2, "ZZ"] [byte, 4, "#!#!"] +// +// Multiple data modes exist to minimise the size of encoded data. For example, +// 8-bit bytes require 8 bits to encode each, but base 10 numeric data can be +// encoded at a higher density of 3 numbers (e.g. 123) per 10 bits. +// +// Some data can be represented in multiple modes. Numeric data can be +// represented in all three modes, whereas alphanumeric data (e.g. 'A') can be +// represented in alphanumeric and byte mode. +// +// Starting a new segment (to use a different Data Mode) has a cost, the bits to +// state the new segment Data Mode and length. To minimise each QR Code's symbol +// size, an optimisation routine coalesces segment types where possible, to +// reduce the encoded data length. +// +// There are several other data modes available (e.g. Kanji mode) which are not +// implemented here. + +// A segment encoding mode. +type dataMode uint8 + +const ( + // Each dataMode is a subset of the subsequent dataMode: + // dataModeNone < dataModeNumeric < dataModeAlphanumeric < dataModeByte + // + // This ordering is important for determining which data modes a character can + // be encoded with. E.g. 'E' can be encoded in both dataModeAlphanumeric and + // dataModeByte. + dataModeNone dataMode = 1 << iota + dataModeNumeric + dataModeAlphanumeric + dataModeByte +) + +// dataModeString returns d as a short printable string. +func dataModeString(d dataMode) string { + switch d { + case dataModeNone: + return "none" + case dataModeNumeric: + return "numeric" + case dataModeAlphanumeric: + return "alphanumeric" + case dataModeByte: + return "byte" + } + + return "unknown" +} + +type dataEncoderType uint8 + +const ( + dataEncoderType1To9 dataEncoderType = iota + dataEncoderType10To26 + dataEncoderType27To40 +) + +// segment is a single segment of data. +type segment struct { + // Data Mode (e.g. numeric). + dataMode dataMode + + // segment data (e.g. "abc"). + data []byte +} + +// A dataEncoder encodes data for a particular QR Code version. +type dataEncoder struct { + // Minimum & maximum versions supported. + minVersion int + maxVersion int + + // Mode indicator bit sequences. + numericModeIndicator *bitset.Bitset + alphanumericModeIndicator *bitset.Bitset + byteModeIndicator *bitset.Bitset + + // Character count lengths. + numNumericCharCountBits int + numAlphanumericCharCountBits int + numByteCharCountBits int + + // The raw input data. + data []byte + + // The data classified into unoptimised segments. + actual []segment + + // The data classified into optimised segments. + optimised []segment +} + +// newDataEncoder constructs a dataEncoder. +func newDataEncoder(t dataEncoderType) *dataEncoder { + d := &dataEncoder{} + + switch t { + case dataEncoderType1To9: + d = &dataEncoder{ + minVersion: 1, + maxVersion: 9, + numericModeIndicator: bitset.New(b0, b0, b0, b1), + alphanumericModeIndicator: bitset.New(b0, b0, b1, b0), + byteModeIndicator: bitset.New(b0, b1, b0, b0), + numNumericCharCountBits: 10, + numAlphanumericCharCountBits: 9, + numByteCharCountBits: 8, + } + case dataEncoderType10To26: + d = &dataEncoder{ + minVersion: 10, + maxVersion: 26, + numericModeIndicator: bitset.New(b0, b0, b0, b1), + alphanumericModeIndicator: bitset.New(b0, b0, b1, b0), + byteModeIndicator: bitset.New(b0, b1, b0, b0), + numNumericCharCountBits: 12, + numAlphanumericCharCountBits: 11, + numByteCharCountBits: 16, + } + case dataEncoderType27To40: + d = &dataEncoder{ + minVersion: 27, + maxVersion: 40, + numericModeIndicator: bitset.New(b0, b0, b0, b1), + alphanumericModeIndicator: bitset.New(b0, b0, b1, b0), + byteModeIndicator: bitset.New(b0, b1, b0, b0), + numNumericCharCountBits: 14, + numAlphanumericCharCountBits: 13, + numByteCharCountBits: 16, + } + default: + log.Panic("Unknown dataEncoderType") + } + + return d +} + +// encode data as one or more segments and return the encoded data. +// +// The returned data does not include the terminator bit sequence. +func (d *dataEncoder) encode(data []byte) (*bitset.Bitset, error) { + d.data = data + d.actual = nil + d.optimised = nil + + if len(data) == 0 { + return nil, errors.New("no data to encode") + } + + // Classify data into unoptimised segments. + d.classifyDataModes() + + // Optimise segments. + err := d.optimiseDataModes() + if err != nil { + return nil, err + } + + // Encode data. + encoded := bitset.New() + for _, s := range d.optimised { + d.encodeDataRaw(s.data, s.dataMode, encoded) + } + + return encoded, nil +} + +// classifyDataModes classifies the raw data into unoptimised segments. +// e.g. "123ZZ#!#!" => +// [numeric, 3, "123"] [alphanumeric, 2, "ZZ"] [byte, 4, "#!#!"]. +func (d *dataEncoder) classifyDataModes() { + var start int + mode := dataModeNone + + for i, v := range d.data { + newMode := dataModeNone + switch { + case v >= 0x30 && v <= 0x39: + newMode = dataModeNumeric + case v == 0x20 || v == 0x24 || v == 0x25 || v == 0x2a || v == 0x2b || v == + 0x2d || v == 0x2e || v == 0x2f || v == 0x3a || (v >= 0x41 && v <= 0x5a): + newMode = dataModeAlphanumeric + default: + newMode = dataModeByte + } + + if newMode != mode { + if i > 0 { + d.actual = append(d.actual, segment{dataMode: mode, data: d.data[start:i]}) + + start = i + } + + mode = newMode + } + } + + d.actual = append(d.actual, segment{dataMode: mode, data: d.data[start:len(d.data)]}) +} + +// optimiseDataModes optimises the list of segments to reduce the overall output +// encoded data length. +// +// The algorithm coalesces adjacent segments. segments are only coalesced when +// the Data Modes are compatible, and when the coalesced segment has a shorter +// encoded length than separate segments. +// +// Multiple segments may be coalesced. For example a string of alternating +// alphanumeric/numeric segments ANANANANA can be optimised to just A. +func (d *dataEncoder) optimiseDataModes() error { + for i := 0; i < len(d.actual); { + mode := d.actual[i].dataMode + numChars := len(d.actual[i].data) + + j := i + 1 + for j < len(d.actual) { + nextNumChars := len(d.actual[j].data) + nextMode := d.actual[j].dataMode + + if nextMode > mode { + break + } + + coalescedLength, err := d.encodedLength(mode, numChars+nextNumChars) + + if err != nil { + return err + } + + seperateLength1, err := d.encodedLength(mode, numChars) + + if err != nil { + return err + } + + seperateLength2, err := d.encodedLength(nextMode, nextNumChars) + + if err != nil { + return err + } + + if coalescedLength < seperateLength1+seperateLength2 { + j++ + numChars += nextNumChars + } else { + break + } + } + + optimised := segment{dataMode: mode, + data: make([]byte, 0, numChars)} + + for k := i; k < j; k++ { + optimised.data = append(optimised.data, d.actual[k].data...) + } + + d.optimised = append(d.optimised, optimised) + + i = j + } + + return nil +} + +// encodeDataRaw encodes data in dataMode. The encoded data is appended to +// encoded. +func (d *dataEncoder) encodeDataRaw(data []byte, dataMode dataMode, encoded *bitset.Bitset) { + modeIndicator := d.modeIndicator(dataMode) + charCountBits := d.charCountBits(dataMode) + + // Append mode indicator. + encoded.Append(modeIndicator) + + // Append character count. + encoded.AppendUint32(uint32(len(data)), charCountBits) + + // Append data. + switch dataMode { + case dataModeNumeric: + for i := 0; i < len(data); i += 3 { + charsRemaining := len(data) - i + + var value uint32 + bitsUsed := 1 + + for j := 0; j < charsRemaining && j < 3; j++ { + value *= 10 + value += uint32(data[i+j] - 0x30) + bitsUsed += 3 + } + encoded.AppendUint32(value, bitsUsed) + } + case dataModeAlphanumeric: + for i := 0; i < len(data); i += 2 { + charsRemaining := len(data) - i + + var value uint32 + for j := 0; j < charsRemaining && j < 2; j++ { + value *= 45 + value += encodeAlphanumericCharacter(data[i+j]) + } + + bitsUsed := 6 + if charsRemaining > 1 { + bitsUsed = 11 + } + + encoded.AppendUint32(value, bitsUsed) + } + case dataModeByte: + for _, b := range data { + encoded.AppendByte(b, 8) + } + } +} + +// modeIndicator returns the segment header bits for a segment of type dataMode. +func (d *dataEncoder) modeIndicator(dataMode dataMode) *bitset.Bitset { + switch dataMode { + case dataModeNumeric: + return d.numericModeIndicator + case dataModeAlphanumeric: + return d.alphanumericModeIndicator + case dataModeByte: + return d.byteModeIndicator + default: + log.Panic("Unknown data mode") + } + + return nil +} + +// charCountBits returns the number of bits used to encode the length of a data +// segment of type dataMode. +func (d *dataEncoder) charCountBits(dataMode dataMode) int { + switch dataMode { + case dataModeNumeric: + return d.numNumericCharCountBits + case dataModeAlphanumeric: + return d.numAlphanumericCharCountBits + case dataModeByte: + return d.numByteCharCountBits + default: + log.Panic("Unknown data mode") + } + + return 0 +} + +// encodedLength returns the number of bits required to encode n symbols in +// dataMode. +// +// The number of bits required is affected by: +// - QR code type - Mode Indicator length. +// - Data mode - number of bits used to represent data length. +// - Data mode - how the data is encoded. +// - Number of symbols encoded. +// +// An error is returned if the mode is not supported, or the length requested is +// too long to be represented. +func (d *dataEncoder) encodedLength(dataMode dataMode, n int) (int, error) { + modeIndicator := d.modeIndicator(dataMode) + charCountBits := d.charCountBits(dataMode) + + if modeIndicator == nil { + return 0, errors.New("mode not supported") + } + + maxLength := (1 << uint8(charCountBits)) - 1 + + if n > maxLength { + return 0, errors.New("length too long to be represented") + } + + length := modeIndicator.Len() + charCountBits + + switch dataMode { + case dataModeNumeric: + length += 10 * (n / 3) + + if n%3 != 0 { + length += 1 + 3*(n%3) + } + case dataModeAlphanumeric: + length += 11 * (n / 2) + length += 6 * (n % 2) + case dataModeByte: + length += 8 * n + } + + return length, nil +} + +// encodeAlphanumericChar returns the QR Code encoded value of v. +// +// v must be a QR Code defined alphanumeric character: 0-9, A-Z, SP, $%*+-./ or +// :. The characters are mapped to values in the range 0-44 respectively. +func encodeAlphanumericCharacter(v byte) uint32 { + c := uint32(v) + + switch { + case c >= '0' && c <= '9': + // 0-9 encoded as 0-9. + return c - '0' + case c >= 'A' && c <= 'Z': + // A-Z encoded as 10-35. + return c - 'A' + 10 + case c == ' ': + return 36 + case c == '$': + return 37 + case c == '%': + return 38 + case c == '*': + return 39 + case c == '+': + return 40 + case c == '-': + return 41 + case c == '.': + return 42 + case c == '/': + return 43 + case c == ':': + return 44 + default: + log.Panicf("encodeAlphanumericCharacter() with non alphanumeric char %v.", v) + } + + return 0 +} |