Updated Rust code to use wrapper struct for BitBuffer, to avoid repeatedly writing mutable borrows.

This commit is contained in:
Project Nayuki 2017-11-15 16:46:15 +00:00
parent 5a5626edb2
commit 27aad80052
2 changed files with 45 additions and 42 deletions

View File

@ -126,12 +126,12 @@ fn do_segment_demo() {
0x0000, 0x0104, 0x0105, 0x0113, 0x0115,
0x0000, 0x0208, 0x01FF, 0x0008,
];
let mut bb = Vec::<bool>::new();
let mut bb = qrcodegen::BitBuffer(Vec::new());
for c in &kanjichars {
qrcodegen::append_bits(&mut bb, *c, 13);
bb.append_bits(*c, 13);
}
let segs = vec![
QrSegment::new(qrcodegen::QrSegmentMode::Kanji, kanjichars.len(), bb),
QrSegment::new(qrcodegen::QrSegmentMode::Kanji, kanjichars.len(), bb.0),
];
let qr = QrCode::encode_segments(&segs, QrCodeEcc::Low).unwrap();
print_qr(&qr);

View File

@ -132,29 +132,29 @@ impl QrCode {
// Create the data bit string by concatenating all segments
let datacapacitybits: usize = QrCode::get_num_data_codewords(version, ecl) * 8;
let mut bb = Vec::<bool>::new();
let mut bb = BitBuffer(Vec::new());
for seg in segs {
append_bits(&mut bb, seg.mode.mode_bits(), 4);
append_bits(&mut bb, seg.numchars as u32, seg.mode.num_char_count_bits(version));
bb.extend_from_slice(&seg.data);
bb.append_bits(seg.mode.mode_bits(), 4);
bb.append_bits(seg.numchars as u32, seg.mode.num_char_count_bits(version));
bb.0.extend_from_slice(&seg.data);
}
// Add terminator and pad up to a byte if applicable
let numzerobits = std::cmp::min(4, datacapacitybits - bb.len());
append_bits(&mut bb, 0, numzerobits as u8);
let numzerobits = bb.len().wrapping_neg() & 7;
append_bits(&mut bb, 0, numzerobits as u8);
let numzerobits = std::cmp::min(4, datacapacitybits - bb.0.len());
bb.append_bits(0, numzerobits as u8);
let numzerobits = bb.0.len().wrapping_neg() & 7;
bb.append_bits(0, numzerobits as u8);
// Pad with alternate bytes until data capacity is reached
let mut padbyte: u32 = 0xEC;
while bb.len() < datacapacitybits {
append_bits(&mut bb, padbyte, 8);
while bb.0.len() < datacapacitybits {
bb.append_bits(padbyte, 8);
padbyte ^= 0xEC ^ 0x11;
}
assert_eq!(bb.len() % 8, 0, "Assertion error");
assert_eq!(bb.0.len() % 8, 0, "Assertion error");
let mut bytes = vec![0u8; bb.len() / 8];
for (i, bit) in bb.iter().enumerate() {
let mut bytes = vec![0u8; bb.0.len() / 8];
for (i, bit) in bb.0.iter().enumerate() {
bytes[i >> 3] |= (*bit as u8) << (7 - (i & 7));
}
@ -855,20 +855,18 @@ impl QrSegment {
// Returns a segment representing the given binary data encoded in byte mode.
pub fn make_bytes(data: &[u8]) -> QrSegment {
let mut bb = Vec::<bool>::with_capacity(data.len() * 8);
let mut bb = BitBuffer(Vec::with_capacity(data.len() * 8));
for b in data {
for i in (0 .. 8).rev() {
bb.push((b >> i) & 1u8 != 0u8);
}
bb.append_bits(*b as u32, 8);
}
QrSegment::new(QrSegmentMode::Byte, data.len(), bb)
QrSegment::new(QrSegmentMode::Byte, data.len(), bb.0)
}
// Returns a segment representing the given string of decimal digits encoded in numeric mode.
// Panics if the string contains non-digit characters.
pub fn make_numeric(text: &[char]) -> QrSegment {
let mut bb = Vec::<bool>::with_capacity(text.len() * 3 + (text.len() + 2) / 3);
let mut bb = BitBuffer(Vec::with_capacity(text.len() * 3 + (text.len() + 2) / 3));
let mut accumdata: u32 = 0;
let mut accumcount: u32 = 0;
for c in text {
@ -876,15 +874,15 @@ impl QrSegment {
accumdata = accumdata * 10 + ((*c as u32) - ('0' as u32));
accumcount += 1;
if accumcount == 3 {
append_bits(&mut bb, accumdata, 10);
bb.append_bits(accumdata, 10);
accumdata = 0;
accumcount = 0;
}
}
if accumcount > 0 { // 1 or 2 digits remaining
append_bits(&mut bb, accumdata, (accumcount as u8) * 3 + 1);
bb.append_bits(accumdata, (accumcount as u8) * 3 + 1);
}
QrSegment::new(QrSegmentMode::Numeric, text.len(), bb)
QrSegment::new(QrSegmentMode::Numeric, text.len(), bb.0)
}
@ -892,7 +890,7 @@ impl QrSegment {
// The characters allowed are: 0 to 9, A to Z (uppercase only), space, dollar, percent, asterisk,
// plus, hyphen, period, slash, colon. Panics if the string contains non-encodable characters.
pub fn make_alphanumeric(text: &[char]) -> QrSegment {
let mut bb = Vec::<bool>::with_capacity(text.len() * 5 + (text.len() + 1) / 2);
let mut bb = BitBuffer(Vec::with_capacity(text.len() * 5 + (text.len() + 1) / 2));
let mut accumdata: u32 = 0;
let mut accumcount: u32 = 0;
for c in text {
@ -903,15 +901,15 @@ impl QrSegment {
accumdata = accumdata * 45 + (i as u32);
accumcount += 1;
if accumcount == 2 {
append_bits(&mut bb, accumdata, 11);
bb.append_bits(accumdata, 11);
accumdata = 0;
accumcount = 0;
}
}
if accumcount > 0 { // 1 character remaining
append_bits(&mut bb, accumdata, 6);
bb.append_bits(accumdata, 6);
}
QrSegment::new(QrSegmentMode::Alphanumeric, text.len(), bb)
QrSegment::new(QrSegmentMode::Alphanumeric, text.len(), bb.0)
}
@ -934,19 +932,19 @@ impl QrSegment {
// Returns a segment representing an Extended Channel Interpretation
// (ECI) designator with the given assignment value.
pub fn make_eci(assignval: u32) -> QrSegment {
let mut bb = Vec::<bool>::with_capacity(24);
let mut bb = BitBuffer(Vec::with_capacity(24));
if assignval < (1 << 7) {
append_bits(&mut bb, assignval, 8);
bb.append_bits(assignval, 8);
} else if assignval < (1 << 14) {
append_bits(&mut bb, 2, 2);
append_bits(&mut bb, assignval, 14);
bb.append_bits(2, 2);
bb.append_bits(assignval, 14);
} else if assignval < 1_000_000 {
append_bits(&mut bb, 6, 3);
append_bits(&mut bb, assignval, 21);
bb.append_bits(6, 3);
bb.append_bits(assignval, 21);
} else {
panic!("ECI assignment value out of range");
}
QrSegment::new(QrSegmentMode::Eci, 0, bb)
QrSegment::new(QrSegmentMode::Eci, 0, bb.0)
}
@ -1078,11 +1076,16 @@ impl QrSegmentMode {
/*---- Bit buffer functionality ----*/
// Appends the given number of low bits of the given value
// to this sequence. Requires 0 <= val < 2^len.
pub fn append_bits(bb: &mut Vec<bool>, val: u32, len: u8) {
assert!(len < 32 && (val >> len) == 0 || len == 32, "Value out of range");
for i in (0 .. len).rev() { // Append bit by bit
bb.push((val >> i) & 1 != 0);
pub struct BitBuffer(pub Vec<bool>);
impl BitBuffer {
// Appends the given number of low bits of the given value
// to this sequence. Requires 0 <= val < 2^len.
pub fn append_bits(&mut self, val: u32, len: u8) {
assert!(len < 32 && (val >> len) == 0 || len == 32, "Value out of range");
for i in (0 .. len).rev() { // Append bit by bit
self.0.push((val >> i) & 1 != 0);
}
}
}