mirror of
https://github.com/starovoid/rxing.git
synced 2026-07-26 12:22:34 +00:00
move pdf417
This commit is contained in:
Henry Schimke
@@ -0,0 +1,632 @@
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import com.google.zxing.ChecksumException;
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import com.google.zxing.pdf417.PDF417Common;
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// NEW FILE: error_correction.rs
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/*
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* Copyright 2012 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// package com::google::zxing::pdf417::decoder::ec;
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/**
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* <p>PDF417 error correction implementation.</p>
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*
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* <p>This <a href="http://en.wikipedia.org/wiki/Reed%E2%80%93Solomon_error_correction#Example">example</a>
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* is quite useful in understanding the algorithm.</p>
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*
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* @author Sean Owen
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* @see com.google.zxing.common.reedsolomon.ReedSolomonDecoder
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*/
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pub struct ErrorCorrection {
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let mut field: ModulusGF;
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}
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impl ErrorCorrection {
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pub fn new() -> ErrorCorrection {
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let .field = ModulusGF::PDF417_GF;
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}
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/**
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* @param received received codewords
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* @param numECCodewords number of those codewords used for EC
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* @param erasures location of erasures
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* @return number of errors
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* @throws ChecksumException if errors cannot be corrected, maybe because of too many errors
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*/
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pub fn decode(&self, received: &Vec<i32>, num_e_c_codewords: i32, erasures: &Vec<i32>) -> /* throws ChecksumException */Result<i32, Rc<Exception>> {
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let poly: ModulusPoly = ModulusPoly::new(self.field, &received);
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const S: [i32; num_e_c_codewords] = [0; num_e_c_codewords];
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let mut error: bool = false;
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{
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let mut i: i32 = num_e_c_codewords;
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while i > 0 {
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{
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let eval: i32 = poly.evaluate_at(&self.field.exp(i));
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S[num_e_c_codewords - i] = eval;
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if eval != 0 {
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error = true;
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}
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}
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i -= 1;
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}
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}
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if !error {
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return Ok(0);
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}
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let known_errors: ModulusPoly = self.field.get_one();
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if erasures != null {
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for let erasure: i32 in erasures {
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let b: i32 = self.field.exp(received.len() - 1 - erasure);
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// Add (1 - bx) term:
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let term: ModulusPoly = ModulusPoly::new(self.field, : vec![i32; 2] = vec![self.field.subtract(0, b), 1, ]
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);
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known_errors = known_errors.multiply(term);
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}
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}
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let syndrome: ModulusPoly = ModulusPoly::new(self.field, &S);
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//syndrome = syndrome.multiply(knownErrors);
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let sigma_omega: Vec<ModulusPoly> = self.run_euclidean_algorithm(&self.field.build_monomial(num_e_c_codewords, 1), syndrome, num_e_c_codewords);
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let sigma: ModulusPoly = sigma_omega[0];
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let omega: ModulusPoly = sigma_omega[1];
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//sigma = sigma.multiply(knownErrors);
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let error_locations: Vec<i32> = self.find_error_locations(sigma);
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let error_magnitudes: Vec<i32> = self.find_error_magnitudes(omega, sigma, &error_locations);
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{
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let mut i: i32 = 0;
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while i < error_locations.len() {
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{
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let mut position: i32 = received.len() - 1 - self.field.log(error_locations[i]);
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if position < 0 {
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throw ChecksumException::get_checksum_instance();
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}
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received[position] = self.field.subtract(received[position], error_magnitudes[i]);
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}
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i += 1;
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}
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}
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return Ok(error_locations.len());
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}
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fn run_euclidean_algorithm(&self, a: &ModulusPoly, b: &ModulusPoly, R: i32) -> /* throws ChecksumException */Result<Vec<ModulusPoly>, Rc<Exception>> {
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// Assume a's degree is >= b's
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if a.get_degree() < b.get_degree() {
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let temp: ModulusPoly = a;
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a = b;
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b = temp;
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}
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let r_last: ModulusPoly = a;
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let mut r: ModulusPoly = b;
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let t_last: ModulusPoly = self.field.get_zero();
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let mut t: ModulusPoly = self.field.get_one();
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// Run Euclidean algorithm until r's degree is less than R/2
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while r.get_degree() >= R / 2 {
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let r_last_last: ModulusPoly = r_last;
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let t_last_last: ModulusPoly = t_last;
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r_last = r;
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t_last = t;
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// Divide rLastLast by rLast, with quotient in q and remainder in r
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if r_last.is_zero() {
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// Oops, Euclidean algorithm already terminated?
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throw ChecksumException::get_checksum_instance();
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}
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r = r_last_last;
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let mut q: ModulusPoly = self.field.get_zero();
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let denominator_leading_term: i32 = r_last.get_coefficient(&r_last.get_degree());
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let dlt_inverse: i32 = self.field.inverse(denominator_leading_term);
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while r.get_degree() >= r_last.get_degree() && !r.is_zero() {
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let degree_diff: i32 = r.get_degree() - r_last.get_degree();
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let scale: i32 = self.field.multiply(&r.get_coefficient(&r.get_degree()), dlt_inverse);
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q = q.add(&self.field.build_monomial(degree_diff, scale));
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r = r.subtract(&r_last.multiply_by_monomial(degree_diff, scale));
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}
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t = q.multiply(t_last).subtract(t_last_last).negative();
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}
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let sigma_tilde_at_zero: i32 = t.get_coefficient(0);
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if sigma_tilde_at_zero == 0 {
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throw ChecksumException::get_checksum_instance();
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}
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let inverse: i32 = self.field.inverse(sigma_tilde_at_zero);
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let sigma: ModulusPoly = t.multiply(inverse);
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let omega: ModulusPoly = r.multiply(inverse);
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return Ok( : vec![ModulusPoly; 2] = vec![sigma, omega, ]
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);
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}
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fn find_error_locations(&self, error_locator: &ModulusPoly) -> /* throws ChecksumException */Result<Vec<i32>, Rc<Exception>> {
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// This is a direct application of Chien's search
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let num_errors: i32 = error_locator.get_degree();
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let mut result: [i32; num_errors] = [0; num_errors];
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let mut e: i32 = 0;
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{
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let mut i: i32 = 1;
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while i < self.field.get_size() && e < num_errors {
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{
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if error_locator.evaluate_at(i) == 0 {
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result[e] = self.field.inverse(i);
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e += 1;
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}
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}
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i += 1;
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}
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}
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if e != num_errors {
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throw ChecksumException::get_checksum_instance();
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}
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return Ok(result);
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}
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fn find_error_magnitudes(&self, error_evaluator: &ModulusPoly, error_locator: &ModulusPoly, error_locations: &Vec<i32>) -> Vec<i32> {
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let error_locator_degree: i32 = error_locator.get_degree();
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if error_locator_degree < 1 {
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return : [i32; 0] = [0; 0];
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}
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let formal_derivative_coefficients: [i32; error_locator_degree] = [0; error_locator_degree];
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{
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let mut i: i32 = 1;
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while i <= error_locator_degree {
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{
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formal_derivative_coefficients[error_locator_degree - i] = self.field.multiply(i, &error_locator.get_coefficient(i));
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}
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i += 1;
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}
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}
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let formal_derivative: ModulusPoly = ModulusPoly::new(self.field, &formal_derivative_coefficients);
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// This is directly applying Forney's Formula
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let s: i32 = error_locations.len();
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let mut result: [i32; s] = [0; s];
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{
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let mut i: i32 = 0;
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while i < s {
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{
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let xi_inverse: i32 = self.field.inverse(error_locations[i]);
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let numerator: i32 = self.field.subtract(0, &error_evaluator.evaluate_at(xi_inverse));
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let denominator: i32 = self.field.inverse(&formal_derivative.evaluate_at(xi_inverse));
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result[i] = self.field.multiply(numerator, denominator);
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}
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i += 1;
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}
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}
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return result;
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}
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}
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// NEW FILE: modulus_g_f.rs
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/*
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* Copyright 2012 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// package com::google::zxing::pdf417::decoder::ec;
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/**
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* <p>A field based on powers of a generator integer, modulo some modulus.</p>
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*
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* @author Sean Owen
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* @see com.google.zxing.common.reedsolomon.GenericGF
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*/
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const PDF417_GF: ModulusGF = ModulusGF::new(PDF417Common.NUMBER_OF_CODEWORDS, 3);
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pub struct ModulusGF {
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let exp_table: Vec<i32>;
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let log_table: Vec<i32>;
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let mut zero: ModulusPoly;
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let mut one: ModulusPoly;
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let modulus: i32;
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}
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impl ModulusGF {
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fn new( modulus: i32, generator: i32) -> ModulusGF {
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let .modulus = modulus;
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exp_table = : [i32; modulus] = [0; modulus];
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log_table = : [i32; modulus] = [0; modulus];
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let mut x: i32 = 1;
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{
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let mut i: i32 = 0;
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while i < modulus {
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{
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exp_table[i] = x;
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x = (x * generator) % modulus;
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}
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i += 1;
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}
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}
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{
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let mut i: i32 = 0;
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while i < modulus - 1 {
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{
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log_table[exp_table[i]] = i;
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}
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i += 1;
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}
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}
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// logTable[0] == 0 but this should never be used
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zero = ModulusPoly::new(let , : vec![i32; 1] = vec![0, ]
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);
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one = ModulusPoly::new(let , : vec![i32; 1] = vec![1, ]
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);
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}
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fn get_zero(&self) -> ModulusPoly {
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return self.zero;
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}
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fn get_one(&self) -> ModulusPoly {
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return self.one;
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}
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fn build_monomial(&self, degree: i32, coefficient: i32) -> ModulusPoly {
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if degree < 0 {
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throw IllegalArgumentException::new();
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}
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if coefficient == 0 {
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return self.zero;
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}
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let mut coefficients: [i32; degree + 1] = [0; degree + 1];
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coefficients[0] = coefficient;
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return ModulusPoly::new(self, &coefficients);
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}
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fn add(&self, a: i32, b: i32) -> i32 {
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return (a + b) % self.modulus;
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}
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fn subtract(&self, a: i32, b: i32) -> i32 {
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return (self.modulus + a - b) % self.modulus;
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}
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fn exp(&self, a: i32) -> i32 {
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return self.exp_table[a];
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}
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fn log(&self, a: i32) -> i32 {
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if a == 0 {
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throw IllegalArgumentException::new();
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}
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return self.log_table[a];
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}
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fn inverse(&self, a: i32) -> i32 {
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if a == 0 {
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throw ArithmeticException::new();
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}
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return self.exp_table[self.modulus - self.log_table[a] - 1];
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}
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fn multiply(&self, a: i32, b: i32) -> i32 {
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if a == 0 || b == 0 {
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return 0;
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}
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return self.exp_table[(self.log_table[a] + self.log_table[b]) % (self.modulus - 1)];
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}
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fn get_size(&self) -> i32 {
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return self.modulus;
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}
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}
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// NEW FILE: modulus_poly.rs
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/*
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* Copyright 2012 ZXing 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
|
||||
*
|
||||
* http://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.
|
||||
*/
|
||||
// package com::google::zxing::pdf417::decoder::ec;
|
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|
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/**
|
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* @author Sean Owen
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*/
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struct ModulusPoly {
|
||||
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let field: ModulusGF;
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||||
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let coefficients: Vec<i32>;
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}
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||||
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impl ModulusPoly {
|
||||
|
||||
fn new( field: &ModulusGF, coefficients: &Vec<i32>) -> ModulusPoly {
|
||||
if coefficients.len() == 0 {
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throw IllegalArgumentException::new();
|
||||
}
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||||
let .field = field;
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||||
let coefficients_length: i32 = coefficients.len();
|
||||
if coefficients_length > 1 && coefficients[0] == 0 {
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||||
// Leading term must be non-zero for anything except the constant polynomial "0"
|
||||
let first_non_zero: i32 = 1;
|
||||
while first_non_zero < coefficients_length && coefficients[first_non_zero] == 0 {
|
||||
first_non_zero += 1;
|
||||
}
|
||||
if first_non_zero == coefficients_length {
|
||||
let .coefficients = : vec![i32; 1] = vec![0, ]
|
||||
;
|
||||
} else {
|
||||
let .coefficients = : [i32; coefficients_length - first_non_zero] = [0; coefficients_length - first_non_zero];
|
||||
System::arraycopy(&coefficients, first_non_zero, let .coefficients, 0, let .coefficients.len());
|
||||
}
|
||||
} else {
|
||||
let .coefficients = coefficients;
|
||||
}
|
||||
}
|
||||
|
||||
fn get_coefficients(&self) -> Vec<i32> {
|
||||
return self.coefficients;
|
||||
}
|
||||
|
||||
/**
|
||||
* @return degree of this polynomial
|
||||
*/
|
||||
fn get_degree(&self) -> i32 {
|
||||
return self.coefficients.len() - 1;
|
||||
}
|
||||
|
||||
/**
|
||||
* @return true iff this polynomial is the monomial "0"
|
||||
*/
|
||||
fn is_zero(&self) -> bool {
|
||||
return self.coefficients[0] == 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* @return coefficient of x^degree term in this polynomial
|
||||
*/
|
||||
fn get_coefficient(&self, degree: i32) -> i32 {
|
||||
return self.coefficients[self.coefficients.len() - 1 - degree];
|
||||
}
|
||||
|
||||
/**
|
||||
* @return evaluation of this polynomial at a given point
|
||||
*/
|
||||
fn evaluate_at(&self, a: i32) -> i32 {
|
||||
if a == 0 {
|
||||
// Just return the x^0 coefficient
|
||||
return self.get_coefficient(0);
|
||||
}
|
||||
if a == 1 {
|
||||
// Just the sum of the coefficients
|
||||
let mut result: i32 = 0;
|
||||
for let coefficient: i32 in self.coefficients {
|
||||
result = self.field.add(result, coefficient);
|
||||
}
|
||||
return result;
|
||||
}
|
||||
let mut result: i32 = self.coefficients[0];
|
||||
let size: i32 = self.coefficients.len();
|
||||
{
|
||||
let mut i: i32 = 1;
|
||||
while i < size {
|
||||
{
|
||||
result = self.field.add(&self.field.multiply(a, result), self.coefficients[i]);
|
||||
}
|
||||
i += 1;
|
||||
}
|
||||
}
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
fn add(&self, other: &ModulusPoly) -> ModulusPoly {
|
||||
if !self.field.equals(other.field) {
|
||||
throw IllegalArgumentException::new("ModulusPolys do not have same ModulusGF field");
|
||||
}
|
||||
if self.is_zero() {
|
||||
return other;
|
||||
}
|
||||
if other.is_zero() {
|
||||
return self;
|
||||
}
|
||||
let smaller_coefficients: Vec<i32> = self.coefficients;
|
||||
let larger_coefficients: Vec<i32> = other.coefficients;
|
||||
if smaller_coefficients.len() > larger_coefficients.len() {
|
||||
let temp: Vec<i32> = smaller_coefficients;
|
||||
smaller_coefficients = larger_coefficients;
|
||||
larger_coefficients = temp;
|
||||
}
|
||||
let sum_diff: [i32; larger_coefficients.len()] = [0; larger_coefficients.len()];
|
||||
let length_diff: i32 = larger_coefficients.len() - smaller_coefficients.len();
|
||||
// Copy high-order terms only found in higher-degree polynomial's coefficients
|
||||
System::arraycopy(&larger_coefficients, 0, &sum_diff, 0, length_diff);
|
||||
{
|
||||
let mut i: i32 = length_diff;
|
||||
while i < larger_coefficients.len() {
|
||||
{
|
||||
sum_diff[i] = self.field.add(smaller_coefficients[i - length_diff], larger_coefficients[i]);
|
||||
}
|
||||
i += 1;
|
||||
}
|
||||
}
|
||||
|
||||
return ModulusPoly::new(self.field, &sum_diff);
|
||||
}
|
||||
|
||||
fn subtract(&self, other: &ModulusPoly) -> ModulusPoly {
|
||||
if !self.field.equals(other.field) {
|
||||
throw IllegalArgumentException::new("ModulusPolys do not have same ModulusGF field");
|
||||
}
|
||||
if other.is_zero() {
|
||||
return self;
|
||||
}
|
||||
return self.add(&other.negative());
|
||||
}
|
||||
|
||||
fn multiply(&self, other: &ModulusPoly) -> ModulusPoly {
|
||||
if !self.field.equals(other.field) {
|
||||
throw IllegalArgumentException::new("ModulusPolys do not have same ModulusGF field");
|
||||
}
|
||||
if self.is_zero() || other.is_zero() {
|
||||
return self.field.get_zero();
|
||||
}
|
||||
let a_coefficients: Vec<i32> = self.coefficients;
|
||||
let a_length: i32 = a_coefficients.len();
|
||||
let b_coefficients: Vec<i32> = other.coefficients;
|
||||
let b_length: i32 = b_coefficients.len();
|
||||
let mut product: [i32; a_length + b_length - 1] = [0; a_length + b_length - 1];
|
||||
{
|
||||
let mut i: i32 = 0;
|
||||
while i < a_length {
|
||||
{
|
||||
let a_coeff: i32 = a_coefficients[i];
|
||||
{
|
||||
let mut j: i32 = 0;
|
||||
while j < b_length {
|
||||
{
|
||||
product[i + j] = self.field.add(product[i + j], &self.field.multiply(a_coeff, b_coefficients[j]));
|
||||
}
|
||||
j += 1;
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
i += 1;
|
||||
}
|
||||
}
|
||||
|
||||
return ModulusPoly::new(self.field, &product);
|
||||
}
|
||||
|
||||
fn negative(&self) -> ModulusPoly {
|
||||
let size: i32 = self.coefficients.len();
|
||||
let negative_coefficients: [i32; size] = [0; size];
|
||||
{
|
||||
let mut i: i32 = 0;
|
||||
while i < size {
|
||||
{
|
||||
negative_coefficients[i] = self.field.subtract(0, self.coefficients[i]);
|
||||
}
|
||||
i += 1;
|
||||
}
|
||||
}
|
||||
|
||||
return ModulusPoly::new(self.field, &negative_coefficients);
|
||||
}
|
||||
|
||||
fn multiply(&self, scalar: i32) -> ModulusPoly {
|
||||
if scalar == 0 {
|
||||
return self.field.get_zero();
|
||||
}
|
||||
if scalar == 1 {
|
||||
return self;
|
||||
}
|
||||
let size: i32 = self.coefficients.len();
|
||||
let mut product: [i32; size] = [0; size];
|
||||
{
|
||||
let mut i: i32 = 0;
|
||||
while i < size {
|
||||
{
|
||||
product[i] = self.field.multiply(self.coefficients[i], scalar);
|
||||
}
|
||||
i += 1;
|
||||
}
|
||||
}
|
||||
|
||||
return ModulusPoly::new(self.field, &product);
|
||||
}
|
||||
|
||||
fn multiply_by_monomial(&self, degree: i32, coefficient: i32) -> ModulusPoly {
|
||||
if degree < 0 {
|
||||
throw IllegalArgumentException::new();
|
||||
}
|
||||
if coefficient == 0 {
|
||||
return self.field.get_zero();
|
||||
}
|
||||
let size: i32 = self.coefficients.len();
|
||||
let mut product: [i32; size + degree] = [0; size + degree];
|
||||
{
|
||||
let mut i: i32 = 0;
|
||||
while i < size {
|
||||
{
|
||||
product[i] = self.field.multiply(self.coefficients[i], coefficient);
|
||||
}
|
||||
i += 1;
|
||||
}
|
||||
}
|
||||
|
||||
return ModulusPoly::new(self.field, &product);
|
||||
}
|
||||
|
||||
pub fn to_string(&self) -> String {
|
||||
let result: StringBuilder = StringBuilder::new(8 * self.get_degree());
|
||||
{
|
||||
let mut degree: i32 = self.get_degree();
|
||||
while degree >= 0 {
|
||||
{
|
||||
let mut coefficient: i32 = self.get_coefficient(degree);
|
||||
if coefficient != 0 {
|
||||
if coefficient < 0 {
|
||||
result.append(" - ");
|
||||
coefficient = -coefficient;
|
||||
} else {
|
||||
if result.length() > 0 {
|
||||
result.append(" + ");
|
||||
}
|
||||
}
|
||||
if degree == 0 || coefficient != 1 {
|
||||
result.append(coefficient);
|
||||
}
|
||||
if degree != 0 {
|
||||
if degree == 1 {
|
||||
result.append('x');
|
||||
} else {
|
||||
result.append("x^");
|
||||
result.append(degree);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
degree -= 1;
|
||||
}
|
||||
}
|
||||
|
||||
return result.to_string();
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
Reference in New Issue
Block a user