diff --git a/src/common/cpp_essentials/concentric_finder.rs b/src/common/cpp_essentials/concentric_finder.rs
index fa6e48e..d33fae5 100644
--- a/src/common/cpp_essentials/concentric_finder.rs
+++ b/src/common/cpp_essentials/concentric_finder.rs
@@ -5,9 +5,11 @@ use crate::{
         },
         BitMatrix, Quadrilateral,
     },
-    point, Point,
+    point, Point, Exceptions,
 };
 
+use crate::common::Result;
+
 use super::{
     BitMatrixCursorTrait, EdgeTracer, FastEdgeToEdgeCounter, Pattern, RegressionLine,
     RegressionLineTrait, UpdateMinMax, UpdateMinMaxFloat,
@@ -223,7 +225,7 @@ pub fn CenterOfRing(
         neighbourMask |= 1
             << (4.0
                 + Point::dot(
-                    Point::round(Point::bresenhamDirection(cur.p() - center)),
+                    Point::floor(Point::bresenhamDirection(cur.p() - center)),
                     point(1.0, 3.0),
                 )) as u32;
 
@@ -400,12 +402,27 @@ pub fn FitQadrilateralToPoints(center: Point, points: &mut [Point]) -> Option<Qu
         points.iter().position(|p| *p == corners[3])?,
     ];
 
-    let lines = [
-        RegressionLine::with_point_slice(&points[corner_positions[0] + 1..corner_positions[1]]),
-        RegressionLine::with_point_slice(&points[corner_positions[1] + 1..corner_positions[2]]),
-        RegressionLine::with_point_slice(&points[corner_positions[2] + 1..corner_positions[3]]),
-        RegressionLine::with_point_slice(&points[corner_positions[3] + 1..points.len()]),
+    let try_get_range = |a:usize, b:usize| -> Option<&[Point]> {
+        if a > b {
+            None
+        }else{
+            Some(&points[a + 1..b])
+        }
+    };
+
+let lines = [
+        RegressionLine::with_point_slice(try_get_range(corner_positions[0],corner_positions[1])?),
+        RegressionLine::with_point_slice(try_get_range(corner_positions[1],corner_positions[2])?),
+        RegressionLine::with_point_slice(try_get_range(corner_positions[2],corner_positions[3])?),
+        RegressionLine::with_point_slice(try_get_range(corner_positions[3],points.len())?),
     ];
+
+    // let lines = [
+    //     RegressionLine::with_point_slice(&points[corner_positions[0] + 1..corner_positions[1]]),
+    //     RegressionLine::with_point_slice(&points[corner_positions[1] + 1..corner_positions[2]]),
+    //     RegressionLine::with_point_slice(&points[corner_positions[2] + 1..corner_positions[3]]),
+    //     RegressionLine::with_point_slice(&points[corner_positions[3] + 1..points.len()]),
+    // ];
     // std::array lines{RegressionLine{corners[0] + 1, corners[1]}, RegressionLine{corners[1] + 1, corners[2]},
     // 				 RegressionLine{corners[2] + 1, corners[3]}, RegressionLine{corners[3] + 1, &points.back() + 1}};
     if lines.iter().any(|line| !line.isValid()) {
diff --git a/src/common/cpp_essentials/dm_regression_line.rs b/src/common/cpp_essentials/dm_regression_line.rs
index 2c4dfd8..74f4a8b 100644
--- a/src/common/cpp_essentials/dm_regression_line.rs
+++ b/src/common/cpp_essentials/dm_regression_line.rs
@@ -225,7 +225,7 @@ impl RegressionLineTrait for DMRegressionLine {
 impl DMRegressionLine {
     pub fn new(point_1: Point, point_2: Point) -> Self {
         let mut new = Self::default();
-        RegressionLineTrait::evaluate(&mut new, &[point_1, point_1]);
+        RegressionLineTrait::evaluate(&mut new, &[point_1, point_2]);
         new
     }
 
diff --git a/src/common/eci_string_builder.rs b/src/common/eci_string_builder.rs
index c5166bb..ea29d17 100644
--- a/src/common/eci_string_builder.rs
+++ b/src/common/eci_string_builder.rs
@@ -128,7 +128,7 @@ impl ECIStringBuilder {
 
             let ecis = self.list_ecis();
 
-            if ecis.len() <= 1 && (ecis.contains(&Eci::Unknown)) {
+            if ecis.len() == 1 && (ecis.contains(&Eci::Unknown)) {
                 self.has_eci = false;
             }
         }
diff --git a/src/multi_use_multi_format_reader.rs b/src/multi_use_multi_format_reader.rs
index 16ecb18..17245f0 100644
--- a/src/multi_use_multi_format_reader.rs
+++ b/src/multi_use_multi_format_reader.rs
@@ -17,6 +17,7 @@
 use std::collections::{HashMap, HashSet};
 
 use crate::common::Result;
+use crate::qrcode::cpp_port::QrReader;
 use crate::{
     aztec::AztecReader, datamatrix::DataMatrixReader, maxicode::MaxiCodeReader,
     oned::MultiFormatOneDReader, pdf417::PDF417Reader, qrcode::QRCodeReader, BarcodeFormat,
@@ -43,6 +44,7 @@ pub struct MultiUseMultiFormatReader {
     aztec_reader: AztecReader,
     pdf417_reader: PDF417Reader,
     maxicode_reader: MaxiCodeReader,
+    cpp_qrcode_reader: QrReader,
 }
 
 impl Reader for MultiUseMultiFormatReader {
@@ -84,6 +86,7 @@ impl Reader for MultiUseMultiFormatReader {
         self.aztec_reader.reset();
         self.pdf417_reader.reset();
         self.maxicode_reader.reset();
+        self.cpp_qrcode_reader.reset();
     }
 }
 
@@ -174,7 +177,15 @@ impl MultiUseMultiFormatReader {
             for possible_format in self.possible_formats.iter() {
                 let res = match possible_format {
                     BarcodeFormat::QR_CODE => {
-                        self.qr_code_reader.decode_with_hints(image, &self.hints)
+                        let a = self.qr_code_reader.decode_with_hints(image, &self.hints);
+                        if a.is_ok() {
+                            a
+                        }else {
+                            self.cpp_qrcode_reader.decode_with_hints(image, &self.hints)
+                        }
+                    }
+                    BarcodeFormat::MICRO_QR_CODE => {
+                        self.cpp_qrcode_reader.decode_with_hints(image, &self.hints)
                     }
                     BarcodeFormat::DATA_MATRIX => self
                         .data_matrix_reader
diff --git a/tests/cpp_qr_code_blackbox_tests.rs b/tests/cpp_qr_code_blackbox_tests.rs
index d4517f8..493cf4d 100644
--- a/tests/cpp_qr_code_blackbox_tests.rs
+++ b/tests/cpp_qr_code_blackbox_tests.rs
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-use rxing::{qrcode::cpp_port::QrReader, BarcodeFormat};
+use rxing::{qrcode::cpp_port::QrReader, BarcodeFormat, MultiUseMultiFormatReader};
 
 mod common;
 
@@ -187,7 +187,7 @@ fn cpp_qrcode_black_box2_test_case() {
     let mut tester = common::AbstractBlackBoxTestCase::new(
         "test_resources/blackbox/cpp/qrcode-2",
         // MultiFormatReader::default(),
-        QrReader {},
+        QrReader::default(),
         BarcodeFormat::QR_CODE,
     );
     tester.add_test(45, 47, 0.0);