From 3ca7797360e563aa6ebdcca10f388431f47f9377 Mon Sep 17 00:00:00 2001
From: sylnsfar <sylnsfar@gmail.com>
Date: Sat, 27 Aug 2016 11:27:09 +0800
Subject: [PATCH] complete ecc

---
 draw.py |  2 ++
 ecc.py  | 52 ++++++++++++++++++++++++++++++++++++----------------
 2 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/draw.py b/draw.py
index e458bc6..ea9736d 100644
--- a/draw.py
+++ b/draw.py
@@ -2,6 +2,7 @@
 
 from PIL import Image, ImageDraw
 
+# test:
 m1 = [[1]*7+[0]*7+[1]*7,
       [1,0,0,0,0,0,1]+[0]*7+[1,0,0,0,0,0,1],
       [1,0,1,1,1,0,1]+[0]*7+[1,0,1,1,1,0,1],
@@ -41,4 +42,5 @@ def draw_qrcode(qrmatrix):
     pic.save('qrcode.jpg')
     pic.show()
 
+# test:
 draw_qrcode(m1)
\ No newline at end of file
diff --git a/ecc.py b/ecc.py
index 7d38973..e74cc1d 100644
--- a/ecc.py
+++ b/ecc.py
@@ -2,31 +2,54 @@
 
 #GP: Generator Polynomial, MP: Message Polynomial
 # test:
-GP = [0, 251, 67, 46, 61, 118, 70, 64, 94, 32, 45]
+GP_list = {
+        7: [0, 87, 229, 146, 149, 238, 102, 21],
+        10: [0, 251, 67, 46, 61, 118, 70, 64, 94, 32, 45],
+        13: [0, 74, 152, 176, 100, 86, 100, 106, 104, 130, 218, 206, 140, 78],
+        15: [0, 8, 183, 61, 91, 202, 37, 51, 58, 58, 237, 140, 124, 5, 99, 105],
+        16: [0, 120, 104, 107, 109, 102, 161, 76, 3, 91, 191, 147, 169, 182, 194, 225, 120],
+        17: [0, 43, 139, 206, 78, 43, 239, 123, 206, 214, 147, 24, 99, 150, 39, 243, 163, 136],
+        18: [0, 215, 234, 158, 94, 184, 97, 118, 170, 79, 187, 152, 148, 252, 179, 5, 98, 96, 153],
+        20: [0, 17, 60, 79, 50, 61, 163, 26, 187, 202, 180, 221, 225, 83, 239, 156, 164, 212, 212, 188, 190],
+        22: [0, 210, 171, 247, 242, 93, 230, 14, 109, 221, 53, 200, 74, 8, 172, 98, 80, 219, 134, 160, 105, 165, 231],
+        23: [0, 229, 121, 135, 48, 211, 117, 251, 126, 159, 180, 169, 152, 192, 226, 228, 218, 111, 117, 232, 87, 96, 227, 21],
+        26: [0, 173, 125, 158, 2, 103, 182, 118, 17, 145, 201, 111, 28, 165, 53, 161, 21, 245, 142, 13, 102, 48, 227, 153, 145, 218, 70],
+        28: [0, 168, 223, 200, 104, 224, 234, 108, 180, 110, 190, 195, 147, 205, 27, 232, 201, 21, 43, 245, 87, 42, 195, 212, 119, 242, 37, 9, 123],
+        30: [0, 41, 173, 145, 152, 216, 31, 179, 182, 50, 48, 110, 86, 239, 96, 222, 125, 42, 173, 226, 193, 224, 130, 156, 37, 251, 216, 238, 40, 192, 180]
+        }
 
 #DC: Data Codewords, ECC: Error Correction Codewords
 def get_ECC(DC, ECC_num):
-    po2 = get_power_of_2_list()
-    log = get_log_list(po2)
-    
-    # ..... get the correct GP according to ECC_num
-    
+    GP = GP_list[ECC_num]    
     remainder = DC
     for i in range(len(DC)):
-        remainder = divide(remainder, GP)
+        remainder = divide(remainder, *GP)
     return remainder
     
-def divide(MP, GP):
+def divide(MP, *GP):
+    po2 = get_power_of_2_list()
+    log = get_log_list(po2)
+    GP = list(GP)
+    for i in range(len(GP)):
+        GP[i] += log[MP[0]]
+        if GP[i] > 255:
+            GP[i] %= 255
+        GP[i] = po2[GP[i]]
+    
+    return XOR(MP, GP)
+    
+    
+def XOR(MP, GP):
     a = len(MP) - len(GP)
     if a < 0:
         MP += [0] * (-a)
     elif a > 0:
         GP += [0] * a
     
-    log(MP[0])
-    
-def XOR():
-    pass
+    remainder = []
+    for i in range(1, len(MP)):
+        remainder.append(MP[i]^GP[i])
+    return remainder
     
 def get_power_of_2_list():
     po2 = [1]
@@ -41,7 +64,4 @@ def get_log_list(po2):
     log = [None]*256
     for i in range(255):
         log[po2[i]] = i
-    return log
-    
-# test:
-dc = '32, 91, 11, 120, 209, 114, 220, 77, 67, 64, 236, 17, 236, 17, 236, 17'
+    return log
\ No newline at end of file