Fixed the initial value of the 16-bit CCITT algorithm.

Renamed the model from ccitt to crc-16-ccitt. Fixes #7. Thanks to Craig McQueen.
tpircher · Oct 25, 2015 · 78d3056 · 78d3056
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diff --git a/ChangeLog b/ChangeLog
@@ -1,3 +1,11 @@
+2015-10-25  Thomas Pircher   <tehpeh-pycrc@tty1.net>
+
+    * crc_models.py:
+    * doc/pycrc.xml:
+    Fixed the initial value of the 16-bit CCITT algorithm. Renamed the model
+    from ccitt to crc-16-ccitt.
+    Fixes #7. Thanks to Craig McQueen.
+
 2015-10-11  Thomas Pircher   <tehpeh-pycrc@tty1.net>
 
     * doc/pycrc.xml:

diff --git a/crc_algorithms.py b/crc_algorithms.py
@@ -40,9 +40,9 @@
 >>> crc = Crc(width = 16, poly = 0x8005,
 ...           reflect_in = True, xor_in = 0x0000,
 ...           reflect_out = True, xor_out = 0x0000)
->>> print("0x{0:x}".format(crc.bit_by_bit("123456789")))
->>> print("0x{0:x}".format(crc.bit_by_bit_fast("123456789")))
->>> print("0x{0:x}".format(crc.table_driven("123456789")))
+>>> print("{0:#x}".format(crc.bit_by_bit("123456789")))
+>>> print("{0:#x}".format(crc.bit_by_bit_fast("123456789")))
+>>> print("{0:#x}".format(crc.table_driven("123456789")))
 """
 
 # Class Crc

diff --git a/crc_models.py b/crc_models.py
@@ -147,14 +147,14 @@ class CrcModels(object):
         'check':         0xd64e,
     })
     models.append({
-        'name':         'ccitt',
+        'name':         'crc-16-ccitt',
         'width':         16,
         'poly':          0x1021,
         'reflect_in':    False,
-        'xor_in':        0xffff,
+        'xor_in':        0x1d0f,
         'reflect_out':   False,
         'xor_out':       0x0,
-        'check':         0x29b1,
+        'check':         0xe5cc,
     })
     models.append({
         'name':         'r-crc-16',

diff --git a/crc_symtable.py b/crc_symtable.py
@@ -1246,7 +1246,7 @@ def __pretty_hex(self, value, width=None):
         if width == None:
             return "{0:#x}".format(value)
         width = (width + 3) // 4
-        hex_str = "0x{{0:0{0:d}x}}".format(width)
+        hex_str = "{{0:#0{0:d}x}}".format(width + 2)
         return hex_str.format(value)
 
 

diff --git a/doc/pycrc.xml b/doc/pycrc.xml
@@ -223,7 +223,7 @@
                     <replaceable>crc-16-usb</replaceable>,
                     <replaceable>crc-16-modbus</replaceable>,
                     <replaceable>crc-16-genibus</replaceable>,
-                    <replaceable>ccitt</replaceable>,
+                    <replaceable>crc-16-ccitt</replaceable>,
                     <replaceable>r-crc-16</replaceable>,
                     <replaceable>kermit</replaceable>,
                     <replaceable>x-25</replaceable>,