added ExcellonFile class

1 files changed, 66 insertions, 42 deletions

diff --git a/gerber/utils.py b/gerber/utils.py
index 35b4fd0..625a9e1 100644
--- a/gerber/utils.py
+++ b/gerber/utils.py
@@ -10,28 +10,29 @@ files.
 """
 
 # Author: Hamilton Kibbe <ham@hamiltonkib.be>
-# License: 
+# License:
+
 
 def parse_gerber_value(value, format=(2, 5), zero_suppression='trailing'):
     """ Convert gerber/excellon formatted string to floating-point number
-    
+
     .. note::
-        Format and zero suppression are configurable. Note that the Excellon 
-        and Gerber formats use opposite terminology with respect to leading 
-        and trailing zeros. The Gerber format specifies which zeros are 
-        suppressed, while the Excellon format specifies which zeros are 
-        included. This function uses the Gerber-file convention, so an 
-        Excellon file in LZ (leading zeros) mode would use 
-        `zero_suppression='trailing'` 
-    
-    
+        Format and zero suppression are configurable. Note that the Excellon
+        and Gerber formats use opposite terminology with respect to leading
+        and trailing zeros. The Gerber format specifies which zeros are
+        suppressed, while the Excellon format specifies which zeros are
+        included. This function uses the Gerber-file convention, so an
+        Excellon file in LZ (leading zeros) mode would use
+        `zero_suppression='trailing'`
+
+
     Parameters
     ----------
     value : string
         A Gerber/Excellon-formatted string representing a numerical value.
 
     format :  tuple (int,int)
-        Gerber/Excellon precision format expressed as a tuple containing: 
+        Gerber/Excellon precision format expressed as a tuple containing:
         (number of integer-part digits, number of decimal-part digits)
 
     zero_suppression : string
@@ -41,12 +42,12 @@ def parse_gerber_value(value, format=(2, 5), zero_suppression='trailing'):
     -------
     value : float
         The specified value as a floating-point number.
-    
+
     """
     # Format precision
     integer_digits, decimal_digits = format
     MAX_DIGITS = integer_digits + decimal_digits
-    
+
     # Absolute maximum number of digits supported. This will handle up to
     # 6:7 format, which is somewhat supported, even though the gerber spec
     # only allows up to 6:6
@@ -59,40 +60,39 @@ def parse_gerber_value(value, format=(2, 5), zero_suppression='trailing'):
     negative = '-' in value
     if negative:
         value = value.strip(' -')
-        
+
     # Handle excellon edge case with explicit decimal. "That was easy!"
     if '.' in value:
         return float(value)
-    
+
     digits = [digit for digit in '0' * MAX_DIGITS]
     offset = 0 if zero_suppression == 'trailing' else (MAX_DIGITS - len(value))
     for i, digit in enumerate(value):
         digits[i + offset] = digit
-    
-    
+
     result = float(''.join(digits[:integer_digits] + ['.'] + digits[integer_digits:]))
     return -1.0 * result if negative else result
-    
-    
+
+
 def write_gerber_value(value, format=(2, 5), zero_suppression='trailing'):
     """ Convert a floating point number to a Gerber/Excellon-formatted string.
-    
+
     .. note::
-        Format and zero suppression are configurable. Note that the Excellon 
-        and Gerber formats use opposite terminology with respect to leading 
-        and trailing zeros. The Gerber format specifies which zeros are 
-        suppressed, while the Excellon format specifies which zeros are 
-        included. This function uses the Gerber-file convention, so an 
-        Excellon file in LZ (leading zeros) mode would use 
+        Format and zero suppression are configurable. Note that the Excellon
+        and Gerber formats use opposite terminology with respect to leading
+        and trailing zeros. The Gerber format specifies which zeros are
+        suppressed, while the Excellon format specifies which zeros are
+        included. This function uses the Gerber-file convention, so an
+        Excellon file in LZ (leading zeros) mode would use
         `zero_suppression='trailing'`
-    
+
     Parameters
     ----------
     value : float
         A floating point value.
 
     format :  tuple (n=2)
-        Gerber/Excellon precision format expressed as a tuple containing: 
+        Gerber/Excellon precision format expressed as a tuple containing:
         (number of integer-part digits, number of decimal-part digits)
 
     zero_suppression : string
@@ -106,12 +106,12 @@ def write_gerber_value(value, format=(2, 5), zero_suppression='trailing'):
     # Format precision
     integer_digits, decimal_digits = format
     MAX_DIGITS = integer_digits + decimal_digits
-    
+
     if MAX_DIGITS > 13 or integer_digits > 6 or decimal_digits > 7:
         raise ValueError('Parser only supports precision up to 6:7 format')
-    
+
     # negative sign affects padding, so deal with it at the end...
-    negative =  value < 0.0
+    negative = value < 0.0
     if negative:
         value = -1.0 * value
 
@@ -119,48 +119,72 @@ def write_gerber_value(value, format=(2, 5), zero_suppression='trailing'):
     fmtstring = '%%0%d.0%df' % (MAX_DIGITS + 1, decimal_digits)
 
     digits = [val for val in fmtstring % value if val != '.']
-    
-    # Suppression... 
+
+    # Suppression...
     if zero_suppression == 'trailing':
         while digits[-1] == '0':
             digits.pop()
     else:
         while digits[0] == '0':
             digits.pop(0)
-        
+
     return ''.join(digits) if not negative else ''.join(['-'] + digits)
-    
 
 
 def decimal_string(value, precision=6):
     """ Convert float to string with limited precision
-    
+
     Parameters
     ----------
     value : float
         A floating point value.
 
-    precision :  
+    precision :
         Maximum number of decimal places to print
 
     Returns
     -------
     value : string
         The specified value as a  string.
-    
+
     """
     floatstr = '%0.20g' % value
     integer = None
     decimal = None
     if '.' in floatstr:
-        integer, decimal = floatstr.split('.') 
+        integer, decimal = floatstr.split('.')
     elif ',' in floatstr:
-        integer, decimal = floatstr.split(',') 
+        integer, decimal = floatstr.split(',')
     if len(decimal) > precision:
         decimal = decimal[:precision]
     if integer or decimal:
         return ''.join([integer, '.', decimal])
     else:
         return int(floatstr)
-    
 
+
+def detect_file_format(filename):
+    """ Determine format of a file
+
+    Parameters
+    ----------
+    filename : string
+        Filename of the file to read.
+
+    Returns
+    -------
+    format : string
+        File format. either 'excellon' or 'rs274x'
+    """
+
+    # Read the first 20 lines
+    with open(filename, 'r') as f:
+        lines = [next(f) for x in xrange(20)]
+
+    # Look for
+    for line in lines:
+        if 'M48' in line:
+            return 'excellon'
+        elif '%FS' in line:
+            return'rs274x'
+    return 'unknown'