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#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
gerber.utils
============
**Gerber and Excellon file handling utilities**
This module provides utility functions for working with Gerber and Excellon
files.
"""
# Author: Hamilton Kibbe <ham@hamiltonkib.be>
# 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'`
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:
(number of integer-part digits, number of decimal-part digits)
zero_suppression : string
Zero-suppression mode. May be 'leading' or 'trailing'
Returns
-------
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
if MAX_DIGITS > 13 or integer_digits > 6 or decimal_digits > 7:
raise ValueError('Parser only supports precision up to 6:7 format')
# Remove extraneous information
value = value.strip()
value = value.strip(' +')
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
`zero_suppression='trailing'`
Parameters
----------
value : float
A floating point value.
format : tuple (n=2)
Gerber/Excellon precision format expressed as a tuple containing:
(number of integer-part digits, number of decimal-part digits)
zero_suppression : string
Zero-suppression mode. May be 'leading' or 'trailing'
Returns
-------
value : string
The specified value as a Gerber/Excellon-formatted string.
"""
# 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
if negative:
value = -1.0 * value
# Format string for padding out in both directions
fmtstring = '%%0%d.0%df' % (MAX_DIGITS + 1, decimal_digits)
digits = [val for val in fmtstring % value if val != '.']
# 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 :
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('.')
elif ',' in floatstr:
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'
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