#!/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') # Edge case... if value == 0: return '00' # 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, padding=False): """ 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 = '%0.10g' % 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] elif padding: decimal = decimal + (precision - len(decimal)) * '0' 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'