Allow files to be read from strings per #37

Adds a loads() method to the top level module which generates a GerberFile or ExcellonFile from a string

10 files changed, 140 insertions, 53 deletions

diff --git a/examples/cairo_example.py b/examples/cairo_example.py
index 49c4d0c..a312e89 100644
--- a/examples/cairo_example.py
+++ b/examples/cairo_example.py
@@ -30,9 +30,6 @@ from gerber.render import GerberCairoContext
 GERBER_FOLDER = os.path.abspath(os.path.join(os.path.dirname(__file__), 'gerbers'))
 
 
-
-
-
 # Open the gerber files
 copper = read(os.path.join(GERBER_FOLDER, 'copper.GTL'))
 mask = read(os.path.join(GERBER_FOLDER, 'soldermask.GTS'))
diff --git a/gerber/__init__.py b/gerber/__init__.py
index 1a11159..b5a9014 100644
--- a/gerber/__init__.py
+++ b/gerber/__init__.py
@@ -23,4 +23,4 @@ gerber-tools provides utilities for working with Gerber (RS-274X) and Excellon
 files in python.
 """
 
-from .common import read
\ No newline at end of file
+from .common import read, loads
\ No newline at end of file
diff --git a/gerber/common.py b/gerber/common.py
index 78da2cd..50ba728 100644
--- a/gerber/common.py
+++ b/gerber/common.py
@@ -15,6 +15,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from . import rs274x
+from . import excellon
+from .utils import detect_file_format
+
 
 def read(filename):
     """ Read a gerber or excellon file and return a representative object.
@@ -30,10 +34,9 @@ def read(filename):
         CncFile object representing the file, either GerberFile or
         ExcellonFile. Returns None if file is not an Excellon or Gerber file.
     """
-    from . import rs274x
-    from . import excellon
-    from .utils import detect_file_format
-    fmt = detect_file_format(filename)
+    with open(filename, 'r') as f:
+        data = f.read()    
+    fmt = detect_file_format(data)
     if fmt == 'rs274x':
         return rs274x.read(filename)
     elif fmt == 'excellon':
@@ -41,3 +44,28 @@ def read(filename):
     else:
         raise TypeError('Unable to detect file format')
 
+def loads(data):
+    """ Read gerber or excellon file contents from a string and return a
+    representative object.
+
+    Parameters
+    ----------
+    data : string
+        gerber or excellon file contents as a string.
+
+    Returns
+    -------
+    file : CncFile subclass
+        CncFile object representing the file, either GerberFile or
+        ExcellonFile. Returns None if file is not an Excellon or Gerber file.
+    """
+    
+    fmt = detect_file_format(data)
+    if fmt == 'rs274x':
+        return rs274x.loads(data)
+    elif fmt == 'excellon':
+        return excellon.loads(data)
+    else:
+        raise TypeError('Unable to detect file format')
+
+
diff --git a/gerber/excellon.py b/gerber/excellon.py
index d89b349..ba8573d 100755
--- a/gerber/excellon.py
+++ b/gerber/excellon.py
@@ -25,6 +25,7 @@ This module provides Excellon file classes and parsing utilities
 

 import math

 import operator

+from cStringIO import StringIO

 

 from .excellon_statements import *

 from .cam import CamFile, FileSettings

@@ -46,9 +47,28 @@ def read(filename):
 

     """

     # File object should use settings from source file by default.

-    settings = FileSettings(**detect_excellon_format(filename))

+    with open(filename, 'r') as f:

+        data = f.read()

+    settings = FileSettings(**detect_excellon_format(data))

     return ExcellonParser(settings).parse(filename)

 

+def loads(data):

+    """ Read data from string and return an ExcellonFile

+    Parameters

+    ----------

+    data : string

+        string containing Excellon file contents

+

+    Returns

+    -------

+    file : :class:`gerber.excellon.ExcellonFile`

+        An ExcellonFile created from the specified file.

+

+    """

+    # File object should use settings from source file by default.

+    settings = FileSettings(**detect_excellon_format(data))

+    return ExcellonParser(settings).parse_raw(data)

+

 

 class DrillHit(object):

     def __init__(self, tool, position):

@@ -302,9 +322,12 @@ class ExcellonParser(object):
 

     def parse(self, filename):

         with open(filename, 'r') as f:

-            for line in f:

-                self._parse(line.strip())

-                

+            data = f.read()

+        return self.parse_raw(data, filename)

+

+    def parse_raw(self, data, filename=None):

+        for line in StringIO(data):

+            self._parse(line.strip())

         for stmt in self.statements:

             stmt.units = self.units

         return ExcellonFile(self.statements, self.tools, self.hits,

@@ -428,14 +451,13 @@ class ExcellonParser(object):
                             zeros=self.zeros, notation=self.notation)

 

 

-def detect_excellon_format(filename):

+def detect_excellon_format(data=None, filename=None):

     """ Detect excellon file decimal format and zero-suppression settings.

 

     Parameters

     ----------

-    filename : string

-        Name of the file to parse. This does not check if the file is actually

-        an Excellon file, so do that before calling this.

+    data : string

+        String containing contents of Excellon file.

 

     Returns

     -------

@@ -449,10 +471,16 @@ def detect_excellon_format(filename):
     detected_format = None

     zeros_options = ('leading', 'trailing', )

     format_options = ((2, 4), (2, 5), (3, 3),)

+    

+    if data is None and filename is None:

+        raise ValueError('Either data or filename arguments must be provided')

+    if data is None:

+        with open(filename, 'r') as f:

+            data = f.read()

 

     # Check for obvious clues:

     p = ExcellonParser()

-    p.parse(filename)

+    p.parse_raw(data)

 

     # Get zero_suppression from a unit statement

     zero_statements = [stmt.zeros for stmt in p.statements

@@ -485,8 +513,8 @@ def detect_excellon_format(filename):
             settings = FileSettings(zeros=zeros, format=fmt)

             try:

                 p = ExcellonParser(settings)

-                p.parse(filename)

-                size = tuple([t[1] - t[0] for t in p.bounds])

+                p.parse_raw(data)

+                size = tuple([t[0] - t[1] for t in p.bounds])

                 hole_area = 0.0

                 for hit in p.hits:

                     tool = hit.tool

diff --git a/gerber/render/cairo_backend.py b/gerber/render/cairo_backend.py
index a97e552..345f331 100644
--- a/gerber/render/cairo_backend.py
+++ b/gerber/render/cairo_backend.py
@@ -172,3 +172,9 @@ class GerberCairoContext(GerberContext):
 

         else:

             self.surface.write_to_png(filename)

+            

+    def dump_svg_str(self):

+        self.surface.finish()

+        self.surface_buffer.flush()

+        return self.surface_buffer.read()

+    
\ No newline at end of file
diff --git a/gerber/render/render.py b/gerber/render/render.py
index 124e743..8f49796 100644
--- a/gerber/render/render.py
+++ b/gerber/render/render.py
@@ -181,3 +181,4 @@ class GerberContext(object):
 
     def _render_test_record(self, primitive, color):
         pass
+
diff --git a/gerber/rs274x.py b/gerber/rs274x.py
index 1df3646..000f7a1 100644
--- a/gerber/rs274x.py
+++ b/gerber/rs274x.py
@@ -21,6 +21,7 @@
 import copy
 import json
 import re
+from cStringIO import StringIO
 
 from .gerber_statements import *
 from .primitives import *
@@ -43,6 +44,9 @@ def read(filename):
     return GerberParser().parse(filename)
 
 
+def loads(data):
+    return GerberParser().parse_raw(data)
+
 class GerberFile(CamFile):
     """ A class representing a single gerber file
 
@@ -75,7 +79,6 @@ class GerberFile(CamFile):
     def __init__(self, statements, settings, primitives, filename=None):
         super(GerberFile, self).__init__(statements, settings, primitives, filename)
 
-
     @property
     def comments(self):
         return [comment.comment for comment in self.statements
@@ -205,12 +208,14 @@ class GerberParser(object):
         self.quadrant_mode = 'multi-quadrant'
         self.step_and_repeat = (1, 1, 0, 0)
 
-
     def parse(self, filename):
-        fp = open(filename, "r")
-        data = fp.readlines()
+        with open(filename, "r") as fp:
+            data = fp.read()
+        return self.parse_raw(data, filename=None)
 
-        for stmt in self._parse(data):
+    def parse_raw(self, data, filename=None):
+        lines = [line for line in StringIO(data)]
+        for stmt in self._parse(lines):
             self.evaluate(stmt)
             self.statements.append(stmt)
 
@@ -225,10 +230,10 @@ class GerberParser(object):
         return json.dumps(stmts)
 
     def dump_str(self):
-        s = ""
+        string = ""
         for stmt in self.statements:
-            s += str(stmt) + "\n"
-        return s
+            string += str(stmt) + "\n"
+        return string
 
     def _parse(self, data):
         oldline = ''
@@ -404,7 +409,6 @@ class GerberParser(object):
         else:
             raise Exception("Invalid statement to evaluate")
 
-
     def _define_aperture(self, d, shape, modifiers):
         aperture = None
         if shape == 'C':
@@ -490,7 +494,7 @@ class GerberParser(object):
                         self.current_region = [Arc(start, end, center, self.direction, self.apertures[self.aperture], level_polarity=self.level_polarity, units=self.settings.units),]
                     else:
                         self.current_region.append(Arc(start, end, center, self.direction, self.apertures[self.aperture], level_polarity=self.level_polarity, units=self.settings.units))
-                                
+
         elif self.op == "D02":
             pass
 
diff --git a/gerber/tests/test_common.py b/gerber/tests/test_common.py
index 76e3991..0ba4b68 100644
--- a/gerber/tests/test_common.py
+++ b/gerber/tests/test_common.py
@@ -2,7 +2,7 @@
 # -*- coding: utf-8 -*-
 
 # Author: Hamilton Kibbe <ham@hamiltonkib.be>
-from ..common import read
+from ..common import read, loads
 from ..excellon import ExcellonFile
 from ..rs274x import GerberFile
 from .tests import *
@@ -23,9 +23,20 @@ def test_file_type_detection():
     assert_true(isinstance(ncdrill, ExcellonFile))
     assert_true(isinstance(top_copper, GerberFile))
 
+
+def test_load_from_string():
+    with open(NCDRILL_FILE, 'r') as f:
+        ncdrill = loads(f.read())
+    with open(TOP_COPPER_FILE, 'r') as f:
+        top_copper = loads(f.read())
+    assert_true(isinstance(ncdrill, ExcellonFile))
+    assert_true(isinstance(top_copper, GerberFile))
+    
+
 def test_file_type_validation():
     """ Test file format validation
     """
     assert_raises(TypeError, read, 'LICENSE')
 
 
+
diff --git a/gerber/tests/test_excellon.py b/gerber/tests/test_excellon.py
index 006277d..b821649 100644
--- a/gerber/tests/test_excellon.py
+++ b/gerber/tests/test_excellon.py
@@ -11,41 +11,51 @@ from .tests import *
 
 
 NCDRILL_FILE = os.path.join(os.path.dirname(__file__),
-                                'resources/ncdrill.DRD')
+                            'resources/ncdrill.DRD')
 
 def test_format_detection():
     """ Test file type detection
     """
-    settings = detect_excellon_format(NCDRILL_FILE)
+    with open(NCDRILL_FILE) as f:
+        data = f.read()
+    settings = detect_excellon_format(data)
     assert_equal(settings['format'], (2, 4))
     assert_equal(settings['zeros'], 'trailing')
 
+    settings = detect_excellon_format(filename=NCDRILL_FILE)
+    assert_equal(settings['format'], (2, 4))
+    assert_equal(settings['zeros'], 'trailing')
+
+
 def test_read():
     ncdrill = read(NCDRILL_FILE)
     assert(isinstance(ncdrill, ExcellonFile))
 
+
 def test_write():
     ncdrill = read(NCDRILL_FILE)
     ncdrill.write('test.ncd')
     with open(NCDRILL_FILE) as src:
-            srclines = src.readlines()
-            
+        srclines = src.readlines()
     with open('test.ncd') as res:
-            for idx, line in enumerate(res):
-                assert_equal(line.strip(), srclines[idx].strip())
+        for idx, line in enumerate(res):
+            assert_equal(line.strip(), srclines[idx].strip())
     os.remove('test.ncd')
 
+
 def test_read_settings():
     ncdrill = read(NCDRILL_FILE)
     assert_equal(ncdrill.settings['format'], (2, 4))
     assert_equal(ncdrill.settings['zeros'], 'trailing')
 
+
 def test_bounds():
     ncdrill = read(NCDRILL_FILE)
     xbound, ybound = ncdrill.bounds
     assert_array_almost_equal(xbound, (0.1300, 2.1430))
     assert_array_almost_equal(ybound, (0.3946, 1.7164))
 
+
 def test_report():
     ncdrill = read(NCDRILL_FILE)
 
@@ -57,9 +67,7 @@ def test_conversion():
     ncdrill_inch = copy.deepcopy(ncdrill)
     ncdrill.to_metric()
     assert_equal(ncdrill.settings.units, 'metric')
-
     inch_primitives = ncdrill_inch.primitives
-    
     for tool in iter(ncdrill_inch.tools.values()):
         tool.to_metric()
     for primitive in inch_primitives:
@@ -80,26 +88,31 @@ def test_parser_hole_count():
     p.parse(NCDRILL_FILE)
     assert_equal(p.hole_count, 36)
 
+
 def test_parser_hole_sizes():
     settings = FileSettings(**detect_excellon_format(NCDRILL_FILE))
     p = ExcellonParser(settings)
     p.parse(NCDRILL_FILE)
     assert_equal(p.hole_sizes, [0.0236, 0.0354, 0.04, 0.126, 0.128])
 
+
 def test_parse_whitespace():
     p = ExcellonParser(FileSettings())
     assert_equal(p._parse('         '), None)
 
+
 def test_parse_comment():
     p = ExcellonParser(FileSettings())
     p._parse(';A comment')
     assert_equal(p.statements[0].comment, 'A comment')
 
+
 def test_parse_format_comment():
     p = ExcellonParser(FileSettings())
     p._parse('; FILE_FORMAT=9:9 ')
     assert_equal(p.format, (9, 9))
 
+
 def test_parse_header():
     p = ExcellonParser(FileSettings())
     p._parse('M48   ')
@@ -107,6 +120,7 @@ def test_parse_header():
     p._parse('M95   ')
     assert_equal(p.state, 'DRILL')
 
+
 def test_parse_rout():
     p = ExcellonParser(FileSettings())
     p._parse('G00  ')
@@ -114,6 +128,7 @@ def test_parse_rout():
     p._parse('G05 ')
     assert_equal(p.state, 'DRILL')
 
+
 def test_parse_version():
     p = ExcellonParser(FileSettings())
     p._parse('VER,1  ')
@@ -121,6 +136,7 @@ def test_parse_version():
     p._parse('VER,2  ')
     assert_equal(p.statements[1].version, 2)
 
+
 def test_parse_format():
     p = ExcellonParser(FileSettings())
     p._parse('FMAT,1  ')
@@ -128,6 +144,7 @@ def test_parse_format():
     p._parse('FMAT,2  ')
     assert_equal(p.statements[1].format, 2)
 
+
 def test_parse_units():
     settings = FileSettings(units='inch', zeros='trailing')
     p = ExcellonParser(settings)
@@ -138,6 +155,7 @@ def test_parse_units():
     assert_equal(p.units, 'metric')
     assert_equal(p.zeros, 'leading')
 
+
 def test_parse_incremental_mode():
     settings = FileSettings(units='inch', zeros='trailing')
     p = ExcellonParser(settings)
@@ -147,6 +165,7 @@ def test_parse_incremental_mode():
     p._parse('ICI,OFF  ')
     assert_equal(p.notation, 'absolute')
 
+
 def test_parse_absolute_mode():
     settings = FileSettings(units='inch', zeros='trailing')
     p = ExcellonParser(settings)
@@ -156,18 +175,21 @@ def test_parse_absolute_mode():
     p._parse('G90  ')
     assert_equal(p.notation, 'absolute')
 
+
 def test_parse_repeat_hole():
     p = ExcellonParser(FileSettings())
     p.active_tool = ExcellonTool(FileSettings(), number=8)
     p._parse('R03X1.5Y1.5')
     assert_equal(p.statements[0].count, 3)
 
+
 def test_parse_incremental_position():
     p = ExcellonParser(FileSettings(notation='incremental'))
     p._parse('X01Y01')
     p._parse('X01Y01')
     assert_equal(p.pos, [2.,2.])
 
+
 def test_parse_unknown():
     p = ExcellonParser(FileSettings())
     p._parse('Not A Valid Statement')
diff --git a/gerber/utils.py b/gerber/utils.py
index df26516..1c0af52 100644
--- a/gerber/utils.py
+++ b/gerber/utils.py
@@ -201,30 +201,20 @@ def decimal_string(value, precision=6, padding=False):
         return int(floatstr)
 
 
-def detect_file_format(filename):
+def detect_file_format(data):
     """ Determine format of a file
 
     Parameters
     ----------
-    filename : string
-        Filename of the file to read.
+    data : string
+        string containing file data.
 
     Returns
     -------
     format : string
-        File format. either 'excellon' or 'rs274x'
+        File format. 'excellon' or 'rs274x' or 'unknown'
     """
-
-    # Read the first 20 lines (if possible)
-    lines = []
-    with open(filename, 'r') as f:
-        try:
-            for i in range(20):
-                lines.append(f.readline())
-        except StopIteration:
-            pass
-
-    # Look for
+    lines = data.split('\n')
     for line in lines:
         if 'M48' in line:
             return 'excellon'