Graft pcb-tools upstream onto gerbonara tree

1 files changed, 255 insertions, 0 deletions

diff --git a/gerber/am_read.py b/gerber/am_read.py
new file mode 100644
index 0000000..4aff00b
--- /dev/null
+++ b/gerber/am_read.py
@@ -0,0 +1,255 @@
+#! /usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# copyright 2014 Hamilton Kibbe <ham@hamiltonkib.be>
+# copyright 2014 Paulo Henrique Silva <ph.silva@gmail.com>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+""" This module provides RS-274-X AM macro modifiers parsing.
+"""
+
+from .am_eval import OpCode, eval_macro
+
+import string
+
+
+class Token:
+    ADD = "+"
+    SUB = "-"
+    # compatibility as many gerber writes do use non compliant X
+    MULT = ("x", "X")
+    DIV = "/"
+    OPERATORS = (ADD, SUB, MULT[0], MULT[1], DIV)
+    LEFT_PARENS = "("
+    RIGHT_PARENS = ")"
+    EQUALS = "="
+    EOF = "EOF"
+
+
+def token_to_opcode(token):
+    if token == Token.ADD:
+        return OpCode.ADD
+    elif token == Token.SUB:
+        return OpCode.SUB
+    elif token in Token.MULT:
+        return OpCode.MUL
+    elif token == Token.DIV:
+        return OpCode.DIV
+    else:
+        return None
+
+
+def precedence(token):
+    if token == Token.ADD or token == Token.SUB:
+        return 1
+    elif token in Token.MULT or token == Token.DIV:
+        return 2
+    else:
+        return 0
+
+
+def is_op(token):
+    return token in Token.OPERATORS
+
+
+class Scanner:
+
+    def __init__(self, s):
+        self.buff = s
+        self.n = 0
+
+    def eof(self):
+        return self.n == len(self.buff)
+
+    def peek(self):
+        if not self.eof():
+            return self.buff[self.n]
+
+        return Token.EOF
+
+    def ungetc(self):
+        if self.n > 0:
+            self.n -= 1
+
+    def getc(self):
+        if self.eof():
+            return ""
+
+        c = self.buff[self.n]
+        self.n += 1
+        return c
+
+    def readint(self):
+        n = ""
+        while not self.eof() and (self.peek() in string.digits):
+            n += self.getc()
+        return int(n)
+
+    def readfloat(self):
+        n = ""
+        while not self.eof() and (self.peek() in string.digits or self.peek() == "."):
+            n += self.getc()
+        # weird case where zero is ommited inthe last modifider, like in ',0.'
+        if n == ".":
+            return 0
+        return float(n)
+
+    def readstr(self, end="*"):
+        s = ""
+        while not self.eof() and self.peek() != end:
+            s += self.getc()
+        return s.strip()
+
+
+def print_instructions(instructions):
+    for opcode, argument in instructions:
+        print("%s %s" % (OpCode.str(opcode),
+                         str(argument) if argument is not None else ""))
+
+
+def read_macro(macro):
+    instructions = []
+
+    for block in macro.split("*"):
+
+        is_primitive = False
+        is_equation = False
+
+        found_equation_left_side = False
+        found_primitive_code = False
+
+        equation_left_side = 0
+        primitive_code = 0
+
+        unary_minus_allowed = False
+        unary_minus = False
+
+        if Token.EQUALS in block:
+            is_equation = True
+        else:
+            is_primitive = True
+
+        scanner = Scanner(block)
+
+        # inlined here for compactness and convenience
+        op_stack = []
+
+        def pop():
+            return op_stack.pop()
+
+        def push(op):
+            op_stack.append(op)
+
+        def top():
+            return op_stack[-1]
+
+        def empty():
+            return len(op_stack) == 0
+
+        while not scanner.eof():
+
+            c = scanner.getc()
+
+            if c == ",":
+                found_primitive_code = True
+
+                # add all instructions on the stack to finish last modifier
+                while not empty():
+                    instructions.append((token_to_opcode(pop()), None))
+
+                unary_minus_allowed = True
+
+            elif c in Token.OPERATORS:
+                if c == Token.SUB and unary_minus_allowed:
+                    unary_minus = True
+                    unary_minus_allowed = False
+                    continue
+
+                while not empty() and is_op(top()) and precedence(top()) >= precedence(c):
+                    instructions.append((token_to_opcode(pop()), None))
+
+                push(c)
+
+            elif c == Token.LEFT_PARENS:
+                push(c)
+
+            elif c == Token.RIGHT_PARENS:
+                while not empty() and top() != Token.LEFT_PARENS:
+                    instructions.append((token_to_opcode(pop()), None))
+
+                if empty():
+                    raise ValueError("unbalanced parentheses")
+
+                # discard "("
+                pop()
+
+            elif c.startswith("$"):
+                n = scanner.readint()
+
+                if is_equation and not found_equation_left_side:
+                    equation_left_side = n
+                else:
+                    instructions.append((OpCode.LOAD, n))
+
+            elif c == Token.EQUALS:
+                found_equation_left_side = True
+
+            elif c == "0":
+                if is_primitive and not found_primitive_code:
+                    instructions.append((OpCode.PUSH, scanner.readstr("*")))
+                    found_primitive_code = True
+                else:
+                    # decimal or integer disambiguation
+                    if scanner.peek() not in '.' or scanner.peek() == Token.EOF:
+                        instructions.append((OpCode.PUSH, 0))
+
+            elif c in "123456789.":
+                scanner.ungetc()
+
+                if is_primitive and not found_primitive_code:
+                    primitive_code = scanner.readint()
+                else:
+                    n = scanner.readfloat()
+                    if unary_minus:
+                        unary_minus = False
+                        n *= -1
+
+                    instructions.append((OpCode.PUSH, n))
+            else:
+                # whitespace or unknown char
+                pass
+
+        # add all instructions on the stack to finish last modifier (if any)
+        while not empty():
+            instructions.append((token_to_opcode(pop()), None))
+
+        # at end, we either have a primitive or a equation
+        if is_primitive and found_primitive_code:
+            instructions.append((OpCode.PRIM, primitive_code))
+
+        if is_equation:
+            instructions.append((OpCode.STORE, equation_left_side))
+
+    return instructions
+
+if __name__ == '__main__':
+    import sys
+
+    instructions = read_macro(sys.argv[1])
+
+    print("insructions:")
+    print_instructions(instructions)
+
+    print("eval:")
+    for primitive in eval_macro(instructions):
+        print(primitive)