Expression: add an Expression parser

1 files changed, 70 insertions, 0 deletions

diff --git a/miasm2/expression/parser.py b/miasm2/expression/parser.py
new file mode 100644
index 00000000..b3f3af1c
--- /dev/null
+++ b/miasm2/expression/parser.py
@@ -0,0 +1,70 @@
+import pyparsing
+from miasm2.expression.expression import ExprInt, ExprId, ExprSlice, ExprMem, \
+    ExprCond, ExprCompose, ExprOp, ExprAff
+
+integer = pyparsing.Word(pyparsing.nums).setParseAction(lambda t:
+                                                        int(t[0]))
+hex_word = pyparsing.Literal('0x') + pyparsing.Word(pyparsing.hexnums)
+hex_int = pyparsing.Combine(hex_word).setParseAction(lambda t:
+                                                     int(t[0], 16))
+
+str_int_pos = (hex_int | integer)
+str_int_neg = (pyparsing.Suppress('-') + \
+                   (hex_int | integer)).setParseAction(lambda t: -t[0])
+
+str_int = str_int_pos | str_int_neg
+
+STR_EXPRINT = pyparsing.Suppress("ExprInt")
+STR_EXPRID = pyparsing.Suppress("ExprId")
+STR_EXPRSLICE = pyparsing.Suppress("ExprSlice")
+STR_EXPRMEM = pyparsing.Suppress("ExprMem")
+STR_EXPRCOND = pyparsing.Suppress("ExprCond")
+STR_EXPRCOMPOSE = pyparsing.Suppress("ExprCompose")
+STR_EXPROP = pyparsing.Suppress("ExprOp")
+STR_EXPRAFF = pyparsing.Suppress("ExprAff")
+
+STR_COMMA = pyparsing.Suppress(",")
+LPARENTHESIS = pyparsing.Suppress("(")
+RPARENTHESIS = pyparsing.Suppress(")")
+
+
+string_quote = pyparsing.QuotedString(quoteChar="'", escChar='\\', escQuote='\\')
+string_dquote = pyparsing.QuotedString(quoteChar='"', escChar='\\', escQuote='\\')
+
+
+string = string_quote | string_dquote
+
+expr = pyparsing.Forward()
+
+expr_int = pyparsing.Group(STR_EXPRINT + LPARENTHESIS + str_int + STR_COMMA + str_int + RPARENTHESIS)
+expr_id = pyparsing.Group(STR_EXPRID + LPARENTHESIS + string + STR_COMMA + str_int + RPARENTHESIS)
+expr_slice = pyparsing.Group(STR_EXPRSLICE + LPARENTHESIS + expr + STR_COMMA + str_int + STR_COMMA + str_int + RPARENTHESIS)
+expr_mem = pyparsing.Group(STR_EXPRMEM + LPARENTHESIS + expr + STR_COMMA + str_int + RPARENTHESIS)
+expr_cond = pyparsing.Group(STR_EXPRCOND + LPARENTHESIS + expr + STR_COMMA + expr + STR_COMMA + expr + RPARENTHESIS)
+expr_compose = pyparsing.Group(STR_EXPRCOMPOSE + LPARENTHESIS + pyparsing.delimitedList(expr, delim=',') + RPARENTHESIS)
+expr_op = pyparsing.Group(STR_EXPROP + LPARENTHESIS + string + STR_COMMA + pyparsing.delimitedList(expr, delim=',') + RPARENTHESIS)
+expr_aff = pyparsing.Group(STR_EXPRAFF + LPARENTHESIS + expr + STR_COMMA + expr + RPARENTHESIS)
+
+expr << (expr_int | expr_id | expr_slice | expr_mem | expr_cond | \
+         expr_compose | expr_op | expr_aff)
+
+expr_int.setParseAction(lambda t: ExprInt(*t[0]))
+expr_id.setParseAction(lambda t: ExprId(*t[0]))
+expr_slice.setParseAction(lambda t: ExprSlice(*t[0]))
+expr_mem.setParseAction(lambda t: ExprMem(*t[0]))
+expr_cond.setParseAction(lambda t: ExprCond(*t[0]))
+expr_compose.setParseAction(lambda t: ExprCompose(*t[0]))
+expr_op.setParseAction(lambda t: ExprOp(*t[0]))
+expr_aff.setParseAction(lambda t: ExprAff(*t[0]))
+
+
+def str_to_expr(str_in):
+    """Parse the @str_in and return the corresponoding Expression
+    @str_in: repr string of an Expression"""
+
+    try:
+        value = expr.parseString(str_in)
+    except:
+        raise RuntimeError("Cannot parse expression %s" % str_in)
+    assert len(value) == 1
+    return value[0]