should work

[c11concurrency-benchmarks.git] / mabain / binaries / expr_parser.cpp

diff --git a/mabain/binaries/expr_parser.cpp b/mabain/binaries/expr_parser.cpp
new file mode 100644 (file)
index 0000000..2fc6049
--- /dev/null
+++ b/mabain/binaries/expr_parser.cpp
@@ -0,0 +1,145 @@
+/**
+ * Copyright (C) 2017 Cisco Inc.
+ *
+ * This program is free software: you can redistribute it and/or  modify
+ * it under the terms of the GNU General Public License, version 2,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+// @author Changxue Deng <chadeng@cisco.com>
+
+#include <string.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <iostream>
+
+#include "expr_parser.h"
+#include "hexbin.h"
+
+ExprParser::ExprParser(const std::string &exp)
+{
+    pos = 0;
+    expr = exp;
+    err_str = "";
+}
+
+ExprParser::~ExprParser()
+{
+}
+
+int ExprParser::Evaluate(std::string &result)
+{
+    result = "";
+    int rval = Parse(result);
+    if(rval < 0)
+    {
+        std::cout << err_str << "\n";
+    }
+    else if(rval == 0 && pos < expr.length())
+    {
+        std::cout << "extra string " + expr.substr(pos)
+                  << " found at the end of expression\n";
+        return -1;
+    }
+
+    return rval;
+}
+
+// Grammer:
+//    S ---> E
+//    E ---> bin( E )
+//    E ---> hex( E )
+//    E ---> T
+//    E ---> T + E (NOT IMPLEMENTED YET)
+//    T ---> literal string
+// Sample expressions
+// literal string: 'abcdefg'
+// convert hex to binary: bin('0001ff01')
+// convert hex to binary and back to hex:
+// hex(bin('4da32feebf1611e7bd98c0b13cdb778c'))=='4da32feebf1611e7bd98c0b13cdb778c'
+int ExprParser::Parse(std::string &result)
+{
+    if(pos >= expr.length())
+        return 0;
+
+    int rval;
+    switch(expr[pos])
+    {
+        case 'b':
+            if(expr.find("in(", pos+1, 3) == std::string::npos)
+            {
+                err_str = "unrecognized expression " + expr.substr(pos);
+                return -1;
+            }
+            pos += 4;
+            rval = Parse(result);
+            if(rval < 0)
+                return rval;
+            if(expr[pos] != ')')
+            {
+                err_str = "missing ) at the end of " + expr.substr(0, pos);
+                return -1;
+            }
+            pos++;
+            rval = hex_2_bin(result.c_str(), result.length(), buffer,
+                             EXPR_PARSER_BUFFER_SIZE);
+            if(rval < 0)
+            {
+                err_str = "failed to convert hex string " + result + " to binary format";
+                return -1;
+            }
+            result = std::string((char *)buffer, rval);
+            break;
+        case 'h':
+            if(expr.find("ex(", pos+1, 3) == std::string::npos)
+            {
+                err_str = "unrecognized expression " + expr.substr(pos);
+                return -1;
+            }
+            pos += 4;
+            rval = Parse(result);
+            if(rval < 0)
+                return rval;
+            if(expr[pos] != ')')
+            {
+                err_str = "missing ) at the end of " + expr.substr(0, pos);
+                return -1;
+            }
+            pos++;
+            rval = bin_2_hex((const uint8_t *)result.data(), result.size(),
+                             (char *)buffer, EXPR_PARSER_BUFFER_SIZE);
+            if(rval < 0)
+            {
+                err_str = "failed to convert binary string to hex";
+                return -1;
+            }
+            result = std::string((char *)buffer, rval);
+            break;
+        case '\'':
+            {
+                size_t endp = expr.find('\'', pos+1);
+                if(endp ==  std::string::npos)
+                {
+                    err_str = "expression " + expr.substr(0, pos) + " missing closing \'";
+                    return -1;
+                }
+                result = expr.substr(pos+1, endp-pos-1);
+                pos = endp + 1;
+            }
+            break;
+        default:
+            err_str  = "unrecognized expression " + expr.substr(pos) + "\n";
+            err_str += "                        ^";
+            return -1; 
+    }
+
+    return 0;
+}