idp.i: added AssembleLine() which is similar to assemble() but assembles into a buffer instead

idautils.py: added Assemble() utility function

python/idautils.py

@@ -13,6 +13,7 @@ idautils.py - High level utility functions for IDA
 """
 import idaapi
 import idc
+import types
 
 def refs(ea, funcfirst, funcnext):
     """
@@ -427,4 +428,45 @@ class Strings:
             return Strings.StringItem(self._si)
         return None
 
+
+def _Assemble(ea, line):
+    """
+    Please refer to Assemble() - INTERNAL USE ONLY
+    """
+    if type(line) == types.StringType:
+        lines = [line]
+    else:
+        lines = line
+    ret = []
+    for line in lines:
+        seg = idaapi.getseg(ea)
+        if not seg:
+            return (False, "No segment at ea")
+        ip  = ea - (idaapi.ask_selector(seg.sel) << 4)
+        buf = idaapi.AssembleLine(ea, seg.sel, ip, seg.bitness, line)
+        if not buf:
+          return (False, "Assembler failed: " + line)
+        ea += len(buf)
+        ret.append(buf)
+    
+    if len(ret) == 1:
+        ret = ret[0]
+    return (True, ret)
+
+
+def Assemble(ea, line):
+    """
+    Assembles one or more lines (does not display an message dialogs)
+    If line is a list then this function will attempt to assemble all the lines
+    This function will turn on batch mode temporarily so that no messages are displayed on the screen
+
+    @param ea:       start address
+    @return: (False, "Error message") or (True, asm_buf) or (True, [asm_buf1, asm_buf2, asm_buf3])
+    """
+    old_batch = idc.Batch(1)
+    ret = _Assemble(ea, line)
+    idc.Batch(old_batch)
+    return ret
+
+
 cpu = _cpu()

swig/idp.i

@@ -279,7 +279,7 @@ int idaapi IDB_Callback(void *ud, int notification_code, va_list va)
     }
 }
 
-// Assemble an instruction (display a warning if an error is found)
+// Assemble an instruction into the database (display a warning if an error is found)
 // args:
 //  ea_t ea -  linear address of instruction
 //  ea_t cs -  cs of instruction
@@ -290,7 +290,7 @@ int idaapi IDB_Callback(void *ud, int notification_code, va_list va)
 inline const int assemble(ea_t ea, ea_t cs, ea_t ip, bool use32, const char *line)
 {
     int inslen;
-    char buf[256]; // FIXME: Shouldn't be longer than this... is there a MAX_INSTR_LENGTH anywhere?
+    char buf[MAXSTR];
 
     if (ph.notify != NULL)
     {
@@ -303,4 +303,24 @@ inline const int assemble(ea_t ea, ea_t cs, ea_t ip, bool use32, const char *lin
     }
     return 0;
 }
+
+// Assemble an instruction to a buffer (display a warning if an error is found)
+// args:
+//  ea_t ea -  linear address of instruction
+//  ea_t cs -  cs of instruction
+//  ea_t ip -  ip of instruction
+//  bool use32 - is 32bit segment?
+//  const char *line - line to assemble
+// returns: 1: success, 0: failure 
+inline const PyObject *AssembleLine(ea_t ea, ea_t cs, ea_t ip, bool use32, const char *line)
+{
+    int inslen;
+    char buf[MAXSTR];
+    if (ph.notify != NULL &&
+        (inslen =  ph.notify(ph.assemble, ea, cs, ip, use32, line, buf)) > 0)
+    {
+        return PyString_FromStringAndSize(buf, inslen);
+    }
+    Py_RETURN_NONE;
+}
 %}