1 files changed, 121 insertions, 0 deletions
diff --git a/mavlink/share/pyshared/pymavlink/generator/mavtemplate.py b/mavlink/share/pyshared/pymavlink/generator/mavtemplate.py
new file mode 100644
index 000000000..6ef015315
--- /dev/null
+++ b/mavlink/share/pyshared/pymavlink/generator/mavtemplate.py
@@ -0,0 +1,121 @@
+#!/usr/bin/env python
+'''
+simple templating system for mavlink generator
+
+Copyright Andrew Tridgell 2011
+Released under GNU GPL version 3 or later
+'''
+
+from mavparse import MAVParseError
+
+class MAVTemplate(object):
+    '''simple templating system'''
+    def __init__(self,
+                 start_var_token="${", 
+                 end_var_token="}", 
+                 start_rep_token="${{", 
+                 end_rep_token="}}",
+                 trim_leading_lf=True,
+                 checkmissing=True):
+        self.start_var_token = start_var_token
+        self.end_var_token = end_var_token
+        self.start_rep_token = start_rep_token
+        self.end_rep_token = end_rep_token
+        self.trim_leading_lf = trim_leading_lf
+        self.checkmissing = checkmissing
+
+    def find_end(self, text, start_token, end_token):
+        '''find the of a token.
+        Returns the offset in the string immediately after the matching end_token'''
+        if not text.startswith(start_token):
+            raise MAVParseError("invalid token start")
+        offset = len(start_token)
+        nesting = 1
+        while nesting > 0:
+            idx1 = text[offset:].find(start_token)
+            idx2 = text[offset:].find(end_token)
+            if idx1 == -1 and idx2 == -1:
+                raise MAVParseError("token nesting error")
+            if idx1 == -1 or idx1 > idx2:
+                offset += idx2 + len(end_token)
+                nesting -= 1
+            else:
+                offset += idx1 + len(start_token)
+                nesting += 1
+        return offset
+
+    def find_var_end(self, text):
+        '''find the of a variable'''
+        return self.find_end(text, self.start_var_token, self.end_var_token)
+
+    def find_rep_end(self, text):
+        '''find the of a repitition'''
+        return self.find_end(text, self.start_rep_token, self.end_rep_token)
+
+    def substitute(self, text, subvars={},
+                   trim_leading_lf=None, checkmissing=None):
+        '''substitute variables in a string'''
+
+        if trim_leading_lf is None:
+            trim_leading_lf = self.trim_leading_lf
+        if checkmissing is None:
+            checkmissing = self.checkmissing
+
+        # handle repititions
+        while True:
+            subidx = text.find(self.start_rep_token)
+            if subidx == -1:
+                break
+            endidx = self.find_rep_end(text[subidx:])
+            if endidx == -1:
+                raise MAVParseError("missing end macro in %s" % text[subidx:])
+            part1 = text[0:subidx]
+            part2 = text[subidx+len(self.start_rep_token):subidx+(endidx-len(self.end_rep_token))]
+            part3 = text[subidx+endidx:]
+            a = part2.split(':')
+            field_name = a[0]
+            rest = ':'.join(a[1:])
+            v = getattr(subvars, field_name, None)
+            if v is None:
+                raise MAVParseError('unable to find field %s' % field_name)
+            t1 = part1
+            for f in v:
+                t1 += self.substitute(rest, f, trim_leading_lf=False, checkmissing=False)
+            if len(v) != 0 and t1[-1] in ["\n", ","]:
+                t1 = t1[:-1]
+            t1 += part3
+            text = t1
+                
+        if trim_leading_lf:
+            if text[0] == '\n':
+                text = text[1:]
+        while True:
+            idx = text.find(self.start_var_token)
+            if idx == -1:
+                return text
+            endidx = text[idx:].find(self.end_var_token)
+            if endidx == -1:
+                raise MAVParseError('missing end of variable: %s' % text[idx:idx+10])
+            varname = text[idx+2:idx+endidx]
+            if isinstance(subvars, dict):
+                if not varname in subvars:
+                    if checkmissing:
+                        raise MAVParseError("unknown variable in '%s%s%s'" % (
+                            self.start_var_token, varname, self.end_var_token))
+                    return text[0:idx+endidx] + self.substitute(text[idx+endidx:], subvars,
+                                                                trim_leading_lf=False, checkmissing=False)
+                value = subvars[varname]
+            else:
+                value = getattr(subvars, varname, None)
+                if value is None:
+                    if checkmissing:
+                        raise MAVParseError("unknown variable in '%s%s%s'" % (
+                            self.start_var_token, varname, self.end_var_token))
+                    return text[0:idx+endidx] + self.substitute(text[idx+endidx:], subvars,
+                                                                trim_leading_lf=False, checkmissing=False)
+            text = text.replace("%s%s%s" % (self.start_var_token, varname, self.end_var_token), str(value))
+        return text
+
+    def write(self, file, text, subvars={}, trim_leading_lf=True):
+        '''write to a file with variable substitution'''
+        file.write(self.substitute(text, subvars=subvars, trim_leading_lf=trim_leading_lf))