dollar quoting

2 files changed, 38 insertions, 0 deletions

diff --git a/python/modules/cquoting.c b/python/modules/cquoting.c
index 2dcfc227..42844ca2 100644
--- a/python/modules/cquoting.c
+++ b/python/modules/cquoting.c
@@ -386,6 +386,33 @@ failed:
 	return NULL;
 }
 
+static PyObject *do_dolq(unsigned char *src, Py_ssize_t src_len)
+{
+	/* src_len >= 2, '$' in start and end */
+	unsigned char *src_end = src + src_len;
+	unsigned char *p1 = src + 1, *p2 = src_end - 2;
+	
+	while (p1 < src_end && *p1 != '$')
+		p1++;
+	while (p2 > src && *p2 != '$')
+		p2--;
+	if (p2 <= p1)
+		goto failed;
+	
+	p1++; /* position after '$' */
+
+	if ((p1 - src) != (src_end - p2))
+		goto failed;
+	if (memcmp(src, p2, p1 - src) != 0)
+		goto failed;
+
+	return PyString_FromStringAndSize((char *)p1, p2 - p1);
+
+failed:
+	PyErr_Format(PyExc_ValueError, "Broken dollar-quoted string");
+	return NULL;
+}
+
 static PyObject *unquote_literal(PyObject *self, PyObject *args)
 {
 	unsigned char *src = NULL;
@@ -400,6 +427,8 @@ static PyObject *unquote_literal(PyObject *self, PyObject *args)
 		Py_INCREF(Py_None);
 		return Py_None;
 	}
+	if (src_len >= 2 && src[0] == '$' && src[src_len - 1] == '$')
+		return do_dolq(src, src_len);
 	if (src_len < 2 || src[src_len - 1] != '\'')
 		goto badstr;
 	if (src[0] == '\'') {
diff --git a/python/skytools/_pyquoting.py b/python/skytools/_pyquoting.py
index 32d548ff..8f72eb5f 100644
--- a/python/skytools/_pyquoting.py
+++ b/python/skytools/_pyquoting.py
@@ -179,6 +179,15 @@ def unquote_literal(val, stdstr = False):
             return _esql_rc.sub(_sub_unescape_sqlext, val[1:-1])
     elif len(val) > 2 and val[0] in ('E', 'e') and val[1] == "'" and val[-1] == "'":
         return _esql_rc.sub(_sub_unescape_sqlext, val[2:-1])
+    elif len(val) >= 2 and val[0] == '$' and val[-1] == '$':
+        p1 = val.find('$', 1)
+        p2 = val.rfind('$', 1, -1)
+        if p1 > 0 and p2 > p1:
+            t1 = val[:p1+1]
+            t2 = val[p2:]
+            if t1 == t2:
+                return val[len(t1):-len(t1)]
+        raise Exception("Bad dollar-quoted string")
     elif val.lower() == "null":
         return None
     return val