re-pcre: Add initial impl of re module using ffi against libpcre.

re-pcre/re.py

@@ -0,0 +1,53 @@
+import ffi
+import array
+
+
+pcre = ffi.open("libpcre.so.3")
+
+#       pcre *pcre_compile(const char *pattern, int options,
+#            const char **errptr, int *erroffset,
+#            const unsigned char *tableptr);
+pcre_compile = pcre.func("p", "pcre_compile", "sipps")
+
+#       int pcre_exec(const pcre *code, const pcre_extra *extra,
+#            const char *subject, int length, int startoffset,
+#            int options, int *ovector, int ovecsize);
+pcre_exec = pcre.func("i", "pcre_exec", "ppsiiipi")
+
+
+class PCREMatch:
+
+    def __init__(self, s, num_matches, offsets):
+        self.s = s
+        self.num = num_matches
+        self.offsets = offsets
+
+    def group(self, n):
+        return self.s[self.offsets[n*2]:self.offsets[n*2+1]]
+
+
+class PCREPattern:
+
+    def __init__(self, compiled_ptn):
+        self.obj = compiled_ptn
+
+    def search(self, s):
+        ov = array.array('i', [0, 0, 0] * 2)
+        num = pcre_exec(self.obj, None, s, len(s), 0, 0, ov, len(ov))
+        if num == -1:
+            # No match
+            return None
+        return PCREMatch(s, num, ov)
+
+
+def compile(pattern, flags=0):
+    errptr = bytes(4)
+    erroffset = bytes(4)
+    regex = pcre_compile(pattern, flags, errptr, erroffset, None)
+    assert regex
+    return PCREPattern(regex)
+
+
+def search(pattern, string, flags=0):
+    r = compile(pattern, flags)
+    return r.search(string)