parsers: speed up hex decoding for manifests

mercurial/parsers.c

@@ -1,169 +1,146 b''
 /*
  parsers.c - efficient content parsing
 
  Copyright 2008 Matt Mackall <[e-mail]> and others
 
  This software may be used and distributed according to the terms of
  the GNU General Public License, incorporated herein by reference.
 */
 
 #include <Python.h>
 #include <ctype.h>
 #include <string.h>
 
 static int hexdigit(char c)
 {
 	if (c >= '0' && c <= '9')
 		return c - '0';
-
+	if (c >= 'a' && c <= 'f')
+		return c - 'a' + 10;
 	if (c >= 'A' && c <= 'F')
 		return c - 'A' + 10;
 
-	if (c >= 'a' && c <= 'f')
-		return c - 'a' + 10;
-
-	return -1;
+	PyErr_SetString(PyExc_ValueError, "input contains non-hex character");
+	return 0;
 }
 
 /*
  * Turn a hex-encoded string into binary.
  */
 static PyObject *unhexlify(const char *str, int len)
 {
-	PyObject *ret = NULL;
+	PyObject *ret;
 	const char *c;
 	char *d;
 
-	if (len % 2) {
-		PyErr_SetString(PyExc_ValueError,
-				"input is not even in length");
-		goto bail;
-	}
-
 	ret = PyString_FromStringAndSize(NULL, len / 2);
 	if (!ret)
-		goto bail;
+		return NULL;
 
-	d = PyString_AsString(ret);
-	if (!d)
-		goto bail;
-
+	d = PyString_AS_STRING(ret);
 	for (c = str; c < str + len;) {
 		int hi = hexdigit(*c++);
 		int lo = hexdigit(*c++);
-
-		if (hi == -1 || lo == -1) {
-			PyErr_SetString(PyExc_ValueError,
-					"input contains non-hex character");
-			goto bail;
-		}
-
 		*d++ = (hi << 4) | lo;
 	}
 
-	goto done;
-
-bail:
-	Py_XDECREF(ret);
-	ret = NULL;
-done:
 	return ret;
 }
 
 /*
  * This code assumes that a manifest is stitched together with newline
  * ('\n') characters.
  */
 static PyObject *parse_manifest(PyObject *self, PyObject *args)
 {
 	PyObject *mfdict, *fdict;
 	char *str, *cur, *start, *zero;
 	int len;
 
 	if (!PyArg_ParseTuple(args, "O!O!s#:parse_manifest",
 			      &PyDict_Type, &mfdict,
 			      &PyDict_Type, &fdict,
 			      &str, &len))
 		goto quit;
 
 	for (start = cur = str, zero = NULL; cur < str + len; cur++) {
 		PyObject *file = NULL, *node = NULL;
 		PyObject *flags = NULL;
 		int nlen;
 
 		if (!*cur) {
 			zero = cur;
 			continue;
 		}
 		else if (*cur != '\n')
 			continue;
 
 		if (!zero) {
 			PyErr_SetString(PyExc_ValueError,
 					"manifest entry has no separator");
 			goto quit;
 		}
 
 		file = PyString_FromStringAndSize(start, zero - start);
 		if (!file)
 			goto bail;
 
 		nlen = cur - zero - 1;
 
 		node = unhexlify(zero + 1, nlen > 40 ? 40 : nlen);
 		if (!node)
 			goto bail;
 
 		if (nlen > 40) {
 			PyObject *flags;
 
 			flags = PyString_FromStringAndSize(zero + 41,
 							   nlen - 40);
 			if (!flags)
 				goto bail;
 
 			if (PyDict_SetItem(fdict, file, flags) == -1)
 				goto bail;
 		}
 
 		if (PyDict_SetItem(mfdict, file, node) == -1)
 			goto bail;
 
 		start = cur + 1;
 		zero = NULL;
 
 		Py_XDECREF(flags);
 		Py_XDECREF(node);
 		Py_XDECREF(file);
 		continue;
 	bail:
 		Py_XDECREF(flags);
 		Py_XDECREF(node);
 		Py_XDECREF(file);
 		goto quit;
 	}
 
 	if (len > 0 && *(cur - 1) != '\n') {
 		PyErr_SetString(PyExc_ValueError,
 				"manifest contains trailing garbage");
 		goto quit;
 	}
 
 	Py_INCREF(Py_None);
 	return Py_None;
 
 quit:
 	return NULL;
 }
 
 static char parsers_doc[] = "Efficient content parsing.";
 
 static PyMethodDef methods[] = {
 	{"parse_manifest", parse_manifest, METH_VARARGS, "parse a manifest\n"},
 	{NULL, NULL}
 };
 
 PyMODINIT_FUNC initparsers(void)
 {
 	Py_InitModule3("parsers", methods, parsers_doc);
 }