Add Google-style StringPrintf.
Change-Id: If333c28b8ed047346a2dd85e591c4bedbab874cc
diff --git a/include/utils/stringprintf.h b/include/utils/stringprintf.h
new file mode 100644
index 0000000..e7dbac7
--- /dev/null
+++ b/include/utils/stringprintf.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef UTILS_STRINGPRINTF_H_
+#define UTILS_STRINGPRINTF_H_
+
+#include <stdarg.h>
+#include <string>
+
+namespace android {
+
+// Returns a string corresponding to printf-like formatting of the arguments.
+std::string StringPrintf(const char* fmt, ...)
+ __attribute__((__format__(__printf__, 1, 2)));
+
+// Appends a printf-like formatting of the arguments to 'dst'.
+void StringAppendF(std::string* dst, const char* fmt, ...)
+ __attribute__((__format__(__printf__, 2, 3)));
+
+// Appends a printf-like formatting of the arguments to 'dst'.
+void StringAppendV(std::string* dst, const char* format, va_list ap);
+
+} // namespace android
+
+#endif
diff --git a/libutils/Android.mk b/libutils/Android.mk
index 701fe0e..7bff14e 100644
--- a/libutils/Android.mk
+++ b/libutils/Android.mk
@@ -41,6 +41,7 @@
VectorImpl.cpp \
file.cpp \
misc.cpp \
+ stringprintf.cpp \
host_commonCflags := -DLIBUTILS_NATIVE=1 $(TOOL_CFLAGS) -Werror
diff --git a/libutils/stringprintf.cpp b/libutils/stringprintf.cpp
new file mode 100644
index 0000000..5eaa293
--- /dev/null
+++ b/libutils/stringprintf.cpp
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <utils/stringprintf.h>
+
+#include <stdio.h>
+
+void android::StringAppendV(std::string* dst, const char* format, va_list ap) {
+ // First try with a small fixed size buffer
+ char space[1024];
+
+ // It's possible for methods that use a va_list to invalidate
+ // the data in it upon use. The fix is to make a copy
+ // of the structure before using it and use that copy instead.
+ va_list backup_ap;
+ va_copy(backup_ap, ap);
+ int result = vsnprintf(space, sizeof(space), format, backup_ap);
+ va_end(backup_ap);
+
+ if (result < static_cast<int>(sizeof(space))) {
+ if (result >= 0) {
+ // Normal case -- everything fit.
+ dst->append(space, result);
+ return;
+ }
+
+ if (result < 0) {
+ // Just an error.
+ return;
+ }
+ }
+
+ // Increase the buffer size to the size requested by vsnprintf,
+ // plus one for the closing \0.
+ int length = result+1;
+ char* buf = new char[length];
+
+ // Restore the va_list before we use it again
+ va_copy(backup_ap, ap);
+ result = vsnprintf(buf, length, format, backup_ap);
+ va_end(backup_ap);
+
+ if (result >= 0 && result < length) {
+ // It fit
+ dst->append(buf, result);
+ }
+ delete[] buf;
+}
+
+std::string android::StringPrintf(const char* fmt, ...) {
+ va_list ap;
+ va_start(ap, fmt);
+ std::string result;
+ StringAppendV(&result, fmt, ap);
+ va_end(ap);
+ return result;
+}
+
+void android::StringAppendF(std::string* dst, const char* format, ...) {
+ va_list ap;
+ va_start(ap, format);
+ StringAppendV(dst, format, ap);
+ va_end(ap);
+}
diff --git a/libutils/tests/Android.mk b/libutils/tests/Android.mk
index 03d5342..ce288ca 100644
--- a/libutils/tests/Android.mk
+++ b/libutils/tests/Android.mk
@@ -30,6 +30,7 @@
Looper_test.cpp \
LruCache_test.cpp \
String8_test.cpp \
+ stringprintf_test.cpp \
Unicode_test.cpp \
Vector_test.cpp \
diff --git a/libutils/tests/stringprintf_test.cpp b/libutils/tests/stringprintf_test.cpp
new file mode 100644
index 0000000..f995452
--- /dev/null
+++ b/libutils/tests/stringprintf_test.cpp
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <utils/stringprintf.h>
+
+#include <gtest/gtest.h>
+
+TEST(StringPrintfTest, HexSizeT) {
+ size_t size = 0x00107e59;
+ EXPECT_EQ("00107e59", android::StringPrintf("%08zx", size));
+ EXPECT_EQ("0x00107e59", android::StringPrintf("0x%08zx", size));
+}
+
+TEST(StringPrintfTest, StringAppendF) {
+ std::string s("a");
+ android::StringAppendF(&s, "b");
+ EXPECT_EQ("ab", s);
+}
+
+TEST(StringPrintfTest, Errno) {
+ errno = 123;
+ android::StringPrintf("hello %s", "world");
+ EXPECT_EQ(123, errno);
+}
+
+void TestN(size_t n) {
+ char* buf = new char[n + 1];
+ memset(buf, 'x', n);
+ buf[n] = '\0';
+ std::string s(android::StringPrintf("%s", buf));
+ EXPECT_EQ(buf, s);
+ delete[] buf;
+}
+
+TEST(StringPrintfTest, At1023) {
+ TestN(1023);
+}
+
+TEST(StringPrintfTest, At1024) {
+ TestN(1024);
+}
+
+TEST(StringPrintfTest, At1025) {
+ TestN(1025);
+}