Merge "audio: Fix fixed size char array conversions"
diff --git a/audio/effect/all-versions/default/util/EffectUtils.cpp b/audio/effect/all-versions/default/util/EffectUtils.cpp
index b4382dc..1156d21 100644
--- a/audio/effect/all-versions/default/util/EffectUtils.cpp
+++ b/audio/effect/all-versions/default/util/EffectUtils.cpp
@@ -25,8 +25,6 @@
 
 #include "util/EffectUtils.h"
 
-#define ARRAY_SIZE(a) (sizeof(a) / sizeof(*(a)))
-
 using ::android::hardware::audio::common::CPP_VERSION::implementation::HidlUtils;
 using ::android::hardware::audio::common::CPP_VERSION::implementation::UuidUtils;
 using ::android::hardware::audio::common::utils::EnumBitfield;
@@ -154,6 +152,29 @@
     return result;
 }
 
+template <std::size_t N>
+inline hidl_string charBufferFromHal(const char (&halBuf)[N]) {
+    // Even if the original field contains a non-terminated string, hidl_string
+    // adds a NUL terminator.
+    return hidl_string(halBuf, strnlen(halBuf, N));
+}
+
+template <std::size_t N>
+inline status_t charBufferToHal(const hidl_string& str, char (&halBuf)[N], const char* fieldName) {
+    static_assert(N > 0);
+    const size_t halBufChars = N - 1;  // Reserve one character for terminating NUL.
+    status_t result = NO_ERROR;
+    size_t strSize = str.size();
+    if (strSize > halBufChars) {
+        ALOGE("%s is too long: %zu (%zu max)", fieldName, strSize, halBufChars);
+        strSize = halBufChars;
+        result = BAD_VALUE;
+    }
+    strncpy(halBuf, str.c_str(), strSize);
+    halBuf[strSize] = '\0';
+    return result;
+}
+
 status_t EffectUtils::effectDescriptorFromHal(const effect_descriptor_t& halDescriptor,
                                               EffectDescriptor* descriptor) {
     UuidUtils::uuidFromHal(halDescriptor.type, &descriptor->type);
@@ -166,9 +187,8 @@
     memcpy(descriptor->implementor.data(), halDescriptor.implementor,
            descriptor->implementor.size());
 #else
-    descriptor->name = hidl_string(halDescriptor.name, ARRAY_SIZE(halDescriptor.name));
-    descriptor->implementor =
-            hidl_string(halDescriptor.implementor, ARRAY_SIZE(halDescriptor.implementor));
+    descriptor->name = charBufferFromHal(halDescriptor.name);
+    descriptor->implementor = charBufferFromHal(halDescriptor.implementor);
 #endif
     return NO_ERROR;
 }
@@ -186,25 +206,11 @@
     memcpy(halDescriptor->implementor, descriptor.implementor.data(),
            descriptor.implementor.size());
 #else
-    // According to 'dumpEffectDescriptor' 'name' and 'implementor' must be NUL-terminated.
-    size_t nameSize = descriptor.name.size();
-    if (nameSize >= ARRAY_SIZE(halDescriptor->name)) {
-        ALOGE("effect name is too long: %zu (%zu max)", nameSize,
-              ARRAY_SIZE(halDescriptor->name) - 1);
-        nameSize = ARRAY_SIZE(halDescriptor->name) - 1;
-        result = BAD_VALUE;
-    }
-    strncpy(halDescriptor->name, descriptor.name.c_str(), nameSize);
-    halDescriptor->name[nameSize] = '\0';
-    size_t implementorSize = descriptor.implementor.size();
-    if (implementorSize >= ARRAY_SIZE(halDescriptor->implementor)) {
-        ALOGE("effect implementor is too long: %zu (%zu max)", implementorSize,
-              ARRAY_SIZE(halDescriptor->implementor) - 1);
-        implementorSize = ARRAY_SIZE(halDescriptor->implementor) - 1;
-        result = BAD_VALUE;
-    }
-    strncpy(halDescriptor->implementor, descriptor.implementor.c_str(), implementorSize);
-    halDescriptor->implementor[implementorSize] = '\0';
+    // According to 'dumpEffectDescriptor', 'name' and 'implementor' must be NUL-terminated.
+    CONVERT_CHECKED(charBufferToHal(descriptor.name, halDescriptor->name, "effect name"), result);
+    CONVERT_CHECKED(charBufferToHal(descriptor.implementor, halDescriptor->implementor,
+                                    "effect implementor"),
+                    result);
 #endif
     return result;
 }
diff --git a/audio/effect/all-versions/default/util/tests/effectutils_tests.cpp b/audio/effect/all-versions/default/util/tests/effectutils_tests.cpp
index f3651de..d021fa0 100644
--- a/audio/effect/all-versions/default/util/tests/effectutils_tests.cpp
+++ b/audio/effect/all-versions/default/util/tests/effectutils_tests.cpp
@@ -154,3 +154,20 @@
     EXPECT_EQ(NO_ERROR, EffectUtils::effectDescriptorFromHal(halDesc, &descBack));
     EXPECT_EQ(desc, descBack);
 }
+
+TEST(EffectUtils, ConvertNameAndImplementor) {
+    for (size_t i = 0; i < EFFECT_STRING_LEN_MAX; ++i) {
+        effect_descriptor_t halDesc{};
+        for (size_t c = 0; c < i; ++c) {  // '<' to accommodate NUL terminator.
+            halDesc.name[c] = halDesc.implementor[c] = 'A' + static_cast<char>(c);
+        }
+        EffectDescriptor desc;
+        EXPECT_EQ(NO_ERROR, EffectUtils::effectDescriptorFromHal(halDesc, &desc));
+        effect_descriptor_t halDescBack;
+        EXPECT_EQ(NO_ERROR, EffectUtils::effectDescriptorToHal(desc, &halDescBack));
+        EXPECT_EQ(i, strlen(halDescBack.name));
+        EXPECT_EQ(i, strlen(halDescBack.implementor));
+        EXPECT_EQ(0, strcmp(halDesc.name, halDescBack.name));
+        EXPECT_EQ(0, strcmp(halDesc.implementor, halDescBack.implementor));
+    }
+}