Remove <iostream> from math headers.

This speeds up our build time by using <iosfwd> and un-inlining the
vector print functions.

libs/math/src/StreamHelpers.cpp

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2020 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 <math/vec2.h>
+#include <math/vec3.h>
+#include <math/vec4.h>
+#include <math/mat2.h>
+#include <math/mat3.h>
+#include <math/mat4.h>
+#include <math/quat.h>
+
+#include <iomanip>
+#include <ostream>
+#include <string>
+
+namespace filament {
+namespace math {
+namespace details {
+
+template<typename T>
+std::ostream& printVector(std::ostream& stream, const T* data, size_t count) {
+    stream << "< ";
+    for (size_t i = 0; i < count - 1; i++) {
+        stream << data[i] << ", ";
+    }
+    stream << data[count - 1] << " >";
+    return stream;
+}
+
+template<typename T>
+std::ostream& printMatrix(std::ostream& stream, const T* m, size_t rows, size_t cols) {
+    for (size_t row = 0; row < rows; ++row) {
+        if (row != 0) {
+            stream << std::endl;
+        }
+        if (row == 0) {
+            stream << "/ ";
+        } else if (row == rows - 1) {
+            stream << "\\ ";
+        } else {
+            stream << "| ";
+        }
+        for (size_t col = 0; col < cols; ++col) {
+            stream << std::setw(10) << std::to_string(m[row + col * rows]);
+        }
+        if (row == 0) {
+            stream << " \\";
+        } else if (row == rows - 1) {
+            stream << " /";
+        } else {
+            stream << " |";
+        }
+    }
+    return stream;
+}
+
+template<template<typename T> class BASE, typename T>
+std::ostream& printQuat(std::ostream& stream, const BASE<T>& q) {
+    return stream << "< " << q.w << " + " << q.x << "i + " << q.y << "j + " << q.z << "k >";
+}
+
+template std::ostream& printMatrix(std::ostream& stream, const double* data, size_t rows, size_t cols);
+template std::ostream& printMatrix(std::ostream& stream, const float* data, size_t rows, size_t cols);
+
+template std::ostream& printVector(std::ostream& stream, const double* data, size_t count);
+template std::ostream& printVector(std::ostream& stream, const float* data, size_t count);
+template std::ostream& printVector(std::ostream& stream, const int* data, size_t count);
+template std::ostream& printVector(std::ostream& stream, const half* data, size_t count);
+
+template std::ostream& printQuat(std::ostream& stream, const quath& q);
+template std::ostream& printQuat(std::ostream& stream, const quatf& q);
+template std::ostream& printQuat(std::ostream& stream, const quat& q);
+
+}  // namespace details
+}  // namespace math
+}  // namespace filament