diff --git a/docs/developer-guide/param-and-model-file-structure.md b/docs/developer-guide/param-and-model-file-structure.md
index 5f5c74d6865..676bacca160 100644
--- a/docs/developer-guide/param-and-model-file-structure.md
+++ b/docs/developer-guide/param-and-model-file-structure.md
@@ -43,6 +43,11 @@ the meaning of existing param key index can be looked up at [operation-param-wei
 * integer array value : [array size],int,int,...,int
 * float array value : [array size],float,float,...,float
 
+In modern ncnn param file
+
+* array could be represented as `3=2.0,3.0` that is much more human friendly
+* string typed value: `4=hello` and the string is no longer than 255
+
 ## net.bin
 ```
   +---------+---------+---------+---------+---------+---------+
diff --git a/src/paramdict.cpp b/src/paramdict.cpp
index 1c28d433524..4704ea169e6 100644
--- a/src/paramdict.cpp
+++ b/src/paramdict.cpp
@@ -38,6 +38,7 @@ class ParamDictPrivate
         // 4 = array of int/float
         // 5 = array of int
         // 6 = array of float
+        // 7 = string
         int type;
         union
         {
@@ -45,6 +46,7 @@ class ParamDictPrivate
             float f;
         };
         Mat v;
+        std::string s;
     } params[NCNN_MAX_PARAM_COUNT];
 };
 
@@ -70,6 +72,10 @@ ParamDict::ParamDict(const ParamDict& rhs)
         {
             d->params[i].i = rhs.d->params[i].i;
         }
+        else if (type == 7)
+        {
+            d->params[i].s = rhs.d->params[i].s;
+        }
         else // if (type == 4 || type == 5 || type == 6)
         {
             d->params[i].v = rhs.d->params[i].v;
@@ -90,6 +96,10 @@ ParamDict& ParamDict::operator=(const ParamDict& rhs)
         {
             d->params[i].i = rhs.d->params[i].i;
         }
+        else if (type == 7)
+        {
+            d->params[i].s = rhs.d->params[i].s;
+        }
         else // if (type == 4 || type == 5 || type == 6)
         {
             d->params[i].v = rhs.d->params[i].v;
@@ -120,6 +130,11 @@ Mat ParamDict::get(int id, const Mat& def) const
     return d->params[id].type ? d->params[id].v : def;
 }
 
+std::string ParamDict::get(int id, const std::string& def) const
+{
+    return d->params[id].type ? d->params[id].s : def;
+}
+
 void ParamDict::set(int id, int i)
 {
     d->params[id].type = 2;
@@ -138,12 +153,20 @@ void ParamDict::set(int id, const Mat& v)
     d->params[id].v = v;
 }
 
+void ParamDict::set(int id, const std::string& s)
+{
+    d->params[id].type = 7;
+    d->params[id].s = s;
+}
+
 void ParamDict::clear()
 {
     for (int i = 0; i < NCNN_MAX_PARAM_COUNT; i++)
     {
         d->params[i].type = 0;
+        d->params[i].i = 0;
         d->params[i].v = Mat();
+        d->params[i].s.clear();
     }
 }
 
@@ -163,6 +186,11 @@ static bool vstr_is_float(const char vstr[16])
     return false;
 }
 
+static bool vstr_is_string(const char vstr[16])
+{
+    return isalpha(vstr[0]);
+}
+
 static float vstr_to_float(const char vstr[16])
 {
     double v = 0.0;
@@ -247,7 +275,8 @@ int ParamDict::load_param(const DataReader& dr)
 {
     clear();
 
-    //     0=100 1=1.250000 -23303=5,0.1,0.2,0.4,0.8,1.0
+    // 0=100 1=1.250000 -23303=5,0.1,0.2,0.4,0.8,1.0
+    // 3=0.1,0.2,0.4,0.8,1.0
 
     // parse each key=value pair
     int id = 0;
@@ -267,6 +296,7 @@ int ParamDict::load_param(const DataReader& dr)
 
         if (is_array)
         {
+            // old style array
             int len = 0;
             int nscan = dr.scan("%d", &len);
             if (nscan != 1)
@@ -307,19 +337,120 @@ int ParamDict::load_param(const DataReader& dr)
 
                 d->params[id].type = is_float ? 6 : 5;
             }
+
+            continue;
         }
-        else
+
+        char vstr[16];
+        char comma[4];
+        int nscan = dr.scan("%15[^,\n ]", vstr);
+        if (nscan != 1)
         {
-            char vstr[16];
-            int nscan = dr.scan("%15s", vstr);
-            if (nscan != 1)
+            NCNN_LOGE("ParamDict read value failed");
+            return -1;
+        }
+
+        bool is_string = vstr_is_string(vstr);
+        if (is_string)
+        {
+            // scan the remaining string
+            char vstr2[256];
+            vstr2[241] = '\0'; // max 255 = 15 + 240
+            nscan = dr.scan("%255[^\n ]", vstr2);
+            if (nscan == 1)
             {
-                NCNN_LOGE("ParamDict read value failed");
-                return -1;
+                if (vstr2[241] != '\0')
+                {
+                    NCNN_LOGE("string too long (id=%d)", id);
+                    return -1;
+                }
+
+                d->params[id].s = std::string(vstr) + vstr2;
+            }
+            else
+            {
+                d->params[id].s = std::string(vstr);
+            }
+
+            d->params[id].type = 7;
+
+            continue;
+        }
+
+        bool is_float = vstr_is_float(vstr);
+
+        nscan = dr.scan("%1[,]", comma);
+        is_array = nscan == 1;
+
+        if (is_array)
+        {
+            std::vector<float> af;
+            std::vector<int> ai;
+
+            if (is_float)
+            {
+                af.push_back(vstr_to_float(vstr));
+            }
+            else
+            {
+                int v = 0;
+                nscan = sscanf(vstr, "%d", &v);
+                if (nscan != 1)
+                {
+                    NCNN_LOGE("ParamDict parse value failed");
+                    return -1;
+                }
+
+                ai.push_back(v);
+            }
+
+            while (1)
+            {
+                nscan = dr.scan("%15[^,\n ]", vstr);
+                if (nscan != 1)
+                {
+                    break;
+                }
+
+                if (is_float)
+                {
+                    af.push_back(vstr_to_float(vstr));
+                }
+                else
+                {
+                    int v = 0;
+                    nscan = sscanf(vstr, "%d", &v);
+                    if (nscan != 1)
+                    {
+                        NCNN_LOGE("ParamDict parse value failed");
+                        return -1;
+                    }
+
+                    ai.push_back(v);
+                }
+
+                nscan = dr.scan("%1[,]", comma);
+                if (nscan != 1)
+                {
+                    break;
+                }
             }
 
-            bool is_float = vstr_is_float(vstr);
+            if (is_float)
+            {
+                d->params[id].v.create((int)af.size());
+                memcpy(d->params[id].v.data, af.data(), af.size() * 4);
+            }
+            else
+            {
+                d->params[id].v.create((int)ai.size());
+                memcpy(d->params[id].v.data, ai.data(), ai.size() * 4);
+            }
 
+            d->params[id].type = is_float ? 6 : 5;
+        }
+        else
+        {
             if (is_float)
             {
                 d->params[id].f = vstr_to_float(vstr);
@@ -375,7 +506,12 @@ int ParamDict::load_param_bin(const DataReader& dr)
     while (id != -233)
     {
         bool is_array = id <= -23300;
-        if (is_array)
+        bool is_string = id <= -23400;
+        if (is_string)
+        {
+            id = -id - 23400;
+        }
+        else if (is_array)
         {
             id = -id - 23300;
         }
@@ -386,7 +522,44 @@ int ParamDict::load_param_bin(const DataReader& dr)
             return -1;
         }
 
-        if (is_array)
+        if (is_string)
+        {
+            int len = 0;
+            nread = dr.read(&len, sizeof(int));
+            if (nread != sizeof(int))
+            {
+                NCNN_LOGE("ParamDict read array length failed %zd", nread);
+                return -1;
+            }
+
+#if __BIG_ENDIAN__
+            swap_endianness_32(&len);
+#endif
+
+            if (len > 255)
+            {
+                NCNN_LOGE("string too long (id=%d)", id);
+                return -1;
+            }
+
+            size_t len_padded = (len + 3) / 4 * 4;
+            std::vector<char> tmpstr(len_padded + 1);
+
+            char* ptr = (char*)tmpstr.data();
+            nread = dr.read(ptr, len_padded);
+            if (nread != len_padded)
+            {
+                NCNN_LOGE("ParamDict read string failed %zd", nread);
+                return -1;
+            }
+
+            tmpstr[len_padded] = '\0';
+
+            d->params[id].s = tmpstr.data();
+
+            d->params[id].type = 7;
+        }
+        else if (is_array)
         {
             int len = 0;
             nread = dr.read(&len, sizeof(int));
diff --git a/src/paramdict.h b/src/paramdict.h
index c2ef1606707..dc306c81596 100644
--- a/src/paramdict.h
+++ b/src/paramdict.h
@@ -48,6 +48,8 @@ class NCNN_EXPORT ParamDict
     float get(int id, float def) const;
     // get array
     Mat get(int id, const Mat& def) const;
+    // get string
+    std::string get(int id, const std::string& def) const;
 
     // set int
     void set(int id, int i);
@@ -55,6 +57,8 @@ class NCNN_EXPORT ParamDict
     void set(int id, float f);
     // set array
     void set(int id, const Mat& v);
+    // set string
+    void set(int id, const std::string& s);
 
 protected:
     friend class Net;
diff --git a/src/simplestl.h b/src/simplestl.h
index 00ff4680186..992bf9bcc4a 100644
--- a/src/simplestl.h
+++ b/src/simplestl.h
@@ -536,15 +536,11 @@ struct NCNN_EXPORT string : public vector<char>
     }
     bool operator==(const string& str2) const
     {
-        return strcmp(data_, str2.data_) == 0;
+        return size_ == str2.size_ && strncmp(data_, str2.data_, size_) == 0;
     }
-    bool operator==(const char* str2) const
+    bool operator!=(const string& str2) const
     {
-        return strcmp(data_, str2) == 0;
-    }
-    bool operator!=(const char* str2) const
-    {
-        return strcmp(data_, str2) != 0;
+        return size_ != str2.size_ || strncmp(data_, str2.data_, size_) != 0;
     }
     string& operator+=(const string& str1)
     {
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index f55859e736e..f216f364d78 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -60,6 +60,7 @@ endif()
 
 ncnn_add_test(c_api)
 ncnn_add_test(cpu)
+ncnn_add_test(paramdict)
 
 if(NCNN_VULKAN)
     ncnn_add_test(command)
diff --git a/tests/test_paramdict.cpp b/tests/test_paramdict.cpp
new file mode 100644
index 00000000000..503de188e17
--- /dev/null
+++ b/tests/test_paramdict.cpp
@@ -0,0 +1,674 @@
+// Tencent is pleased to support the open source community by making ncnn available.
+//
+// Copyright (C) 2025 THL A29 Limited, a Tencent company. All rights reserved.
+//
+// Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
+// in compliance with the License. You may obtain a copy of the License at
+//
+// https://opensource.org/licenses/BSD-3-Clause
+//
+// 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 <stdio.h>
+
+#include "datareader.h"
+#include "paramdict.h"
+
+class ParamDictTest : public ncnn::ParamDict
+{
+public:
+    int load_param(const char* str);
+    int load_param_bin(const unsigned char* mem);
+};
+
+int ParamDictTest::load_param(const char* str)
+{
+    const unsigned char* mem = (const unsigned char*)str;
+    ncnn::DataReaderFromMemory dr(mem);
+    return ncnn::ParamDict::load_param(dr);
+}
+
+int ParamDictTest::load_param_bin(const unsigned char* mem)
+{
+    ncnn::DataReaderFromMemory dr(mem);
+    return ncnn::ParamDict::load_param_bin(dr);
+}
+
+static int test_paramdict_0()
+{
+    ParamDictTest pdt;
+    pdt.load_param("0=100 1=1,-1,4,5,1,4 2=1.250000 -23303=5,0.1,0.2,-0.4,0.8,1.0 -23304=3,-1,10,-88");
+
+    // int
+    int typei = pdt.type(0);
+    if (typei != 2)
+    {
+        fprintf(stderr, "test_paramdict int type failed %d != 2\n", typei);
+        return -1;
+    }
+    int i = pdt.get(0, 0);
+    if (i != 100)
+    {
+        fprintf(stderr, "test_paramdict int value failed %d != 100\n", i);
+        return -1;
+    }
+
+    // int array
+    int typeai = pdt.type(1);
+    if (typeai != 5)
+    {
+        fprintf(stderr, "test_paramdict int array type failed %d != 5\n", typeai);
+        return -1;
+    }
+    ncnn::Mat ai = pdt.get(1, ncnn::Mat());
+    if (ai.w != 6)
+    {
+        fprintf(stderr, "test_paramdict int array size failed %d != 6\n", ai.w);
+        return -1;
+    }
+    const int* p = ai;
+    if (p[0] != 1 || p[1] != -1 || p[2] != 4 || p[3] != 5 || p[4] != 1 || p[5] != 4)
+    {
+        fprintf(stderr, "test_paramdict int array value failed %d %d %d %d %d %d\n", p[0], p[1], p[2], p[3], p[4], p[5]);
+        return -1;
+    }
+
+    // float
+    int typef = pdt.type(2);
+    if (typef != 3)
+    {
+        fprintf(stderr, "test_paramdict float type failed %d != 3\n", typef);
+        return -1;
+    }
+    float f = pdt.get(2, 0.f);
+    if (f != 1.25f)
+    {
+        fprintf(stderr, "test_paramdict float value failed %f != 1.25f\n", f);
+        return -1;
+    }
+
+    // float array
+    int typeaf = pdt.type(3);
+    if (typeaf != 6)
+    {
+        fprintf(stderr, "test_paramdict float array type failed %d != 6\n", typeaf);
+        return -1;
+    }
+    ncnn::Mat af = pdt.get(3, ncnn::Mat());
+    if (af.w != 5)
+    {
+        fprintf(stderr, "test_paramdict float array size failed %d != 5\n", af.w);
+        return -1;
+    }
+    if (af[0] != 0.1f || af[1] != 0.2f || af[2] != -0.4f || af[3] != 0.8f || af[4] != 1.0f)
+    {
+        fprintf(stderr, "test_paramdict float array value failed %f %f %f %f %f\n", af[0], af[1], af[2], af[3], af[4]);
+        return -1;
+    }
+
+    // int array
+    typeai = pdt.type(4);
+    if (typeai != 5)
+    {
+        fprintf(stderr, "test_paramdict int array type failed %d != 5\n", typeai);
+        return -1;
+    }
+    ai = pdt.get(4, ncnn::Mat());
+    if (ai.w != 3)
+    {
+        fprintf(stderr, "test_paramdict int array size failed %d != 3\n", ai.w);
+        return -1;
+    }
+    p = ai;
+    if (p[0] != -1 || p[1] != 10 || p[2] != -88)
+    {
+        fprintf(stderr, "test_paramdict int array value failed %d %d %d\n", p[0], p[1], p[2]);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int test_paramdict_1()
+{
+    ParamDictTest pdt;
+    pdt.load_param("0=-1 1=4, 2=0.01 3=-1.45e-2,3.14");
+
+    // int
+    int typei = pdt.type(0);
+    if (typei != 2)
+    {
+        fprintf(stderr, "test_paramdict int type failed %d != 2\n", typei);
+        return -1;
+    }
+    int i = pdt.get(0, 0);
+    if (i != -1)
+    {
+        fprintf(stderr, "test_paramdict int value failed %d != -1\n", i);
+        return -1;
+    }
+
+    // int array
+    int typeai = pdt.type(1);
+    if (typeai != 5)
+    {
+        fprintf(stderr, "test_paramdict int array type failed %d != 5\n", typeai);
+        return -1;
+    }
+    ncnn::Mat ai = pdt.get(1, ncnn::Mat());
+    if (ai.w != 1)
+    {
+        fprintf(stderr, "test_paramdict int array size failed %d != 1\n", ai.w);
+        return -1;
+    }
+    const int* p = ai;
+    if (p[0] != 4)
+    {
+        fprintf(stderr, "test_paramdict int array value failed %d\n", p[0]);
+        return -1;
+    }
+
+    // float
+    int typef = pdt.type(2);
+    if (typef != 3)
+    {
+        fprintf(stderr, "test_paramdict float type failed %d != 3\n", typef);
+        return -1;
+    }
+    float f = pdt.get(2, 0.f);
+    if (f != 0.01f)
+    {
+        fprintf(stderr, "test_paramdict float value failed %f != 0.01f\n", f);
+        return -1;
+    }
+
+    // float array
+    int typeaf = pdt.type(3);
+    if (typeaf != 6)
+    {
+        fprintf(stderr, "test_paramdict float array type failed %d != 6\n", typeaf);
+        return -1;
+    }
+    ncnn::Mat af = pdt.get(3, ncnn::Mat());
+    if (af.w != 2)
+    {
+        fprintf(stderr, "test_paramdict float array size failed %d != 2\n", af.w);
+        return -1;
+    }
+    if (af[0] != -0.0145f || af[1] != 3.14f)
+    {
+        fprintf(stderr, "test_paramdict float array value failed %f %f\n", af[0], af[1]);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int test_paramdict_2()
+{
+    ParamDictTest pdt;
+    pdt.load_param("0=bij,bjk->bik 1=This_is_a_very_long_long_string 2=X");
+
+    // string
+    int types = pdt.type(0);
+    if (types != 7)
+    {
+        fprintf(stderr, "test_paramdict string type failed %d != 7\n", types);
+        return -1;
+    }
+    std::string s = pdt.get(0, "");
+    if (s != "bij,bjk->bik")
+    {
+        fprintf(stderr, "test_paramdict string text failed %s != bij,bjk->bik\n", s.c_str());
+        return -1;
+    }
+
+    // string
+    types = pdt.type(1);
+    if (types != 7)
+    {
+        fprintf(stderr, "test_paramdict string type failed %d != 7\n", types);
+        return -1;
+    }
+    s = pdt.get(1, "");
+    if (s != "This_is_a_very_long_long_string")
+    {
+        fprintf(stderr, "test_paramdict string text failed %s != This_is_a_very_long_long_string\n", s.c_str());
+        return -1;
+    }
+
+    // string
+    types = pdt.type(2);
+    if (types != 7)
+    {
+        fprintf(stderr, "test_paramdict string type failed %d != 7\n", types);
+        return -1;
+    }
+    s = pdt.get(2, "");
+    if (s != "X")
+    {
+        fprintf(stderr, "test_paramdict string text failed %s != X\n", s.c_str());
+        return -1;
+    }
+
+    return 0;
+}
+
+static int test_paramdict_3()
+{
+    const unsigned char mem[] = {
+        0x00, 0x00, 0x00, 0x00,
+        0x64, 0x00, 0x00, 0x00,
+        0xfb, 0xa4, 0xff, 0xff,
+        0x06, 0x00, 0x00, 0x00,
+        0x01, 0x00, 0x00, 0x00,
+        0xff, 0xff, 0xff, 0xff,
+        0x04, 0x00, 0x00, 0x00,
+        0x05, 0x00, 0x00, 0x00,
+        0x01, 0x00, 0x00, 0x00,
+        0x04, 0x00, 0x00, 0x00,
+        0x02, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0xa0, 0x3f,
+        0xf9, 0xa4, 0xff, 0xff,
+        0x05, 0x00, 0x00, 0x00,
+        0xcd, 0xcc, 0xcc, 0x3d,
+        0xcd, 0xcc, 0x4c, 0x3e,
+        0xcd, 0xcc, 0xcc, 0xbe,
+        0xcd, 0xcc, 0x4c, 0x3f,
+        0x00, 0x00, 0x80, 0x3f,
+        0x17, 0xff, 0xff, 0xff
+    };
+
+    ParamDictTest pdt;
+    pdt.load_param_bin(mem);
+
+    // int
+    int typei = pdt.type(0);
+    if (typei != 1)
+    {
+        fprintf(stderr, "test_paramdict int type failed %d != 1\n", typei);
+        return -1;
+    }
+    int i = pdt.get(0, 0);
+    if (i != 100)
+    {
+        fprintf(stderr, "test_paramdict int value failed %d != 100\n", i);
+        return -1;
+    }
+
+    // int array
+    int typeai = pdt.type(1);
+    if (typeai != 4)
+    {
+        fprintf(stderr, "test_paramdict int array type failed %d != 4\n", typeai);
+        return -1;
+    }
+    ncnn::Mat ai = pdt.get(1, ncnn::Mat());
+    if (ai.w != 6)
+    {
+        fprintf(stderr, "test_paramdict int array size failed %d != 6\n", ai.w);
+        return -1;
+    }
+    const int* p = ai;
+    if (p[0] != 1 || p[1] != -1 || p[2] != 4 || p[3] != 5 || p[4] != 1 || p[5] != 4)
+    {
+        fprintf(stderr, "test_paramdict int array value failed %d %d %d %d %d %d\n", p[0], p[1], p[2], p[3], p[4], p[5]);
+        return -1;
+    }
+
+    // float
+    int typef = pdt.type(2);
+    if (typef != 1)
+    {
+        fprintf(stderr, "test_paramdict float type failed %d != 1\n", typef);
+        return -1;
+    }
+    float f = pdt.get(2, 0.f);
+    if (f != 1.25f)
+    {
+        fprintf(stderr, "test_paramdict float value failed %f != 1.25f\n", f);
+        return -1;
+    }
+
+    // float array
+    int typeaf = pdt.type(3);
+    if (typeaf != 4)
+    {
+        fprintf(stderr, "test_paramdict float array type failed %d != 4\n", typeaf);
+        return -1;
+    }
+    ncnn::Mat af = pdt.get(3, ncnn::Mat());
+    if (af.w != 5)
+    {
+        fprintf(stderr, "test_paramdict float array size failed %d != 5\n", af.w);
+        return -1;
+    }
+    if (af[0] != 0.1f || af[1] != 0.2f || af[2] != -0.4f || af[3] != 0.8f || af[4] != 1.0f)
+    {
+        fprintf(stderr, "test_paramdict float array value failed %f %f %f %f %f\n", af[0], af[1], af[2], af[3], af[4]);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int test_paramdict_4()
+{
+    const unsigned char mem[] = {
+        0x00, 0x00, 0x00, 0x00,
+        0xff, 0xff, 0xff, 0xff,
+        0xfb, 0xa4, 0xff, 0xff,
+        0x01, 0x00, 0x00, 0x00,
+        0x04, 0x00, 0x00, 0x00,
+        0x02, 0x00, 0x00, 0x00,
+        0x0a, 0xd7, 0x23, 0x3c,
+        0xf9, 0xa4, 0xff, 0xff,
+        0x02, 0x00, 0x00, 0x00,
+        0x68, 0x91, 0x6d, 0xbc,
+        0xc3, 0xf5, 0x48, 0x40,
+        0x17, 0xff, 0xff, 0xff
+    };
+
+    ParamDictTest pdt;
+    pdt.load_param_bin(mem);
+
+    // int
+    int typei = pdt.type(0);
+    if (typei != 1)
+    {
+        fprintf(stderr, "test_paramdict int type failed %d != 1\n", typei);
+        return -1;
+    }
+    int i = pdt.get(0, 0);
+    if (i != -1)
+    {
+        fprintf(stderr, "test_paramdict int value failed %d != -1\n", i);
+        return -1;
+    }
+
+    // int array
+    int typeai = pdt.type(1);
+    if (typeai != 4)
+    {
+        fprintf(stderr, "test_paramdict int array type failed %d != 4\n", typeai);
+        return -1;
+    }
+    ncnn::Mat ai = pdt.get(1, ncnn::Mat());
+    if (ai.w != 1)
+    {
+        fprintf(stderr, "test_paramdict int array size failed %d != 1\n", ai.w);
+        return -1;
+    }
+    const int* p = ai;
+    if (p[0] != 4)
+    {
+        fprintf(stderr, "test_paramdict int array value failed %d\n", p[0]);
+        return -1;
+    }
+
+    // float
+    int typef = pdt.type(2);
+    if (typef != 1)
+    {
+        fprintf(stderr, "test_paramdict float type failed %d != 1\n", typef);
+        return -1;
+    }
+    float f = pdt.get(2, 0.f);
+    if (f != 0.01f)
+    {
+        fprintf(stderr, "test_paramdict float value failed %f != 0.01f\n", f);
+        return -1;
+    }
+
+    // float array
+    int typeaf = pdt.type(3);
+    if (typeaf != 4)
+    {
+        fprintf(stderr, "test_paramdict float array type failed %d != 4\n", typeaf);
+        return -1;
+    }
+    ncnn::Mat af = pdt.get(3, ncnn::Mat());
+    if (af.w != 2)
+    {
+        fprintf(stderr, "test_paramdict float array size failed %d != 2\n", af.w);
+        return -1;
+    }
+    if (af[0] != -0.0145f || af[1] != 3.14f)
+    {
+        fprintf(stderr, "test_paramdict float array value failed %f %f\n", af[0], af[1]);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int test_paramdict_5()
+{
+    const unsigned char mem[] = {
+        0x98, 0xa4, 0xff, 0xff,
+        0x0c, 0x00, 0x00, 0x00,
+        0x62, 0x69, 0x6a, 0x2c,
+        0x62, 0x6a, 0x6b, 0x2d,
+        0x3e, 0x62, 0x69, 0x6b,
+        0x97, 0xa4, 0xff, 0xff,
+        0x1f, 0x00, 0x00, 0x00,
+        0x54, 0x68, 0x69, 0x73,
+        0x5f, 0x69, 0x73, 0x5f,
+        0x61, 0x5f, 0x76, 0x65,
+        0x72, 0x79, 0x5f, 0x6c,
+        0x6f, 0x6e, 0x67, 0x5f,
+        0x6c, 0x6f, 0x6e, 0x67,
+        0x5f, 0x73, 0x74, 0x72,
+        0x69, 0x6e, 0x67, 0x00,
+        0x96, 0xa4, 0xff, 0xff,
+        0x01, 0x00, 0x00, 0x00,
+        0x58, 0x00, 0x00, 0x00,
+        0x17, 0xff, 0xff, 0xff
+    };
+
+    ParamDictTest pdt;
+    pdt.load_param_bin(mem);
+
+    // string
+    int types = pdt.type(0);
+    if (types != 7)
+    {
+        fprintf(stderr, "test_paramdict string type failed %d != 7\n", types);
+        return -1;
+    }
+    std::string s = pdt.get(0, "");
+    if (s != "bij,bjk->bik")
+    {
+        fprintf(stderr, "test_paramdict string text failed %s != bij,bjk->bik\n", s.c_str());
+        return -1;
+    }
+
+    // string
+    types = pdt.type(1);
+    if (types != 7)
+    {
+        fprintf(stderr, "test_paramdict string type failed %d != 7\n", types);
+        return -1;
+    }
+    s = pdt.get(1, "");
+    if (s != "This_is_a_very_long_long_string")
+    {
+        fprintf(stderr, "test_paramdict string text failed %s != This_is_a_very_long_long_string\n", s.c_str());
+        return -1;
+    }
+
+    // string
+    types = pdt.type(2);
+    if (types != 7)
+    {
+        fprintf(stderr, "test_paramdict string type failed %d != 7\n", types);
+        return -1;
+    }
+    s = pdt.get(2, "");
+    if (s != "X")
+    {
+        fprintf(stderr, "test_paramdict string text failed %s != X\n", s.c_str());
+        return -1;
+    }
+
+    return 0;
+}
+
+static int compare_paramdict(const ncnn::ParamDict& pd, const ncnn::ParamDict& pd0)
+{
+    for (int id = 0;; id++)
+    {
+        const int type0 = pd0.type(id);
+        if (type0 == 0)
+        {
+            break;
+        }
+        else if (type0 == 2)
+        {
+            const int i0 = pd0.get(id, 0);
+            int i = pd.get(id, 0);
+            if (i != i0)
+            {
+                fprintf(stderr, "compare_paramdict int failed %d != %d\n", i, i0);
+                return -1;
+            }
+        }
+        else if (type0 == 3)
+        {
+            const float f0 = pd0.get(id, 0.f);
+            int f = pd.get(id, 0.f);
+            if (f != f0)
+            {
+                fprintf(stderr, "compare_paramdict float failed %f != %f\n", f, f0);
+                return -1;
+            }
+        }
+        else if (type0 == 5)
+        {
+            const ncnn::Mat ai0 = pd0.get(id, ncnn::Mat());
+            ncnn::Mat ai = pd.get(id, ncnn::Mat());
+            if (ai.w != ai0.w)
+            {
+                fprintf(stderr, "compare_paramdict int array size failed %d != %d\n", ai.w, ai0.w);
+                return -1;
+            }
+            for (int q = 0; q < ai0.w; q++)
+            {
+                int i0 = ((const int*)ai0)[q];
+                int i = ((const int*)ai)[q];
+                if (i != i0)
+                {
+                    fprintf(stderr, "compare_paramdict int array element %d failed %d != %d\n", q, i, i0);
+                    return -1;
+                }
+            }
+        }
+        else if (type0 == 6)
+        {
+            const ncnn::Mat af0 = pd0.get(id, ncnn::Mat());
+            ncnn::Mat af = pd.get(id, ncnn::Mat());
+            if (af.w != af0.w)
+            {
+                fprintf(stderr, "compare_paramdict float array size failed %d != %d\n", af.w, af0.w);
+                return -1;
+            }
+            for (int q = 0; q < af0.w; q++)
+            {
+                float f0 = af0[q];
+                float f = af[q];
+                if (f != f0)
+                {
+                    fprintf(stderr, "compare_paramdict float array element %d failed %f != %f\n", q, f, f0);
+                    return -1;
+                }
+            }
+        }
+        else if (type0 == 7)
+        {
+            const std::string s0 = pd0.get(id, "");
+            std::string s = pd.get(id, "");
+            if (s != s0)
+            {
+                fprintf(stderr, "compare_paramdict string failed %s != %s\n", s.c_str(), s0.c_str());
+                return -1;
+            }
+        }
+        else
+        {
+            fprintf(stderr, "unexpected paramdict type %d\n", type0);
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+static int test_paramdict_6()
+{
+    const int i0 = 11;
+    const float f0 = -2.2f;
+    const std::string s0 = "qwqwqwq";
+    ncnn::Mat ai0(1);
+    {
+        int* p = ai0;
+        p[0] = 233;
+    }
+
+    ncnn::Mat af0(4);
+    {
+        float* p = af0;
+        p[0] = 2.33f;
+        p[1] = -0.2f;
+        p[2] = 0.f;
+        p[3] = 9494.f;
+    }
+
+    ncnn::ParamDict pd0;
+    pd0.set(1, i0);
+    pd0.set(2, ai0);
+    pd0.set(3, f0);
+    pd0.set(4, af0);
+    pd0.set(5, s0);
+
+    // copy
+    {
+        ncnn::ParamDict pd(pd0);
+
+        int ret = compare_paramdict(pd, pd0);
+        if (ret != 0)
+        {
+            fprintf(stderr, "paramdict copy failed\n");
+            return -1;
+        }
+    }
+
+    // assign
+    {
+        ncnn::ParamDict pd;
+        pd = pd0;
+
+        int ret = compare_paramdict(pd, pd0);
+        if (ret != 0)
+        {
+            fprintf(stderr, "paramdict assign failed\n");
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+int main()
+{
+    return 0
+           || test_paramdict_0()
+           || test_paramdict_1()
+           || test_paramdict_2()
+           || test_paramdict_3()
+           || test_paramdict_4()
+           || test_paramdict_5()
+           || test_paramdict_6();
+}