create order and generate qr through console

8 files changed, 1839 insertions, 300 deletions

diff --git a/main/CMakeLists.txt b/main/CMakeLists.txt
index 50060f1..f35667a 100644
--- a/main/CMakeLists.txt
+++ b/main/CMakeLists.txt
@@ -5,8 +5,9 @@
 
 idf_component_register(
     SRCS
-        "main.c"
+        "qrcodegen.c" "esp_qrcode_wrapper.c" "esp_qrcode_main.c" "main.c"
     INCLUDE_DIRS
         "." "include"
         EMBED_TXTFILES inet_sec.pem
 )
+
diff --git a/main/esp_qrcode_main.c b/main/esp_qrcode_main.c
new file mode 100644
index 0000000..7b03d5d
--- /dev/null
+++ b/main/esp_qrcode_main.c
@@ -0,0 +1,121 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// 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 <stdio.h>
+#include <esp_err.h>
+#include "esp_log.h"
+
+#include "qrcodegen.h"
+#include "qrcode.h"
+
+static const char *TAG = "QRCODE";
+
+static const char *lt[] = {
+    /* 0 */ "  ",
+    /* 1 */ "\u2580 ",
+    /* 2 */ " \u2580",
+    /* 3 */ "\u2580\u2580",
+    /* 4 */ "\u2584 ",
+    /* 5 */ "\u2588 ",
+    /* 6 */ "\u2584\u2580",
+    /* 7 */ "\u2588\u2580",
+    /* 8 */ " \u2584",
+    /* 9 */ "\u2580\u2584",
+    /* 10 */ " \u2588",
+    /* 11 */ "\u2580\u2588",
+    /* 12 */ "\u2584\u2584",
+    /* 13 */ "\u2588\u2584",
+    /* 14 */ "\u2584\u2588",
+    /* 15 */ "\u2588\u2588",
+};
+
+void esp_qrcode_print_console(esp_qrcode_handle_t qrcode)
+{
+    int size = qrcodegen_getSize(qrcode);
+    int border = 2;
+    unsigned char num = 0;
+
+    for (int y = -border; y < size + border; y+=2) {
+        for (int x = -border; x < size + border; x+=2) {
+            num = 0;
+            if (qrcodegen_getModule(qrcode, x, y)) {
+                num |= 1 << 0;
+            }
+            if ((x < size + border) && qrcodegen_getModule(qrcode, x+1, y)) {
+                num |= 1 << 1;
+            }
+            if ((y < size + border) && qrcodegen_getModule(qrcode, x, y+1)) {
+                num |= 1 << 2;
+            }
+            if ((x < size + border) && (y < size + border) && qrcodegen_getModule(qrcode, x+1, y+1)) {
+                num |= 1 << 3;
+            }
+            printf("%s", lt[num]);
+        }
+        printf("\n");
+    }
+    printf("\n");
+}
+
+esp_err_t esp_qrcode_generate(esp_qrcode_config_t *cfg, const char *text)
+{
+    enum qrcodegen_Ecc ecc_lvl;
+    uint8_t *qrcode, *tempbuf;
+    esp_err_t err = ESP_FAIL;
+
+    qrcode = calloc(1, qrcodegen_BUFFER_LEN_FOR_VERSION(cfg->max_qrcode_version));
+    if (!qrcode) {
+        return ESP_ERR_NO_MEM;
+    }
+
+    tempbuf = calloc(1, qrcodegen_BUFFER_LEN_FOR_VERSION(cfg->max_qrcode_version));
+    if (!tempbuf) {
+        free(qrcode);
+        return ESP_ERR_NO_MEM;
+    }
+
+    switch(cfg->qrcode_ecc_level) {
+        case ESP_QRCODE_ECC_LOW:
+            ecc_lvl = qrcodegen_Ecc_LOW;
+            break;
+        case ESP_QRCODE_ECC_MED:
+            ecc_lvl = qrcodegen_Ecc_MEDIUM;
+            break;
+        case ESP_QRCODE_ECC_QUART:
+            ecc_lvl = qrcodegen_Ecc_QUARTILE;
+            break;
+        case ESP_QRCODE_ECC_HIGH:
+            ecc_lvl = qrcodegen_Ecc_HIGH;
+            break;
+        default:
+            ecc_lvl = qrcodegen_Ecc_LOW;
+            break;
+    }
+
+    ESP_LOGI(TAG, "Encoding below text with ECC LVL %d & QR Code Version %d",
+             ecc_lvl, cfg->max_qrcode_version);
+    ESP_LOGI(TAG, "%s", text);
+    // Make and print the QR Code symbol
+    bool ok = qrcodegen_encodeText(text, tempbuf, qrcode, ecc_lvl,
+                                   qrcodegen_VERSION_MIN, cfg->max_qrcode_version,
+                                   qrcodegen_Mask_AUTO, true);
+    if (ok && cfg->display_func) {
+        cfg->display_func((esp_qrcode_handle_t)qrcode);
+        err = ESP_OK;
+    }
+
+    free(qrcode);
+    free(tempbuf);
+    return err;
+}
diff --git a/main/esp_qrcode_wrapper.c b/main/esp_qrcode_wrapper.c
new file mode 100644
index 0000000..cde5165
--- /dev/null
+++ b/main/esp_qrcode_wrapper.c
@@ -0,0 +1,29 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// 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 <stdio.h>
+#include <esp_err.h>
+
+#include "qrcodegen.h"
+#include "qrcode.h"
+
+int esp_qrcode_get_size(esp_qrcode_handle_t qrcode)
+{
+    return qrcodegen_getSize(qrcode);
+}
+
+bool esp_qrcode_get_module(esp_qrcode_handle_t qrcode, int x, int y)
+{
+    return qrcodegen_getModule(qrcode, x, y);
+}
diff --git a/main/http-client.c b/main/http-client.c
new file mode 100644
index 0000000..95d392d
--- /dev/null
+++ b/main/http-client.c
@@ -0,0 +1,103 @@
+/*
+ * This example code is in the Public Domain (or CC0 licensed, at your option.)
+ * Unless required by applicable law or agreed to in writing, this
+ * software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+ * CONDITIONS OF ANY KIND, either express or implied.
+ */
+
+#include "main.h"
+/* Root cert for howsmyssl.com, taken from howsmyssl_com_root_cert.pem
+
+   The PEM file was extracted from the output of this command:
+   openssl s_client -showcerts -connect www.howsmyssl.com:443 </dev/null
+
+   The CA root cert is the last cert given in the chain of certs.
+
+   To embed it in the app binary, the PEM file is named
+   in the component.mk COMPONENT_EMBED_TXTFILES variable.
+*/
+extern const char inet_sec_root_cert_pem_start[] asm("_binary_inet_sec_pem_start");
+extern const char inet_sec_root_cert_pem_end[] asm("_binary_inet_sec_pem_end");
+
+#define MAX_HTTP_RECV_BUFFER 512
+#define MAX_HTTP_OUTPUT_BUFFER 2048
+
+esp_err_t _http_event_handler(esp_http_client_event_t *evt)
+{
+  static char *output_buffer; // Buffer to store response of http request from event handler
+  static int output_len;      // Stores number of bytes read
+  switch (evt->event_id)
+  {
+  case HTTP_EVENT_ERROR:
+    ESP_LOGI(TAG, "HTTP_EVENT_ERROR");
+    break;
+  case HTTP_EVENT_ON_CONNECTED:
+    ESP_LOGI(TAG, "HTTP_EVENT_ON_CONNECTED");
+    break;
+  case HTTP_EVENT_HEADER_SENT:
+    ESP_LOGI(TAG, "HTTP_EVENT_HEADER_SENT");
+    break;
+  case HTTP_EVENT_ON_HEADER:
+    ESP_LOGI(TAG, "HTTP_EVENT_ON_HEADER, key=%s, value=%s", evt->header_key, evt->header_value);
+    break;
+  case HTTP_EVENT_ON_DATA:
+    ESP_LOGI(TAG, "HTTP_EVENT_ON_DATA, len=%d", evt->data_len);
+    /*
+     *  Check for chunked encoding is added as the URL for chunked encoding used in this example returns binary data.
+     *  However, event handler can also be used in case chunked encoding is used.
+     */
+    if (!esp_http_client_is_chunked_response(evt->client))
+    {
+      // If user_data buffer is configured, copy the response into the buffer
+      if (evt->user_data)
+      {
+        memcpy(evt->user_data + output_len, evt->data, evt->data_len);
+      }
+      else
+      {
+        if (output_buffer == NULL)
+        {
+          output_buffer = (char *)malloc(esp_http_client_get_content_length(evt->client));
+          output_len = 0;
+          if (output_buffer == NULL)
+          {
+            ESP_LOGE(TAG, "Failed to allocate memory for output buffer");
+            return ESP_FAIL;
+          }
+        }
+        memcpy(output_buffer + output_len, evt->data, evt->data_len);
+      }
+      output_len += evt->data_len;
+    }
+
+    break;
+  case HTTP_EVENT_ON_FINISH:
+    ESP_LOGI(TAG, "HTTP_EVENT_ON_FINISH");
+    if (output_buffer != NULL)
+    {
+      // Response is accumulated in output_buffer. Uncomment the below line to print the accumulated response
+      // ESP_LOG_BUFFER_HEX(TAG, output_buffer, output_len);
+      free(output_buffer);
+      output_buffer = NULL;
+    }
+    output_len = 0;
+    break;
+  case HTTP_EVENT_DISCONNECTED:
+    ESP_LOGI(TAG, "HTTP_EVENT_DISCONNECTED");
+    int mbedtls_err = 0;
+    esp_err_t err = esp_tls_get_and_clear_last_error(evt->data, &mbedtls_err, NULL);
+    if (err != 0)
+    {
+      ESP_LOGI(TAG, "Last esp error code: 0x%x", err);
+      ESP_LOGI(TAG, "Last mbedtls failure: 0x%x", mbedtls_err);
+    }
+    if (output_buffer != NULL)
+    {
+      free(output_buffer);
+      output_buffer = NULL;
+    }
+    output_len = 0;
+    break;
+  }
+  return ESP_OK;
+}
\ No newline at end of file
diff --git a/main/include/qrcode.h b/main/include/qrcode.h
new file mode 100644
index 0000000..75002c3
--- /dev/null
+++ b/main/include/qrcode.h
@@ -0,0 +1,104 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// 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.
+#pragma once
+
+#include <esp_err.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+  * @brief  QR Code handle used by the display function
+  */
+typedef const uint8_t * esp_qrcode_handle_t;
+
+/**
+  * @brief  QR Code configuration options
+  */
+typedef struct {
+    void (*display_func)(esp_qrcode_handle_t qrcode);   /**< Function called for displaying the QR Code after encoding is complete */
+    int max_qrcode_version;                             /**< Max QR Code Version to be used. Range: 2 - 40 */
+    int qrcode_ecc_level;                               /**< Error Correction Level for QR Code */
+} esp_qrcode_config_t;
+
+/**
+  * @brief  Error Correction Level in a QR Code Symbol
+  */
+enum {
+    ESP_QRCODE_ECC_LOW,     /**< QR Code Error Tolerance of 7% */
+    ESP_QRCODE_ECC_MED,     /**< QR Code Error Tolerance of 15% */
+    ESP_QRCODE_ECC_QUART,   /**< QR Code Error Tolerance of 25% */
+    ESP_QRCODE_ECC_HIGH     /**< QR Code Error Tolerance of 30% */
+};
+
+/**
+  * @brief  Encodes the given string into a QR Code and calls the display function
+  *
+  * @attention 1. Can successfully encode a UTF-8 string of up to 2953 bytes or an alphanumeric
+  *               string of up to 4296 characters or any digit string of up to 7089 characters
+  *
+  * @param  cfg   Configuration used for QR Code encoding.
+  * @param  text  String to encode into a QR Code.
+  *
+  * @return
+  *    - ESP_OK: succeed
+  *    - ESP_FAIL: Failed to encode string into a QR Code
+  *    - ESP_ERR_NO_MEM: Failed to allocate buffer for given max_qrcode_version
+  */
+esp_err_t esp_qrcode_generate(esp_qrcode_config_t *cfg, const char *text);
+
+/**
+  * @brief  Displays QR Code on the console
+  *
+  * @param  qrcode  QR Code handle used by the display function.
+  */
+void esp_qrcode_print_console(esp_qrcode_handle_t qrcode);
+
+/**
+  * @brief  Returns the side length of the given QR Code
+  *
+  * @param  qrcode  QR Code handle used by the display function.
+  *
+  * @return
+  *    - val[21, 177]: Side length of QR Code
+  */
+int esp_qrcode_get_size(esp_qrcode_handle_t qrcode);
+
+/**
+  * @brief  Returns the Pixel value for the given coordinates
+  *         False indicates White and True indicates Black
+  *
+  * @attention 1. Coordinates for top left corner are (x=0, y=0)
+  * @attention 2. For out of bound coordinates false (White) is returned
+  *
+  * @param  qrcode  QR Code handle used by the display function.
+  * @param  x  X-Coordinate of QR Code module
+  * @param  y  Y-Coordinate of QR Code module
+  *
+  * @return
+  *    - true: (x, y) Pixel is Black
+  *    - false: (x, y) Pixel is White
+  */
+bool esp_qrcode_get_module(esp_qrcode_handle_t qrcode, int x, int y);
+
+#define ESP_QRCODE_CONFIG_DEFAULT() (esp_qrcode_config_t) { \
+    .display_func = esp_qrcode_print_console, \
+    .max_qrcode_version = 10, \
+    .qrcode_ecc_level = ESP_QRCODE_ECC_LOW, \
+}
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/main/main.c b/main/main.c
index b3218aa..7806193 100644
--- a/main/main.c
+++ b/main/main.c
@@ -10,11 +10,17 @@
 
 #include "main.h"
 
+static const char *TAG = "TALER";
+
+// #include "wifi.c"
+#include "http-client.c"
+
 static pax_buf_t buf;
 xQueueHandle buttonQueue;
 
 #include <esp_log.h>
-static const char *TAG = "TALER";
+#include <cJSON.h>
+#include "qrcode.h"
 
 // Updates the screen with the latest buffer.
 void disp_flush()
@@ -29,125 +35,6 @@ void exit_to_launcher()
     esp_restart();
 }
 
-/* Root cert for howsmyssl.com, taken from howsmyssl_com_root_cert.pem
-
-   The PEM file was extracted from the output of this command:
-   openssl s_client -showcerts -connect www.howsmyssl.com:443 </dev/null
-
-   The CA root cert is the last cert given in the chain of certs.
-
-   To embed it in the app binary, the PEM file is named
-   in the component.mk COMPONENT_EMBED_TXTFILES variable.
-*/
-extern const char inet_sec_root_cert_pem_start[] asm("_binary_inet_sec_pem_start");
-extern const char inet_sec_root_cert_pem_end[] asm("_binary_inet_sec_pem_end");
-
-esp_err_t _http_event_handler(esp_http_client_event_t *evt)
-{
-    static char *output_buffer; // Buffer to store response of http request from event handler
-    static int output_len;      // Stores number of bytes read
-    switch (evt->event_id)
-    {
-    case HTTP_EVENT_ERROR:
-        ESP_LOGD(TAG, "HTTP_EVENT_ERROR");
-        break;
-    case HTTP_EVENT_ON_CONNECTED:
-        ESP_LOGD(TAG, "HTTP_EVENT_ON_CONNECTED");
-        break;
-    case HTTP_EVENT_HEADER_SENT:
-        ESP_LOGD(TAG, "HTTP_EVENT_HEADER_SENT");
-        break;
-    case HTTP_EVENT_ON_HEADER:
-        ESP_LOGD(TAG, "HTTP_EVENT_ON_HEADER, key=%s, value=%s", evt->header_key, evt->header_value);
-        break;
-    case HTTP_EVENT_ON_DATA:
-        ESP_LOGD(TAG, "HTTP_EVENT_ON_DATA, len=%d", evt->data_len);
-        /*
-         *  Check for chunked encoding is added as the URL for chunked encoding used in this example returns binary data.
-         *  However, event handler can also be used in case chunked encoding is used.
-         */
-        if (!esp_http_client_is_chunked_response(evt->client))
-        {
-            // If user_data buffer is configured, copy the response into the buffer
-            if (evt->user_data)
-            {
-                memcpy(evt->user_data + output_len, evt->data, evt->data_len);
-            }
-            else
-            {
-                if (output_buffer == NULL)
-                {
-                    output_buffer = (char *)malloc(esp_http_client_get_content_length(evt->client));
-                    output_len = 0;
-                    if (output_buffer == NULL)
-                    {
-                        ESP_LOGE(TAG, "Failed to allocate memory for output buffer");
-                        return ESP_FAIL;
-                    }
-                }
-                memcpy(output_buffer + output_len, evt->data, evt->data_len);
-            }
-            output_len += evt->data_len;
-        }
-
-        break;
-    case HTTP_EVENT_ON_FINISH:
-        ESP_LOGD(TAG, "HTTP_EVENT_ON_FINISH");
-        if (output_buffer != NULL)
-        {
-
-            // order_id = (char *)malloc(output_len);
-            // memcpy(order_id, output_buffer, output_len);
-            // Response is accumulated in output_buffer. Uncomment the below line to print the accumulated response
-            // ESP_LOG_BUFFER_HEX(TAG, output_buffer, output_len);
-            const pax_font_t *font = pax_font_saira_condensed;
-
-            pax_vec1_t dims = pax_text_size(font, font->default_size, output_buffer);
-
-            // Draw the centered text.
-            pax_draw_text(
-                &buf,                     // Buffer to draw to.
-                0xff000000,               // color
-                font, font->default_size, // Font and size to use.
-                // Position (top left corner) of the app.
-                (buf.width - dims.x) / 2.0,
-                (buf.height - dims.y) / 2.0,
-                // The text to be rendered.
-                output_buffer);
-
-            // Draws the entire graphics buffer to the screen.
-            disp_flush();
-
-            free(output_buffer);
-            output_buffer = NULL;
-        }
-        output_len = 0;
-        break;
-    case HTTP_EVENT_DISCONNECTED:
-        ESP_LOGI(TAG, "HTTP_EVENT_DISCONNECTED");
-        int mbedtls_err = 0;
-        esp_err_t err = esp_tls_get_and_clear_last_error((esp_tls_error_handle_t)evt->data, &mbedtls_err, NULL);
-        if (err != 0)
-        {
-            ESP_LOGI(TAG, "Last esp error code: 0x%x", err);
-            ESP_LOGI(TAG, "Last mbedtls failure: 0x%x", mbedtls_err);
-        }
-        if (output_buffer != NULL)
-        {
-            free(output_buffer);
-            output_buffer = NULL;
-        }
-        output_len = 0;
-        break;
-        // case HTTP_EVENT_REDIRECT:
-        //     ESP_LOGD(TAG, "HTTP_EVENT_REDIRECT");
-        //     esp_http_client_set_header(evt->client, "From", "user@example.com");
-        //     esp_http_client_set_header(evt->client, "Accept", "text/html");
-        //     break;
-    }
-    return ESP_OK;
-}
-
 void initialize_things(void)
 {
     // Initialize the screen, the I2C and the SPI busses.
@@ -174,206 +61,167 @@ void initialize_things(void)
     pax_background(&buf, col);
 }
 
-#define MAX_HTTP_OUTPUT_BUFFER 2048
-
-/* Set the SSID and Password via project configuration, or can set directly here */
-#define DEFAULT_SSID "MCH2022-open"
-#define DEFAULT_PWD ""
-
-#if CONFIG_EXAMPLE_WIFI_ALL_CHANNEL_SCAN
-#define DEFAULT_SCAN_METHOD WIFI_ALL_CHANNEL_SCAN
-#elif CONFIG_EXAMPLE_WIFI_FAST_SCAN
-#define DEFAULT_SCAN_METHOD WIFI_FAST_SCAN
-#else
-#define DEFAULT_SCAN_METHOD WIFI_FAST_SCAN
-#endif /*CONFIG_EXAMPLE_SCAN_METHOD*/
-
-#if CONFIG_EXAMPLE_WIFI_CONNECT_AP_BY_SIGNAL
-#define DEFAULT_SORT_METHOD WIFI_CONNECT_AP_BY_SIGNAL
-#elif CONFIG_EXAMPLE_WIFI_CONNECT_AP_BY_SECURITY
-#define DEFAULT_SORT_METHOD WIFI_CONNECT_AP_BY_SECURITY
-#else
-#define DEFAULT_SORT_METHOD WIFI_CONNECT_AP_BY_SIGNAL
-#endif /*CONFIG_EXAMPLE_SORT_METHOD*/
-
-#if CONFIG_EXAMPLE_FAST_SCAN_THRESHOLD
-#define DEFAULT_RSSI CONFIG_EXAMPLE_FAST_SCAN_MINIMUM_SIGNAL
-#if CONFIG_EXAMPLE_FAST_SCAN_WEAKEST_AUTHMODE_OPEN
-#define DEFAULT_AUTHMODE WIFI_AUTH_OPEN
-#elif CONFIG_EXAMPLE_FAST_SCAN_WEAKEST_AUTHMODE_WEP
-#define DEFAULT_AUTHMODE WIFI_AUTH_WEP
-#elif CONFIG_EXAMPLE_FAST_SCAN_WEAKEST_AUTHMODE_WPA
-#define DEFAULT_AUTHMODE WIFI_AUTH_WPA_PSK
-#elif CONFIG_EXAMPLE_FAST_SCAN_WEAKEST_AUTHMODE_WPA2
-#define DEFAULT_AUTHMODE WIFI_AUTH_WPA2_PSK
-#else
-#define DEFAULT_AUTHMODE WIFI_AUTH_OPEN
-#endif
-#else
-#define DEFAULT_RSSI -127
-#define DEFAULT_AUTHMODE WIFI_AUTH_OPEN
-#endif
-/*CONFIG_EXAMPLE_FAST_SCAN_THRESHOLD*/
-
-static void event_handler(void *arg, esp_event_base_t event_base,
-                          int32_t event_id, void *event_data)
+void show_message(const char *message)
+{
+    const pax_font_t *font = pax_font_saira_condensed;
+
+    int hue = esp_random() & 255;
+    pax_col_t col = pax_col_hsv(hue, 255 /*saturation*/, 255 /*brighness*/);
+    pax_background(&buf, col);
+
+    // Determine how the text dimensions so we can display it centered on
+    // screen.
+    pax_vec1_t dims = pax_text_size(font, font->default_size / 2, message);
+
+    // Draw the centered text.
+    pax_draw_text(
+        &buf,                         // Buffer to draw to.
+        0xff000000,                   // color
+        font, font->default_size / 2, // Font and size to use.
+        // Position (top left corner) of the app.
+        (buf.width - dims.x) / 2.0,
+        (buf.height - dims.y) / 2.0,
+        // The text to be rendered.
+        message);
+
+    // Draws the entire graphics buffer to the screen.
+    disp_flush();
+}
+
+void wait_any_key_or_exit()
 {
-    if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START)
+    // Structure used to receive data.
+    rp2040_input_message_t message;
+    // Wait forever for a button press (because of portMAX_DELAY)
+    xQueueReceive(buttonQueue, &message, portMAX_DELAY);
+    // Which button is currently pressed?
+    if (message.input == RP2040_INPUT_BUTTON_START && message.state)
     {
-        esp_wifi_connect();
+        // If home is pressed, exit to launcher.
+        exit_to_launcher();
     }
-    else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED)
+}
+
+#define TALER_MERCHANT_HOST "merchant-backend.taler.ar"
+#define TALER_MERCHANT_NAME "mch2022"
+#define TALER_CREATE_ORDER_URL "/instances/" TALER_MERCHANT_NAME "/private/orders"
+#define TALER_PAYMENT_URI "taler://pay/" TALER_MERCHANT_HOST "/instances/" TALER_MERCHANT_NAME "/"
+#define TALER_PAYMENT_TEMPLATE TALER_PAYMENT_URI "%s/"
+
+bool create_new_order(float amount, char *token, char **paymentURI)
+{
+    char local_response_buffer[MAX_HTTP_OUTPUT_BUFFER] = {0};
+    int token_len = strlen(token);
+
+    const char post_data[128];
+
+    // return "2022.204-123123123123";
+    // POST
+    // static const char *host = TALER_MERCHANT_HOST;
+    // static const char *path = TALER_CREATE_ORDER_URL;
+    ESP_LOGI(TAG, "creating config");
+    esp_http_client_config_t config = {
+        .port = 443,
+        .host = "merchant-backend.taler.ar",
+        .path = "/instances/mch2022/private/orders",
+        // .host = host,
+        // .path = path,
+        // .keep_alive_enable = true,
+        .method = HTTP_METHOD_POST,
+        .transport_type = HTTP_TRANSPORT_OVER_SSL,
+        .cert_pem = inet_sec_root_cert_pem_start,
+        .user_data = local_response_buffer,
+        .event_handler = _http_event_handler,
+    };
+    esp_http_client_handle_t client = esp_http_client_init(&config);
+    esp_http_client_set_header(client, "Content-Type", "application/json");
+
     {
-        esp_wifi_connect();
+        char *auth_buffer = (char *)malloc(sizeof("Bearer secret-token:") + token_len + 1);
+        sprintf(auth_buffer, "Bearer secret-token:%s", token);
+        esp_http_client_set_header(client, "Authorization", auth_buffer);
+        free(auth_buffer);
     }
-    else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP)
+
+    sprintf(post_data, "{\"order\":{\"summary\":\"sold in mch2022\",\"amount\":\"ARS:%f\"},\"create_token\":false}", amount);
+    esp_http_client_set_post_field(client, post_data, strlen(post_data));
+
+    ESP_LOGI(TAG, "about to perform the http query");
+    esp_err_t err = esp_http_client_perform(client);
+
+    if (err == ESP_OK)
     {
-        ip_event_got_ip_t *event = (ip_event_got_ip_t *)event_data;
-        ESP_LOGI(TAG, "got ip:" IPSTR, IP2STR(&event->ip_info.ip));
+        ESP_LOGI(TAG, "buffer has %s", local_response_buffer);
+        cJSON *response_json = cJSON_Parse(local_response_buffer);
+        cJSON *orderId = cJSON_GetObjectItemCaseSensitive(response_json, "order_id");
+        show_message(orderId->valuestring);
+        int order_len = strlen(orderId->valuestring);
+        // static const char *uri = TALER_PAYMENT_URI;
+        // static const char *template = TALER_PAYMENT_TEMPLATE;
+        // *paymentURI = (char *)malloc(sizeof(uri) + order_len + /*last slash*/ 1 + /*0*/ 1);
+        // sprintf(*paymentURI, template, orderId->valuestring);
+        *paymentURI = (char *)malloc(sizeof("taler://pay/merchant-backend.taler.ar/instances/mch2022/") + order_len + /*last slash*/ 1 + /*0*/ 1);
+        sprintf(*paymentURI, "taler://pay/merchant-backend.taler.ar/instances/mch2022/%s/", orderId->valuestring);
+        ESP_LOGI(TAG, "payment uri %s", *paymentURI);
+        cJSON_Delete(response_json);
+    }
+    else
+    {
+        const char buffer[200];
+        sprintf(buffer, "failed = %d, %s",
+                esp_http_client_get_status_code(client),
+                esp_err_to_name(err));
+        show_message(buffer);
     }
-}
 
-/* Initialize Wi-Fi as sta and set scan method */
-static void fast_scan(void)
-{
-    ESP_ERROR_CHECK(esp_netif_init());
-    ESP_ERROR_CHECK(esp_event_loop_create_default());
-
-    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
-    ESP_ERROR_CHECK(esp_wifi_init(&cfg));
-
-    ESP_ERROR_CHECK(esp_event_handler_instance_register(WIFI_EVENT, ESP_EVENT_ANY_ID, &event_handler, NULL, NULL));
-    ESP_ERROR_CHECK(esp_event_handler_instance_register(IP_EVENT, IP_EVENT_STA_GOT_IP, &event_handler, NULL, NULL));
-
-    // Initialize default station as network interface instance (esp-netif)
-    esp_netif_t *sta_netif = esp_netif_create_default_wifi_sta();
-    assert(sta_netif);
-
-    // Initialize and start WiFi
-    wifi_config_t wifi_config = {
-        .sta = {
-            .ssid = DEFAULT_SSID,
-            .password = DEFAULT_PWD,
-            .scan_method = DEFAULT_SCAN_METHOD,
-            .sort_method = DEFAULT_SORT_METHOD,
-            .threshold.rssi = DEFAULT_RSSI,
-            .threshold.authmode = DEFAULT_AUTHMODE,
-        },
-    };
-    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
-    ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_config));
-    ESP_ERROR_CHECK(esp_wifi_start());
+    ESP_LOGI(TAG, "almos done");
+    esp_http_client_cleanup(client);
+    ESP_LOGI(TAG, "done");
+    return err == ESP_OK;
 }
 
 void app_main()
 {
 
-    ESP_LOGI(TAG, "Starting app!");
+    ESP_LOGI(TAG, "Starting...");
     initialize_things();
-    fast_scan();
-
-    // This text is shown on screen.
-    char *text = "Just starting!";
 
-    // Pick the font (Saira is the only one that looks nice in this size).
-    const pax_font_t *font = pax_font_saira_condensed;
+    show_message("Connecting to MCH2022");
+    // wifi_connect_to_stored();
+    ESP_LOGI(TAG, "Initializing wifi...");
+    wifi_init();
+    bool connected = false;
+    while (!connected)
     {
-
-        // Determine how the text dimensions so we can display it centered on
-        // screen.
-        pax_vec1_t dims = pax_text_size(font, font->default_size, text);
-
-        // Draw the centered text.
-        pax_draw_text(
-            &buf,                     // Buffer to draw to.
-            0xff000000,               // color
-            font, font->default_size, // Font and size to use.
-            // Position (top left corner) of the app.
-            (buf.width - dims.x) / 2.0,
-            (buf.height - dims.y) / 2.0,
-            // The text to be rendered.
-            text);
-
-        // Draws the entire graphics buffer to the screen.
-        disp_flush();
+        connected = wifi_connect_ent("MCH2022", "badge", "badge", "badge", ESP_EAP_TTLS_PHASE2_PAP, 3);
+        if (!connected)
+        {
+            ESP_LOGI(TAG, "could not connect, trying again...");
+            show_message("go near an MCH2022 access point");
+        }
     }
-
-    // curl https://merchant-backend.taler.ar/instances/mch2022/private/orders
-    // -H "Authorization: Bearer secret-token:305a16ce7cc2e2793060e39b9210a700"
+    ESP_LOGI(TAG, "Connected.");
+    show_message("connected!");
 
     while (1)
     {
-        char local_response_buffer[MAX_HTTP_OUTPUT_BUFFER] = {0};
-
-        // POST
-        // const char *post_data = "{\"order\":{\"summary\":\"s\",\"amount\":\"ARS:1\"}}";
-        // esp_http_client_set_url(client, "https://merchant-backend.taler.ar/instances/mch2022/private/orders");
-        // esp_http_client_set_url(client, "http://arcade.taler.ar/test/instances/mch2022/private/orders");
-        // esp_http_client_set_method(client, HTTP_METHOD_POST);
-        // esp_http_client_set_header(client, "Content-Type", "application/json");
-        // esp_http_client_set_header(client, "Authorization", "Bearer secret-token:305a16ce7cc2e2793060e39b9210a700");
-        // esp_http_client_set_post_field(client, post_data, strlen(post_data));
-        esp_http_client_config_t config = {
-            .host = "arcade.taler.ar",
-            .port = 443,
-            .user_data = local_response_buffer, // Pass address of local buffer to get response
-            .path = "/test/badge",
-            .keep_alive_enable = true,
-            .transport_type = HTTP_TRANSPORT_OVER_SSL,
-            // .event_handler = _http_event_handler,
-            .cert_pem = inet_sec_root_cert_pem_start,
-        };
-        esp_http_client_handle_t client = esp_http_client_init(&config);
-
-        esp_err_t err = esp_http_client_perform(client);
-        // if (err == ESP_OK)
-        // {
-        //     // ESP_LOGI(TAG, "HTTP POST Status = %d, content_length = %lld",
-        //     //          esp_http_client_get_status_code(client),
-        //     //          esp_http_client_get_content_length(client));
-
-        //     // Determine how the text dimensions so we can display it centered on
-        //     // screen.
-        // }
-        // else
-        // {
-        //     ESP_LOGE(TAG, "HTTP POST request failed: %s", esp_err_to_name(err));
-        // }
-
-        // Wait for button presses and do another cycle.
-        int hue = esp_random() & 255;
-        pax_col_t col = pax_col_hsv(hue, 255 /*saturation*/, 255 /*brighness*/);
-        pax_background(&buf, col);
-
-        // Determine how the text dimensions so we can display it centered on
-        // screen.
-        pax_vec1_t dims = pax_text_size(font, font->default_size, local_response_buffer);
-
-        // Draw the centered text.
-        pax_draw_text(
-            &buf,                     // Buffer to draw to.
-            0xff000000,               // color
-            font, font->default_size, // Font and size to use.
-            // Position (top left corner) of the app.
-            (buf.width - dims.x) / 2.0,
-            (buf.height - dims.y) / 2.0,
-            // The text to be rendered.
-            local_response_buffer);
-
-        // Draws the entire graphics buffer to the screen.
-        disp_flush();
-
-        // Structure used to receive data.
-        rp2040_input_message_t message;
-
-        // Wait forever for a button press (because of portMAX_DELAY)
-        xQueueReceive(buttonQueue, &message, portMAX_DELAY);
-
-        // Which button is currently pressed?
-        if (message.input == RP2040_INPUT_BUTTON_START && message.state)
+        const char *orderId = NULL;
+        bool ok = create_new_order(3.2, "305a16ce7cc2e2793060e39b9210a700", &orderId);
+        ESP_LOGI(TAG, "order generated!");
+
+        if (ok)
         {
-            // If home is pressed, exit to launcher.
-            exit_to_launcher();
+            esp_qrcode_config_t cfg = {
+                .max_qrcode_version = 10,
+                .display_func = esp_qrcode_print_console,
+                .qrcode_ecc_level = ESP_QRCODE_ECC_LOW,
+            };
+
+            esp_qrcode_generate(&cfg, orderId);
+            free(orderId);
         }
+
+        wait_any_key_or_exit();
+        show_message("again...");
     }
 }
diff --git a/main/qrcodegen.c b/main/qrcodegen.c
new file mode 100644
index 0000000..9fce6b0
--- /dev/null
+++ b/main/qrcodegen.c
@@ -0,0 +1,1022 @@
+/*
+ * QR Code generator library (C)
+ *
+ * Copyright (c) Project Nayuki. (MIT License)
+ * https://www.nayuki.io/page/qr-code-generator-library
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ * - The above copyright notice and this permission notice shall be included in
+ *   all copies or substantial portions of the Software.
+ * - The Software is provided "as is", without warranty of any kind, express or
+ *   implied, including but not limited to the warranties of merchantability,
+ *   fitness for a particular purpose and noninfringement. In no event shall the
+ *   authors or copyright holders be liable for any claim, damages or other
+ *   liability, whether in an action of contract, tort or otherwise, arising from,
+ *   out of or in connection with the Software or the use or other dealings in the
+ *   Software.
+ */
+
+#include <assert.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#include "qrcodegen.h"
+
+#ifndef QRCODEGEN_TEST
+	#define testable static  // Keep functions private
+#else
+	#define testable  // Expose private functions
+#endif
+
+
+/*---- Forward declarations for private functions ----*/
+
+// Regarding all public and private functions defined in this source file:
+// - They require all pointer/array arguments to be not null unless the array length is zero.
+// - They only read input scalar/array arguments, write to output pointer/array
+//   arguments, and return scalar values; they are "pure" functions.
+// - They don't read mutable global variables or write to any global variables.
+// - They don't perform I/O, read the clock, print to console, etc.
+// - They allocate a small and constant amount of stack memory.
+// - They don't allocate or free any memory on the heap.
+// - They don't recurse or mutually recurse. All the code
+//   could be inlined into the top-level public functions.
+// - They run in at most quadratic time with respect to input arguments.
+//   Most functions run in linear time, and some in constant time.
+//   There are no unbounded loops or non-obvious termination conditions.
+// - They are completely thread-safe if the caller does not give the
+//   same writable buffer to concurrent calls to these functions.
+
+testable void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[], int *bitLen);
+
+testable void addEccAndInterleave(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]);
+testable int getNumDataCodewords(int version, enum qrcodegen_Ecc ecl);
+testable int getNumRawDataModules(int ver);
+
+testable void reedSolomonComputeDivisor(int degree, uint8_t result[]);
+testable void reedSolomonComputeRemainder(const uint8_t data[], int dataLen,
+	const uint8_t generator[], int degree, uint8_t result[]);
+testable uint8_t reedSolomonMultiply(uint8_t x, uint8_t y);
+
+testable void initializeFunctionModules(int version, uint8_t qrcode[]);
+static void drawWhiteFunctionModules(uint8_t qrcode[], int version);
+static void drawFormatBits(enum qrcodegen_Ecc ecl, enum qrcodegen_Mask mask, uint8_t qrcode[]);
+testable int getAlignmentPatternPositions(int version, uint8_t result[7]);
+static void fillRectangle(int left, int top, int width, int height, uint8_t qrcode[]);
+
+static void drawCodewords(const uint8_t data[], int dataLen, uint8_t qrcode[]);
+static void applyMask(const uint8_t functionModules[], uint8_t qrcode[], enum qrcodegen_Mask mask);
+static long getPenaltyScore(const uint8_t qrcode[]);
+static int finderPenaltyCountPatterns(const int runHistory[7], int qrsize);
+static int finderPenaltyTerminateAndCount(bool currentRunColor, int currentRunLength, int runHistory[7], int qrsize);
+static void finderPenaltyAddHistory(int currentRunLength, int runHistory[7]);
+
+testable bool getModule(const uint8_t qrcode[], int x, int y);
+testable void setModule(uint8_t qrcode[], int x, int y, bool isBlack);
+testable void setModuleBounded(uint8_t qrcode[], int x, int y, bool isBlack);
+static bool getBit(int x, int i);
+
+testable int calcSegmentBitLength(enum qrcodegen_Mode mode, size_t numChars);
+testable int getTotalBits(const struct qrcodegen_Segment segs[], size_t len, int version);
+static int numCharCountBits(enum qrcodegen_Mode mode, int version);
+
+
+
+/*---- Private tables of constants ----*/
+
+// The set of all legal characters in alphanumeric mode, where each character
+// value maps to the index in the string. For checking text and encoding segments.
+static const char *ALPHANUMERIC_CHARSET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:";
+
+// For generating error correction codes.
+testable const int8_t ECC_CODEWORDS_PER_BLOCK[4][41] = {
+	// Version: (note that index 0 is for padding, and is set to an illegal value)
+	//0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40    Error correction level
+	{-1,  7, 10, 15, 20, 26, 18, 20, 24, 30, 18, 20, 24, 26, 30, 22, 24, 28, 30, 28, 28, 28, 28, 30, 30, 26, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30},  // Low
+	{-1, 10, 16, 26, 18, 24, 16, 18, 22, 22, 26, 30, 22, 22, 24, 24, 28, 28, 26, 26, 26, 26, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28},  // Medium
+	{-1, 13, 22, 18, 26, 18, 24, 18, 22, 20, 24, 28, 26, 24, 20, 30, 24, 28, 28, 26, 30, 28, 30, 30, 30, 30, 28, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30},  // Quartile
+	{-1, 17, 28, 22, 16, 22, 28, 26, 26, 24, 28, 24, 28, 22, 24, 24, 30, 28, 28, 26, 28, 30, 24, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30},  // High
+};
+
+#define qrcodegen_REED_SOLOMON_DEGREE_MAX 30  // Based on the table above
+
+// For generating error correction codes.
+testable const int8_t NUM_ERROR_CORRECTION_BLOCKS[4][41] = {
+	// Version: (note that index 0 is for padding, and is set to an illegal value)
+	//0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40    Error correction level
+	{-1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 4,  4,  4,  4,  4,  6,  6,  6,  6,  7,  8,  8,  9,  9, 10, 12, 12, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 21, 22, 24, 25},  // Low
+	{-1, 1, 1, 1, 2, 2, 4, 4, 4, 5, 5,  5,  8,  9,  9, 10, 10, 11, 13, 14, 16, 17, 17, 18, 20, 21, 23, 25, 26, 28, 29, 31, 33, 35, 37, 38, 40, 43, 45, 47, 49},  // Medium
+	{-1, 1, 1, 2, 2, 4, 4, 6, 6, 8, 8,  8, 10, 12, 16, 12, 17, 16, 18, 21, 20, 23, 23, 25, 27, 29, 34, 34, 35, 38, 40, 43, 45, 48, 51, 53, 56, 59, 62, 65, 68},  // Quartile
+	{-1, 1, 1, 2, 4, 4, 4, 5, 6, 8, 8, 11, 11, 16, 16, 18, 16, 19, 21, 25, 25, 25, 34, 30, 32, 35, 37, 40, 42, 45, 48, 51, 54, 57, 60, 63, 66, 70, 74, 77, 81},  // High
+};
+
+// For automatic mask pattern selection.
+static const int PENALTY_N1 =  3;
+static const int PENALTY_N2 =  3;
+static const int PENALTY_N3 = 40;
+static const int PENALTY_N4 = 10;
+
+
+
+/*---- High-level QR Code encoding functions ----*/
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_encodeText(const char *text, uint8_t tempBuffer[], uint8_t qrcode[],
+		enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl) {
+
+	size_t textLen = strlen(text);
+	if (textLen == 0)
+		return qrcodegen_encodeSegmentsAdvanced(NULL, 0, ecl, minVersion, maxVersion, mask, boostEcl, tempBuffer, qrcode);
+	size_t bufLen = (size_t)qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion);
+
+	struct qrcodegen_Segment seg;
+	if (qrcodegen_isNumeric(text)) {
+		if (qrcodegen_calcSegmentBufferSize(qrcodegen_Mode_NUMERIC, textLen) > bufLen)
+			goto fail;
+		seg = qrcodegen_makeNumeric(text, tempBuffer);
+	} else if (qrcodegen_isAlphanumeric(text)) {
+		if (qrcodegen_calcSegmentBufferSize(qrcodegen_Mode_ALPHANUMERIC, textLen) > bufLen)
+			goto fail;
+		seg = qrcodegen_makeAlphanumeric(text, tempBuffer);
+	} else {
+		if (textLen > bufLen)
+			goto fail;
+		for (size_t i = 0; i < textLen; i++)
+			tempBuffer[i] = (uint8_t)text[i];
+		seg.mode = qrcodegen_Mode_BYTE;
+		seg.bitLength = calcSegmentBitLength(seg.mode, textLen);
+		if (seg.bitLength == -1)
+			goto fail;
+		seg.numChars = (int)textLen;
+		seg.data = tempBuffer;
+	}
+	return qrcodegen_encodeSegmentsAdvanced(&seg, 1, ecl, minVersion, maxVersion, mask, boostEcl, tempBuffer, qrcode);
+
+fail:
+	qrcode[0] = 0;  // Set size to invalid value for safety
+	return false;
+}
+
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_encodeBinary(uint8_t dataAndTemp[], size_t dataLen, uint8_t qrcode[],
+		enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl) {
+
+	struct qrcodegen_Segment seg;
+	seg.mode = qrcodegen_Mode_BYTE;
+	seg.bitLength = calcSegmentBitLength(seg.mode, dataLen);
+	if (seg.bitLength == -1) {
+		qrcode[0] = 0;  // Set size to invalid value for safety
+		return false;
+	}
+	seg.numChars = (int)dataLen;
+	seg.data = dataAndTemp;
+	return qrcodegen_encodeSegmentsAdvanced(&seg, 1, ecl, minVersion, maxVersion, mask, boostEcl, dataAndTemp, qrcode);
+}
+
+
+// Appends the given number of low-order bits of the given value to the given byte-based
+// bit buffer, increasing the bit length. Requires 0 <= numBits <= 16 and val < 2^numBits.
+testable void appendBitsToBuffer(unsigned int val, int numBits, uint8_t buffer[], int *bitLen) {
+	assert(0 <= numBits && numBits <= 16 && (unsigned long)val >> numBits == 0);
+	for (int i = numBits - 1; i >= 0; i--, (*bitLen)++)
+		buffer[*bitLen >> 3] |= ((val >> i) & 1) << (7 - (*bitLen & 7));
+}
+
+
+
+/*---- Low-level QR Code encoding functions ----*/
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
+		enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]) {
+	return qrcodegen_encodeSegmentsAdvanced(segs, len, ecl,
+		qrcodegen_VERSION_MIN, qrcodegen_VERSION_MAX, qrcodegen_Mask_AUTO, true, tempBuffer, qrcode);
+}
+
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
+		int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]) {
+	assert(segs != NULL || len == 0);
+	assert(qrcodegen_VERSION_MIN <= minVersion && minVersion <= maxVersion && maxVersion <= qrcodegen_VERSION_MAX);
+	assert(0 <= (int)ecl && (int)ecl <= 3 && -1 <= (int)mask && (int)mask <= 7);
+
+	// Find the minimal version number to use
+	int version, dataUsedBits;
+	for (version = minVersion; ; version++) {
+		int dataCapacityBits = getNumDataCodewords(version, ecl) * 8;  // Number of data bits available
+		dataUsedBits = getTotalBits(segs, len, version);
+		if (dataUsedBits != -1 && dataUsedBits <= dataCapacityBits)
+			break;  // This version number is found to be suitable
+		if (version >= maxVersion) {  // All versions in the range could not fit the given data
+			qrcode[0] = 0;  // Set size to invalid value for safety
+			return false;
+		}
+	}
+	assert(dataUsedBits != -1);
+
+	// Increase the error correction level while the data still fits in the current version number
+	for (int i = (int)qrcodegen_Ecc_MEDIUM; i <= (int)qrcodegen_Ecc_HIGH; i++) {  // From low to high
+		if (boostEcl && dataUsedBits <= getNumDataCodewords(version, (enum qrcodegen_Ecc)i) * 8)
+			ecl = (enum qrcodegen_Ecc)i;
+	}
+
+	// Concatenate all segments to create the data bit string
+	memset(qrcode, 0, (size_t)qrcodegen_BUFFER_LEN_FOR_VERSION(version) * sizeof(qrcode[0]));
+	int bitLen = 0;
+	for (size_t i = 0; i < len; i++) {
+		const struct qrcodegen_Segment *seg = &segs[i];
+		appendBitsToBuffer((unsigned int)seg->mode, 4, qrcode, &bitLen);
+		appendBitsToBuffer((unsigned int)seg->numChars, numCharCountBits(seg->mode, version), qrcode, &bitLen);
+		for (int j = 0; j < seg->bitLength; j++) {
+			int bit = (seg->data[j >> 3] >> (7 - (j & 7))) & 1;
+			appendBitsToBuffer((unsigned int)bit, 1, qrcode, &bitLen);
+		}
+	}
+	assert(bitLen == dataUsedBits);
+
+	// Add terminator and pad up to a byte if applicable
+	int dataCapacityBits = getNumDataCodewords(version, ecl) * 8;
+	assert(bitLen <= dataCapacityBits);
+	int terminatorBits = dataCapacityBits - bitLen;
+	if (terminatorBits > 4)
+		terminatorBits = 4;
+	appendBitsToBuffer(0, terminatorBits, qrcode, &bitLen);
+	appendBitsToBuffer(0, (8 - bitLen % 8) % 8, qrcode, &bitLen);
+	assert(bitLen % 8 == 0);
+
+	// Pad with alternating bytes until data capacity is reached
+	for (uint8_t padByte = 0xEC; bitLen < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
+		appendBitsToBuffer(padByte, 8, qrcode, &bitLen);
+
+	// Draw function and data codeword modules
+	addEccAndInterleave(qrcode, version, ecl, tempBuffer);
+	initializeFunctionModules(version, qrcode);
+	drawCodewords(tempBuffer, getNumRawDataModules(version) / 8, qrcode);
+	drawWhiteFunctionModules(qrcode, version);
+	initializeFunctionModules(version, tempBuffer);
+
+	// Handle masking
+	if (mask == qrcodegen_Mask_AUTO) {  // Automatically choose best mask
+		long minPenalty = LONG_MAX;
+		for (int i = 0; i < 8; i++) {
+			enum qrcodegen_Mask msk = (enum qrcodegen_Mask)i;
+			applyMask(tempBuffer, qrcode, msk);
+			drawFormatBits(ecl, msk, qrcode);
+			long penalty = getPenaltyScore(qrcode);
+			if (penalty < minPenalty) {
+				mask = msk;
+				minPenalty = penalty;
+			}
+			applyMask(tempBuffer, qrcode, msk);  // Undoes the mask due to XOR
+		}
+	}
+	assert(0 <= (int)mask && (int)mask <= 7);
+	applyMask(tempBuffer, qrcode, mask);
+	drawFormatBits(ecl, mask, qrcode);
+	return true;
+}
+
+
+
+/*---- Error correction code generation functions ----*/
+
+// Appends error correction bytes to each block of the given data array, then interleaves
+// bytes from the blocks and stores them in the result array. data[0 : dataLen] contains
+// the input data. data[dataLen : rawCodewords] is used as a temporary work area and will
+// be clobbered by this function. The final answer is stored in result[0 : rawCodewords].
+testable void addEccAndInterleave(uint8_t data[], int version, enum qrcodegen_Ecc ecl, uint8_t result[]) {
+	// Calculate parameter numbers
+	assert(0 <= (int)ecl && (int)ecl < 4 && qrcodegen_VERSION_MIN <= version && version <= qrcodegen_VERSION_MAX);
+	int numBlocks = NUM_ERROR_CORRECTION_BLOCKS[(int)ecl][version];
+	int blockEccLen = ECC_CODEWORDS_PER_BLOCK  [(int)ecl][version];
+	int rawCodewords = getNumRawDataModules(version) / 8;
+	int dataLen = getNumDataCodewords(version, ecl);
+	int numShortBlocks = numBlocks - rawCodewords % numBlocks;
+	int shortBlockDataLen = rawCodewords / numBlocks - blockEccLen;
+
+	// Split data into blocks, calculate ECC, and interleave
+	// (not concatenate) the bytes into a single sequence
+	uint8_t rsdiv[qrcodegen_REED_SOLOMON_DEGREE_MAX];
+	reedSolomonComputeDivisor(blockEccLen, rsdiv);
+	const uint8_t *dat = data;
+	for (int i = 0; i < numBlocks; i++) {
+		int datLen = shortBlockDataLen + (i < numShortBlocks ? 0 : 1);
+		uint8_t *ecc = &data[dataLen];  // Temporary storage
+		reedSolomonComputeRemainder(dat, datLen, rsdiv, blockEccLen, ecc);
+		for (int j = 0, k = i; j < datLen; j++, k += numBlocks) {  // Copy data
+			if (j == shortBlockDataLen)
+				k -= numShortBlocks;
+			result[k] = dat[j];
+		}
+		for (int j = 0, k = dataLen + i; j < blockEccLen; j++, k += numBlocks)  // Copy ECC
+			result[k] = ecc[j];
+		dat += datLen;
+	}
+}
+
+
+// Returns the number of 8-bit codewords that can be used for storing data (not ECC),
+// for the given version number and error correction level. The result is in the range [9, 2956].
+testable int getNumDataCodewords(int version, enum qrcodegen_Ecc ecl) {
+	int v = version, e = (int)ecl;
+	assert(0 <= e && e < 4);
+	return getNumRawDataModules(v) / 8
+		- ECC_CODEWORDS_PER_BLOCK    [e][v]
+		* NUM_ERROR_CORRECTION_BLOCKS[e][v];
+}
+
+
+// Returns the number of data bits that can be stored in a QR Code of the given version number, after
+// all function modules are excluded. This includes remainder bits, so it might not be a multiple of 8.
+// The result is in the range [208, 29648]. This could be implemented as a 40-entry lookup table.
+testable int getNumRawDataModules(int ver) {
+	assert(qrcodegen_VERSION_MIN <= ver && ver <= qrcodegen_VERSION_MAX);
+	int result = (16 * ver + 128) * ver + 64;
+	if (ver >= 2) {
+		int numAlign = ver / 7 + 2;
+		result -= (25 * numAlign - 10) * numAlign - 55;
+		if (ver >= 7)
+			result -= 36;
+	}
+	assert(208 <= result && result <= 29648);
+	return result;
+}
+
+
+
+/*---- Reed-Solomon ECC generator functions ----*/
+
+// Computes a Reed-Solomon ECC generator polynomial for the given degree, storing in result[0 : degree].
+// This could be implemented as a lookup table over all possible parameter values, instead of as an algorithm.
+testable void reedSolomonComputeDivisor(int degree, uint8_t result[]) {
+	assert(1 <= degree && degree <= qrcodegen_REED_SOLOMON_DEGREE_MAX);
+	// Polynomial coefficients are stored from highest to lowest power, excluding the leading term which is always 1.
+	// For example the polynomial x^3 + 255x^2 + 8x + 93 is stored as the uint8 array {255, 8, 93}.
+	memset(result, 0, (size_t)degree * sizeof(result[0]));
+	result[degree - 1] = 1;  // Start off with the monomial x^0
+
+	// Compute the product polynomial (x - r^0) * (x - r^1) * (x - r^2) * ... * (x - r^{degree-1}),
+	// drop the highest monomial term which is always 1x^degree.
+	// Note that r = 0x02, which is a generator element of this field GF(2^8/0x11D).
+	uint8_t root = 1;
+	for (int i = 0; i < degree; i++) {
+		// Multiply the current product by (x - r^i)
+		for (int j = 0; j < degree; j++) {
+			result[j] = reedSolomonMultiply(result[j], root);
+			if (j + 1 < degree)
+				result[j] ^= result[j + 1];
+		}
+		root = reedSolomonMultiply(root, 0x02);
+	}
+}
+
+
+// Computes the Reed-Solomon error correction codeword for the given data and divisor polynomials.
+// The remainder when data[0 : dataLen] is divided by divisor[0 : degree] is stored in result[0 : degree].
+// All polynomials are in big endian, and the generator has an implicit leading 1 term.
+testable void reedSolomonComputeRemainder(const uint8_t data[], int dataLen,
+		const uint8_t generator[], int degree, uint8_t result[]) {
+	assert(1 <= degree && degree <= qrcodegen_REED_SOLOMON_DEGREE_MAX);
+	memset(result, 0, (size_t)degree * sizeof(result[0]));
+	for (int i = 0; i < dataLen; i++) {  // Polynomial division
+		uint8_t factor = data[i] ^ result[0];
+		memmove(&result[0], &result[1], (size_t)(degree - 1) * sizeof(result[0]));
+		result[degree - 1] = 0;
+		for (int j = 0; j < degree; j++)
+			result[j] ^= reedSolomonMultiply(generator[j], factor);
+	}
+}
+
+#undef qrcodegen_REED_SOLOMON_DEGREE_MAX
+
+
+// Returns the product of the two given field elements modulo GF(2^8/0x11D).
+// All inputs are valid. This could be implemented as a 256*256 lookup table.
+testable uint8_t reedSolomonMultiply(uint8_t x, uint8_t y) {
+	// Russian peasant multiplication
+	uint8_t z = 0;
+	for (int i = 7; i >= 0; i--) {
+		z = (uint8_t)((z << 1) ^ ((z >> 7) * 0x11D));
+		z ^= ((y >> i) & 1) * x;
+	}
+	return z;
+}
+
+
+
+/*---- Drawing function modules ----*/
+
+// Clears the given QR Code grid with white modules for the given
+// version's size, then marks every function module as black.
+testable void initializeFunctionModules(int version, uint8_t qrcode[]) {
+	// Initialize QR Code
+	int qrsize = version * 4 + 17;
+	memset(qrcode, 0, (size_t)((qrsize * qrsize + 7) / 8 + 1) * sizeof(qrcode[0]));
+	qrcode[0] = (uint8_t)qrsize;
+
+	// Fill horizontal and vertical timing patterns
+	fillRectangle(6, 0, 1, qrsize, qrcode);
+	fillRectangle(0, 6, qrsize, 1, qrcode);
+
+	// Fill 3 finder patterns (all corners except bottom right) and format bits
+	fillRectangle(0, 0, 9, 9, qrcode);
+	fillRectangle(qrsize - 8, 0, 8, 9, qrcode);
+	fillRectangle(0, qrsize - 8, 9, 8, qrcode);
+
+	// Fill numerous alignment patterns
+	uint8_t alignPatPos[7];
+	int numAlign = getAlignmentPatternPositions(version, alignPatPos);
+	for (int i = 0; i < numAlign; i++) {
+		for (int j = 0; j < numAlign; j++) {
+			// Don't draw on the three finder corners
+			if (!((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0)))
+				fillRectangle(alignPatPos[i] - 2, alignPatPos[j] - 2, 5, 5, qrcode);
+		}
+	}
+
+	// Fill version blocks
+	if (version >= 7) {
+		fillRectangle(qrsize - 11, 0, 3, 6, qrcode);
+		fillRectangle(0, qrsize - 11, 6, 3, qrcode);
+	}
+}
+
+
+// Draws white function modules and possibly some black modules onto the given QR Code, without changing
+// non-function modules. This does not draw the format bits. This requires all function modules to be previously
+// marked black (namely by initializeFunctionModules()), because this may skip redrawing black function modules.
+static void drawWhiteFunctionModules(uint8_t qrcode[], int version) {
+	// Draw horizontal and vertical timing patterns
+	int qrsize = qrcodegen_getSize(qrcode);
+	for (int i = 7; i < qrsize - 7; i += 2) {
+		setModule(qrcode, 6, i, false);
+		setModule(qrcode, i, 6, false);
+	}
+
+	// Draw 3 finder patterns (all corners except bottom right; overwrites some timing modules)
+	for (int dy = -4; dy <= 4; dy++) {
+		for (int dx = -4; dx <= 4; dx++) {
+			int dist = abs(dx);
+			if (abs(dy) > dist)
+				dist = abs(dy);
+			if (dist == 2 || dist == 4) {
+				setModuleBounded(qrcode, 3 + dx, 3 + dy, false);
+				setModuleBounded(qrcode, qrsize - 4 + dx, 3 + dy, false);
+				setModuleBounded(qrcode, 3 + dx, qrsize - 4 + dy, false);
+			}
+		}
+	}
+
+	// Draw numerous alignment patterns
+	uint8_t alignPatPos[7];
+	int numAlign = getAlignmentPatternPositions(version, alignPatPos);
+	for (int i = 0; i < numAlign; i++) {
+		for (int j = 0; j < numAlign; j++) {
+			if ((i == 0 && j == 0) || (i == 0 && j == numAlign - 1) || (i == numAlign - 1 && j == 0))
+				continue;  // Don't draw on the three finder corners
+			for (int dy = -1; dy <= 1; dy++) {
+				for (int dx = -1; dx <= 1; dx++)
+					setModule(qrcode, alignPatPos[i] + dx, alignPatPos[j] + dy, dx == 0 && dy == 0);
+			}
+		}
+	}
+
+	// Draw version blocks
+	if (version >= 7) {
+		// Calculate error correction code and pack bits
+		int rem = version;  // version is uint6, in the range [7, 40]
+		for (int i = 0; i < 12; i++)
+			rem = (rem << 1) ^ ((rem >> 11) * 0x1F25);
+		long bits = (long)version << 12 | rem;  // uint18
+		assert(bits >> 18 == 0);
+
+		// Draw two copies
+		for (int i = 0; i < 6; i++) {
+			for (int j = 0; j < 3; j++) {
+				int k = qrsize - 11 + j;
+				setModule(qrcode, k, i, (bits & 1) != 0);
+				setModule(qrcode, i, k, (bits & 1) != 0);
+				bits >>= 1;
+			}
+		}
+	}
+}
+
+
+// Draws two copies of the format bits (with its own error correction code) based
+// on the given mask and error correction level. This always draws all modules of
+// the format bits, unlike drawWhiteFunctionModules() which might skip black modules.
+static void drawFormatBits(enum qrcodegen_Ecc ecl, enum qrcodegen_Mask mask, uint8_t qrcode[]) {
+	// Calculate error correction code and pack bits
+	assert(0 <= (int)mask && (int)mask <= 7);
+	static const int table[] = {1, 0, 3, 2};
+	int data = table[(int)ecl] << 3 | (int)mask;  // errCorrLvl is uint2, mask is uint3
+	int rem = data;
+	for (int i = 0; i < 10; i++)
+		rem = (rem << 1) ^ ((rem >> 9) * 0x537);
+	int bits = (data << 10 | rem) ^ 0x5412;  // uint15
+	assert(bits >> 15 == 0);
+
+	// Draw first copy
+	for (int i = 0; i <= 5; i++)
+		setModule(qrcode, 8, i, getBit(bits, i));
+	setModule(qrcode, 8, 7, getBit(bits, 6));
+	setModule(qrcode, 8, 8, getBit(bits, 7));
+	setModule(qrcode, 7, 8, getBit(bits, 8));
+	for (int i = 9; i < 15; i++)
+		setModule(qrcode, 14 - i, 8, getBit(bits, i));
+
+	// Draw second copy
+	int qrsize = qrcodegen_getSize(qrcode);
+	for (int i = 0; i < 8; i++)
+		setModule(qrcode, qrsize - 1 - i, 8, getBit(bits, i));
+	for (int i = 8; i < 15; i++)
+		setModule(qrcode, 8, qrsize - 15 + i, getBit(bits, i));
+	setModule(qrcode, 8, qrsize - 8, true);  // Always black
+}
+
+
+// Calculates and stores an ascending list of positions of alignment patterns
+// for this version number, returning the length of the list (in the range [0,7]).
+// Each position is in the range [0,177), and are used on both the x and y axes.
+// This could be implemented as lookup table of 40 variable-length lists of unsigned bytes.
+testable int getAlignmentPatternPositions(int version, uint8_t result[7]) {
+	if (version == 1)
+		return 0;
+	int numAlign = version / 7 + 2;
+	int step = (version == 32) ? 26 :
+		(version*4 + numAlign*2 + 1) / (numAlign*2 - 2) * 2;
+	for (int i = numAlign - 1, pos = version * 4 + 10; i >= 1; i--, pos -= step)
+		result[i] = (uint8_t)pos;
+	result[0] = 6;
+	return numAlign;
+}
+
+
+// Sets every pixel in the range [left : left + width] * [top : top + height] to black.
+static void fillRectangle(int left, int top, int width, int height, uint8_t qrcode[]) {
+	for (int dy = 0; dy < height; dy++) {
+		for (int dx = 0; dx < width; dx++)
+			setModule(qrcode, left + dx, top + dy, true);
+	}
+}
+
+
+
+/*---- Drawing data modules and masking ----*/
+
+// Draws the raw codewords (including data and ECC) onto the given QR Code. This requires the initial state of
+// the QR Code to be black at function modules and white at codeword modules (including unused remainder bits).
+static void drawCodewords(const uint8_t data[], int dataLen, uint8_t qrcode[]) {
+	int qrsize = qrcodegen_getSize(qrcode);
+	int i = 0;  // Bit index into the data
+	// Do the funny zigzag scan
+	for (int right = qrsize - 1; right >= 1; right -= 2) {  // Index of right column in each column pair
+		if (right == 6)
+			right = 5;
+		for (int vert = 0; vert < qrsize; vert++) {  // Vertical counter
+			for (int j = 0; j < 2; j++) {
+				int x = right - j;  // Actual x coordinate
+				bool upward = ((right + 1) & 2) == 0;
+				int y = upward ? qrsize - 1 - vert : vert;  // Actual y coordinate
+				if (!getModule(qrcode, x, y) && i < dataLen * 8) {
+					bool black = getBit(data[i >> 3], 7 - (i & 7));
+					setModule(qrcode, x, y, black);
+					i++;
+				}
+				// If this QR Code has any remainder bits (0 to 7), they were assigned as
+				// 0/false/white by the constructor and are left unchanged by this method
+			}
+		}
+	}
+	assert(i == dataLen * 8);
+}
+
+
+// XORs the codeword modules in this QR Code with the given mask pattern.
+// The function modules must be marked and the codeword bits must be drawn
+// before masking. Due to the arithmetic of XOR, calling applyMask() with
+// the same mask value a second time will undo the mask. A final well-formed
+// QR Code needs exactly one (not zero, two, etc.) mask applied.
+static void applyMask(const uint8_t functionModules[], uint8_t qrcode[], enum qrcodegen_Mask mask) {
+	assert(0 <= (int)mask && (int)mask <= 7);  // Disallows qrcodegen_Mask_AUTO
+	int qrsize = qrcodegen_getSize(qrcode);
+	for (int y = 0; y < qrsize; y++) {
+		for (int x = 0; x < qrsize; x++) {
+			if (getModule(functionModules, x, y))
+				continue;
+			bool invert;
+			switch ((int)mask) {
+				case 0:  invert = (x + y) % 2 == 0;                    break;
+				case 1:  invert = y % 2 == 0;                          break;
+				case 2:  invert = x % 3 == 0;                          break;
+				case 3:  invert = (x + y) % 3 == 0;                    break;
+				case 4:  invert = (x / 3 + y / 2) % 2 == 0;            break;
+				case 5:  invert = x * y % 2 + x * y % 3 == 0;          break;
+				case 6:  invert = (x * y % 2 + x * y % 3) % 2 == 0;    break;
+				case 7:  invert = ((x + y) % 2 + x * y % 3) % 2 == 0;  break;
+				default:  assert(false);  return;
+			}
+			bool val = getModule(qrcode, x, y);
+			setModule(qrcode, x, y, val ^ invert);
+		}
+	}
+}
+
+
+// Calculates and returns the penalty score based on state of the given QR Code's current modules.
+// This is used by the automatic mask choice algorithm to find the mask pattern that yields the lowest score.
+static long getPenaltyScore(const uint8_t qrcode[]) {
+	int qrsize = qrcodegen_getSize(qrcode);
+	long result = 0;
+
+	// Adjacent modules in row having same color, and finder-like patterns
+	for (int y = 0; y < qrsize; y++) {
+		bool runColor = false;
+		int runX = 0;
+		int runHistory[7] = {0};
+		int padRun = qrsize;  // Add white border to initial run
+		for (int x = 0; x < qrsize; x++) {
+			if (getModule(qrcode, x, y) == runColor) {
+				runX++;
+				if (runX == 5)
+					result += PENALTY_N1;
+				else if (runX > 5)
+					result++;
+			} else {
+				finderPenaltyAddHistory(runX + padRun, runHistory);
+				padRun = 0;
+				if (!runColor)
+					result += finderPenaltyCountPatterns(runHistory, qrsize) * PENALTY_N3;
+				runColor = getModule(qrcode, x, y);
+				runX = 1;
+			}
+		}
+		result += finderPenaltyTerminateAndCount(runColor, runX + padRun, runHistory, qrsize) * PENALTY_N3;
+	}
+	// Adjacent modules in column having same color, and finder-like patterns
+	for (int x = 0; x < qrsize; x++) {
+		bool runColor = false;
+		int runY = 0;
+		int runHistory[7] = {0};
+		int padRun = qrsize;  // Add white border to initial run
+		for (int y = 0; y < qrsize; y++) {
+			if (getModule(qrcode, x, y) == runColor) {
+				runY++;
+				if (runY == 5)
+					result += PENALTY_N1;
+				else if (runY > 5)
+					result++;
+			} else {
+				finderPenaltyAddHistory(runY + padRun, runHistory);
+				padRun = 0;
+				if (!runColor)
+					result += finderPenaltyCountPatterns(runHistory, qrsize) * PENALTY_N3;
+				runColor = getModule(qrcode, x, y);
+				runY = 1;
+			}
+		}
+		result += finderPenaltyTerminateAndCount(runColor, runY + padRun, runHistory, qrsize) * PENALTY_N3;
+	}
+
+	// 2*2 blocks of modules having same color
+	for (int y = 0; y < qrsize - 1; y++) {
+		for (int x = 0; x < qrsize - 1; x++) {
+			bool  color = getModule(qrcode, x, y);
+			if (  color == getModule(qrcode, x + 1, y) &&
+			      color == getModule(qrcode, x, y + 1) &&
+			      color == getModule(qrcode, x + 1, y + 1))
+				result += PENALTY_N2;
+		}
+	}
+
+	// Balance of black and white modules
+	int black = 0;
+	for (int y = 0; y < qrsize; y++) {
+		for (int x = 0; x < qrsize; x++) {
+			if (getModule(qrcode, x, y))
+				black++;
+		}
+	}
+	int total = qrsize * qrsize;  // Note that size is odd, so black/total != 1/2
+	// Compute the smallest integer k >= 0 such that (45-5k)% <= black/total <= (55+5k)%
+	int k = (int)((labs(black * 20L - total * 10L) + total - 1) / total) - 1;
+	result += k * PENALTY_N4;
+	return result;
+}
+
+
+// Can only be called immediately after a white run is added, and
+// returns either 0, 1, or 2. A helper function for getPenaltyScore().
+static int finderPenaltyCountPatterns(const int runHistory[7], int qrsize) {
+	int n = runHistory[1];
+	assert(n <= qrsize * 3);
+	bool core = n > 0 && runHistory[2] == n && runHistory[3] == n * 3 && runHistory[4] == n && runHistory[5] == n;
+	// The maximum QR Code size is 177, hence the black run length n <= 177.
+	// Arithmetic is promoted to int, so n*4 will not overflow.
+	return (core && runHistory[0] >= n * 4 && runHistory[6] >= n ? 1 : 0)
+	     + (core && runHistory[6] >= n * 4 && runHistory[0] >= n ? 1 : 0);
+}
+
+
+// Must be called at the end of a line (row or column) of modules. A helper function for getPenaltyScore().
+static int finderPenaltyTerminateAndCount(bool currentRunColor, int currentRunLength, int runHistory[7], int qrsize) {
+	if (currentRunColor) {  // Terminate black run
+		finderPenaltyAddHistory(currentRunLength, runHistory);
+		currentRunLength = 0;
+	}
+	currentRunLength += qrsize;  // Add white border to final run
+	finderPenaltyAddHistory(currentRunLength, runHistory);
+	return finderPenaltyCountPatterns(runHistory, qrsize);
+}
+
+
+// Pushes the given value to the front and drops the last value. A helper function for getPenaltyScore().
+static void finderPenaltyAddHistory(int currentRunLength, int runHistory[7]) {
+	memmove(&runHistory[1], &runHistory[0], 6 * sizeof(runHistory[0]));
+	runHistory[0] = currentRunLength;
+}
+
+
+
+/*---- Basic QR Code information ----*/
+
+// Public function - see documentation comment in header file.
+int qrcodegen_getSize(const uint8_t qrcode[]) {
+	assert(qrcode != NULL);
+	int result = qrcode[0];
+	assert((qrcodegen_VERSION_MIN * 4 + 17) <= result
+		&& result <= (qrcodegen_VERSION_MAX * 4 + 17));
+	return result;
+}
+
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_getModule(const uint8_t qrcode[], int x, int y) {
+	assert(qrcode != NULL);
+	int qrsize = qrcode[0];
+	return (0 <= x && x < qrsize && 0 <= y && y < qrsize) && getModule(qrcode, x, y);
+}
+
+
+// Gets the module at the given coordinates, which must be in bounds.
+testable bool getModule(const uint8_t qrcode[], int x, int y) {
+	int qrsize = qrcode[0];
+	assert(21 <= qrsize && qrsize <= 177 && 0 <= x && x < qrsize && 0 <= y && y < qrsize);
+	int index = y * qrsize + x;
+	return getBit(qrcode[(index >> 3) + 1], index & 7);
+}
+
+
+// Sets the module at the given coordinates, which must be in bounds.
+testable void setModule(uint8_t qrcode[], int x, int y, bool isBlack) {
+	int qrsize = qrcode[0];
+	assert(21 <= qrsize && qrsize <= 177 && 0 <= x && x < qrsize && 0 <= y && y < qrsize);
+	int index = y * qrsize + x;
+	int bitIndex = index & 7;
+	int byteIndex = (index >> 3) + 1;
+	if (isBlack)
+		qrcode[byteIndex] |= 1 << bitIndex;
+	else
+		qrcode[byteIndex] &= (1 << bitIndex) ^ 0xFF;
+}
+
+
+// Sets the module at the given coordinates, doing nothing if out of bounds.
+testable void setModuleBounded(uint8_t qrcode[], int x, int y, bool isBlack) {
+	int qrsize = qrcode[0];
+	if (0 <= x && x < qrsize && 0 <= y && y < qrsize)
+		setModule(qrcode, x, y, isBlack);
+}
+
+
+// Returns true iff the i'th bit of x is set to 1. Requires x >= 0 and 0 <= i <= 14.
+static bool getBit(int x, int i) {
+	return ((x >> i) & 1) != 0;
+}
+
+
+
+/*---- Segment handling ----*/
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_isAlphanumeric(const char *text) {
+	assert(text != NULL);
+	for (; *text != '\0'; text++) {
+		if (strchr(ALPHANUMERIC_CHARSET, *text) == NULL)
+			return false;
+	}
+	return true;
+}
+
+
+// Public function - see documentation comment in header file.
+bool qrcodegen_isNumeric(const char *text) {
+	assert(text != NULL);
+	for (; *text != '\0'; text++) {
+		if (*text < '0' || *text > '9')
+			return false;
+	}
+	return true;
+}
+
+
+// Public function - see documentation comment in header file.
+size_t qrcodegen_calcSegmentBufferSize(enum qrcodegen_Mode mode, size_t numChars) {
+	int temp = calcSegmentBitLength(mode, numChars);
+	if (temp == -1)
+		return SIZE_MAX;
+	assert(0 <= temp && temp <= INT16_MAX);
+	return ((size_t)temp + 7) / 8;
+}
+
+
+// Returns the number of data bits needed to represent a segment
+// containing the given number of characters using the given mode. Notes:
+// - Returns -1 on failure, i.e. numChars > INT16_MAX or
+//   the number of needed bits exceeds INT16_MAX (i.e. 32767).
+// - Otherwise, all valid results are in the range [0, INT16_MAX].
+// - For byte mode, numChars measures the number of bytes, not Unicode code points.
+// - For ECI mode, numChars must be 0, and the worst-case number of bits is returned.
+//   An actual ECI segment can have shorter data. For non-ECI modes, the result is exact.
+testable int calcSegmentBitLength(enum qrcodegen_Mode mode, size_t numChars) {
+	// All calculations are designed to avoid overflow on all platforms
+	if (numChars > (unsigned int)INT16_MAX)
+		return -1;
+	long result = (long)numChars;
+	if (mode == qrcodegen_Mode_NUMERIC)
+		result = (result * 10 + 2) / 3;  // ceil(10/3 * n)
+	else if (mode == qrcodegen_Mode_ALPHANUMERIC)
+		result = (result * 11 + 1) / 2;  // ceil(11/2 * n)
+	else if (mode == qrcodegen_Mode_BYTE)
+		result *= 8;
+	else if (mode == qrcodegen_Mode_KANJI)
+		result *= 13;
+	else if (mode == qrcodegen_Mode_ECI && numChars == 0)
+		result = 3 * 8;
+	else {  // Invalid argument
+		assert(false);
+		return -1;
+	}
+	assert(result >= 0);
+	if (result > INT16_MAX)
+		return -1;
+	return (int)result;
+}
+
+
+// Public function - see documentation comment in header file.
+struct qrcodegen_Segment qrcodegen_makeBytes(const uint8_t data[], size_t len, uint8_t buf[]) {
+	assert(data != NULL || len == 0);
+	struct qrcodegen_Segment result;
+	result.mode = qrcodegen_Mode_BYTE;
+	result.bitLength = calcSegmentBitLength(result.mode, len);
+	assert(result.bitLength != -1);
+	result.numChars = (int)len;
+	if (len > 0)
+		memcpy(buf, data, len * sizeof(buf[0]));
+	result.data = buf;
+	return result;
+}
+
+
+// Public function - see documentation comment in header file.
+struct qrcodegen_Segment qrcodegen_makeNumeric(const char *digits, uint8_t buf[]) {
+	assert(digits != NULL);
+	struct qrcodegen_Segment result;
+	size_t len = strlen(digits);
+	result.mode = qrcodegen_Mode_NUMERIC;
+	int bitLen = calcSegmentBitLength(result.mode, len);
+	assert(bitLen != -1);
+	result.numChars = (int)len;
+	if (bitLen > 0)
+		memset(buf, 0, ((size_t)bitLen + 7) / 8 * sizeof(buf[0]));
+	result.bitLength = 0;
+
+	unsigned int accumData = 0;
+	int accumCount = 0;
+	for (; *digits != '\0'; digits++) {
+		char c = *digits;
+		assert('0' <= c && c <= '9');
+		accumData = accumData * 10 + (unsigned int)(c - '0');
+		accumCount++;
+		if (accumCount == 3) {
+			appendBitsToBuffer(accumData, 10, buf, &result.bitLength);
+			accumData = 0;
+			accumCount = 0;
+		}
+	}
+	if (accumCount > 0)  // 1 or 2 digits remaining
+		appendBitsToBuffer(accumData, accumCount * 3 + 1, buf, &result.bitLength);
+	assert(result.bitLength == bitLen);
+	result.data = buf;
+	return result;
+}
+
+
+// Public function - see documentation comment in header file.
+struct qrcodegen_Segment qrcodegen_makeAlphanumeric(const char *text, uint8_t buf[]) {
+	assert(text != NULL);
+	struct qrcodegen_Segment result;
+	size_t len = strlen(text);
+	result.mode = qrcodegen_Mode_ALPHANUMERIC;
+	int bitLen = calcSegmentBitLength(result.mode, len);
+	assert(bitLen != -1);
+	result.numChars = (int)len;
+	if (bitLen > 0)
+		memset(buf, 0, ((size_t)bitLen + 7) / 8 * sizeof(buf[0]));
+	result.bitLength = 0;
+
+	unsigned int accumData = 0;
+	int accumCount = 0;
+	for (; *text != '\0'; text++) {
+		const char *temp = strchr(ALPHANUMERIC_CHARSET, *text);
+		assert(temp != NULL);
+		accumData = accumData * 45 + (unsigned int)(temp - ALPHANUMERIC_CHARSET);
+		accumCount++;
+		if (accumCount == 2) {
+			appendBitsToBuffer(accumData, 11, buf, &result.bitLength);
+			accumData = 0;
+			accumCount = 0;
+		}
+	}
+	if (accumCount > 0)  // 1 character remaining
+		appendBitsToBuffer(accumData, 6, buf, &result.bitLength);
+	assert(result.bitLength == bitLen);
+	result.data = buf;
+	return result;
+}
+
+
+// Public function - see documentation comment in header file.
+struct qrcodegen_Segment qrcodegen_makeEci(long assignVal, uint8_t buf[]) {
+	struct qrcodegen_Segment result;
+	result.mode = qrcodegen_Mode_ECI;
+	result.numChars = 0;
+	result.bitLength = 0;
+	if (assignVal < 0)
+		assert(false);
+	else if (assignVal < (1 << 7)) {
+		memset(buf, 0, 1 * sizeof(buf[0]));
+		appendBitsToBuffer((unsigned int)assignVal, 8, buf, &result.bitLength);
+	} else if (assignVal < (1 << 14)) {
+		memset(buf, 0, 2 * sizeof(buf[0]));
+		appendBitsToBuffer(2, 2, buf, &result.bitLength);
+		appendBitsToBuffer((unsigned int)assignVal, 14, buf, &result.bitLength);
+	} else if (assignVal < 1000000L) {
+		memset(buf, 0, 3 * sizeof(buf[0]));
+		appendBitsToBuffer(6, 3, buf, &result.bitLength);
+		appendBitsToBuffer((unsigned int)(assignVal >> 10), 11, buf, &result.bitLength);
+		appendBitsToBuffer((unsigned int)(assignVal & 0x3FF), 10, buf, &result.bitLength);
+	} else
+		assert(false);
+	result.data = buf;
+	return result;
+}
+
+
+// Calculates the number of bits needed to encode the given segments at the given version.
+// Returns a non-negative number if successful. Otherwise returns -1 if a segment has too
+// many characters to fit its length field, or the total bits exceeds INT16_MAX.
+testable int getTotalBits(const struct qrcodegen_Segment segs[], size_t len, int version) {
+	assert(segs != NULL || len == 0);
+	long result = 0;
+	for (size_t i = 0; i < len; i++) {
+		int numChars  = segs[i].numChars;
+		int bitLength = segs[i].bitLength;
+		assert(0 <= numChars  && numChars  <= INT16_MAX);
+		assert(0 <= bitLength && bitLength <= INT16_MAX);
+		int ccbits = numCharCountBits(segs[i].mode, version);
+		assert(0 <= ccbits && ccbits <= 16);
+		if (numChars >= (1L << ccbits))
+			return -1;  // The segment's length doesn't fit the field's bit width
+		result += 4L + ccbits + bitLength;
+		if (result > INT16_MAX)
+			return -1;  // The sum might overflow an int type
+	}
+	assert(0 <= result && result <= INT16_MAX);
+	return (int)result;
+}
+
+
+// Returns the bit width of the character count field for a segment in the given mode
+// in a QR Code at the given version number. The result is in the range [0, 16].
+static int numCharCountBits(enum qrcodegen_Mode mode, int version) {
+	assert(qrcodegen_VERSION_MIN <= version && version <= qrcodegen_VERSION_MAX);
+	int i = (version + 7) / 17;
+	switch (mode) {
+		case qrcodegen_Mode_NUMERIC     : { static const int temp[] = {10, 12, 14}; return temp[i]; }
+		case qrcodegen_Mode_ALPHANUMERIC: { static const int temp[] = { 9, 11, 13}; return temp[i]; }
+		case qrcodegen_Mode_BYTE        : { static const int temp[] = { 8, 16, 16}; return temp[i]; }
+		case qrcodegen_Mode_KANJI       : { static const int temp[] = { 8, 10, 12}; return temp[i]; }
+		case qrcodegen_Mode_ECI         : return 0;
+		default:  assert(false);  return -1;  // Dummy value
+	}
+}
diff --git a/main/qrcodegen.h b/main/qrcodegen.h
new file mode 100644
index 0000000..f76be20
--- /dev/null
+++ b/main/qrcodegen.h
@@ -0,0 +1,311 @@
+/*
+ * QR Code generator library (C)
+ *
+ * Copyright (c) Project Nayuki. (MIT License)
+ * https://www.nayuki.io/page/qr-code-generator-library
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ * - The above copyright notice and this permission notice shall be included in
+ *   all copies or substantial portions of the Software.
+ * - The Software is provided "as is", without warranty of any kind, express or
+ *   implied, including but not limited to the warranties of merchantability,
+ *   fitness for a particular purpose and noninfringement. In no event shall the
+ *   authors or copyright holders be liable for any claim, damages or other
+ *   liability, whether in an action of contract, tort or otherwise, arising from,
+ *   out of or in connection with the Software or the use or other dealings in the
+ *   Software.
+ */
+
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/*
+ * This library creates QR Code symbols, which is a type of two-dimension barcode.
+ * Invented by Denso Wave and described in the ISO/IEC 18004 standard.
+ * A QR Code structure is an immutable square grid of black and white cells.
+ * The library provides functions to create a QR Code from text or binary data.
+ * The library covers the QR Code Model 2 specification, supporting all versions (sizes)
+ * from 1 to 40, all 4 error correction levels, and 4 character encoding modes.
+ *
+ * Ways to create a QR Code object:
+ * - High level: Take the payload data and call qrcodegen_encodeText() or qrcodegen_encodeBinary().
+ * - Low level: Custom-make the list of segments and call
+ *   qrcodegen_encodeSegments() or qrcodegen_encodeSegmentsAdvanced().
+ * (Note that all ways require supplying the desired error correction level and various byte buffers.)
+ */
+
+
+/*---- Enum and struct types----*/
+
+/*
+ * The error correction level in a QR Code symbol.
+ */
+enum qrcodegen_Ecc {
+	// Must be declared in ascending order of error protection
+	// so that an internal qrcodegen function works properly
+	qrcodegen_Ecc_LOW = 0 ,  // The QR Code can tolerate about  7% erroneous codewords
+	qrcodegen_Ecc_MEDIUM  ,  // The QR Code can tolerate about 15% erroneous codewords
+	qrcodegen_Ecc_QUARTILE,  // The QR Code can tolerate about 25% erroneous codewords
+	qrcodegen_Ecc_HIGH    ,  // The QR Code can tolerate about 30% erroneous codewords
+};
+
+
+/*
+ * The mask pattern used in a QR Code symbol.
+ */
+enum qrcodegen_Mask {
+	// A special value to tell the QR Code encoder to
+	// automatically select an appropriate mask pattern
+	qrcodegen_Mask_AUTO = -1,
+	// The eight actual mask patterns
+	qrcodegen_Mask_0 = 0,
+	qrcodegen_Mask_1,
+	qrcodegen_Mask_2,
+	qrcodegen_Mask_3,
+	qrcodegen_Mask_4,
+	qrcodegen_Mask_5,
+	qrcodegen_Mask_6,
+	qrcodegen_Mask_7,
+};
+
+
+/*
+ * Describes how a segment's data bits are interpreted.
+ */
+enum qrcodegen_Mode {
+	qrcodegen_Mode_NUMERIC      = 0x1,
+	qrcodegen_Mode_ALPHANUMERIC = 0x2,
+	qrcodegen_Mode_BYTE         = 0x4,
+	qrcodegen_Mode_KANJI        = 0x8,
+	qrcodegen_Mode_ECI          = 0x7,
+};
+
+
+/*
+ * A segment of character/binary/control data in a QR Code symbol.
+ * The mid-level way to create a segment is to take the payload data
+ * and call a factory function such as qrcodegen_makeNumeric().
+ * The low-level way to create a segment is to custom-make the bit buffer
+ * and initialize a qrcodegen_Segment struct with appropriate values.
+ * Even in the most favorable conditions, a QR Code can only hold 7089 characters of data.
+ * Any segment longer than this is meaningless for the purpose of generating QR Codes.
+ * Moreover, the maximum allowed bit length is 32767 because
+ * the largest QR Code (version 40) has 31329 modules.
+ */
+struct qrcodegen_Segment {
+	// The mode indicator of this segment.
+	enum qrcodegen_Mode mode;
+
+	// The length of this segment's unencoded data. Measured in characters for
+	// numeric/alphanumeric/kanji mode, bytes for byte mode, and 0 for ECI mode.
+	// Always zero or positive. Not the same as the data's bit length.
+	int numChars;
+
+	// The data bits of this segment, packed in bitwise big endian.
+	// Can be null if the bit length is zero.
+	uint8_t *data;
+
+	// The number of valid data bits used in the buffer. Requires
+	// 0 <= bitLength <= 32767, and bitLength <= (capacity of data array) * 8.
+	// The character count (numChars) must agree with the mode and the bit buffer length.
+	int bitLength;
+};
+
+
+
+/*---- Macro constants and functions ----*/
+
+#define qrcodegen_VERSION_MIN   1  // The minimum version number supported in the QR Code Model 2 standard
+#define qrcodegen_VERSION_MAX  40  // The maximum version number supported in the QR Code Model 2 standard
+
+// Calculates the number of bytes needed to store any QR Code up to and including the given version number,
+// as a compile-time constant. For example, 'uint8_t buffer[qrcodegen_BUFFER_LEN_FOR_VERSION(25)];'
+// can store any single QR Code from version 1 to 25 (inclusive). The result fits in an int (or int16).
+// Requires qrcodegen_VERSION_MIN <= n <= qrcodegen_VERSION_MAX.
+#define qrcodegen_BUFFER_LEN_FOR_VERSION(n)  ((((n) * 4 + 17) * ((n) * 4 + 17) + 7) / 8 + 1)
+
+// The worst-case number of bytes needed to store one QR Code, up to and including
+// version 40. This value equals 3918, which is just under 4 kilobytes.
+// Use this more convenient value to avoid calculating tighter memory bounds for buffers.
+#define qrcodegen_BUFFER_LEN_MAX  qrcodegen_BUFFER_LEN_FOR_VERSION(qrcodegen_VERSION_MAX)
+
+
+
+/*---- Functions (high level) to generate QR Codes ----*/
+
+/*
+ * Encodes the given text string to a QR Code, returning true if encoding succeeded.
+ * If the data is too long to fit in any version in the given range
+ * at the given ECC level, then false is returned.
+ * - The input text must be encoded in UTF-8 and contain no NULs.
+ * - The variables ecl and mask must correspond to enum constant values.
+ * - Requires 1 <= minVersion <= maxVersion <= 40.
+ * - The arrays tempBuffer and qrcode must each have a length
+ *   of at least qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion).
+ * - After the function returns, tempBuffer contains no useful data.
+ * - If successful, the resulting QR Code may use numeric,
+ *   alphanumeric, or byte mode to encode the text.
+ * - In the most optimistic case, a QR Code at version 40 with low ECC
+ *   can hold any UTF-8 string up to 2953 bytes, or any alphanumeric string
+ *   up to 4296 characters, or any digit string up to 7089 characters.
+ *   These numbers represent the hard upper limit of the QR Code standard.
+ * - Please consult the QR Code specification for information on
+ *   data capacities per version, ECC level, and text encoding mode.
+ */
+bool qrcodegen_encodeText(const char *text, uint8_t tempBuffer[], uint8_t qrcode[],
+	enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl);
+
+
+/*
+ * Encodes the given binary data to a QR Code, returning true if encoding succeeded.
+ * If the data is too long to fit in any version in the given range
+ * at the given ECC level, then false is returned.
+ * - The input array range dataAndTemp[0 : dataLen] should normally be
+ *   valid UTF-8 text, but is not required by the QR Code standard.
+ * - The variables ecl and mask must correspond to enum constant values.
+ * - Requires 1 <= minVersion <= maxVersion <= 40.
+ * - The arrays dataAndTemp and qrcode must each have a length
+ *   of at least qrcodegen_BUFFER_LEN_FOR_VERSION(maxVersion).
+ * - After the function returns, the contents of dataAndTemp may have changed,
+ *   and does not represent useful data anymore.
+ * - If successful, the resulting QR Code will use byte mode to encode the data.
+ * - In the most optimistic case, a QR Code at version 40 with low ECC can hold any byte
+ *   sequence up to length 2953. This is the hard upper limit of the QR Code standard.
+ * - Please consult the QR Code specification for information on
+ *   data capacities per version, ECC level, and text encoding mode.
+ */
+bool qrcodegen_encodeBinary(uint8_t dataAndTemp[], size_t dataLen, uint8_t qrcode[],
+	enum qrcodegen_Ecc ecl, int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl);
+
+
+/*---- Functions (low level) to generate QR Codes ----*/
+
+/*
+ * Renders a QR Code representing the given segments at the given error correction level.
+ * The smallest possible QR Code version is automatically chosen for the output. Returns true if
+ * QR Code creation succeeded, or false if the data is too long to fit in any version. The ECC level
+ * of the result may be higher than the ecl argument if it can be done without increasing the version.
+ * This function allows the user to create a custom sequence of segments that switches
+ * between modes (such as alphanumeric and byte) to encode text in less space.
+ * This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
+ * To save memory, the segments' data buffers can alias/overlap tempBuffer, and will
+ * result in them being clobbered, but the QR Code output will still be correct.
+ * But the qrcode array must not overlap tempBuffer or any segment's data buffer.
+ */
+bool qrcodegen_encodeSegments(const struct qrcodegen_Segment segs[], size_t len,
+	enum qrcodegen_Ecc ecl, uint8_t tempBuffer[], uint8_t qrcode[]);
+
+
+/*
+ * Renders a QR Code representing the given segments with the given encoding parameters.
+ * Returns true if QR Code creation succeeded, or false if the data is too long to fit in the range of versions.
+ * The smallest possible QR Code version within the given range is automatically
+ * chosen for the output. Iff boostEcl is true, then the ECC level of the result
+ * may be higher than the ecl argument if it can be done without increasing the
+ * version. The mask is either between qrcodegen_Mask_0 to 7 to force that mask, or
+ * qrcodegen_Mask_AUTO to automatically choose an appropriate mask (which may be slow).
+ * This function allows the user to create a custom sequence of segments that switches
+ * between modes (such as alphanumeric and byte) to encode text in less space.
+ * This is a low-level API; the high-level API is qrcodegen_encodeText() and qrcodegen_encodeBinary().
+ * To save memory, the segments' data buffers can alias/overlap tempBuffer, and will
+ * result in them being clobbered, but the QR Code output will still be correct.
+ * But the qrcode array must not overlap tempBuffer or any segment's data buffer.
+ */
+bool qrcodegen_encodeSegmentsAdvanced(const struct qrcodegen_Segment segs[], size_t len, enum qrcodegen_Ecc ecl,
+	int minVersion, int maxVersion, enum qrcodegen_Mask mask, bool boostEcl, uint8_t tempBuffer[], uint8_t qrcode[]);
+
+
+/*
+ * Tests whether the given string can be encoded as a segment in alphanumeric mode.
+ * A string is encodable iff each character is in the following set: 0 to 9, A to Z
+ * (uppercase only), space, dollar, percent, asterisk, plus, hyphen, period, slash, colon.
+ */
+bool qrcodegen_isAlphanumeric(const char *text);
+
+
+/*
+ * Tests whether the given string can be encoded as a segment in numeric mode.
+ * A string is encodable iff each character is in the range 0 to 9.
+ */
+bool qrcodegen_isNumeric(const char *text);
+
+
+/*
+ * Returns the number of bytes (uint8_t) needed for the data buffer of a segment
+ * containing the given number of characters using the given mode. Notes:
+ * - Returns SIZE_MAX on failure, i.e. numChars > INT16_MAX or
+ *   the number of needed bits exceeds INT16_MAX (i.e. 32767).
+ * - Otherwise, all valid results are in the range [0, ceil(INT16_MAX / 8)], i.e. at most 4096.
+ * - It is okay for the user to allocate more bytes for the buffer than needed.
+ * - For byte mode, numChars measures the number of bytes, not Unicode code points.
+ * - For ECI mode, numChars must be 0, and the worst-case number of bytes is returned.
+ *   An actual ECI segment can have shorter data. For non-ECI modes, the result is exact.
+ */
+size_t qrcodegen_calcSegmentBufferSize(enum qrcodegen_Mode mode, size_t numChars);
+
+
+/*
+ * Returns a segment representing the given binary data encoded in
+ * byte mode. All input byte arrays are acceptable. Any text string
+ * can be converted to UTF-8 bytes and encoded as a byte mode segment.
+ */
+struct qrcodegen_Segment qrcodegen_makeBytes(const uint8_t data[], size_t len, uint8_t buf[]);
+
+
+/*
+ * Returns a segment representing the given string of decimal digits encoded in numeric mode.
+ */
+struct qrcodegen_Segment qrcodegen_makeNumeric(const char *digits, uint8_t buf[]);
+
+
+/*
+ * Returns a segment representing the given text string encoded in alphanumeric mode.
+ * The characters allowed are: 0 to 9, A to Z (uppercase only), space,
+ * dollar, percent, asterisk, plus, hyphen, period, slash, colon.
+ */
+struct qrcodegen_Segment qrcodegen_makeAlphanumeric(const char *text, uint8_t buf[]);
+
+
+/*
+ * Returns a segment representing an Extended Channel Interpretation
+ * (ECI) designator with the given assignment value.
+ */
+struct qrcodegen_Segment qrcodegen_makeEci(long assignVal, uint8_t buf[]);
+
+
+/*---- Functions to extract raw data from QR Codes ----*/
+
+/*
+ * Returns the side length of the given QR Code, assuming that encoding succeeded.
+ * The result is in the range [21, 177]. Note that the length of the array buffer
+ * is related to the side length - every 'uint8_t qrcode[]' must have length at least
+ * qrcodegen_BUFFER_LEN_FOR_VERSION(version), which equals ceil(size^2 / 8 + 1).
+ */
+int qrcodegen_getSize(const uint8_t qrcode[]);
+
+
+/*
+ * Returns the color of the module (pixel) at the given coordinates, which is false
+ * for white or true for black. The top left corner has the coordinates (x=0, y=0).
+ * If the given coordinates are out of bounds, then false (white) is returned.
+ */
+bool qrcodegen_getModule(const uint8_t qrcode[], int x, int y);
+
+
+#ifdef __cplusplus
+}
+#endif