Add pcewing Speedo v3 keymap (#18118)

* Add pcewing Speedo v3 keymap

* Add readme and code quality improvements

4 files changed, 322 insertions, 0 deletions

diff --git a/users/pcewing/README.md b/users/pcewing/README.md
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+# User Space Code for Paul Ewing
+
+This folder contains my user space code.
+
+## Key Repeater
+
+I've implemented a key repeater utility in [./key_repeater.h](./key_repeater.h)
+and [./key_repeater.c](./key_repeater.c) that is similar in concept to the
+"rapid fire" feature many game controllers come with. The intent behind this is
+that the user can hold down a key and while it is pressed, a keycode will be
+repeatedly sent. I have found this useful in certain games and during game
+development.
+
+The duration of the key press as well as the time between key presses is
+slightly randomized by design. This is to simulate more realistic human
+behavior. By setting the minimum and maximum duration fields to the same value
+in the configuration, this randomization can be disabled.
+
+**Note:** Please be aware that this might be against the terms of service in
+certain games so use your own discretion before using this feature.
+
+### How to Use
+
+Define the repeater and then configure and allocate it in your keymap's
+initialization process:
+
+```c
+static struct key_repeater_t* click_repeater = NULL;
+
+void keyboard_post_init_user(void) {
+    // Seed the random number generator which is used by the key repeater
+    srand(timer_read32());
+
+    // Configure and instantiate a key repeater for mouse button 1 "rapid fire"
+    struct key_repeater_config_t cfg = {
+        .key = KC_BTN1,             // Press mouse button 1 (Left click)
+        .key_duration_min = 20,     // Press key for 20 to 50 milliseconds
+        .key_duration_max = 50,
+        .wait_duration_min = 90,    // Wait for 90 to 140 milliseconds before pressing again
+        .wait_duration_max = 140,
+    };
+
+    click_repeater = kr_new(&cfg);
+}
+```
+
+Make sure the key repeater is polled during matrix scanning:
+
+```c
+void matrix_scan_user(void) {
+    kr_poll(click_repeater);
+}
+```
+
+Define a custom keycode that will enable/disable the repeater: 
+
+```c
+enum {
+    RP_BTN1 = SAFE_RANGE, // Click repeatedly while key is held
+};
+```
+
+Assign the keycode to a key in your `LAYOUT(...)` macro.
+
+Define the logic to enable/disable the repeater when the custom keycode is
+pressed or released:
+
+```c
+bool process_record_user(uint16_t keycode, keyrecord_t *record) {
+    switch (keycode) {
+    case RP_BTN1:
+        if (record->event.pressed) {
+            kr_enable(click_repeater);
+        } else {
+            kr_disable(click_repeater);
+        }
+        return false;
+    default:
+        return true;
+    }
+}
+```
+
+For a full working example in own of my own keymaps, see:
+[keyboards/cozykeys/speedo/v3/keymaps/pcewing/keymap.c](../../keyboards/cozykeys/speedo/v3/keymaps/pcewing/keymap.c)
diff --git a/users/pcewing/key_repeater.c b/users/pcewing/key_repeater.c
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index 0000000000..6c77d45b5f
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+++ b/users/pcewing/key_repeater.c
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+/*
+ * Copyright 2022 Paul Ewing
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "key_repeater.h"
+#include <stdlib.h>
+#include QMK_KEYBOARD_H
+
+enum key_repeater_state {
+    KR_DISABLED,
+    KR_WAITING,
+    KR_BUTTON_DOWN,
+
+    __KR_STATE_COUNT
+};
+
+struct key_repeater_t {
+    int key;
+    uint32_t key_duration_min;
+    uint32_t key_duration_max;
+    uint32_t wait_duration_min;
+    uint32_t wait_duration_max;
+
+    enum key_repeater_state state;
+    uint32_t previous_button_down;
+    uint32_t previous_button_up;
+    uint32_t key_duration;
+    uint32_t wait_duration;
+};
+
+// Utility functions
+uint32_t get_rand(uint32_t min, uint32_t max);
+
+// State handler function table
+void kr_waiting(struct key_repeater_t *kr);
+void kr_button_down(struct key_repeater_t *kr);
+
+typedef void (*kr_state_handler)(struct key_repeater_t *kr);
+static kr_state_handler kr_state_handlers[] = {
+    [KR_DISABLED] = NULL,
+    [KR_WAITING] = kr_waiting,
+    [KR_BUTTON_DOWN] = kr_button_down,
+};
+
+struct key_repeater_t* kr_new(struct key_repeater_config_t* cfg) {
+    struct key_repeater_t* kr = (struct key_repeater_t*)malloc(sizeof(struct key_repeater_t));
+
+    if (cfg) {
+        kr->key = cfg->key;
+        kr->key_duration_min = cfg->key_duration_min;
+        kr->key_duration_max = cfg->key_duration_max;
+        kr->wait_duration_min = cfg->wait_duration_min;
+        kr->wait_duration_max = cfg->wait_duration_max;
+    } else {
+        kr->key = KC_NO;
+        kr->key_duration_min = 0;
+        kr->key_duration_max = 0;
+        kr->wait_duration_min = 0;
+        kr->wait_duration_max = 0;
+    }
+ 
+    kr->state = KR_DISABLED;
+    kr->previous_button_down = 0;
+    kr->previous_button_up = 0;
+    kr->key_duration = 0;
+    kr->wait_duration = 0;
+    
+    return kr;
+}
+
+void kr_free(struct key_repeater_t **kr) {
+    if (kr && *kr) {
+        free(*kr);
+        *kr = NULL;
+    }
+}
+
+void kr_enable(struct key_repeater_t *kr) {
+    if (!kr || kr->key == KC_NO) {
+        return;
+    }
+
+    if (kr->state != KR_DISABLED) {
+        return;
+    }
+    kr->state = KR_WAITING;
+    kr->previous_button_down = 0;
+    kr->previous_button_up = 0;
+    kr->key_duration = 0;
+    kr->wait_duration = 0;
+}
+
+void kr_disable(struct key_repeater_t *kr) {
+    if (!kr || kr->key == KC_NO) {
+        return;
+    }
+
+    if (kr->state == KR_BUTTON_DOWN) {
+        unregister_code(kr->key);
+    }
+    kr->state = KR_DISABLED;
+}
+
+void kr_poll(struct key_repeater_t *kr) {
+    if (!kr || kr->key == KC_NO) {
+        return;
+    }
+
+    kr_state_handler handler = kr_state_handlers[kr->state];
+    if (handler) {
+        (handler)(kr);
+    }
+}
+
+void kr_waiting(struct key_repeater_t *kr) {
+    if (!kr || kr->key == KC_NO) {
+        return;
+    }
+
+    uint32_t now = timer_read32();
+    if (now > (kr->previous_button_up + kr->wait_duration)) {
+        kr->state = KR_BUTTON_DOWN;
+        kr->previous_button_down = now;
+        if (kr->key_duration_min == kr->key_duration_max) {
+            kr->key_duration = kr->key_duration_min;
+        } else {
+            kr->key_duration = get_rand(kr->key_duration_min, kr->key_duration_max);
+        }
+        register_code(kr->key);
+    }
+}
+
+void kr_button_down(struct key_repeater_t *kr) {
+    if (!kr || kr->key == KC_NO) {
+        return;
+    }
+
+    uint32_t now = timer_read32();
+    if (now > (kr->previous_button_down + kr->key_duration)) {
+        kr->state = KR_WAITING;
+        kr->previous_button_up = now;
+        if (kr->wait_duration_min == kr->wait_duration_max) {
+            kr->wait_duration = kr->wait_duration_min;
+        } else {
+            kr->wait_duration = get_rand(kr->wait_duration_min, kr->wait_duration_max);
+        }
+        unregister_code(kr->key);
+    }
+}
+
+// Return a random number between min and max; assumes that the random number
+// generator has already been seeded
+uint32_t get_rand(uint32_t min, uint32_t max) {
+    return (rand() % (max - min)) + min;
+}
diff --git a/users/pcewing/key_repeater.h b/users/pcewing/key_repeater.h
new file mode 100644
index 0000000000..30b7f748ff
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+/*
+ * Copyright 2022 Paul Ewing
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+// The key_repeater_config_t type holds user configurable options set when
+// allocating a new key repeater.
+struct key_repeater_config_t {
+    // The key code that will be repeatedly registered
+    int key;
+
+    // The minimum amount of time to press down the key when registered
+    const uint32_t key_duration_min;
+
+    // The maximum amount of time to press down the key when registered
+    const uint32_t key_duration_max;
+
+    // The minimum amount of time to wait between registering key presses
+    const uint32_t wait_duration_min;
+
+    // The maximum amount of time to wait between registering key presses
+    const uint32_t wait_duration_max;
+};
+
+// The key_repeater_t type represents a key repeater. This is similar to the
+// "Rapid fire" feature on many game controllers. The intention behind this is
+// to periodically send a key code while the user is pressing a key.
+//
+// The duration of the key press as well as the time between key presses is
+// slightly randomized by design. This is to simulate more realistic human
+// behavior. By setting the minimum and maximum duration fields to the same
+// value in the configuration, this randomization can be disabled.
+//
+// This type is intentionally opaque to avoid the user setting internal fields
+// directly. It must be allocated and destroyed using the kr_new() and
+// kr_free() functions respectively.
+struct key_repeater_t;
+
+// Allocate a new key repeater.
+struct key_repeater_t* kr_new(struct key_repeater_config_t* cfg);
+
+// Release an allocated key repeater.
+void kr_free(struct key_repeater_t** kr);
+
+// Enable the key repeater such that it will start periodically registering the
+// configured key code.
+void kr_enable(struct key_repeater_t* kr);
+
+// Disable the key repeater such that it will stop periodically registering the
+// configured key code.
+void kr_disable(struct key_repeater_t* kr);
+
+// Poll the key repeater to execute, tyically called from matrix_scan_user().
+void kr_poll(struct key_repeater_t* kr);
diff --git a/users/pcewing/rules.mk b/users/pcewing/rules.mk
new file mode 100644
index 0000000000..35d0bc3ab7
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+++ b/users/pcewing/rules.mk
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+SRC += key_repeater.c