text: /*
   * Copyright © 2008-2011 Kristian Høgsberg
   * Copyright © 2011 Intel Corporation
   * Copyright © 2013-2015 Red Hat, Inc.
   *
   * 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 (including the next
   * paragraph) 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.
   */
  
  /*
   * This list data structure is verbatim copy from wayland-util.h from the
   * Wayland project; except that wl_ prefix has been removed.
   */
  
  #include "config.h"
  
  #include <ctype.h>
  #include <locale.h>
  #include <stdarg.h>
  #include <stdbool.h>
  #include <stdio.h>
  #include <stdlib.h>
  
  #include "libinput-util.h"
  #include "libinput-private.h"
  
  void
  list_init(struct list *list)
  {
  	list->prev = list;
  	list->next = list;
  }
  
  void
  list_insert(struct list *list, struct list *elm)
  {
  	elm->prev = list;
  	elm->next = list->next;
  	list->next = elm;
  	elm->next->prev = elm;
  }
  
  void
  list_remove(struct list *elm)
  {
  	elm->prev->next = elm->next;
  	elm->next->prev = elm->prev;
  	elm->next = NULL;
  	elm->prev = NULL;
  }
  
  bool
  list_empty(const struct list *list)
  {
  	return list->next == list;
  }
  
  void
  ratelimit_init(struct ratelimit *r, uint64_t ival_us, unsigned int burst)
  {
  	r->interval = ival_us;
  	r->begin = 0;
  	r->burst = burst;
  	r->num = 0;
  }
  
  /*
   * Perform rate-limit test. Returns RATELIMIT_PASS if the rate-limited action
   * is still allowed, RATELIMIT_THRESHOLD if the limit has been reached with
   * this call, and RATELIMIT_EXCEEDED if you're beyond the threshold.
   * It's safe to treat the return-value as boolean, if you're not interested in
   * the exact state. It evaluates to "true" if the threshold hasn't been
   * exceeded, yet.
   *
   * The ratelimit object must be initialized via ratelimit_init().
   *
   * Modelled after Linux' lib/ratelimit.c by Dave Young
   * <hidave.darkstar@gmail.com>, which is licensed GPLv2.
   */
  enum ratelimit_state
  ratelimit_test(struct ratelimit *r)
  {
  	struct timespec ts;
  	uint64_t utime;
  
  	if (r->interval <= 0 || r->burst <= 0)
  		return RATELIMIT_PASS;
  
  	clock_gettime(CLOCK_MONOTONIC, &ts);
  	utime = s2us(ts.tv_sec) + ns2us(ts.tv_nsec);
  
  	if (r->begin <= 0 || r->begin + r->interval < utime) {
  		/* reset counter */
  		r->begin = utime;
  		r->num = 1;
  		return RATELIMIT_PASS;
  	} else if (r->num < r->burst) {
  		/* continue burst */
  		return (++r->num == r->burst) ? RATELIMIT_THRESHOLD
  					      : RATELIMIT_PASS;
  	}
  
  	return RATELIMIT_EXCEEDED;
  }
  
  /* Helper function to parse the mouse DPI tag from udev.
   * The tag is of the form:
   * MOUSE_DPI=400 *1000 2000
   * or
   * MOUSE_DPI=400@125 *1000@125 2000@125
   * Where the * indicates the default value and @number indicates device poll
   * rate.
   * Numbers should be in ascending order, and if rates are present they should
   * be present for all entries.
   *
   * When parsing the mouse DPI property, if we find an error we just return 0
   * since it's obviously invalid, the caller will treat that as an error and
   * use a reasonable default instead. If the property contains multiple DPI
   * settings but none flagged as default, we return the last because we're
   * lazy and that's a silly way to set the property anyway.
   *
   * @param prop The value of the udev property (without the MOUSE_DPI=)
   * @return The default dpi value on success, 0 on error
   */
  int
  parse_mouse_dpi_property(const char *prop)
  {
  	bool is_default = false;
  	int nread, dpi = 0, rate;
  
  	if (!prop)
  		return 0;
  
  	while (*prop != 0) {
  		if (*prop == ' ') {
  			prop++;
  			continue;
  		}
  		if (*prop == '*') {
  			prop++;
  			is_default = true;
  			if (!isdigit(prop[0]))
  				return 0;
  		}
  
  		/* While we don't do anything with the rate right now we
  		 * will validate that, if it's present, it is non-zero and
  		 * positive
  		 */
  		rate = 1;
  		nread = 0;
  		sscanf(prop, "%d@%d%n", &dpi, &rate, &nread);
  		if (!nread)
  			sscanf(prop, "%d%n", &dpi, &nread);
  		if (!nread || dpi <= 0 || rate <= 0 || prop[nread] == '@')
  			return 0;
  
  		if (is_default)
  			break;
  		prop += nread;
  	}
  	return dpi;
  }
  
  /**
   * Helper function to parse the MOUSE_WHEEL_CLICK_COUNT property from udev.
   * Property is of the form:
   * MOUSE_WHEEL_CLICK_COUNT=<integer>
   * Where the number indicates the number of wheel clicks per 360 deg
   * rotation.
   *
   * @param prop The value of the udev property (without the MOUSE_WHEEL_CLICK_COUNT=)
   * @return The click count of the wheel (may be negative) or 0 on error.
   */
  int
  parse_mouse_wheel_click_count_property(const char *prop)
  {
  	int count = 0;
  
  	if (!prop)
  		return 0;
  
  	if (!safe_atoi(prop, &count) || abs(count) > 360)
  		return 0;
  
          return count;
  }
  
  /**
   *
   * Helper function to parse the MOUSE_WHEEL_CLICK_ANGLE property from udev.
   * Property is of the form:
   * MOUSE_WHEEL_CLICK_ANGLE=<integer>
   * Where the number indicates the degrees travelled for each click.
   *
   * @param prop The value of the udev property (without the MOUSE_WHEEL_CLICK_ANGLE=)
   * @return The angle of the wheel (may be negative) or 0 on error.
   */
  int
  parse_mouse_wheel_click_angle_property(const char *prop)
  {
  	int angle = 0;
  
  	if (!prop)
  		return 0;
  
  	if (!safe_atoi(prop, &angle) || abs(angle) > 360)
  		return 0;
  
          return angle;
  }
  
  /**
   * Helper function to parse the TRACKPOINT_CONST_ACCEL property from udev.
   * Property is of the form:
   * TRACKPOINT_CONST_ACCEL=<float>
   *
   * @param prop The value of the udev property (without the TRACKPOINT_CONST_ACCEL=)
   * @return The acceleration, or 0.0 on error.
   */
  double
  parse_trackpoint_accel_property(const char *prop)
  {
  	double accel;
  
  	if (!prop)
  		return 0.0;
  
  	if (!safe_atod(prop, &accel))
  		accel = 0.0;
  
  	return accel;
  }
  
  /**
   * Parses a simple dimension string in the form of "10x40". The two
   * numbers must be positive integers in decimal notation.
   * On success, the two numbers are stored in w and h. On failure, w and h
   * are unmodified.
   *
   * @param prop The value of the property
   * @param w Returns the first component of the dimension
   * @param h Returns the second component of the dimension
   * @return true on success, false otherwise
   */
  bool
  parse_dimension_property(const char *prop, size_t *w, size_t *h)
  {
  	int x, y;
  
  	if (!prop)
  		return false;
  
  	if (sscanf(prop, "%dx%d", &x, &y) != 2)
  		return false;
  
  	if (x < 0 || y < 0)
  		return false;
  
  	*w = (size_t)x;
  	*h = (size_t)y;
  	return true;
  }
  
  /**
   * Parses a set of 6 space-separated floats.
   *
   * @param prop The string value of the property
   * @param calibration Returns the six components
   * @return true on success, false otherwise
   */
  bool
  parse_calibration_property(const char *prop, float calibration_out[6])
  {
  	int idx;
  	char **strv;
  	float calibration[6];
  
  	if (!prop)
  		return false;
  
  	strv = strv_from_string(prop, " ");
  	if (!strv)
  		return false;
  
  	for (idx = 0; idx < 6; idx++) {
  		double v;
  		if (strv[idx] == NULL || !safe_atod(strv[idx], &v)) {
  			strv_free(strv);
  			return false;
  		}
  
  		calibration[idx] = v;
  	}
  
  	strv_free(strv);
  
  	memcpy(calibration_out, calibration, sizeof(calibration));
  
  	return true;
  }
  
  bool
  parse_switch_reliability_property(const char *prop,
  				  enum switch_reliability *reliability)
  {
  	if (!prop) {
  		*reliability = RELIABILITY_UNKNOWN;
  		return true;
  	}
  
  	if (streq(prop, "reliable"))
  		*reliability = RELIABILITY_RELIABLE;
  	else if (streq(prop, "write_open"))
  		*reliability = RELIABILITY_WRITE_OPEN;
  	else
  		return false;
  
  	return true;
  }
  
  /**
   * Parses a string with the allowed values: "below"
   * The value refers to the position of the touchpad (relative to the
   * keyboard, i.e. your average laptop would be 'below')
   *
   * @param prop The value of the property
   * @param layout The layout
   * @return true on success, false otherwise
   */
  bool
  parse_tpkbcombo_layout_poperty(const char *prop,
  			       enum tpkbcombo_layout *layout)
  {
  	if (!prop)
  		return false;
  
  	if (streq(prop, "below")) {
  		*layout = TPKBCOMBO_LAYOUT_BELOW;
  		return true;
  	}
  
  	return false;
  }
  
  /**
   * Return the next word in a string pointed to by state before the first
   * separator character. Call repeatedly to tokenize a whole string.
   *
   * @param state Current state
   * @param len String length of the word returned
   * @param separators List of separator characters
   *
   * @return The first word in *state, NOT null-terminated
   */
  static const char *
  next_word(const char **state, size_t *len, const char *separators)
  {
  	const char *next = *state;
  	size_t l;
  
  	if (!*next)
  		return NULL;
  
  	next += strspn(next, separators);
  	if (!*next) {
  		*state = next;
  		return NULL;
  	}
  
  	l = strcspn(next, separators);
  	*state = next + l;
  	*len = l;
  
  	return next;
  }
  
  /**
   * Return a null-terminated string array with the tokens in the input
   * string, e.g. "one two\tthree" with a separator list of " \t" will return
   * an array [ "one", "two", "three", NULL ].
   *
   * Use strv_free() to free the array.
   *
   * @param in Input string
   * @param separators List of separator characters
   *
   * @return A null-terminated string array or NULL on errors
   */
  char **
  strv_from_string(const char *in, const char *separators)
  {
  	const char *s, *word;
  	char **strv = NULL;
  	int nelems = 0, idx;
  	size_t l;
  
  	assert(in != NULL);
  
  	s = in;
  	while ((word = next_word(&s, &l, separators)) != NULL)
  	       nelems++;
  
  	if (nelems == 0)
  		return NULL;
  
  	nelems++; /* NULL-terminated */
  	strv = zalloc(nelems * sizeof *strv);
  	if (!strv)
  		return NULL;
  
  	idx = 0;
  
  	s = in;
  	while ((word = next_word(&s, &l, separators)) != NULL) {
  		char *copy = strndup(word, l);
  		if (!copy) {
  			strv_free(strv);
  			return NULL;
  		}
  
  		strv[idx++] = copy;
  	}
  
  	return strv;
  }
  