picom/src/utils.h

// SPDX-License-Identifier: MPL-2.0
// Copyright (c) 2018 Yuxuan Shui <yshuiv7@gmail.com>
#pragma once
#include <ctype.h>
#include <stddef.h>
#include <stdlib.h>

/**
 * Normalize an int value to a specific range.
 *
 * @param i int value to normalize
 * @param min minimal value
 * @param max maximum value
 * @return normalized value
 */
static inline int __attribute__((const))
normalize_i_range(int i, int min, int max) {
  if (i > max) return max;
  if (i < min) return min;
  return i;
}

/**
 * Select the larger integer of two.
 */
static inline int __attribute__((const))
max_i(int a, int b) {
  return (a > b ? a : b);
}

/**
 * Select the smaller integer of two.
 */
static inline int __attribute__((const))
min_i(int a, int b) {
  return (a > b ? b : a);
}

/**
 * Select the larger long integer of two.
 */
static inline long __attribute__((const))
max_l(long a, long b) {
  return (a > b ? a : b);
}

/**
 * Select the smaller long integer of two.
 */
static inline long __attribute__((const))
min_l(long a, long b) {
  return (a > b ? b : a);
}

/**
 * Normalize a double value to a specific range.
 *
 * @param d double value to normalize
 * @param min minimal value
 * @param max maximum value
 * @return normalized value
 */
static inline double __attribute__((const))
normalize_d_range(double d, double min, double max) {
  if (d > max) return max;
  if (d < min) return min;
  return d;
}

/**
 * Normalize a double value to 0.\ 0 - 1.\ 0.
 *
 * @param d double value to normalize
 * @return normalized value
 */
static inline double __attribute__((const))
normalize_d(double d) {
  return normalize_d_range(d, 0.0, 1.0);
}

static inline const char *
skip_space_const(const char *src) {
  if (!src)
    return NULL;
  while (*src && isspace(*src))
    src++;
  return src;
}

static inline char *
skip_space_mut(char *src) {
  if (!src)
    return NULL;
  while (*src && isspace(*src))
    src++;
  return src;
}

#define skip_space(x) _Generic((x), \
  char *: skip_space_mut, \
  const char *: skip_space_const \
)(x)

/// RC_TYPE generates a reference counted type from `type`
///
/// parameters:
///   name = the generated type will be called `name`_t.
///   ctor = the constructor of `type`, will be called when
///          a value of `type` is created. should take one
///          argument of `type *`.
///   dtor = the destructor. will be called when all reference
///          is gone. has same signature as ctor
///   Q    = function qualifier. this is the qualifier that
///          will be put before generated functions
//
/// functions generated:
///   `name`_new:   create a new reference counted object of `type`
///   `name`_ref:   increment the reference counter, return a
///                 reference to the object
///   `name`_unref: decrement the reference counter. take a `type **`
///                 because it needs to nullify the reference.
#define RC_TYPE(type, name, ctor, dtor, Q) \
typedef struct { \
  type inner; \
  int ref_count; \
} name##_internal_t; \
typedef type name##_t; \
Q type *name##_new(void) { \
  name##_internal_t *ret = malloc(sizeof(name##_internal_t)); \
  ctor((type *)ret); \
  ret->ref_count = 1; \
  return (type *)ret; \
} \
Q type *name##_ref(type *a) { \
  __auto_type b = (name##_internal_t *)a; \
  b->ref_count++; \
  return a; \
} \
Q void name##_unref(type **a) { \
  __auto_type b = (name##_internal_t *)*a; \
  if (!b) \
    return; \
  b->ref_count--; \
  if (!b->ref_count) {\
    dtor((type *)b); \
    free(b); \
  } \
  *a = NULL; \
}

/// Generate prototypes for functions generated by RC_TYPE
#define RC_TYPE_PROTO(type, name) \
typedef type name##_t; \
type *name##_new(void); \
void name##_ref(type *a); \
void name##_unref(type **a);