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kc3-lang/libxkbcommon/src/darray.h

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  • Author : Pierre Le Marre
    Date : 2025-05-12 07:07:57
    Hash : 8f5270c0
    Message : utils: Improve darray - Introduce `darray_size_t` - Document struct fields: the `alloc` field may be particularly confusing

  • src/darray.h
  • /*
     * Copyright (C) 2011 Joseph Adams <joeyadams3.14159@gmail.com>
     * SPDX-License-Identifier: MIT
     */
    #pragma once
    
    /* Originally taken from: https://ccodearchive.net/info/darray.html
     * But modified for libxkbcommon. */
    
    #include <stdlib.h>
    #include <string.h>
    #include <assert.h>
    #include <limits.h>
    
    typedef unsigned int darray_size_t;
    
    #define darray(type) struct {       \
        /** Array of items */           \
        type *item;                     \
        /** Current size */             \
        darray_size_t size;             \
        /** Count of allocated items */ \
        darray_size_t alloc;            \
    }
    
    #define darray_new() { 0, 0, 0 }
    
    #define darray_init(arr) do { \
        (arr).item = 0; (arr).size = 0; (arr).alloc = 0; \
    } while (0)
    
    #define darray_free(arr) do { \
        free((arr).item); \
        darray_init(arr); \
    } while (0)
    
    #define darray_steal(arr, to, to_size) do { \
        *(to) = (arr).item; \
        if (to_size) \
            *(darray_size_t *) (to_size) = (arr).size; \
        darray_init(arr); \
    } while (0)
    
    /*
     * Typedefs for darrays of common types.  These are useful
     * when you want to pass a pointer to an darray(T) around.
     *
     * The following will produce an incompatible pointer warning:
     *
     *     void foo(darray(int) *arr);
     *     darray(int) arr = darray_new();
     *     foo(&arr);
     *
     * The workaround:
     *
     *     void foo(darray_int *arr);
     *     darray_int arr = darray_new();
     *     foo(&arr);
     */
    
    typedef darray (char)           darray_char;
    typedef darray (signed char)    darray_schar;
    typedef darray (unsigned char)  darray_uchar;
    
    typedef darray (short)          darray_short;
    typedef darray (int)            darray_int;
    typedef darray (long)           darray_long;
    
    typedef darray (unsigned short) darray_ushort;
    typedef darray (unsigned int)   darray_uint;
    typedef darray (unsigned long)  darray_ulong;
    
    /*** Access ***/
    
    #define darray_item(arr, i)     ((arr).item[i])
    #define darray_items(arr)       ((arr).item)
    #define darray_size(arr)        ((arr).size)
    #define darray_empty(arr)       ((arr).size == 0)
    
    /*** Insertion (single item) ***/
    
    #define darray_append(arr, ...)  do { \
        darray_resize(arr, (arr).size + 1); \
        (arr).item[(arr).size - 1] = (__VA_ARGS__); \
    } while (0)
    
    /*** Insertion (multiple items) ***/
    
    #define darray_append_items(arr, items, count) do { \
        darray_size_t __count = (count), __oldSize = (arr).size; \
        darray_resize(arr, __oldSize + __count); \
        memcpy((arr).item + __oldSize, items, __count * sizeof(*(arr).item)); \
    } while (0)
    
    #define darray_from_items(arr, items, count) do { \
        darray_size_t __count = (count); \
        darray_resize(arr, __count); \
        if (__count != 0) \
            memcpy((arr).item, items, __count * sizeof(*(arr).item)); \
    } while (0)
    
    #define darray_copy(arr_to, arr_from) \
        darray_from_items((arr_to), (arr_from).item, (arr_from).size)
    
    #define darray_concat(arr_to, arr_from) do { \
        if ((arr_from).size > 0) \
            darray_append_items((arr_to), (arr_from).item, (arr_from).size); \
    } while (0)
    
    /*** Removal ***/
    
    /* Warning: Do not call darray_remove_last on an empty darray. */
    #define darray_remove_last(arr) (--(arr).size)
    
    /*** String buffer ***/
    
    #define darray_append_string(arr, str) do { \
        const char *__str = (str); \
        darray_append_items(arr, __str, (darray_size_t) strlen(__str) + 1); \
        (arr).size--; \
    } while (0)
    
    #define darray_append_lit(arr, stringLiteral) do { \
        darray_append_items(arr, stringLiteral, \
                            (darray_size_t) sizeof(stringLiteral)); \
        (arr).size--; \
    } while (0)
    
    #define darray_appends_nullterminate(arr, items, count) do { \
        darray_size_t __count = (count), __oldSize = (arr).size; \
        darray_resize(arr, __oldSize + __count + 1); \
        memcpy((arr).item + __oldSize, items, __count * sizeof(*(arr).item)); \
        (arr).item[--(arr).size] = 0; \
    } while (0)
    
    #define darray_prepends_nullterminate(arr, items, count) do { \
        darray_size_t __count = (count), __oldSize = (arr).size; \
        darray_resize(arr, __count + __oldSize + 1); \
        memmove((arr).item + __count, (arr).item, \
                __oldSize * sizeof(*(arr).item)); \
        memcpy((arr).item, items, __count * sizeof(*(arr).item)); \
        (arr).item[--(arr).size] = 0; \
    } while (0)
    
    /*** Size management ***/
    
    #define darray_resize(arr, newSize) \
        darray_growalloc(arr, (arr).size = (newSize))
    
    #define darray_resize0(arr, newSize) do { \
        darray_size_t __oldSize = (arr).size, __newSize = (newSize); \
        (arr).size = __newSize; \
        if (__newSize > __oldSize) { \
            darray_growalloc(arr, __newSize); \
            memset(&(arr).item[__oldSize], 0, \
                   (__newSize - __oldSize) * sizeof(*(arr).item)); \
        } \
    } while (0)
    
    #define darray_realloc(arr, newAlloc) do { \
        (arr).item = realloc((arr).item, \
                             ((arr).alloc = (newAlloc)) * sizeof(*(arr).item)); \
    } while (0)
    
    #define darray_growalloc(arr, need)   do { \
        darray_size_t __need = (need); \
        if (__need > (arr).alloc) \
            darray_realloc(arr, darray_next_alloc((arr).alloc, __need, \
                                                  sizeof(*(arr).item))); \
    } while (0)
    
    #define darray_shrink(arr) do { \
        if ((arr).size > 0) \
            (arr).item = realloc((arr).item, \
                                 ((arr).alloc = (arr).size) * sizeof(*(arr).item)); \
    } while (0)
    
    #define darray_max_alloc(itemSize) (UINT_MAX / (itemSize))
    
    static inline darray_size_t
    darray_next_alloc(darray_size_t alloc, darray_size_t need, size_t itemSize)
    {
        assert(need < darray_max_alloc(itemSize) / 2); /* Overflow. */
        if (alloc == 0)
            alloc = 4;
        while (alloc < need)
            alloc *= 2;
        return alloc;
    }
    
    /*** Traversal ***/
    
    #define darray_foreach(i, arr) \
        if ((arr).item) \
        for ((i) = &(arr).item[0]; (i) < &(arr).item[(arr).size]; (i)++)
    
    #define darray_foreach_from(i, arr, from) \
        if ((arr).item) \
        for ((i) = &(arr).item[from]; (i) < &(arr).item[(arr).size]; (i)++)
    
    /* Iterate on index and value at the same time, like Python's enumerate. */
    #define darray_enumerate(idx, val, arr) \
        if ((arr).item) \
        for ((idx) = 0, (val) = &(arr).item[0]; \
             (idx) < (arr).size; \
             (idx)++, (val)++)
    
    #define darray_enumerate_from(idx, val, arr, from) \
        if ((arr).item) \
        for ((idx) = (from), (val) = &(arr).item[from]; \
             (idx) < (arr).size; \
             (idx)++, (val)++)
    
    #define darray_foreach_reverse(i, arr) \
        if ((arr).item) \
        for ((i) = &(arr).item[(arr).size - 1]; (arr).size > 0 && (i) >= &(arr).item[0]; (i)--)