ucx: src/stack.c@a6184aff5108

     1 /*

     2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

     3  *

     4  * Copyright 2017 Mike Becker, Olaf Wintermann All rights reserved.

     5  *

     6  * Redistribution and use in source and binary forms, with or without

     7  * modification, are permitted provided that the following conditions are met:

     8  *

     9  *   1. Redistributions of source code must retain the above copyright

    10  *      notice, this list of conditions and the following disclaimer.

    11  *

    12  *   2. Redistributions in binary form must reproduce the above copyright

    13  *      notice, this list of conditions and the following disclaimer in the

    14  *      documentation and/or other materials provided with the distribution.

    15  *

    16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

    17  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

    18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

    19  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE

    20  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

    21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

    22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

    23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

    24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

    25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

    26  * POSSIBILITY OF SUCH DAMAGE.

    27  */

    29 #include "ucx/stack.h"

    31 #include <string.h>

    33 static size_t ucx_stack_align(size_t n) {

    34     int align = n % sizeof(void*);

    35     if (align) {

    36         n += sizeof(void*) - align;

    37     }

    38     return n;

    39 }

    41 void ucx_stack_init(UcxStack *stack, char* space, size_t size) {

    42     stack->size = size - size % sizeof(void*);

    43     stack->space = space;

    44     stack->top = NULL;

    46     stack->allocator.pool = stack;

    47     stack->allocator.malloc = (ucx_allocator_malloc) ucx_stack_malloc;

    48     stack->allocator.calloc = (ucx_allocator_calloc) ucx_stack_calloc;

    49     stack->allocator.realloc = (ucx_allocator_realloc) ucx_stack_realloc;

    50     stack->allocator.free = (ucx_allocator_free) ucx_stack_free;

    51 }

    53 void *ucx_stack_malloc(UcxStack *stack, size_t n) {

    55     if (ucx_stack_avail(stack) < ucx_stack_align(n)) {

    56         return NULL;

    57     } else {

    58         char *prev = stack->top;

    59         if (stack->top) {

    60             stack->top += ucx_stack_align(ucx_stack_topsize(stack));

    61         } else {

    62             stack->top = stack->space;

    63         }

    65         ((struct ucx_stack_metadata*)stack->top)->prev = prev;

    66         ((struct ucx_stack_metadata*)stack->top)->size = n;

    67         stack->top += sizeof(struct ucx_stack_metadata);

    69         return stack->top;

    70     }

    71 }

    73 void *ucx_stack_calloc(UcxStack *stack, size_t nelem, size_t elsize) {

    74     void *mem = ucx_stack_malloc(stack, nelem*elsize);

    75     memset(mem, 0, nelem*elsize);

    76     return mem;

    77 }

    79 void *ucx_stack_realloc(UcxStack *stack, void *ptr, size_t n) {

    80     if (ptr == stack->top) {

    81         if (stack->size - (stack->top - stack->space) < ucx_stack_align(n)) {

    82             return NULL;

    83         } else {

    84             ((struct ucx_stack_metadata*)stack->top - 1)->size = n;

    85             return ptr;

    86         }

    87     } else {

    88         if (ucx_stack_align(((struct ucx_stack_metadata*)ptr - 1)->size) <

    89                 ucx_stack_align(n)) {

    90             void *nptr = ucx_stack_malloc(stack, n);

    91             if (nptr) {

    92                 memcpy(nptr, ptr, n);

    93                 ucx_stack_free(stack, ptr);

    95                 return nptr;

    96             } else {

    97                 return NULL;

    98             }

    99         } else {

   100             ((struct ucx_stack_metadata*)ptr - 1)->size = n;

   101             return ptr;

   102         }

   103     }

   104 }

   106 void ucx_stack_free(UcxStack *stack, void *ptr) {

   107     if (ptr == stack->top) {

   108         stack->top = ((struct ucx_stack_metadata*) stack->top - 1)->prev;

   109     } else {

   110         struct ucx_stack_metadata *next = (struct ucx_stack_metadata*)(

   111             (char*)ptr +

   112             ucx_stack_align(((struct ucx_stack_metadata*) ptr - 1)->size)

   113         );

   114         next->prev = ((struct ucx_stack_metadata*) ptr - 1)->prev;

   115     }

   116 }

   118 void ucx_stack_popn(UcxStack *stack, void *dest, size_t n) {

   119     if (ucx_stack_empty(stack)) {

   120         return;

   121     }

   123     size_t len = ucx_stack_topsize(stack);

   124     if (len > n) {

   125         len = n;

   126     }

   128     memcpy(dest, stack->top, len);

   130     ucx_stack_free(stack, stack->top);

   131 }

   133 size_t ucx_stack_avail(UcxStack *stack) {

   134     size_t avail = ((stack->top ? (stack->size

   135                     - (stack->top - stack->space)

   136                     - ucx_stack_align(ucx_stack_topsize(stack)))

   137                     : stack->size));

   139     if (avail > sizeof(struct ucx_stack_metadata)) {

   140         return avail - sizeof(struct ucx_stack_metadata);

   141     } else {

   142         return 0;

   143     }

   144 }

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