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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2016 Olaf Wintermann. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#ifdef __cplusplus
#define __STDC_FORMAT_MACROS
#endif
#include <inttypes.h>

#include "mempool.h"

/** Capsule for destructible memory chunks. */
typedef struct {
    /** The destructor for the memory chunk. */
    ucx_destructor destructor;
    /**
     * First byte of the memory chunk.
     * Note, that the address <code>&amp;c</code> is also the address
     * of the whole memory chunk.
     */
    char c;
} ucx_memchunk;

/** Capsule for data and its destructor. */
typedef struct {
    /** The destructor for the data. */
    ucx_destructor destructor;
    /** A pointer to the data. */
    void           *ptr;
} ucx_regdestr;

UCX_EXTERN void ucx_mempool_shared_destr(void* ptr) {
    ucx_regdestr *rd = (ucx_regdestr*)ptr;
    rd->destructor(rd->ptr);
}

UcxMempool *ucx_mempool_new(size_t n) {
    UcxMempool *pool = (UcxMempool*)malloc(sizeof(UcxMempool));
    if (!pool) {
        return NULL;
    }
    
    pool->data = (void**) malloc(n * sizeof(void*));
    if (pool->data == NULL) {
        free(pool);
        return NULL;
    }
    
    pool->ndata = 0;
    pool->size = n;
    
    UcxAllocator *allocator = (UcxAllocator*)malloc(sizeof(UcxAllocator));
    if(!allocator) {
        free(pool->data);
        free(pool);
        return NULL;
    }
    allocator->malloc = (ucx_allocator_malloc)ucx_mempool_malloc;
    allocator->calloc = (ucx_allocator_calloc)ucx_mempool_calloc;
    allocator->realloc = (ucx_allocator_realloc)ucx_mempool_realloc;
    allocator->free = (ucx_allocator_free)ucx_mempool_free;
    allocator->pool = pool;
    pool->allocator = allocator;
    
    return pool;
}

int ucx_mempool_chcap(UcxMempool *pool, size_t newcap) {
    void **data = (void**) realloc(pool->data, newcap*sizeof(void*));
    if (data) {
        pool->data = data; 
        pool->size = newcap;
        return EXIT_SUCCESS;
    } else {
        return EXIT_FAILURE;
    }
}

void *ucx_mempool_malloc(UcxMempool *pool, size_t n) {
    if (pool->ndata >= pool->size) {
        // The hard coded 16 is documented for this function and ucx_mempool_new
        if (ucx_mempool_chcap(pool, pool->size + 16) == EXIT_FAILURE) {
            return NULL;
        }
    }

    ucx_memchunk *mem = (ucx_memchunk*)malloc(sizeof(ucx_destructor) + n);
    if (!mem) {
        return NULL;
    }

    mem->destructor = NULL;
    pool->data[pool->ndata] = mem;
    pool->ndata++;

    return &(mem->c);
}

void *ucx_mempool_calloc(UcxMempool *pool, size_t nelem, size_t elsize) {
    void *ptr = ucx_mempool_malloc(pool, nelem*elsize);
    if (!ptr) {
        return NULL;
    }
    memset(ptr, 0, nelem * elsize);
    return ptr;
}

void *ucx_mempool_realloc(UcxMempool *pool, void *ptr, size_t n) {
    char *mem = ((char*)ptr) - sizeof(ucx_destructor);
    char *newm = (char*) realloc(mem, n + sizeof(ucx_destructor));
    if (!newm) {
        return NULL;
    }
    if (mem != newm) {
        for(size_t i=0 ; i < pool->ndata ; i++) {
            if(pool->data[i] == mem) {
                pool->data[i] = newm;
                return newm + sizeof(ucx_destructor);
            }
        }
        fprintf(stderr, "FATAL: 0x%08" PRIxPTR" not in mpool 0x%08" PRIxPTR"\n",
          (intptr_t)ptr, (intptr_t)pool);
        exit(EXIT_FAILURE);
    } else {
        return newm + sizeof(ucx_destructor);
    }
}

void ucx_mempool_free(UcxMempool *pool, void *ptr) {
    ucx_memchunk *chunk = (ucx_memchunk*)((char*)ptr-sizeof(ucx_destructor));
    for(size_t i=0 ; i<pool->ndata ; i++) {
        if(chunk == pool->data[i]) {
            if(chunk->destructor != NULL) {
                chunk->destructor(&(chunk->c));
            }
            free(chunk);
            size_t last_index = pool->ndata - 1;
            if(i != last_index) {
                pool->data[i] = pool->data[last_index];
                pool->data[last_index] = NULL;
            }
            pool->ndata--;
            return;
        }
    }
    fprintf(stderr, "FATAL: 0x%08" PRIxPTR" not in mpool 0x%08" PRIxPTR"\n",
            (intptr_t)ptr, (intptr_t)pool);
    exit(EXIT_FAILURE);
}

void ucx_mempool_destroy(UcxMempool *pool) {
    ucx_memchunk *chunk;
    for(size_t i=0 ; i<pool->ndata ; i++) {
        chunk = (ucx_memchunk*) pool->data[i];
        if(chunk) {
            if(chunk->destructor) {
                chunk->destructor(&(chunk->c));
            }
            free(chunk);
        }
    }
    free(pool->data);
    free(pool->allocator);
    free(pool);
}

void ucx_mempool_set_destr(void *ptr, ucx_destructor func) {
    *(ucx_destructor*)((char*)ptr-sizeof(ucx_destructor)) = func;
}

void ucx_mempool_reg_destr(UcxMempool *pool, void *ptr, ucx_destructor destr) {
    ucx_regdestr *rd = (ucx_regdestr*)ucx_mempool_malloc(
            pool,
            sizeof(ucx_regdestr));
    rd->destructor = destr;
    rd->ptr = ptr;
    ucx_mempool_set_destr(rd, ucx_mempool_shared_destr);
}