/*

 * Copyright (c) 2008-2024 Stefan Krah. 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 AUTHOR 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 AUTHOR 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 <assert.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "mpalloc.h"

#include "mpdecimal.h"

#include "typearith.h"

#if defined(_MSC_VER)

  #pragma warning(disable : 4232)

#endif

/* Guaranteed minimum allocation for a coefficient. May be changed once

   at program start using mpd_setminalloc(). */

mpd_ssize_t MPD_MINALLOC = MPD_MINALLOC_MIN;

/* Custom allocation and free functions */

void *(* mpd_mallocfunc)(size_t size) = malloc;

void *(* mpd_reallocfunc)(void *ptr, size_t size) = realloc;

void *(* mpd_callocfunc)(size_t nmemb, size_t size) = calloc;

void (* mpd_free)(void *ptr) = free;

/* emulate calloc if it is not available */

void *

mpd_callocfunc_em(size_t nmemb, size_t size)

{

    void *ptr;

    size_t req;

    mpd_size_t overflow;

    req = mul_size_t_overflow((mpd_size_t)nmemb, (mpd_size_t)size,

                              &overflow);

    if (overflow) {

        return NULL;

    }

    ptr = mpd_mallocfunc(req);

    if (ptr == NULL) {

        return NULL;

    }

    /* used on uint32_t or uint64_t */

    memset(ptr, 0, req);

    return ptr;

}

/* malloc with overflow checking */

void *

mpd_alloc(mpd_size_t nmemb, mpd_size_t size)

{

    mpd_size_t req, overflow;

    req = mul_size_t_overflow(nmemb, size, &overflow);

    if (overflow) {

        return NULL;

    }

    return mpd_mallocfunc(req);

}

/* calloc with overflow checking */

void *

mpd_calloc(mpd_size_t nmemb, mpd_size_t size)

{

    mpd_size_t overflow;

    (void)mul_size_t_overflow(nmemb, size, &overflow);

    if (overflow) {

        return NULL;

    }

    return mpd_callocfunc(nmemb, size);

}

/* realloc with overflow checking */

void *

mpd_realloc(void *ptr, mpd_size_t nmemb, mpd_size_t size, uint8_t *err)

{

    void *new;

    mpd_size_t req, overflow;

    req = mul_size_t_overflow(nmemb, size, &overflow);

    if (overflow) {

        *err = 1;

        return ptr;

    }

    new = mpd_reallocfunc(ptr, req);

    if (new == NULL) {

        *err = 1;

        return ptr;

    }

    return new;

}

/* struct hack malloc with overflow checking */

void *

mpd_sh_alloc(mpd_size_t struct_size, mpd_size_t nmemb, mpd_size_t size)

{

    mpd_size_t req, overflow;

    req = mul_size_t_overflow(nmemb, size, &overflow);

    if (overflow) {

        return NULL;

    }

    req = add_size_t_overflow(req, struct_size, &overflow);

    if (overflow) {

        return NULL;

    }

    return mpd_mallocfunc(req);

}

/* Allocate a new decimal with a coefficient of length 'nwords'. In case

   of an error the return value is NULL. */

mpd_t *

mpd_qnew_size(mpd_ssize_t nwords)

{

    mpd_t *result;

    nwords = (nwords < MPD_MINALLOC) ? MPD_MINALLOC : nwords;

    result = mpd_alloc(1, sizeof *result);

    if (result == NULL) {

        return NULL;

    }

    result->data = mpd_alloc(nwords, sizeof *result->data);

    if (result->data == NULL) {

        mpd_free(result);

        return NULL;

    }

    result->flags = 0;

    result->exp = 0;

    result->digits = 0;

    result->len = 0;

    result->alloc = nwords;

    return result;

}

/* Allocate a new decimal with a coefficient of length MPD_MINALLOC.

   In case of an error the return value is NULL. */

mpd_t *

mpd_qnew(void)

{

    return mpd_qnew_size(MPD_MINALLOC);

}

/* Allocate new decimal. Caller can check for NULL or MPD_Malloc_error.

   Raises on error. */

mpd_t *

mpd_new(mpd_context_t *ctx)

{

    mpd_t *result;

    result = mpd_qnew();

    if (result == NULL) {

        mpd_addstatus_raise(ctx, MPD_Malloc_error);

    }

    return result;

}

/*

 * Input: 'result' is a static mpd_t with a static coefficient.

 * Assumption: 'nwords' >= result->alloc.

 *

 * Resize the static coefficient to a larger dynamic one and copy the

 * existing data. If successful, the value of 'result' is unchanged.

 * Otherwise, set 'result' to NaN and update 'status' with MPD_Malloc_error.

 */

int

mpd_switch_to_dyn(mpd_t *result, mpd_ssize_t nwords, uint32_t *status)

{

    mpd_uint_t *p = result->data;

    assert(nwords >= result->alloc);

    result->data = mpd_alloc(nwords, sizeof *result->data);

    if (result->data == NULL) {

        result->data = p;

        mpd_set_qnan(result);

        mpd_set_positive(result);

        result->exp = result->digits = result->len = 0;

        *status |= MPD_Malloc_error;

        return 0;

    }

    memcpy(result->data, p, result->alloc * (sizeof *result->data));

    result->alloc = nwords;

    mpd_set_dynamic_data(result);

    return 1;

}

/*

 * Input: 'result' is a static mpd_t with a static coefficient.

 *

 * Convert the coefficient to a dynamic one that is initialized to zero. If

 * malloc fails, set 'result' to NaN and update 'status' with MPD_Malloc_error.

 */

int

mpd_switch_to_dyn_zero(mpd_t *result, mpd_ssize_t nwords, uint32_t *status)

{

    mpd_uint_t *p = result->data;

    result->data = mpd_calloc(nwords, sizeof *result->data);

    if (result->data == NULL) {

        result->data = p;

        mpd_set_qnan(result);

        mpd_set_positive(result);

        result->exp = result->digits = result->len = 0;

        *status |= MPD_Malloc_error;

        return 0;

    }

    result->alloc = nwords;

    mpd_set_dynamic_data(result);

    return 1;

}

/*

 * Input: 'result' is a static or a dynamic mpd_t with a dynamic coefficient.

 * Resize the coefficient to length 'nwords':

 *   Case nwords > result->alloc:

 *     If realloc is successful:

 *       'result' has a larger coefficient but the same value. Return 1.

 *     Otherwise:

 *       Set 'result' to NaN, update status with MPD_Malloc_error and return 0.

 *   Case nwords < result->alloc:

 *     If realloc is successful:

 *       'result' has a smaller coefficient. result->len is undefined. Return 1.

 *     Otherwise (unlikely):

 *       'result' is unchanged. Reuse the now oversized coefficient. Return 1.

 */

int

mpd_realloc_dyn(mpd_t *result, mpd_ssize_t nwords, uint32_t *status)

{

    uint8_t err = 0;

    result->data = mpd_realloc(result->data, nwords, sizeof *result->data, &err);

    if (!err) {

        result->alloc = nwords;

    }

    else if (nwords > result->alloc) {

        mpd_set_qnan(result);

        mpd_set_positive(result);

        result->exp = result->digits = result->len = 0;

        *status |= MPD_Malloc_error;

        return 0;

    }

    return 1;

}

/*

 * Input: 'result' is a static mpd_t with a static coefficient.

 * Assumption: 'nwords' >= result->alloc.

 *

 * Resize the static coefficient to a larger dynamic one and copy the

 * existing data.

 *

 * On failure the value of 'result' is unchanged.

 */

int

mpd_switch_to_dyn_cxx(mpd_t *result, mpd_ssize_t nwords)

{

    assert(nwords >= result->alloc);

    mpd_uint_t *data = mpd_alloc(nwords, sizeof *result->data);

    if (data == NULL) {

        return 0;

    }

    memcpy(data, result->data, result->alloc * (sizeof *result->data));

    result->data = data;

    result->alloc = nwords;

    mpd_set_dynamic_data(result);

    return 1;

}

/*

 * Input: 'result' is a static or a dynamic mpd_t with a dynamic coefficient.

 * Resize the coefficient to length 'nwords':

 *   Case nwords > result->alloc:

 *     If realloc is successful:

 *       'result' has a larger coefficient but the same value. Return 1.

 *     Otherwise:

 *       'result' has a the same coefficient. Return 0.

 *   Case nwords < result->alloc:

 *     If realloc is successful:

 *       'result' has a smaller coefficient. result->len is undefined. Return 1.

 *     Otherwise (unlikely):

 *       'result' is unchanged. Reuse the now oversized coefficient. Return 1.

 */

int

mpd_realloc_dyn_cxx(mpd_t *result, mpd_ssize_t nwords)

{

    uint8_t err = 0;

    mpd_uint_t *p = mpd_realloc(result->data, nwords, sizeof *result->data, &err);

    if (!err) {

        result->data = p;

        result->alloc = nwords;

    }

    else if (nwords > result->alloc) {

        return 0;

    }

    return 1;

}