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https://github.com/GrammaticalFramework/gf-core.git
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112 lines
2.6 KiB
C
112 lines
2.6 KiB
C
/*
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* Copyright 2010 University of Helsinki.
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*
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* This file is part of libgu.
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*
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* Libgu is free software: you can redistribute it and/or modify it under
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* the terms of the GNU Lesser General Public License as published by the
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* Free Software Foundation, either version 3 of the License, or (at your
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* option) any later version.
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*
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* Libgu is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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* License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with libgu. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "variant.h"
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#include "bits.h"
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enum {
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GU_VARIANT_ALIGNMENT = sizeof(uintptr_t)
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};
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void*
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gu_alloc_variant(uint8_t tag, size_t size,
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size_t align, GuVariant* variant_out, GuPool* pool)
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{
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align = gu_max(align, GU_VARIANT_ALIGNMENT);
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if (((size_t)tag) > GU_VARIANT_ALIGNMENT - 2) {
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uint8_t* alloc = gu_malloc_aligned(pool, align + size, align);
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alloc[align - 1] = tag;
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void* p = &alloc[align];
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*variant_out = (uintptr_t)p;
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return p;
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}
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void* p = gu_malloc_aligned(pool, size, align);
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*variant_out = ((uintptr_t)p) | (tag + 1);
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return p;
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}
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GuVariant
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gu_make_variant(uint8_t tag, size_t size, size_t align, const void* init,
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GuPool* pool)
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{
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GuVariant v;
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void* data = gu_alloc_variant(tag, size, align, &v, pool);
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memcpy(data, init, size);
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return v;
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}
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int
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gu_variant_tag(GuVariant variant)
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{
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if (gu_variant_is_null(variant)) {
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return GU_VARIANT_NULL;
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}
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int u = variant % GU_VARIANT_ALIGNMENT;
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if (u == 0) {
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uint8_t* mem = (uint8_t*)variant;
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return mem[-1];
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}
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return u - 1;
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}
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void*
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gu_variant_data(GuVariant variant)
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{
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if (gu_variant_is_null(variant)) {
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return NULL;
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}
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return (void*)gu_align_backward(variant, GU_VARIANT_ALIGNMENT);
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}
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GuVariantInfo gu_variant_open(GuVariant variant)
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{
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GuVariantInfo info = {
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.tag = gu_variant_tag(variant),
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.data = gu_variant_data(variant)
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};
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return info;
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}
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GuVariant gu_variant_close(GuVariantInfo info)
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{
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GuVariant variant;
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if (((size_t)info.tag) > GU_VARIANT_ALIGNMENT - 2) {
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variant = (uintptr_t)info.data;
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assert(gu_variant_tag(variant) == info.tag);
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} else {
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variant = ((uintptr_t)info.data) | (info.tag + 1);
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}
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return variant;
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}
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int
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gu_variant_intval(GuVariant variant)
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{
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int u = variant % GU_VARIANT_ALIGNMENT;
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if (u == 0) {
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int* mem = (int*)variant;
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return *mem;
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}
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return (variant / GU_VARIANT_ALIGNMENT);
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}
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const GuVariant gu_null_variant = { (GuWord) NULL };
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