57 lines
1.5 KiB
C
57 lines
1.5 KiB
C
#include "cig.h"
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static void *buffer_allocator_alloc(buffer_allocator_t *this, size_t bytes) {
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size_t address_of_new_data = (size_t) &this->data[this->size];
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size_t offset = address_of_new_data % MAX_ALIGN;
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size_t new_size = this->size + offset + bytes;
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if (new_size > this->capacity) {
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return NULL;
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}
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this->size += offset;
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void *ptr = &this->data[this->size];
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this->size = new_size;
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return ptr;
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}
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static void *buffer_allocator_resize(buffer_allocator_t *this, void *old_ptr, size_t bytes) {
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void *new_ptr = buffer_allocator_alloc(this, bytes);
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if (new_ptr == NULL) {
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return NULL;
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}
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for (size_t i = 0; i < bytes; i++) {
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unsigned char *new_ptr_b = (unsigned char *)new_ptr;
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unsigned char *old_ptr_b = (unsigned char *)old_ptr;
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new_ptr_b[i] = old_ptr_b[i];
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}
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return new_ptr;
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}
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static void buffer_allocator_reset(buffer_allocator_t *this) {
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this->size = 0;
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}
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static void *buffer_alloc_impl(void *this, size_t bytes) {
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return buffer_allocator_alloc((buffer_allocator_t *)this, bytes);
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}
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static void *buffer_resize_impl(void *this, void *old_ptr, size_t bytes) {
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return buffer_allocator_resize((buffer_allocator_t *)this, old_ptr, bytes);
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}
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static void buffer_reset_impl(void *this) {
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buffer_allocator_reset((buffer_allocator_t *)this);
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}
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static const allocator_vtbl_t buffer_vtbl = {
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.alloc = buffer_alloc_impl,
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.resize = buffer_resize_impl,
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.reset = buffer_reset_impl,
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};
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allocator_t allocator_from_buffer(buffer_allocator_t *this) {
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return (allocator_t) {
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.this=this,
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.vtbl=&buffer_vtbl,
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};
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}
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