mirror of https://github.com/mgba-emu/mgba.git
68 lines
1.9 KiB
C
68 lines
1.9 KiB
C
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/* Copyright (c) 2013-2014 Jeffrey Pfau
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "ring-fifo.h"
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void RingFIFOInit(struct RingFIFO* buffer, size_t capacity, size_t maxalloc) {
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buffer->data = malloc(capacity);
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buffer->capacity = capacity;
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buffer->maxalloc = maxalloc;
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RingFIFOClear(buffer);
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}
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void RingFIFODeinit(struct RingFIFO* buffer) {
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free(buffer->data);
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buffer->data = 0;
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}
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size_t RingFIFOCapacity(const struct RingFIFO* buffer) {
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return buffer->capacity;
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}
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void RingFIFOClear(struct RingFIFO* buffer) {
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buffer->readPtr = buffer->data;
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buffer->writePtr = buffer->data;
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}
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size_t RingFIFOWrite(struct RingFIFO* buffer, const void* value, size_t length) {
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void* data = buffer->writePtr;
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void* end = buffer->readPtr;
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size_t remaining;
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if ((intptr_t) data - (intptr_t) buffer->data + buffer->maxalloc >= buffer->capacity) {
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data = buffer->data;
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}
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if (data >= end) {
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remaining = (intptr_t) buffer->data + buffer->capacity - (intptr_t) data;
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} else {
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remaining = (intptr_t) end - (intptr_t) data;
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}
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if (remaining <= length) {
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return 0;
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}
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memcpy(data, value, length);
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buffer->writePtr = (void*) ((intptr_t) data + length);
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return length;
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}
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size_t RingFIFORead(struct RingFIFO* buffer, void* output, size_t length) {
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void* data = buffer->readPtr;
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void* end = buffer->writePtr;
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size_t remaining;
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if ((intptr_t) data - (intptr_t) buffer->data + buffer->maxalloc >= buffer->capacity) {
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data = buffer->data;
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}
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if (data > end) {
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remaining = (intptr_t) buffer->data + buffer->capacity - (intptr_t) data;
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} else {
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remaining = (intptr_t) end - (intptr_t) data;
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}
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if (remaining <= length) {
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return 0;
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}
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memcpy(output, data, length);
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buffer->readPtr = (void*) ((intptr_t) data + length);
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return length;
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}
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