mirror of
https://github.com/CTCaer/RetroArch.git
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102 lines
2.6 KiB
C
102 lines
2.6 KiB
C
/* RetroArch - A frontend for libretro.
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* Copyright (C) 2010-2013 - Hans-Kristian Arntzen
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*
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* RetroArch is free software: you can redistribute it and/or modify it under the terms
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* of the GNU General Public License as published by the Free Software Found-
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* ation, either version 3 of the License, or (at your option) any later version.
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*
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* RetroArch is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along with RetroArch.
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* If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "fifo_buffer.h"
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#include <stdint.h>
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struct fifo_buffer
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{
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uint8_t *buffer;
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size_t bufsize;
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size_t first;
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size_t end;
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};
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fifo_buffer_t *fifo_new(size_t size)
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{
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fifo_buffer_t *buf = (fifo_buffer_t*)calloc(1, sizeof(*buf));
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if (buf == NULL)
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return NULL;
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buf->buffer = (uint8_t*)calloc(1, size + 1);
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if (buf->buffer == NULL)
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{
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free(buf);
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return NULL;
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}
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buf->bufsize = size + 1;
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return buf;
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}
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void fifo_free(fifo_buffer_t *buffer)
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{
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free(buffer->buffer);
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free(buffer);
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}
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size_t fifo_read_avail(fifo_buffer_t *buffer)
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{
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size_t first = buffer->first;
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size_t end = buffer->end;
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if (end < first)
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end += buffer->bufsize;
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return end - first;
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}
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size_t fifo_write_avail(fifo_buffer_t *buffer)
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{
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size_t first = buffer->first;
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size_t end = buffer->end;
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if (end < first)
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end += buffer->bufsize;
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return (buffer->bufsize - 1) - (end - first);
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}
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void fifo_write(fifo_buffer_t *buffer, const void *in_buf, size_t size)
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{
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size_t first_write = size;
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size_t rest_write = 0;
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if (buffer->end + size > buffer->bufsize)
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{
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first_write = buffer->bufsize - buffer->end;
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rest_write = size - first_write;
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}
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memcpy(buffer->buffer + buffer->end, in_buf, first_write);
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memcpy(buffer->buffer, (const uint8_t*)in_buf + first_write, rest_write);
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buffer->end = (buffer->end + size) % buffer->bufsize;
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}
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void fifo_read(fifo_buffer_t *buffer, void *in_buf, size_t size)
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{
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size_t first_read = size;
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size_t rest_read = 0;
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if (buffer->first + size > buffer->bufsize)
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{
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first_read = buffer->bufsize - buffer->first;
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rest_read = size - first_read;
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}
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memcpy(in_buf, (const uint8_t*)buffer->buffer + buffer->first, first_read);
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memcpy((uint8_t*)in_buf + first_read, buffer->buffer, rest_read);
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buffer->first = (buffer->first + size) % buffer->bufsize;
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}
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