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/*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* mpv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <stdint.h>
#include "osdep/io.h"
#include "common/common.h"
#include "common/msg.h"
#include "options/options.h"
#include "stream.h"
#define BLOCK_SIZE 1024LL
#define BLOCK_ALIGN(p) ((p) & ~(BLOCK_SIZE - 1))
struct priv {
struct stream *original;
FILE *cache_file;
uint8_t *block_bits; // 1 bit for each BLOCK_SIZE, whether block was read
int64_t size; // currently known size
int64_t max_size; // max. size for block_bits and cache_file
};
static bool test_bit(struct priv *p, int64_t pos)
{
if (pos < 0 || pos >= p->size)
return false;
size_t block = pos / BLOCK_SIZE;
return p->block_bits[block / 8] & (1 << (block % 8));
}
static void set_bit(struct priv *p, int64_t pos, bool bit)
{
if (pos < 0 || pos >= p->size)
return;
size_t block = pos / BLOCK_SIZE;
unsigned int m = (1 << (block % 8));
p->block_bits[block / 8] = (p->block_bits[block / 8] & ~m) | (bit ? m : 0);
}
static int fill_buffer(stream_t *s, char *buffer, int max_len)
{
struct priv *p = s->priv;
if (s->pos < 0)
return -1;
if (s->pos >= p->max_size) {
if (stream_seek(p->original, s->pos) < 1)
return -1;
return stream_read(p->original, buffer, max_len);
}
// Size of file changes -> invalidate last block
if (s->pos >= p->size - BLOCK_SIZE) {
int64_t new_size = stream_get_size(s);
if (p->size >= 0 && new_size != p->size)
set_bit(p, BLOCK_ALIGN(p->size), 0);
p->size = MPMIN(p->max_size, new_size);
}
int64_t aligned = BLOCK_ALIGN(s->pos);
if (!test_bit(p, aligned)) {
char tmp[BLOCK_SIZE];
stream_seek(p->original, aligned);
int r = stream_read(p->original, tmp, BLOCK_SIZE);
if (r < BLOCK_SIZE) {
if (p->size < 0) {
MP_WARN(s, "suspected EOF\n");
} else if (aligned + r < p->size) {
MP_ERR(s, "unexpected EOF\n");
return -1;
}
}
if (fseeko(p->cache_file, aligned, SEEK_SET))
return -1;
if (fwrite(tmp, r, 1, p->cache_file) != 1)
return -1;
set_bit(p, aligned, 1);
}
if (fseeko(p->cache_file, s->pos, SEEK_SET))
return -1;
// align/limit to blocks
max_len = MPMIN(max_len, BLOCK_SIZE - (s->pos % BLOCK_SIZE));
// Limit to max. known file size
if (p->size >= 0)
max_len = MPMIN(max_len, p->size - s->pos);
return fread(buffer, 1, max_len, p->cache_file);
}
static int seek(stream_t *s, int64_t newpos)
{
return 1;
}
static int control(stream_t *s, int cmd, void *arg)
{
struct priv *p = s->priv;
return stream_control(p->original, cmd, arg);
}
static void s_close(stream_t *s)
{
struct priv *p = s->priv;
if (p->cache_file)
fclose(p->cache_file);
talloc_free(p);
}
// return 1 on success, 0 if disabled, -1 on error
int stream_file_cache_init(stream_t *cache, stream_t *stream,
struct mp_cache_opts *opts)
{
if (!opts->file || !opts->file[0] || opts->file_max < 1)
return 0;
if (!stream->seekable) {
MP_ERR(cache, "can't cache unseekable stream\n");
return -1;
}
bool use_anon_file = strcmp(opts->file, "TMP") == 0;
FILE *file = use_anon_file ? tmpfile() : fopen(opts->file, "wb+");
if (!file) {
MP_ERR(cache, "can't open cache file '%s'\n", opts->file);
return -1;
}
struct priv *p = talloc_zero(NULL, struct priv);
cache->priv = p;
p->original = stream;
p->cache_file = file;
p->max_size = opts->file_max * 1024LL;
// file_max can be INT_MAX, so this is at most about 256MB
p->block_bits = talloc_zero_size(p, (p->max_size / BLOCK_SIZE + 1) / 8 + 1);
cache->seek = seek;
cache->fill_buffer = fill_buffer;
cache->control = control;
cache->close = s_close;
return 1;
}
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