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Implemented a primitive single tile cache for image reading

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This commit is contained in:
Thomas Schmitt 2008-02-07 15:50:37 +00:00
parent f3ef042a09
commit 09569774dc
2 changed files with 93 additions and 6 deletions
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97
libisoburn/data_source.c
View File

@ -4,8 +4,10 @@
Copyright 2007 Vreixo Formoso Lopes <metalpain2002@yahoo.es>
*/
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#ifndef Xorriso_standalonE
@ -24,6 +26,81 @@
#include "isoburn.h"
/* Cached reading of image tree data */
/* Current implementation : single tile 128 kB */
/* powers of 2 only ! */
#define Libisoburn_cache_blockS 64
struct isoburn_cached_drive {
struct burn_drive *drive;
char cache_data[Libisoburn_cache_blockS * 2048];
uint32_t cache_lba;
int cache_hits;
};
/* Debugging only: This reports cache loads on stderr.
#define Libisoburn_read_cache_reporT 1
*/
#define Libisoburn_read_cache_experimenT
#ifdef Libisoburn_read_cache_experimenT
int
ds_read_block(IsoDataSource *src, uint32_t lba, uint8_t *buffer)
{
int ret;
struct burn_drive *d;
off_t count;
uint32_t aligned_lba;
struct isoburn_cached_drive *icd;
if(src == NULL || buffer == NULL)
return -1;
icd = (struct isoburn_cached_drive *) src->data;
d = (struct burn_drive*) icd->drive;
aligned_lba= lba & ~(Libisoburn_cache_blockS - 1);
if(aligned_lba == icd->cache_lba && icd->cache_lba != 0xffffffff) {
(icd->cache_hits)++;
memcpy(buffer, icd->cache_data + (lba - aligned_lba) * 2048, 2048);
count= 2048;
return 1;
}
icd->cache_lba= 0xffffffff; /* invalidate cache */
ret = burn_read_data(d, (off_t) aligned_lba * (off_t) 2048,
(char *) icd->cache_data,
Libisoburn_cache_blockS * 2048, &count, 0);
if (ret <= 0 ) {
/* Read-ahead failure ? Try to read 2048 directly. */
ret = burn_read_data(d, (off_t) lba * (off_t) 2048, (char *) buffer,
2048, &count, 0);
if (ret > 0)
return 1;
return -1;
}
#ifdef Libisoburn_read_cache_reporT
fprintf(stderr, "After %3d hits, new load from %8x , count= %d\n",
icd->cache_hits, aligned_lba, (int) count);
#endif
icd->cache_lba= aligned_lba;
icd->cache_hits= 1;
memcpy(buffer, icd->cache_data + (lba - aligned_lba) * 2048, 2048);
count= 2048;
return 1;
}
#else /* Libisoburn_read_cache_experimenT */
static int
ds_read_block(IsoDataSource *src, uint32_t lba, uint8_t *buffer)
{
@ -31,9 +108,10 @@ ds_read_block(IsoDataSource *src, uint32_t lba, uint8_t *buffer)
struct burn_drive *d;
off_t count;
assert(src && buffer);
if(src == NULL || buffer == NULL)
return -1;
d = (struct burn_drive*)src->data;
d = (struct burn_drive*) ((struct isoburn_cached_drive *) src->data)->drive;
ret = burn_read_data(d, (off_t) lba * (off_t) 2048, (char *) buffer,
2048, &count, 0);
@ -42,6 +120,9 @@ ds_read_block(IsoDataSource *src, uint32_t lba, uint8_t *buffer)
return 1;
}
#endif /* ! Libisoburn_read_cache_experimenT */
static int
ds_open(IsoDataSource *src)
@ -67,17 +148,23 @@ IsoDataSource *
isoburn_data_source_new(struct burn_drive *d)
{
IsoDataSource *ret;
struct isoburn_cached_drive *icd= NULL;
if (d==NULL)
return NULL;
ret = malloc(sizeof(IsoDataSource));
if (!ret)
icd = calloc(1,sizeof(struct isoburn_cached_drive));
if (ret == NULL || icd == NULL)
return NULL;
ret->refcount = 1;
ret->read_block = ds_read_block;
ret->open = ds_open;
ret->close = ds_close;
ret->free_data = ds_free_data;
ret->data = d;
ret->data = icd;
icd->drive = d;
icd->cache_lba = 0xffffffff;
icd->cache_hits = 0;
return ret;
}

2
xorriso/xorriso_timestamp.h
View File

@ -1 +1 @@
#define Xorriso_timestamP "2008.02.07.074248"
#define Xorriso_timestamP "2008.02.07.154947"