Implemented a primitive single tile cache for image reading
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@ -4,8 +4,10 @@
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Copyright 2007 Vreixo Formoso Lopes <metalpain2002@yahoo.es>
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*/
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#include <assert.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#ifndef Xorriso_standalonE
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@ -24,6 +26,81 @@
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#include "isoburn.h"
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/* Cached reading of image tree data */
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/* Current implementation : single tile 128 kB */
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/* powers of 2 only ! */
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#define Libisoburn_cache_blockS 64
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struct isoburn_cached_drive {
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struct burn_drive *drive;
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char cache_data[Libisoburn_cache_blockS * 2048];
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uint32_t cache_lba;
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int cache_hits;
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};
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/* Debugging only: This reports cache loads on stderr.
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#define Libisoburn_read_cache_reporT 1
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*/
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#define Libisoburn_read_cache_experimenT
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#ifdef Libisoburn_read_cache_experimenT
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int
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ds_read_block(IsoDataSource *src, uint32_t lba, uint8_t *buffer)
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{
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int ret;
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struct burn_drive *d;
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off_t count;
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uint32_t aligned_lba;
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struct isoburn_cached_drive *icd;
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if(src == NULL || buffer == NULL)
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return -1;
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icd = (struct isoburn_cached_drive *) src->data;
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d = (struct burn_drive*) icd->drive;
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aligned_lba= lba & ~(Libisoburn_cache_blockS - 1);
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if(aligned_lba == icd->cache_lba && icd->cache_lba != 0xffffffff) {
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(icd->cache_hits)++;
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memcpy(buffer, icd->cache_data + (lba - aligned_lba) * 2048, 2048);
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count= 2048;
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return 1;
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}
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icd->cache_lba= 0xffffffff; /* invalidate cache */
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ret = burn_read_data(d, (off_t) aligned_lba * (off_t) 2048,
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(char *) icd->cache_data,
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Libisoburn_cache_blockS * 2048, &count, 0);
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if (ret <= 0 ) {
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/* Read-ahead failure ? Try to read 2048 directly. */
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ret = burn_read_data(d, (off_t) lba * (off_t) 2048, (char *) buffer,
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2048, &count, 0);
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if (ret > 0)
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return 1;
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return -1;
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}
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#ifdef Libisoburn_read_cache_reporT
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fprintf(stderr, "After %3d hits, new load from %8x , count= %d\n",
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icd->cache_hits, aligned_lba, (int) count);
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#endif
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icd->cache_lba= aligned_lba;
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icd->cache_hits= 1;
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memcpy(buffer, icd->cache_data + (lba - aligned_lba) * 2048, 2048);
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count= 2048;
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return 1;
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}
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#else /* Libisoburn_read_cache_experimenT */
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static int
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ds_read_block(IsoDataSource *src, uint32_t lba, uint8_t *buffer)
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{
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@ -31,9 +108,10 @@ ds_read_block(IsoDataSource *src, uint32_t lba, uint8_t *buffer)
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struct burn_drive *d;
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off_t count;
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assert(src && buffer);
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if(src == NULL || buffer == NULL)
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return -1;
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d = (struct burn_drive*)src->data;
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d = (struct burn_drive*) ((struct isoburn_cached_drive *) src->data)->drive;
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ret = burn_read_data(d, (off_t) lba * (off_t) 2048, (char *) buffer,
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2048, &count, 0);
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@ -42,6 +120,9 @@ ds_read_block(IsoDataSource *src, uint32_t lba, uint8_t *buffer)
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return 1;
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}
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#endif /* ! Libisoburn_read_cache_experimenT */
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static int
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ds_open(IsoDataSource *src)
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@ -67,17 +148,23 @@ IsoDataSource *
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isoburn_data_source_new(struct burn_drive *d)
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{
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IsoDataSource *ret;
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struct isoburn_cached_drive *icd= NULL;
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if (d==NULL)
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return NULL;
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ret = malloc(sizeof(IsoDataSource));
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if (!ret)
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icd = calloc(1,sizeof(struct isoburn_cached_drive));
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if (ret == NULL || icd == NULL)
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return NULL;
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ret->refcount = 1;
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ret->read_block = ds_read_block;
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ret->open = ds_open;
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ret->close = ds_close;
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ret->free_data = ds_free_data;
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ret->data = d;
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ret->data = icd;
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icd->drive = d;
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icd->cache_lba = 0xffffffff;
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icd->cache_hits = 0;
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return ret;
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}
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@ -1 +1 @@
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#define Xorriso_timestamP "2008.02.07.074248"
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#define Xorriso_timestamP "2008.02.07.154947"
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