From 94c4eac0cbc32475fedca1fec0259036599baa84 Mon Sep 17 00:00:00 2001 From: Michael Chisholm Date: Sat, 22 Nov 2008 13:37:16 +0000 Subject: [PATCH] Read/write contigious clusters in one operation to improve speed. --- source/common.h | 2 ++ source/disc.h | 10 +++--- source/fatfile.c | 81 ++++++++++++++++++++++++++++++++---------------- 3 files changed, 63 insertions(+), 30 deletions(-) diff --git a/source/common.h b/source/common.h index 354c689..1800fbe 100644 --- a/source/common.h +++ b/source/common.h @@ -67,8 +67,10 @@ #elif defined (NDS) #define DEFAULT_CACHE_PAGES 8 #define USE_RTC_TIME + #define LIMIT_SECTORS 128 #elif defined (GBA) #define DEFAULT_CACHE_PAGES 2 + #define LIMIT_SECTORS 128 #endif #endif // _COMMON_H diff --git a/source/disc.h b/source/disc.h index d9f3c04..5c955f9 100644 --- a/source/disc.h +++ b/source/disc.h @@ -51,8 +51,9 @@ static inline bool _FAT_disc_isInserted (const DISC_INTERFACE* disc) { /* Read numSectors sectors from a disc, starting at sector. -numSectors is between 1 and 256 -sector is from 0 to 2^28 +numSectors is between 1 and LIMIT_SECTORS if LIMIT_SECTORS is defined, +else it is at least 1 +sector is 0 or greater buffer is a pointer to the memory to fill */ static inline bool _FAT_disc_readSectors (const DISC_INTERFACE* disc, sec_t sector, sec_t numSectors, void* buffer) { @@ -61,8 +62,9 @@ static inline bool _FAT_disc_readSectors (const DISC_INTERFACE* disc, sec_t sect /* Write numSectors sectors to a disc, starting at sector. -numSectors is between 1 and 256 -sector is from 0 to 2^28 +numSectors is between 1 and LIMIT_SECTORS if LIMIT_SECTORS is defined, +else it is at least 1 +sector is 0 or greater buffer is a pointer to the memory to read from */ static inline bool _FAT_disc_writeSectors (const DISC_INTERFACE* disc, sec_t sector, sec_t numSectors, const void* buffer) { diff --git a/source/fatfile.c b/source/fatfile.c index 6b8fa8d..0132204 100644 --- a/source/fatfile.c +++ b/source/fatfile.c @@ -329,6 +329,7 @@ int _FAT_close_r (struct _reent *r, int fd) { return ret; } + ssize_t _FAT_read_r (struct _reent *r, int fd, char *ptr, size_t len) { FILE_STRUCT* file = (FILE_STRUCT*) fd; PARTITION* partition; @@ -426,29 +427,42 @@ ssize_t _FAT_read_r (struct _reent *r, int fd, char *ptr, size_t len) { } } - // Read in whole clusters + // Read in whole clusters, contiguous blocks at a time while ((remain >= partition->bytesPerCluster) && flagNoError) { - if ( !_FAT_disc_readSectors ( - partition->disc, _FAT_fat_clusterToSector (partition, position.cluster), - partition->sectorsPerCluster, ptr)) + uint32_t chunkEnd; + uint32_t nextChunkStart = position.cluster; + size_t chunkSize = 0; + + do { + chunkEnd = nextChunkStart; + nextChunkStart = _FAT_fat_nextCluster (partition, chunkEnd); + chunkSize += partition->bytesPerCluster; + } while ((nextChunkStart == chunkEnd + 1) && +#ifdef LIMIT_SECTORS + (chunkSize + partition->bytesPerCluster <= LIMIT_SECTORS * BYTES_PER_READ) && +#endif + (chunkSize + partition->bytesPerCluster <= remain)); + + if (!_FAT_disc_readSectors (partition->disc, _FAT_fat_clusterToSector (partition, position.cluster), + chunkSize / BYTES_PER_READ, ptr)) { flagNoError = false; r->_errno = EIO; break; } - ptr += partition->bytesPerCluster; - remain -= partition->bytesPerCluster; + ptr += chunkSize; + remain -= chunkSize; // Advance to next cluster - tempNextCluster = _FAT_fat_nextCluster(partition, position.cluster); - if ((remain == 0) && (tempNextCluster == CLUSTER_EOF)) { + if ((remain == 0) && (nextChunkStart == CLUSTER_EOF)) { position.sector = partition->sectorsPerCluster; - } else if (!_FAT_fat_isValidCluster(partition, tempNextCluster)) { + position.cluster = chunkEnd; + } else if (!_FAT_fat_isValidCluster(partition, nextChunkStart)) { r->_errno = EIO; flagNoError = false; } else { position.sector = 0; - position.cluster = tempNextCluster; + position.cluster = nextChunkStart; } } @@ -735,30 +749,45 @@ ssize_t _FAT_write_r (struct _reent *r, int fd, const char *ptr, size_t len) { // Write whole clusters while ((remain >= partition->bytesPerCluster) && flagNoError) { + uint32_t chunkEnd; + uint32_t nextChunkStart = position.cluster; + size_t chunkSize = 0; + + do { + chunkEnd = nextChunkStart; + nextChunkStart = _FAT_fat_nextCluster (partition, chunkEnd); + if ((nextChunkStart == CLUSTER_EOF) || (nextChunkStart == CLUSTER_FREE)) { + // Ran out of clusters so get a new one + nextChunkStart = _FAT_fat_linkFreeCluster(partition, chunkEnd); + } + if (!_FAT_fat_isValidCluster(partition, nextChunkStart)) { + // Couldn't get a cluster, so abort + r->_errno = ENOSPC; + flagNoError = false; + } else { + chunkSize += partition->bytesPerCluster; + } + } while (flagNoError && (nextChunkStart == chunkEnd + 1) && +#ifdef LIMIT_SECTORS + (chunkSize + partition->bytesPerCluster <= LIMIT_SECTORS * BYTES_PER_READ) && +#endif + (chunkSize + partition->bytesPerCluster <= remain)); + if ( !_FAT_disc_writeSectors (partition->disc, _FAT_fat_clusterToSector(partition, position.cluster), - partition->sectorsPerCluster, ptr)) + chunkSize / BYTES_PER_READ, ptr)) { flagNoError = false; r->_errno = EIO; break; } - ptr += partition->bytesPerCluster; - remain -= partition->bytesPerCluster; - if (remain > 0) { - tempNextCluster = _FAT_fat_nextCluster(partition, position.cluster); - if ((tempNextCluster == CLUSTER_EOF) || (tempNextCluster == CLUSTER_FREE)) { - // Ran out of clusters so get a new one - tempNextCluster = _FAT_fat_linkFreeCluster(partition, position.cluster); - } - if (!_FAT_fat_isValidCluster(partition, tempNextCluster)) { - // Couldn't get a cluster, so abort - r->_errno = ENOSPC; - flagNoError = false; - } else { - position.cluster = tempNextCluster; - } + ptr += chunkSize; + remain -= chunkSize; + + if (_FAT_fat_isValidCluster(partition, nextChunkStart)) { + position.cluster = nextChunkStart; } else { // Allocate a new cluster when next writing the file + position.cluster = chunkEnd; position.sector = partition->sectorsPerCluster; } }