diff options
Diffstat (limited to 'nuttx/fs/fat/fs_fat32util.c')
| -rw-r--r-- | nuttx/fs/fat/fs_fat32util.c | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/nuttx/fs/fat/fs_fat32util.c b/nuttx/fs/fat/fs_fat32util.c index c70c4cb1e..c6680b6f0 100644 --- a/nuttx/fs/fat/fs_fat32util.c +++ b/nuttx/fs/fat/fs_fat32util.c @@ -986,11 +986,11 @@ ssize_t fat_getcluster(struct fat_mountpt_s *fs, uint32 clusterno) /**************************************************************************** * Name: fat_putcluster * - * Desciption: Write a new cluster start sector into the FAT + * Desciption: Write a new cluster into the FAT * ****************************************************************************/ -int fat_putcluster(struct fat_mountpt_s *fs, uint32 clusterno, size_t startsector) +int fat_putcluster(struct fat_mountpt_s *fs, uint32 clusterno, size_t nextcluster) { /* Verify that the cluster number is within range. Zero erases the cluster. */ @@ -1021,21 +1021,26 @@ int fat_putcluster(struct fat_mountpt_s *fs, uint32 clusterno, size_t startsecto if (fat_fscacheread(fs, fatsector)< 0) { /* Read error */ + break; } - /* Output the LS byte first handling the 12-bit alignment within + /* Get the LS byte first handling the 12-bit alignment within * the 16-bits */ fatindex = fatoffset & SEC_NDXMASK(fs); if ((clusterno & 1) != 0) { - value = (fs->fs_buffer[fatindex] & 0x0f) | startsector << 4; + /* Save the LS four bits of the next cluster */ + + value = (fs->fs_buffer[fatindex] & 0x0f) | nextcluster << 4; } else { - value = (ubyte)startsector; + /* Save the LS eight bits of the next cluster */ + + value = (ubyte)nextcluster; } fs->fs_buffer[fatindex] = value; @@ -1069,11 +1074,15 @@ int fat_putcluster(struct fat_mountpt_s *fs, uint32 clusterno, size_t startsecto if ((clusterno & 1) != 0) { - value = (ubyte)(startsector >> 4); + /* Save the MS eight bits of the next cluster */ + + value = (ubyte)(nextcluster >> 4); } else { - value = (fs->fs_buffer[fatindex] & 0xf0) | (startsector & 0x0f); + /* Save the MS four bits of the next cluster */ + + value = (fs->fs_buffer[fatindex] & 0xf0) | ((nextcluster >> 8) & 0x0f); } fs->fs_buffer[fatindex] = value; } @@ -1090,7 +1099,7 @@ int fat_putcluster(struct fat_mountpt_s *fs, uint32 clusterno, size_t startsecto /* Read error */ break; } - FAT_PUTFAT16(fs->fs_buffer, fatindex, startsector & 0xffff); + FAT_PUTFAT16(fs->fs_buffer, fatindex, nextcluster & 0xffff); } break; @@ -1105,7 +1114,7 @@ int fat_putcluster(struct fat_mountpt_s *fs, uint32 clusterno, size_t startsecto /* Read error */ break; } - FAT_PUTFAT32(fs->fs_buffer, fatindex, startsector & 0x0fffffff); + FAT_PUTFAT32(fs->fs_buffer, fatindex, nextcluster & 0x0fffffff); } break; @@ -1213,16 +1222,19 @@ sint32 fat_extendchain(struct fat_mountpt_s *fs, uint32 cluster) if (startsector < 0) { /* An error occurred, return the error value */ + return startsector; } else if (startsector < 2) { + /* Oops.. this cluster does not exist. */ return 0; } else if (startsector < fs->fs_nclusters) { /* It is already followed by next cluster */ + return startsector; } |