diff options
Diffstat (limited to 'fs/ntfs3/lznt.c')
| -rw-r--r-- | fs/ntfs3/lznt.c | 86 |
1 files changed, 43 insertions, 43 deletions
diff --git a/fs/ntfs3/lznt.c b/fs/ntfs3/lznt.c index eb43b9f5149b..3acf0d9f0b15 100644 --- a/fs/ntfs3/lznt.c +++ b/fs/ntfs3/lznt.c @@ -4,6 +4,7 @@ * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved. * */ + #include <linux/blkdev.h> #include <linux/buffer_head.h> #include <linux/fs.h> @@ -14,7 +15,7 @@ #include "ntfs_fs.h" // clang-format off -/* src buffer is zero */ +/* Src buffer is zero. */ #define LZNT_ERROR_ALL_ZEROS 1 #define LZNT_CHUNK_SIZE 0x1000 // clang-format on @@ -72,7 +73,7 @@ static size_t longest_match_std(const u8 *src, struct lznt *ctx) hash[1] + 3, ctx->max_len - 3); } - /* Compare two matches and select the best one */ + /* Compare two matches and select the best one. */ if (len1 < len2) { ctx->best_match = hash[1]; len1 = len2; @@ -129,10 +130,10 @@ static inline size_t parse_pair(u16 pair, size_t *offset, size_t index) /* * compress_chunk * - * returns one of the three values: - * 0 - ok, 'cmpr' contains 'cmpr_chunk_size' bytes of compressed data - * 1 - input buffer is full zero - * -2 - the compressed buffer is too small to hold the compressed data + * Return: + * * 0 - Ok, @cmpr contains @cmpr_chunk_size bytes of compressed data. + * * 1 - Input buffer is full zero. + * * -2 - The compressed buffer is too small to hold the compressed data. */ static inline int compress_chunk(size_t (*match)(const u8 *, struct lznt *), const u8 *unc, const u8 *unc_end, u8 *cmpr, @@ -145,7 +146,7 @@ static inline int compress_chunk(size_t (*match)(const u8 *, struct lznt *), u8 *cp = cmpr + 3; u8 *cp2 = cmpr + 2; u8 not_zero = 0; - /* Control byte of 8-bit values: ( 0 - means byte as is, 1 - short pair ) */ + /* Control byte of 8-bit values: ( 0 - means byte as is, 1 - short pair ). */ u8 ohdr = 0; u8 *last; u16 t16; @@ -165,7 +166,7 @@ static inline int compress_chunk(size_t (*match)(const u8 *, struct lznt *), while (unc + s_max_off[idx] < up) ctx->max_len = s_max_len[++idx]; - // Find match + /* Find match. */ max_len = up + 3 <= unc_end ? (*match)(up, ctx) : 0; if (!max_len) { @@ -211,7 +212,7 @@ NotCompressed: return -2; /* - * Copy non cmpr data + * Copy non cmpr data. * 0x3FFF == ((LZNT_CHUNK_SIZE + 2 - 3) | 0x3000) */ cmpr[0] = 0xff; @@ -233,38 +234,38 @@ static inline ssize_t decompress_chunk(u8 *unc, u8 *unc_end, const u8 *cmpr, u16 pair; size_t offset, length; - /* Do decompression until pointers are inside range */ + /* Do decompression until pointers are inside range. */ while (up < unc_end && cmpr < cmpr_end) { /* Correct index */ while (unc + s_max_off[index] < up) index += 1; - /* Check the current flag for zero */ + /* Check the current flag for zero. */ if (!(ch & (1 << bit))) { - /* Just copy byte */ + /* Just copy byte. */ *up++ = *cmpr++; goto next; } - /* Check for boundary */ + /* Check for boundary. */ if (cmpr + 1 >= cmpr_end) return -EINVAL; - /* Read a short from little endian stream */ + /* Read a short from little endian stream. */ pair = cmpr[1]; pair <<= 8; pair |= cmpr[0]; cmpr += 2; - /* Translate packed information into offset and length */ + /* Translate packed information into offset and length. */ length = parse_pair(pair, &offset, index); - /* Check offset for boundary */ + /* Check offset for boundary. */ if (unc + offset > up) return -EINVAL; - /* Truncate the length if necessary */ + /* Truncate the length if necessary. */ if (up + length >= unc_end) length = unc_end - up; @@ -273,7 +274,7 @@ static inline ssize_t decompress_chunk(u8 *unc, u8 *unc_end, const u8 *cmpr, *up = *(up - offset); next: - /* Advance flag bit value */ + /* Advance flag bit value. */ bit = (bit + 1) & 7; if (!bit) { @@ -284,13 +285,14 @@ next: } } - /* return the size of uncompressed data */ + /* Return the size of uncompressed data. */ return up - unc; } /* - * 0 - standard compression - * !0 - best compression, requires a lot of cpu + * get_lznt_ctx + * @level: 0 - Standard compression. + * !0 - Best compression, requires a lot of cpu. */ struct lznt *get_lznt_ctx(int level) { @@ -303,11 +305,11 @@ struct lznt *get_lznt_ctx(int level) } /* - * compress_lznt + * compress_lznt - Compresses @unc into @cmpr * - * Compresses "unc" into "cmpr" - * +x - ok, 'cmpr' contains 'final_compressed_size' bytes of compressed data - * 0 - input buffer is full zero + * Return: + * * +x - Ok, @cmpr contains 'final_compressed_size' bytes of compressed data. + * * 0 - Input buffer is full zero. */ size_t compress_lznt(const void *unc, size_t unc_size, void *cmpr, size_t cmpr_size, struct lznt *ctx) @@ -327,7 +329,7 @@ size_t compress_lznt(const void *unc, size_t unc_size, void *cmpr, match = &longest_match_best; } - /* compression cycle */ + /* Compression cycle. */ for (; unc_chunk < unc_end; unc_chunk += LZNT_CHUNK_SIZE) { cmpr_size = 0; err = compress_chunk(match, unc_chunk, unc_end, p, end, @@ -348,9 +350,7 @@ size_t compress_lznt(const void *unc, size_t unc_size, void *cmpr, } /* - * decompress_lznt - * - * decompresses "cmpr" into "unc" + * decompress_lznt - Decompress @cmpr into @unc. */ ssize_t decompress_lznt(const void *cmpr, size_t cmpr_size, void *unc, size_t unc_size) @@ -364,24 +364,24 @@ ssize_t decompress_lznt(const void *cmpr, size_t cmpr_size, void *unc, if (cmpr_size < sizeof(short)) return -EINVAL; - /* read chunk header */ + /* Read chunk header. */ chunk_hdr = cmpr_chunk[1]; chunk_hdr <<= 8; chunk_hdr |= cmpr_chunk[0]; - /* loop through decompressing chunks */ + /* Loop through decompressing chunks. */ for (;;) { size_t chunk_size_saved; size_t unc_use; size_t cmpr_use = 3 + (chunk_hdr & (LZNT_CHUNK_SIZE - 1)); - /* Check that the chunk actually fits the supplied buffer */ + /* Check that the chunk actually fits the supplied buffer. */ if (cmpr_chunk + cmpr_use > cmpr_end) return -EINVAL; - /* First make sure the chunk contains compressed data */ + /* First make sure the chunk contains compressed data. */ if (chunk_hdr & 0x8000) { - /* Decompress a chunk and return if we get an error */ + /* Decompress a chunk and return if we get an error. */ ssize_t err = decompress_chunk(unc_chunk, unc_end, cmpr_chunk + sizeof(chunk_hdr), @@ -390,7 +390,7 @@ ssize_t decompress_lznt(const void *cmpr, size_t cmpr_size, void *unc, return err; unc_use = err; } else { - /* This chunk does not contain compressed data */ + /* This chunk does not contain compressed data. */ unc_use = unc_chunk + LZNT_CHUNK_SIZE > unc_end ? unc_end - unc_chunk : LZNT_CHUNK_SIZE; @@ -404,21 +404,21 @@ ssize_t decompress_lznt(const void *cmpr, size_t cmpr_size, void *unc, unc_use); } - /* Advance pointers */ + /* Advance pointers. */ cmpr_chunk += cmpr_use; unc_chunk += unc_use; - /* Check for the end of unc buffer */ + /* Check for the end of unc buffer. */ if (unc_chunk >= unc_end) break; - /* Proceed the next chunk */ + /* Proceed the next chunk. */ if (cmpr_chunk > cmpr_end - 2) break; chunk_size_saved = LZNT_CHUNK_SIZE; - /* read chunk header */ + /* Read chunk header. */ chunk_hdr = cmpr_chunk[1]; chunk_hdr <<= 8; chunk_hdr |= cmpr_chunk[0]; @@ -426,12 +426,12 @@ ssize_t decompress_lznt(const void *cmpr, size_t cmpr_size, void *unc, if (!chunk_hdr) break; - /* Check the size of unc buffer */ + /* Check the size of unc buffer. */ if (unc_use < chunk_size_saved) { size_t t1 = chunk_size_saved - unc_use; u8 *t2 = unc_chunk + t1; - /* 'Zero' memory */ + /* 'Zero' memory. */ if (t2 >= unc_end) break; @@ -440,13 +440,13 @@ ssize_t decompress_lznt(const void *cmpr, size_t cmpr_size, void *unc, } } - /* Check compression boundary */ + /* Check compression boundary. */ if (cmpr_chunk > cmpr_end) return -EINVAL; /* * The unc size is just a difference between current - * pointer and original one + * pointer and original one. */ return PtrOffset(unc, unc_chunk); } |