Messages in this thread Patch in this message | | | Date | Mon, 25 Jun 2007 14:11:58 +0200 (CEST) | From | Roman Zippel <> | Subject | Re: [patch 1/2] HFS+: Refactor ASCII to unicode conversion routine for later reuse |
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Hi,
On Wed, 20 Jun 2007, Duane Griffin wrote:
> Refactor existing HFS+ ASCII to unicode string conversion routine to > split out character conversion functionality. This will be reused by > the custom dentry hash and comparison routines. This approach avoids > unnecessary memory allocation compared to using the string conversion > routine directly in the new functions.
I like the idea of this, but not that it generates larger code, so I reformatted it a little to get rid of the decomposed_uc struct which required an unnecessary data copy, so now the it even generates slightly smaller code. :)
bye, Roman
From: Duane Griffin <duaneg@dghda.com>
Refactor existing HFS+ ASCII to unicode string conversion routine to split out character conversion functionality. This will be reused by the custom dentry hash and comparison routines. This approach avoids unnecessary memory allocation compared to using the string conversion routine directly in the new functions.
Signed-off-by: Duane Griffin <duaneg@dghda.com> Signed-off-by: Roman Zippel <zippel@linux-m68k.org> --- fs/hfsplus/unicode.c | 105 +++++++++++++++++++++++++++++---------------------- 1 file changed, 60 insertions(+), 45 deletions(-)
Index: linux-2.6/fs/hfsplus/unicode.c =================================================================== --- linux-2.6.orig/fs/hfsplus/unicode.c +++ linux-2.6/fs/hfsplus/unicode.c @@ -239,58 +239,73 @@ out: return res; } -int hfsplus_asc2uni(struct super_block *sb, struct hfsplus_unistr *ustr, const char *astr, int len) +/* + * Convert one or more ASCII characters into a single unicode character. + * Returns the number of ASCII characters corresponding to the unicode char. + */ +static inline int asc2unichar(struct super_block *sb, const char *astr, int len, + wchar_t *uc) { - struct nls_table *nls = HFSPLUS_SB(sb).nls; - int size, off, decompose; + int size = HFSPLUS_SB(sb).nls->char2uni(astr, len, uc); + if (size <= 0) { + *uc = '?'; + size = 1; + } + switch (*uc) { + case 0x2400: + *uc = 0; + break; + case ':': + *uc = '/'; + break; + } + return size; +} + +/* Decomposes a single unicode character. */ +static inline u16 *decompose_unichar(wchar_t uc, int *size) +{ + int off; + + off = hfsplus_decompose_table[(uc >> 12) & 0xf]; + if (off == 0 || off == 0xffff) + return NULL; + + off = hfsplus_decompose_table[off + ((uc >> 8) & 0xf)]; + if (!off) + return NULL; + + off = hfsplus_decompose_table[off + ((uc >> 4) & 0xf)]; + if (!off) + return NULL; + + off = hfsplus_decompose_table[off + (uc & 0xf)]; + *size = off & 3; + return hfsplus_decompose_table + (off / 4); +} + +int hfsplus_asc2uni(struct super_block *sb, struct hfsplus_unistr *ustr, + const char *astr, int len) +{ + int size, dsize, decompose; + u16 *dstr, outlen = 0; wchar_t c; - u16 outlen = 0; decompose = !(HFSPLUS_SB(sb).flags & HFSPLUS_SB_NODECOMPOSE); - while (outlen < HFSPLUS_MAX_STRLEN && len > 0) { - size = nls->char2uni(astr, len, &c); - if (size <= 0) { - c = '?'; - size = 1; - } - astr += size; - len -= size; - switch (c) { - case 0x2400: - c = 0; - break; - case ':': - c = '/'; - break; - } - if (c >= 0xc0 && decompose) { - off = hfsplus_decompose_table[(c >> 12) & 0xf]; - if (!off) - goto done; - if (off == 0xffff) { - goto done; - } - off = hfsplus_decompose_table[off + ((c >> 8) & 0xf)]; - if (!off) - goto done; - off = hfsplus_decompose_table[off + ((c >> 4) & 0xf)]; - if (!off) - goto done; - off = hfsplus_decompose_table[off + (c & 0xf)]; - size = off & 3; - if (!size) - goto done; - off /= 4; - if (outlen + size > HFSPLUS_MAX_STRLEN) + size = asc2unichar(sb, astr, len, &c); + + if (decompose && (dstr = decompose_unichar(c, &dsize))) { + if (outlen + dsize > HFSPLUS_MAX_STRLEN) break; do { - ustr->unicode[outlen++] = cpu_to_be16(hfsplus_decompose_table[off++]); - } while (--size > 0); - continue; - } - done: - ustr->unicode[outlen++] = cpu_to_be16(c); + ustr->unicode[outlen++] = cpu_to_be16(*dstr++); + } while (--dsize > 0); + } else + ustr->unicode[outlen++] = cpu_to_be16(c); + + astr += size; + len -= size; } ustr->length = cpu_to_be16(outlen); if (len > 0) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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