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    Subject[RFCv3][PATCH 1/4] replace string_get_size() arrays
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    Instead of explicitly storing the entire string for each
    possible units, just store the thing that varies: the
    first character.

    We have to special-case the 'B' unit (index==0).

    This shaves about 100 bytes off of my .o file.

    Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
    ---

    linux-2.6.git-dave/lib/string_helpers.c | 30 ++++++++++++++++++++----------
    1 file changed, 20 insertions(+), 10 deletions(-)

    diff -puN lib/string_helpers.c~string_get_size-pow2 lib/string_helpers.c
    --- linux-2.6.git/lib/string_helpers.c~string_get_size-pow2 2011-09-30 16:50:31.628981352 -0700
    +++ linux-2.6.git-dave/lib/string_helpers.c 2011-09-30 17:04:02.211607364 -0700
    @@ -8,6 +8,23 @@
    #include <linux/module.h>
    #include <linux/string_helpers.h>

    +static const char byte_units[] = "_KMGTPEZY";
    +
    +static char *__units_str(enum string_size_units unit, char *buf, int index)
    +{
    + int place = 0;
    +
    + /* index=0 is plain 'B' with no other unit */
    + if (index) {
    + buf[place++] = byte_units[index];
    + if (unit == STRING_UNITS_2)
    + buf[place++] = 'i';
    + }
    + buf[place++] = 'B';
    + buf[place++] = '\0';
    + return buf;
    +}
    +
    /**
    * string_get_size - get the size in the specified units
    * @size: The size to be converted
    @@ -23,26 +40,19 @@
    int string_get_size(u64 size, const enum string_size_units units,
    char *buf, int len)
    {
    - const char *units_10[] = { "B", "kB", "MB", "GB", "TB", "PB",
    - "EB", "ZB", "YB", NULL};
    - const char *units_2[] = {"B", "KiB", "MiB", "GiB", "TiB", "PiB",
    - "EiB", "ZiB", "YiB", NULL };
    - const char **units_str[] = {
    - [STRING_UNITS_10] = units_10,
    - [STRING_UNITS_2] = units_2,
    - };
    const unsigned int divisor[] = {
    [STRING_UNITS_10] = 1000,
    [STRING_UNITS_2] = 1024,
    };
    int i, j;
    u64 remainder = 0, sf_cap;
    + char unit_buf[4];
    char tmp[8];

    tmp[0] = '\0';
    i = 0;
    if (size >= divisor[units]) {
    - while (size >= divisor[units] && units_str[units][i]) {
    + while (size >= divisor[units] && (i < strlen(byte_units))) {
    remainder = do_div(size, divisor[units]);
    i++;
    }
    @@ -61,7 +71,7 @@ int string_get_size(u64 size, const enum
    }

    snprintf(buf, len, "%lld%s %s", (unsigned long long)size,
    - tmp, units_str[units][i]);
    + tmp, __units_str(units, unit_buf, i));

    return 0;
    }
    diff -puN include/linux/string_helpers.h~string_get_size-pow2 include/linux/string_helpers.h
    _


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