57 lines
1.5 KiB
Diff
57 lines
1.5 KiB
Diff
From f1fc04d7609ab074647aa00e96d4c66d5135b155 Mon Sep 17 00:00:00 2001
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From: Michael Heimpold <michael.heimpold@i2se.com>
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Date: Tue, 18 Dec 2018 15:02:25 +0100
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Subject: [PATCH 4/9] Optimize to_binstr() function
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Appending multiple times to same string is slow since strcat() needs
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to determine the end during each run. So manually maintain a pointer
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to the end to speed-up things.
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Signed-off-by: Michael Heimpold <michael.heimpold@i2se.com>
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Cc: Michael Heimpold <mhei@heimpold.de>
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---
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lsmmc.c | 11 +++++++----
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1 file changed, 7 insertions(+), 4 deletions(-)
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diff --git a/lsmmc.c b/lsmmc.c
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index e64117c..86713f7 100644
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--- a/lsmmc.c
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+++ b/lsmmc.c
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@@ -371,12 +371,14 @@ char *to_binstr(char *hexstr)
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"0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111",
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"1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111",
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};
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- char *binstr;
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+ char *binstr, *tail;
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binstr = calloc(strlen(hexstr) * 4 + 1, sizeof(char));
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if (!binstr)
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return NULL;
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+ tail = binstr;
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+
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while (hexstr && *hexstr != '\0') {
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if (!isxdigit(*hexstr)) {
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free(binstr);
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@@ -384,13 +386,14 @@ char *to_binstr(char *hexstr)
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}
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if (isdigit(*hexstr))
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- strcat(binstr, bindigits[*hexstr - '0']);
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+ strcat(tail, bindigits[*hexstr - '0']);
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else if (islower(*hexstr))
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- strcat(binstr, bindigits[*hexstr - 'a' + 10]);
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+ strcat(tail, bindigits[*hexstr - 'a' + 10]);
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else
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- strcat(binstr, bindigits[*hexstr - 'A' + 10]);
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+ strcat(tail, bindigits[*hexstr - 'A' + 10]);
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hexstr++;
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+ tail += 4;
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}
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return binstr;
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--
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2.17.1
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