Author: Maciej Fijalkowski <[email protected]>
Branch: extradoc
Changeset: r3854:9c28e3872bf2
Date: 2011-07-31 00:44 +0200
http://bitbucket.org/pypy/extradoc/changeset/9c28e3872bf2/
Log: update
diff --git a/blog/draft/string-formatting.rst b/blog/draft/string-formatting.rst
--- a/blog/draft/string-formatting.rst
+++ b/blog/draft/string-formatting.rst
@@ -4,16 +4,19 @@
String formatting is probably something you do just about every day in Python,
and never think about. It's so easy, just ``"%d %d" % (i, i)`` and you're
done. No thinking about how to size your result buffer, whether your output
-has an appropriae NUL byte at the end, or any other details. A simple C
+has an appropriae NULL byte at the end, or any other details. A C
equivilant might be::
- char x[23];
+ char x[41];
sprintf(x, "%d %d", i, i);
-Which is fine, except you can't even return ``x`` from this function, a more
+Note that we had to stop for a second and consider how big numbers might get
+and overestimate the size (41 = length of the biggest number on 64bit + 1 for
+the sign).
+This is fine, except you can't even return ``x`` from this function, a more
fair comparison might be::
- char *x = calloc(23, sizeof(char));
+ char *x = malloc(41 * sizeof(char));
sprintf(x, "%d %d", i, i);
``x`` is slightly overallocated in some situations, but that's fine.
@@ -36,7 +39,7 @@
int main() {
int i = 0;
- char x[23];
+ char x[41];
for (i = 0; i < 10000000; i++) {
sprintf(x, "%d %d", i, i);
}
@@ -64,4 +67,4 @@
}
}
-Which as discussed above, is more comperable to the Python, takes 1.93 seconds.
\ No newline at end of file
+Which as discussed above, is more comperable to the Python, takes 1.93 seconds.
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