Re: [9fans] realloc

[rog@vitanuova.com]

> This code cause my problem...

i'm not surprised, i'm afraid. this is really horrible code.
you need to sort out your ideas about how C pointers work.
for instance, given that Text is an array of runes,

		*((Rune*)(Text+text_pos))=r;

is exactly equivalent to:

		Text[text_pos] = r;

i haven't time to work out exactly how you're going wrong,
(you *are* scribbling over the end of a malloc block)
but here's a likely candidate:

	memmove(Text+text_pos+2,Text+text_pos,text_count-text_pos);

you're using text_pos in two different ways here:
as an index into a array of Runes, and as a byte offset
as expected by memmove.

i *think* you're probably trying to write code something like:

	if(text_count >= msize(Text) / sizeof(Rune))
		Text = realloc(Text, (text_count+BLOCKSIZE)*sizeof(Rune));
	memmove(Text+textpos+1, Text+textpos, (text_count-text_pos)*sizeof(Rune));
	Text[text_pos] = r;
	text_pos++;
	text_count++;

which seems to work ok.

if you're going to write Plan 9 code, it would a good idea to look at
some existing Plan 9 code (try /sys/src/cmd, for starters) and copy
the style, as far as you can, in particular regarding naming
conventions and code layout.  there's loads of inspiration there.  it
*is* possible to write simple, understandable code.

  cheers,
    rog.