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|
#include <u.h>
#include <base.h>
// -----------------------------------------------------------------------
// reader
error
bufio·initreader(io·Buffer *buf, io·Reader rdr, void *h)
{
if (buf->state) {
errorf("attemped to initialize an active buffer, state is '%d'", buf->state);
return bufio·err;
}
buf->state = bufio·rdr;
buf->runesize = 0;
buf->h = h;
buf->rdr = rdr;
buf->beg = buf->buf + bufio·ungets;
buf->pos = buf->beg;
buf->end = buf->pos;
buf->size = bufio·size - bufio·ungets;
return 0;
}
void
bufio·finireader(io·Buffer *buf)
{
buf->state = bufio·nil;
buf->runesize = 0;
buf->rdr = (io·Reader){ .read = nil };
}
static
int
refill(io·Buffer *buf)
{
int n;
if (buf->state & bufio·end) {
return bufio·err;
}
memcpy(buf->buf, buf->pos - bufio·ungets, bufio·ungets);
n = buf->rdr.read(buf->h, 1, buf->size, buf->beg);
if (n < 0)
return bufio·err;
if (n == 0) {
buf->state |= bufio·end;
return 0;
}
buf->pos = buf->beg;
buf->end = buf->pos + n;
// TEST: put a physical EOF byte at the end
// this would allow for an unget operation
if (n < buf->size)
*buf->end++ = EOF;
return n;
}
int
bufio·getbyte(io·Buffer *buf)
{
getbyte:
if (buf->pos < buf->end) {
return *buf->pos++;
}
memmove(buf->buf, buf->end - bufio·ungets, bufio·ungets);
if (refill(buf) <= 0)
return bufio·eof;
goto getbyte;
}
error
bufio·ungetbyte(io·Buffer *buf, byte c)
{
if (!(buf->state & bufio·rdr)) {
errorf("attempted to unget on non-active reader");
return bufio·err;
}
if (buf->pos == buf->buf) {
errorf("attempted to unget past end of buffer");
return bufio·err;
}
buf->pos--;
return 0;
}
#if 0
rune
bufio·getrune(io·Buffer *buf)
{
ubyte b;
int i;
byte str[UTFmax+1];
rune r;
// NOTE: I'm worried about the sign here...
b = bufio·getbyte(buf);
if (b < RuneSelf) {
buf->runesize = 1;
return b;
}
i = 0;
str[i++] = b;
nextbyte:
b = bufio·getbyte(buf);
if (b < 0) return b;
if (i >= arrlen(str)) return RuneErr;
str[i++] = b;
if (!utf8·fullrune(str, i))
goto nextbyte;
buf->runesize = utf8·bytetorune(&r, str);
if (r == RuneErr && b == 1) {
errorf("illegal UTF-8 sequence");
for (; i >= 0; i--)
errorf("%s%.2x", i > 0 ? " " : "", *(ubyte*)(str+i));
errorf("\n");
buf->runesize = 0;
} else
for (; i > buf->runesize; i--)
bufio·ungetbyte(buf, str[i]);
return r;
}
// TODO: Check that we are given the correct rune!
error
bufio·ungetrune(io·Buffer *buf, rune r)
{
if (buf->state & bufio·rdr) {
errorf("attempted to unget on non-active reader");
return bufio·err;
}
if (buf->pos == buf->buf) {
errorf("attempted to unget past end of buffer");
return bufio·err;
}
buf->pos -= buf->runesize;
return 0;
}
#endif
int
bufio·read(io·Buffer *buf, int sz, int n, void *out)
{
byte *wtr;
int nr, rem, diff;
if (n == 0 || buf->state & bufio·end)
return bufio·err;
assert(buf->state & bufio·rdr);
wtr = out;
rem = n*sz;
while (rem > 0) {
diff = buf->end - buf->pos;
nr = MIN(diff, rem);
if (!nr) {
if (buf->state & bufio·end)
break;
if (refill(buf) <= 0)
break;
continue;
}
memmove(wtr, buf->pos, nr);
wtr += nr;
buf->pos += nr;
rem -= nr;
}
return n - rem/sz;
}
// -----------------------------------------------------------------------
// writer
|
