/*
- * Sherlock Library -- Fast Buffered I/O on Memory Streams
+ * UCW Library -- Fast Buffered I/O on Memory Streams
*
- * (c) 1997--2000 Martin Mares <mj@ucw.cz>
+ * (c) 1997--2002 Martin Mares <mj@ucw.cz>
*
* This software may be freely distributed and used according to the terms
* of the GNU Lesser General Public License.
#include "lib/fastbuf.h"
#include <stdio.h>
-#include <stdlib.h>
struct memstream {
unsigned blocksize;
struct msblock {
struct msblock *next;
+ sh_off_t pos;
unsigned size;
byte data[0];
};
+struct fb_mem {
+ struct fastbuf fb;
+ struct memstream *stream;
+ struct msblock *block;
+};
+#define FB_MEM(f) ((struct fb_mem *)(f)->is_fastbuf)
+
static int
fbmem_refill(struct fastbuf *f)
{
- struct memstream *s = f->lldata;
- struct msblock *b = f->llpos;
+ struct memstream *s = FB_MEM(f)->stream;
+ struct msblock *b = FB_MEM(f)->block;
if (!b)
{
else if (f->buffer == b->data && f->bstop < b->data + b->size)
{
f->bstop = b->data + b->size;
+ f->pos = b->pos + b->size;
return 1;
}
+ else if (!b->next)
+ return 0;
else
- {
- if (!b->next)
- return 0;
- f->pos += b->size;
- b = b->next;
- }
+ b = b->next;
if (!b->size)
return 0;
f->buffer = f->bptr = b->data;
f->bufend = f->bstop = b->data + b->size;
- f->llpos = b;
+ f->pos = b->pos + b->size;
+ FB_MEM(f)->block = b;
return 1;
}
static void
fbmem_spout(struct fastbuf *f)
{
- struct memstream *s = f->lldata;
- struct msblock *b = f->llpos;
+ struct memstream *s = FB_MEM(f)->stream;
+ struct msblock *b = FB_MEM(f)->block;
struct msblock *bb;
if (b)
b->size = f->bptr - b->data;
if (b->size < s->blocksize)
return;
- f->pos += b->size;
}
bb = xmalloc(sizeof(struct msblock) + s->blocksize);
if (b)
- b->next = bb;
+ {
+ b->next = bb;
+ bb->pos = b->pos + b->size;
+ }
else
- s->first = bb;
+ {
+ s->first = bb;
+ bb->pos = 0;
+ }
bb->next = NULL;
bb->size = 0;
f->buffer = f->bptr = f->bstop = bb->data;
f->bufend = bb->data + s->blocksize;
- f->llpos = bb;
+ f->pos = bb->pos;
+ FB_MEM(f)->block = bb;
}
-static void
+static int
fbmem_seek(struct fastbuf *f, sh_off_t pos, int whence)
{
- struct memstream *m = f->lldata;
+ struct memstream *m = FB_MEM(f)->stream;
struct msblock *b;
- unsigned int p = 0;
- /* FIXME: Milan's quick hack to allow SEEK_END */
+ ASSERT(whence == SEEK_SET || whence == SEEK_END);
if (whence == SEEK_END)
- {
- for (b=m->first; b; b=b->next)
- p += b->size;
- pos += p;
- p=0;
- whence = SEEK_SET;
- }
- /* EOQH */
-
- if (whence != SEEK_SET)
- die("fbmem_seek: only SEEK_SET supported");
+ {
+ for (b=m->first; b; b=b->next)
+ pos += b->size;
+ }
+ /* Yes, this is linear. But considering the average number of buckets, it doesn't matter. */
for (b=m->first; b; b=b->next)
{
- if ((unsigned) pos <= p + b->size) /* <=, because we need to be able to seek just after file end */
+ if (pos <= b->pos + (sh_off_t)b->size) /* <=, because we need to be able to seek just after file end */
{
- f->pos = p;
f->buffer = b->data;
- f->bptr = b->data + (pos - p);
+ f->bptr = b->data + (pos - b->pos);
f->bufend = f->bstop = b->data + b->size;
- f->llpos = b;
- return;
+ f->pos = b->pos + b->size;
+ FB_MEM(f)->block = b;
+ return 1;
}
- p += b->size;
+ }
+ if (!m->first && !pos)
+ {
+ /* Seeking to offset 0 in an empty file needs an exception */
+ f->buffer = f->bptr = f->bufend = NULL;
+ f->pos = 0;
+ FB_MEM(f)->block = NULL;
+ return 1;
}
die("fbmem_seek to invalid offset");
}
static void
fbmem_close(struct fastbuf *f)
{
- struct memstream *m = f->lldata;
+ struct memstream *m = FB_MEM(f)->stream;
struct msblock *b;
- if (--m->uc)
- return;
-
- while (b = m->first)
+ if (!--m->uc)
{
- m->first = b->next;
- xfree(b);
+ while (b = m->first)
+ {
+ m->first = b->next;
+ xfree(b);
+ }
+ xfree(m);
}
- xfree(m);
+ xfree(f);
}
struct fastbuf *
fbmem_create(unsigned blocksize)
{
- struct fastbuf *f = xmalloc_zero(sizeof(struct fastbuf));
- struct memstream *m = xmalloc_zero(sizeof(struct memstream));
+ struct fastbuf *f = xmalloc_zero(sizeof(struct fb_mem));
+ struct memstream *s = xmalloc_zero(sizeof(struct memstream));
- m->blocksize = blocksize;
- m->uc = 1;
+ s->blocksize = blocksize;
+ s->uc = 1;
+ FB_MEM(f)->stream = s;
f->name = "<fbmem-write>";
- f->lldata = m;
f->spout = fbmem_spout;
f->close = fbmem_close;
return f;
struct fastbuf *
fbmem_clone_read(struct fastbuf *b)
{
- struct fastbuf *f = xmalloc_zero(sizeof(struct fastbuf));
- struct memstream *s = b->lldata;
+ struct fastbuf *f = xmalloc_zero(sizeof(struct fb_mem));
+ struct memstream *s = FB_MEM(b)->stream;
bflush(b);
s->uc++;
+ FB_MEM(f)->stream = s;
f->name = "<fbmem-read>";
- f->lldata = s;
f->refill = fbmem_refill;
f->seek = fbmem_seek;
f->close = fbmem_close;
+ f->can_overwrite_buffer = 1;
return f;
}
r = fbmem_clone_read(w);
bwrite(w, "12345", 5);
bwrite(w, "12345", 5);
- printf("<%d>", btell(w));
+ printf("<%d>", (int)btell(w));
bflush(w);
- printf("<%d>", btell(w));
- printf("<%d>", btell(r));
+ printf("<%d>", (int)btell(w));
+ printf("<%d>", (int)btell(r));
while ((t = bgetc(r)) >= 0)
putchar(t);
- printf("<%d>", btell(r));
+ printf("<%d>", (int)btell(r));
bwrite(w, "12345", 5);
bwrite(w, "12345", 5);
- printf("<%d>", btell(w));
+ printf("<%d>", (int)btell(w));
bclose(w);
bsetpos(r, 0);
- printf("<!%d>", btell(r));
+ printf("<!%d>", (int)btell(r));
while ((t = bgetc(r)) >= 0)
putchar(t);
bsetpos(r, 3);
- printf("<!%d>", btell(r));
+ printf("<!%d>", (int)btell(r));
while ((t = bgetc(r)) >= 0)
putchar(t);
fflush(stdout);
projects / libucw.git / blobdiff