commit f757761b310a899dc8ece7ad7845ed0a22ff752b
Author: Mattias Andrée <[email protected]>
AuthorDate: Thu Jan 26 07:26:42 2017 +0100
Commit: Mattias Andrée <[email protected]>
CommitDate: Thu Jan 26 07:26:42 2017 +0100
Add blind-compress and blind-decompress
Signed-off-by: Mattias Andrée <[email protected]>
diff --git a/src/blind-compress.c b/src/blind-compress.c
new file mode 100644
index 0000000..768ef06
--- /dev/null
+++ b/src/blind-compress.c
@@ -0,0 +1,69 @@
+/* See LICENSE file for copyright and license details. */
+#include "stream.h"
+#include "util.h"
+
+#include <string.h>
+#include <unistd.h>
+
+USAGE("")
+
+static size_t
+compare(const char *restrict new, const char *restrict old, size_t n, size_t
**cmp, size_t *cmpsize)
+{
+ size_t i, start1, start2, ptr, same, diff;
+ for (ptr = i = 0; i < n;) {
+ for (start1 = i; i < n && old[i] == new[i]; i++);
+ for (start2 = i; i < n && old[i] != new[i]; i++);
+ same = start2 - start1;
+ diff = i - start2;
+ if (ptr && same < 2 * sizeof(size_t) && same + diff <= SIZE_MAX
- (*cmp)[ptr - 1]) {
+ (*cmp)[ptr - 1] += same + diff;
+ } else {
+ if (ptr + 2 > *cmpsize)
+ *cmp = erealloc(*cmp, (*cmpsize += 128) *
sizeof(size_t));
+ (*cmp)[ptr++] = same;
+ (*cmp)[ptr++] = diff;
+ }
+ }
+ return ptr;
+}
+
+int
+main(int argc, char *argv[])
+{
+ struct stream stream;
+ char *buf[2];
+ size_t n, parts, part, off;
+ int i;
+ size_t *cmp = NULL;
+ size_t cmpsize = 0;
+
+ ENOFLAGS(argc);
+
+ stream.file = "<stdin>";
+ stream.fd = STDIN_FILENO;
+ einit_stream(&stream);
+ fprint_stream_head(stdout, &stream);
+ efflush(stdout, "<stdout>");
+
+ echeck_frame_size(stream.width, stream.height, stream.pixel_size, 0,
"<stdin>");
+ n = stream.width * stream.height * stream.pixel_size;
+ buf[0] = emalloc(n);
+ buf[1] = ecalloc(1, n);
+
+ memcpy(buf[0], stream.buf, stream.ptr);
+ for (i = 0; eread_frame(&stream, buf[i], n); i ^= 1) {
+ parts = compare(buf[i], buf[i ^ 1], n, &cmp, &cmpsize);
+ for (off = part = 0; part < parts; part += 2) {
+ off += cmp[part];
+ ewriteall(STDOUT_FILENO, cmp + part, 2 *
sizeof(size_t), "<stdout>");
+ ewriteall(STDOUT_FILENO, buf[i] + off, cmp[part + 1],
"<stdout>");
+ off += cmp[part + 1];
+ }
+ }
+
+ free(cmp);
+ free(buf[0]);
+ free(buf[1]);
+ return 0;
+}
diff --git a/src/blind-decompress.c b/src/blind-decompress.c
new file mode 100644
index 0000000..ea24fc6
--- /dev/null
+++ b/src/blind-decompress.c
@@ -0,0 +1,64 @@
+/* See LICENSE file for copyright and license details. */
+#include "stream.h"
+#include "util.h"
+
+#include <string.h>
+#include <unistd.h>
+
+USAGE("")
+
+int
+main(int argc, char *argv[])
+{
+ struct stream stream;
+ char *buf;
+ size_t n, m, fptr, sptr, same = 0, diff = 0;
+
+ ENOFLAGS(argc);
+
+ stream.file = "<stdin>";
+ stream.fd = STDIN_FILENO;
+ einit_stream(&stream);
+ fprint_stream_head(stdout, &stream);
+ efflush(stdout, "<stdout>");
+
+ echeck_frame_size(stream.width, stream.height, stream.pixel_size, 0,
"<stdin>");
+ n = stream.width * stream.height * stream.pixel_size;
+ buf = ecalloc(1, n);
+
+ fptr = 0;
+ do {
+ sptr = 0;
+ again:
+ while (same) {
+ m = same < n - fptr ? same : n - fptr;
+ ewriteall(STDOUT_FILENO, buf + fptr, m, "<stdout>");
+ fptr = (fptr + m) % n;
+ same -= m;
+ }
+
+ while (diff && sptr < stream.ptr) {
+ m = diff < n - fptr ? diff : n - fptr;
+ m = m < stream.ptr - sptr ? m : stream.ptr - sptr;
+ memcpy(buf + fptr, stream.buf + sptr, m);
+ ewriteall(STDOUT_FILENO, buf + fptr, m, "<stdout>");
+ fptr = (fptr + m) % n;
+ diff -= m;
+ sptr += m;
+ }
+
+ if (diff || sptr + 2 * sizeof(size_t) > stream.ptr) {
+ memmove(stream.buf, stream.buf + sptr, stream.ptr -=
sptr);
+ } else {
+ same = ((size_t *)(stream.buf + sptr))[0];
+ diff = ((size_t *)(stream.buf + sptr))[1];
+ sptr += 2 * sizeof(size_t);
+ goto again;
+ }
+ } while (eread_stream(&stream, SIZE_MAX));
+
+ free(buf);
+ if (same || diff)
+ eprintf("<stdin>: corrupt input\n");
+ return 0;
+}
