thodg/got

diff --git a/lib/deflate.c b/lib/deflate.c
new file mode 100644
index 0000000..def641f
--- /dev/null
+++ b/lib/deflate.c
@@ -0,0 +1,164 @@
+/*
+ * Copyright (c) 2019 Stefan Sperling <stsp@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/queue.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sha1.h>
+#include <zlib.h>
+#include <time.h>
+
+#include "got_error.h"
+#include "got_object.h"
+
+#include "got_lib_path.h"
+#include "got_lib_deflate.h"
+
+#ifndef MIN
+#define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
+#endif
+
+const struct got_error *
+got_deflate_init(struct got_deflate_buf *zb, uint8_t *outbuf, size_t bufsize)
+{
+	const struct got_error *err = NULL;
+	int zerr;
+
+	memset(&zb->z, 0, sizeof(zb->z));
+
+	zb->z.zalloc = Z_NULL;
+	zb->z.zfree = Z_NULL;
+	zerr = deflateInit(&zb->z, Z_DEFAULT_COMPRESSION);
+	if (zerr != Z_OK) {
+		if  (zerr == Z_ERRNO)
+			return got_error_from_errno();
+		if  (zerr == Z_MEM_ERROR) {
+			errno = ENOMEM;
+			return got_error_from_errno();
+		}
+		return got_error(GOT_ERR_COMPRESSION);
+	}
+
+	zb->inlen = zb->outlen = bufsize;
+
+	zb->inbuf = calloc(1, zb->inlen);
+	if (zb->inbuf == NULL) {
+		err = got_error_from_errno();
+		goto done;
+	}
+
+	zb->flags = 0;
+	if (outbuf == NULL) {
+		zb->outbuf = calloc(1, zb->outlen);
+		if (zb->outbuf == NULL) {
+			err = got_error_from_errno();
+			goto done;
+		}
+		zb->flags |= GOT_DEFLATE_F_OWN_OUTBUF;
+	} else
+		zb->outbuf = outbuf;
+
+done:
+	if (err)
+		got_deflate_end(zb);
+	return err;
+}
+
+const struct got_error *
+got_deflate_read(struct got_deflate_buf *zb, FILE *f, size_t *outlenp)
+{
+	size_t last_total_out = zb->z.total_out;
+	z_stream *z = &zb->z;
+	int ret = Z_ERRNO;
+
+	z->next_out = zb->outbuf;
+	z->avail_out = zb->outlen;
+
+	*outlenp = 0;
+	do {
+		if (z->avail_in == 0) {
+			size_t n = fread(zb->inbuf, 1, zb->inlen, f);
+			if (n == 0) {
+				if (ferror(f))
+					return got_ferror(f, GOT_ERR_IO);
+				/* EOF */
+				ret = Z_STREAM_END;
+				break;
+			}
+			z->next_in = zb->inbuf;
+			z->avail_in = n;
+		}
+		ret = deflate(z, Z_NO_FLUSH);
+	} while (ret == Z_OK && z->avail_out > 0);
+
+	if (ret == Z_OK) {
+		zb->flags |= GOT_DEFLATE_F_HAVE_MORE;
+	} else {
+		if (ret != Z_STREAM_END)
+			return got_error(GOT_ERR_COMPRESSION);
+		zb->flags &= ~GOT_DEFLATE_F_HAVE_MORE;
+	}
+
+	*outlenp = z->total_out - last_total_out;
+	return NULL;
+}
+
+void
+got_deflate_end(struct got_deflate_buf *zb)
+{
+	free(zb->inbuf);
+	if (zb->flags & GOT_DEFLATE_F_OWN_OUTBUF)
+		free(zb->outbuf);
+	deflateEnd(&zb->z);
+}
+
+const struct got_error *
+got_deflate_to_file(size_t *outlen, FILE *infile, FILE *outfile)
+{
+	const struct got_error *err;
+	size_t avail;
+	struct got_deflate_buf zb;
+
+	err = got_deflate_init(&zb, NULL, GOT_DEFLATE_BUFSIZE);
+	if (err)
+		goto done;
+
+	*outlen = 0;
+
+	do {
+		err = got_deflate_read(&zb, infile, &avail);
+		if (err)
+			goto done;
+		if (avail > 0) {
+			size_t n;
+			n = fwrite(zb.outbuf, avail, 1, outfile);
+			if (n != 1) {
+				err = got_ferror(outfile, GOT_ERR_IO);
+				goto done;
+			}
+			*outlen += avail;
+		}
+	} while (zb.flags & GOT_DEFLATE_F_HAVE_MORE);
+
+done:
+	if (err == NULL)
+		rewind(outfile);
+	got_deflate_end(&zb);
+	return err;
+}
diff --git a/lib/got_lib_deflate.h b/lib/got_lib_deflate.h
new file mode 100644
index 0000000..1777eab
--- /dev/null
+++ b/lib/got_lib_deflate.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2019 Stefan Sperling <stsp@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+struct got_deflate_buf {
+	z_stream z;
+	char *inbuf;
+	size_t inlen;
+	char *outbuf;
+	size_t outlen;
+	int flags;
+#define GOT_DEFLATE_F_HAVE_MORE		0x01
+#define GOT_DEFLATE_F_OWN_OUTBUF	0x02
+};
+
+#define GOT_DEFLATE_BUFSIZE		8192
+
+const struct got_error *got_deflate_init(struct got_deflate_buf *, uint8_t *,
+    size_t);
+const struct got_error *got_deflate_read(struct got_deflate_buf *, FILE *,
+    size_t *);
+void got_deflate_end(struct got_deflate_buf *);
+const struct got_error *got_deflate_to_file(size_t *, FILE *, FILE *);