thodg/libgit2

diff --git a/src/odb.c b/src/odb.c
index 627513e..be896cc 100644
--- a/src/odb.c
+++ b/src/odb.c
@@ -29,6 +29,7 @@
 #include "fileops.h"
 #include "hash.h"
 #include "odb.h"
+#include "delta-apply.h"
 
 #define GIT_PACK_NAME_MAX (5 + 40 + 1)
 
@@ -74,6 +75,9 @@ struct git_pack {
 	/** File descriptor for the .pack file. */
 	git_file pack_fd;
 
+	/** Memory map of the pack's contents */
+	git_map pack_map;
+
 	/** The size of the .pack file. */
 	off_t pack_size;
 
@@ -437,7 +441,7 @@ static int inflate_buffer(void *in, size_t inlen, void *out, size_t outlen)
 
 	inflateEnd(&zs);
 
-	if ((status != Z_STREAM_END) || (zs.avail_in != 0))
+	if ((status != Z_STREAM_END) /*|| (zs.avail_in != 0) */)
 		return GIT_ERROR;
 
 	if (zs.total_out != outlen)
@@ -1160,23 +1164,26 @@ static int open_pack(git_pack *p)
 	if (pack_openidx(p))
 		return GIT_ERROR;
 
-	if ((p->pack_fd = gitfo_open(pb, O_RDONLY)) < 0) {
-		p->pack_fd = -1;
-		pack_decidx(p);
-		return GIT_ERROR;
-	}
+	if ((p->pack_fd = gitfo_open(pb, O_RDONLY)) < 0)
+		goto error_cleanup;
 
 	if (gitfo_fstat(p->pack_fd, &sb)
 		|| !S_ISREG(sb.st_mode) || p->pack_size != sb.st_size
-		|| check_pack_hdr(p) || check_pack_sha1(p)) {
-		gitfo_close(p->pack_fd);
-		p->pack_fd = -1;
-		pack_decidx(p);
-		return GIT_ERROR;
-	}
+		|| check_pack_hdr(p) || check_pack_sha1(p))
+		goto error_cleanup;
+
+	if (!git__is_sizet(p->pack_size) ||
+		gitfo_map_ro(&p->pack_map, p->pack_fd, 0, (size_t)p->pack_size) < 0)
+		goto error_cleanup;
 
 	pack_decidx(p);
 	return GIT_SUCCESS;
+
+error_cleanup:
+	gitfo_close(p->pack_fd);
+	p->pack_fd = -1;
+	pack_decidx(p);
+	return GIT_ERROR;
 }
 
 static void pack_dec(git_pack *p)
@@ -1194,8 +1201,10 @@ static void pack_dec(git_pack *p)
 			free(p->im_fanout);
 			free(p->im_off_idx);
 			free(p->im_off_next);
-			if (p->pack_fd != -1)
+			if (p->pack_fd != -1) {
 				gitfo_close(p->pack_fd);
+				gitfo_free_map(&p->pack_map);
+			}
 		}
 
 		gitlck_free(&p->lock);
@@ -1475,14 +1484,141 @@ int git_odb__read_loose(git_obj *out, git_odb *db, const git_oid *id)
 	return GIT_SUCCESS;
 }
 
+static int unpack_object(git_obj *out, git_pack *p, index_entry *e);
+
+static int unpack_object_delta(git_obj *out, git_pack *p, 
+		index_entry *base_entry, 
+		uint8_t *delta_buffer, 
+		size_t delta_deflated_size,
+		size_t delta_inflated_size)
+{
+	int res = 0;
+	uint8_t *delta = NULL;
+	git_obj base_obj;
+
+	base_obj.data = NULL;
+	base_obj.type = GIT_OBJ_BAD;
+	base_obj.len = 0;
+
+	if ((res = unpack_object(&base_obj, p, base_entry)) < 0)
+		goto cleanup;
+
+	delta = git__malloc(delta_inflated_size + 1);
+
+	if ((res = inflate_buffer(delta_buffer, delta_deflated_size, 
+			delta, delta_inflated_size)) < 0)
+		goto cleanup;
+
+	res = git__delta_apply(out, base_obj.data, base_obj.len, delta, delta_inflated_size);
+
+	out->type = base_obj.type;
+
+cleanup:
+	free(delta);
+	git_obj_close(&base_obj);
+	return res;
+}
+
 static int unpack_object(git_obj *out, git_pack *p, index_entry *e)
 {
-	assert(out && p && e);
+	git_otype object_type;
+	size_t inflated_size, deflated_size, shift;
+	uint8_t *buffer, byte;
+
+	assert(out && p && e && git__is_sizet(e->size));
 
 	if (open_pack(p))
 		return GIT_ERROR;
 
-	/* TODO - actually unpack the data! */
+	buffer = (uint8_t *)p->pack_map.data + e->offset;
+	deflated_size = (size_t)e->size;
+
+	if (deflated_size == 0)
+		deflated_size = p->pack_size - e->offset;
+
+	byte = *buffer++ & 0xFF;
+	deflated_size--;
+	object_type = (byte >> 4) & 0x7;
+	inflated_size = byte & 0xF;
+	shift = 4;
+
+	while (byte & 0x80) {
+		byte = *buffer++ & 0xFF;
+		deflated_size--;
+		inflated_size += (byte & 0x7F) << shift;
+		shift += 7;
+	}
+
+	switch (object_type) {
+		case GIT_OBJ_COMMIT:
+		case GIT_OBJ_TREE:
+		case GIT_OBJ_BLOB:
+		case GIT_OBJ_TAG: {
+
+			/* Handle a normal zlib stream */
+			out->len = inflated_size;
+			out->type = object_type;
+			out->data = git__malloc(inflated_size + 1);
+
+			if (inflate_buffer(buffer, deflated_size, out->data, out->len) < 0) {
+				free(out->data);
+				out->data = NULL;
+				return GIT_ERROR;
+			}
+
+			return GIT_SUCCESS;
+		}
+
+		case GIT_OBJ_OFS_DELTA: {
+
+			off_t delta_offset;
+			index_entry entry;
+
+			byte = *buffer++ & 0xFF;
+			delta_offset = byte & 0x7F;
+
+			while (byte & 0x80) {
+				delta_offset += 1;
+				byte = *buffer++ & 0xFF;
+				delta_offset <<= 7;
+				delta_offset += (byte & 0x7F);
+			}
+
+			entry.n = 0; 
+			entry.oid = NULL;
+			entry.offset = e->offset - delta_offset; 
+			entry.size = 0;
+
+			if (unpack_object_delta(out, p, &entry, 
+					buffer, deflated_size, inflated_size) < 0)
+				return GIT_ERROR;
+			
+			return GIT_SUCCESS;
+		}
+
+		case GIT_OBJ_REF_DELTA: {
+
+			git_oid base_id;
+			uint32_t n;
+			index_entry entry;
+			int res = GIT_ERROR;
+
+			git_oid_mkraw(&base_id, buffer);
+
+			if (!p->idx_search(&n, p, &base_id) &&
+				!p->idx_get(&entry, p, n)) {
+
+				/* FIXME: deflated_size - 20 ? */
+				res = unpack_object_delta(out, p, &entry, 
+					buffer + GIT_OID_RAWSZ, deflated_size, inflated_size);
+			}
+
+			return res;
+		}
+
+		default:
+			return GIT_EOBJCORRUPTED;
+	}
 
 	return GIT_SUCCESS;
 }
@@ -1497,15 +1633,15 @@ static int read_packed(git_obj *out, git_pack *p, const git_oid *id)
 
 	if (pack_openidx(p))
 		return GIT_ERROR;
+
 	res = p->idx_search(&n, p, id);
 	if (!res)
 		res = p->idx_get(&e, p, n);
-	pack_decidx(p);
 
-	if (!res) {
-		/* TODO unpack object */
+	if (!res)
 		res = unpack_object(out, p, &e);
-	}
+
+	pack_decidx(p);
 
 	return res;
 }
diff --git a/tests/resources/pack-odb/info/packs b/tests/resources/pack-odb/info/packs
new file mode 100644
index 0000000..895b1c3
--- /dev/null
+++ b/tests/resources/pack-odb/info/packs
@@ -0,0 +1,2 @@
+P pack-d85f5d483273108c9d8dd0e4728ccf0b2982423a.pack
+
diff --git a/tests/resources/pack-odb/pack/pack-a81e489679b7d3418f9ab594bda8ceb37dd4c695.idx b/tests/resources/pack-odb/pack/pack-a81e489679b7d3418f9ab594bda8ceb37dd4c695.idx
new file mode 100644
index 0000000..5068f28
Binary files /dev/null and b/tests/resources/pack-odb/pack/pack-a81e489679b7d3418f9ab594bda8ceb37dd4c695.idx differ
diff --git a/tests/resources/pack-odb/pack/pack-a81e489679b7d3418f9ab594bda8ceb37dd4c695.pack b/tests/resources/pack-odb/pack/pack-a81e489679b7d3418f9ab594bda8ceb37dd4c695.pack
new file mode 100644
index 0000000..a6a1f30
Binary files /dev/null and b/tests/resources/pack-odb/pack/pack-a81e489679b7d3418f9ab594bda8ceb37dd4c695.pack differ
diff --git a/tests/resources/pack-odb/pack/pack-d85f5d483273108c9d8dd0e4728ccf0b2982423a.idx b/tests/resources/pack-odb/pack/pack-d85f5d483273108c9d8dd0e4728ccf0b2982423a.idx
new file mode 100644
index 0000000..555cfa9
Binary files /dev/null and b/tests/resources/pack-odb/pack/pack-d85f5d483273108c9d8dd0e4728ccf0b2982423a.idx differ
diff --git a/tests/resources/pack-odb/pack/pack-d85f5d483273108c9d8dd0e4728ccf0b2982423a.pack b/tests/resources/pack-odb/pack/pack-d85f5d483273108c9d8dd0e4728ccf0b2982423a.pack
new file mode 100644
index 0000000..4d539ed
Binary files /dev/null and b/tests/resources/pack-odb/pack/pack-d85f5d483273108c9d8dd0e4728ccf0b2982423a.pack differ
diff --git a/tests/t0204-readpack.c b/tests/t0204-readpack.c
new file mode 100644
index 0000000..49ae9af
--- /dev/null
+++ b/tests/t0204-readpack.c
@@ -0,0 +1,154 @@
+#include "test_lib.h"
+#include "test_helpers.h"
+#include <git/odb.h>
+
+#define ODB_FOLDER "../resources/pack-odb"
+
+static const char *packed_objects[] = {
+	"0266163a49e280c4f5ed1e08facd36a2bd716bcf",
+	"53fc32d17276939fc79ed05badaef2db09990016",
+	"6336846bd5c88d32f93ae57d846683e61ab5c530",
+	"6dcf9bf7541ee10456529833502442f385010c3d",
+	"bed08a0b30b72a9d4aed7f1af8c8ca124e8d64b9",
+	"e90810b8df3e80c413d903f631643c716887138d",
+	"fc3c3a2083e9f6f89e6bd53e9420e70d1e357c9b",
+	"fc58168adf502d0c0ef614c3111a7038fc8c09c8",
+	"fd0ec0333948dfe23265ac46be0205a436a8c3a5",
+	"fd8430bc864cfcd5f10e5590f8a447e01b942bfe",
+	"fd899f45951c15c1c5f7c34b1c864e91bd6556c6",
+	"fda23b974899e7e1f938619099280bfda13bdca9",
+	"fdbec189efb657c8325962b494875987881a356b",
+	"fe1ca6bd22b5d8353ce6c2f3aba80805c438a7a5",
+	"fe3a6a42c87ff1239370c741a265f3997add87c1",
+	"deb106bfd2d36ecf9f0079224c12022201a39ad1",
+	"dec93efc79e60f2680de3e666755d335967eec30",
+	"def425bf8568b9c1e20879bf5be6f9c52b7361c4",
+	"df48000ac4f48570054e3a71a81916357997b680",
+	"dfae6ed8f6dd8acc3b40a31811ea316239223559",
+	"dff79e27d3d2cdc09790ded80fe2ea8ff5d61034",
+	"e00e46abe4c542e17c8bc83d72cf5be8018d7b0e",
+	"e01b107b4f77f8f98645adac0206a504f2d29d7c",
+	"e032d863f512c47b479bd984f8b6c8061f66b7d4",
+	"e044baa468a1c74f9f9da36805445f6888358b49",
+	"e04529998989ba8ae3419538dd57969af819b241",
+	"e0637ddfbea67c8d7f557c709e095af8906e9176",
+	"e0743ad4031231e71700abdc6fdbe94f189d20e5",
+	"cf33ac7a3d8b2b8f6bb266518aadbf59de397608",
+	"cf5f7235b9c9689b133f6ea12015720b411329bd",
+	"cf6cccf1297284833a9a03138a1f5738fa1c6c94",
+	"cf7992bde17ce7a79cab5f0c1fcbe8a0108721ed",
+	"cfe3a027ab12506d4144ee8a35669ae8fc4b7ab1",
+	"cfe96f31dfad7bab49977aa1df7302f7fafcb025",
+	"cff54d138945ef4de384e9d2759291d0c13ea90a",
+	"d01f7573ac34c2f502bd1cf18cde73480c741151",
+	"d03f567593f346a1ca96a57f8191def098d126e3",
+	"d047b47aadf88501238f36f5c17dd0a50dc62087",
+	"d0a0d63086fae3b0682af7261df21f7d0f7f066d",
+	"d0a44bd6ed0be21b725a96c0891bbc79bc1a540c",
+	"d0d7e736e536a41bcb885005f8bf258c61cad682",
+	"d0e7959d4b95ffec6198df6f5a7ae259b23a5f50",
+	"bf2fe2acca17d13356ce802ba9dc8343f710dfb7",
+	"bf55f407d6d9418e51f42ea7a3a6aadf17388349",
+	"bf92206f8b633b88a66dca4a911777630b06fbac",
+	"bfaf8c42eb8842abe206179fee864cfba87e3ca9",
+	"bfe05675d4e8f6b59d50932add8790f1a06b10ee",
+	"bff8618112330763327cfa6ce6e914db84f51ddf",
+	"bff873e9853ed99fed52c25f7ad29f78b27dcec2",
+	"c01c3fae7251098d7af1b459bcd0786e81d4616d",
+	"c0220fca67f48b8a5d4163d53b1486224be3a198",
+	"c02d0b160b82ee72469c269f13de4c26a7ea09cb",
+	"c059510ad1b45ab58390e042d7dee1ac46703854",
+	"c07204a1897aeeaa3c248d29dbfa9b033baf9755",
+	"c073337a4dd7276931b4b3fdbc3f0040e9441793",
+	"0fd7e4bfba5b3a82be88d1057757ca8b2c5e6d26",
+	"100746511cc45c9f1ad6721c4ef5be49222fee4d",
+	"1088490171d9b984d68b8b9be9ca003f4eafff59",
+	"1093c8ff4cb78fcf5f79dbbeedcb6e824bd4e253",
+	"10aa3fa72afab7ee31e116ae06442fe0f7b79df2",
+	"10b759e734e8299aa0dca08be935d95d886127b6",
+	"111d5ccf0bb010c4e8d7af3eedfa12ef4c5e265b",
+	"11261fbff21758444d426356ff6327ee01e90752",
+	"112998d425717bb922ce74e8f6f0f831d8dc4510",
+	"2ef4e5d838b6507bd61d457cf6466662b791c5c0",
+	"2ef4faa0f82efa00eeac6cae9e8b2abccc8566ee",
+	"2f06098183b0d7be350acbe39cdbaccff2df0c4a",
+	"2f1c5d509ac5bffb3c62f710a1c2c542e126dfd1",
+	"2f205b20fc16423c42b3ba51b2ea78d7b9ff3578",
+	"2f9b6b6e3d9250ba09360734aa47973a993b59d1",
+	"30c62a2d5a8d644f1311d4f7fe3f6a788e4c8188",
+	"31438e245492d85fd6da4d1406eba0fbde8332a4",
+	"3184a3abdfea231992254929ff4e275898e5bbf6",
+	"3188ffdbb3a3d52e0f78f30c484533899224436e",
+	"32581d0093429770d044a60eb0e9cc0462bedb13",
+	"32679a9544d83e5403202c4d5efb61ad02492847",
+	"4e7e9f60b7e2049b7f5697daf133161a18ef688f",
+	"4e8cda27ddc8be7db875ceb0f360c37734724c6d",
+	"4ea481c61c59ab55169b7cbaae536ad50b49d6f0",
+	"4f0adcd0e61eabe06fe32be66b16559537124b7a",
+	"4f1355c91100d12f9e7202f91b245df0c110867c",
+	"4f6eadeb08b9d0d1e8b1b3eac8a34940adf29a2d",
+	"4f9339df943c53117a5fc8e86e2f38716ff3a668",
+	"4fc3874b118752e40de556b1c3e7b4a9f1737d00",
+	"4ff1dd0992dd6baafdb5e166be6f9f23b59bdf87",
+	"5018a35e0b7e2eec7ce5050baf9c7343f3f74164",
+	"50298f44a45eda3a29dae82dbe911b5aa176ac07",
+	"502acd164fb115768d723144da2e7bb5a24891bb",
+	"50330c02bd4fd95c9db1fcf2f97f4218e42b7226",
+	"5052bf355d9f8c52446561a39733a8767bf31e37",
+	"6f2cd729ae42988c1dd43588d3a6661ba48ad7a0",
+	"6f4e2c42d9138bfbf3e0f908f1308828cc6f2178",
+	"6f6a17db05a83620cef4572761831c20a70ba9b9",
+	"6faad60901e36538634f0d8b8ff3f21f83503c71",
+	"6fc72e46de3df0c3842dab302bbacf697a63abab",
+	"6fdccd49f442a7204399ca9b418f017322dbded8",
+	"6fe7568fc3861c334cb008fd85d57d9647249ef5",
+	"700f55d91d7b55665594676a4bada1f1457a0598",
+	"702bd70595a7b19afc48a1f784a6505be68469d4",
+	"7033f9ee0e52b08cb5679cd49b7b7999eaf9eaf8",
+	"70957110ce446c4e250f865760fb3da513cdcc92",
+	"8ec696a4734f16479d091bc70574d23dd9fe7443",
+	"8ed341c55ed4d6f4cdc8bf4f0ca18a08c93f6962",
+	"8edc2805f1f11b63e44bf81f4557f8b473612b69",
+	"8ef9060a954118a698fc10e20acdc430566a100f",
+	"8f0c4b543f4bb6eb1518ecfc3d4699e43108d393",
+	"8fac94df3035405c2e60b3799153ce7c428af6b9",
+	"904c0ac12b23548de524adae712241b423d765a3",
+	"90bbaa9a809c3a768d873a9cc7d52b4f3bf3d1b9",
+	"90d4d2f0fc362beabbbf76b4ffda0828229c198d",
+	"90f9ff6755330b685feff6c3d81782ee3592ab04",
+	"91822c50ebe4f9bf5bbb8308ecf9f6557062775c",
+	"91d973263a55708fa8255867b3202d81ef9c2868",
+	"af292c99c6148d772af3315a1c74e83330e7ead7",
+	"af3b99d5be330dbbce0b9250c3a5fb05911908cc",
+	"af55d0cdeb280af2db8697e5afa506e081012719",
+	"af795e498d411142ddb073e8ca2c5447c3295a4c",
+	"afadc73a392f8cc8e2cc77dd62a7433dd3bafa8c",
+	"affd84ed8ec7ce67612fe3c12a80f8164b101f6a",
+	"b0941f9c70ffe67f0387a827b338e64ecf3190f0",
+	"b0a3077f9ef6e093f8d9869bdb0c07095bd722cb",
+	"b0a8568a7614806378a54db5706ee3b06ae58693",
+	"b0fb7372f242233d1d35ce7d8e74d3990cbc5841",
+	"b10489944b9ead17427551759d180d10203e06ba",
+	"b196a807b323f2748ffc6b1d42cd0812d04c9a40",
+	"b1bb1d888f0c5e19278536d49fa77db035fac7ae"
+};
+
+BEGIN_TEST(readpacked_test)
+	unsigned int i;
+    git_odb *db;
+
+    must_pass(git_odb_open(&db, ODB_FOLDER));
+
+	for (i = 0; i < ARRAY_SIZE(packed_objects); ++i) {
+		git_oid id;
+		git_obj obj;
+
+		must_pass(git_oid_mkstr(&id, packed_objects[i]));
+		must_be_true(git_odb_exists(db, &id) == 1);
+		must_pass(git_odb__read_packed(&obj, db, &id));
+
+		git_obj_close(&obj);
+	}
+
+    git_odb_close(db);
+END_TEST