From cb8b1eebd20a4e8d8596de18d3ea22bd2e94ddc5 Mon Sep 17 00:00:00 2001
From: decafcode <tau@nowhere>
Date: Fri, 24 Nov 2023 11:16:23 -0500
Subject: [PATCH] feat(573file): add headered LZ file reader

---
 573file/lz-file.c   | 93 +++++++++++++++++++++++++++++++++++++++++++++
 573file/lz-file.h   |  7 ++++
 573file/meson.build |  2 +
 3 files changed, 102 insertions(+)
 create mode 100644 573file/lz-file.c
 create mode 100644 573file/lz-file.h

diff --git a/573file/lz-file.c b/573file/lz-file.c
new file mode 100644
index 0000000..a27c9d4
--- /dev/null
+++ b/573file/lz-file.c
@@ -0,0 +1,93 @@
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+
+#include "573file/lz.h"
+
+#include "util/iobuf.h"
+#include "util/log.h"
+
+int lz_file_read(struct const_iobuf *src, void **out_bytes,
+                 size_t *out_nbytes) {
+  struct iobuf dest;
+  uint32_t h_orig_size;
+  uint32_t h_comp_size;
+  size_t orig_size;
+  size_t comp_size;
+  const void *payload;
+  void *bytes;
+  int r;
+
+  assert(src != NULL);
+  assert(out_bytes != NULL);
+  assert(out_nbytes != NULL);
+
+  bytes = NULL;
+  *out_bytes = NULL;
+  *out_nbytes = 0;
+
+  r = iobuf_read_be32(src, &h_orig_size);
+
+  if (r < 0) {
+    log_error(r);
+
+    goto end;
+  }
+
+  r = iobuf_read_be32(src, &h_comp_size);
+
+  if (r < 0) {
+    log_error(r);
+
+    goto end;
+  }
+
+  comp_size = src->nbytes - src->pos;
+
+  if (comp_size != h_comp_size) {
+    r = -EBADMSG;
+    log_write(
+        "Compressed size mismatch: Header says %#x bytes, actual size is %#lx",
+        h_comp_size, (unsigned long)comp_size);
+
+    goto end;
+  }
+
+  payload = src->bytes + src->pos;
+  memset(&dest, 0, sizeof(dest));
+  lz_dec_decompress(payload, comp_size, &dest);
+
+  orig_size = dest.pos;
+
+  if (orig_size != h_orig_size) {
+    r = -EBADMSG;
+    log_write(
+        "Original size mismatch: Header says %#x bytes, actual size is #%lx",
+        h_orig_size, (unsigned long)orig_size);
+
+    goto end;
+  }
+
+  bytes = malloc(orig_size);
+
+  if (bytes == NULL) {
+    r = -EBADMSG;
+
+    goto end;
+  }
+
+  dest.bytes = bytes;
+  dest.nbytes = orig_size;
+  dest.pos = 0;
+
+  lz_dec_decompress(payload, comp_size, &dest);
+
+  *out_bytes = bytes;
+  *out_nbytes = orig_size;
+  bytes = NULL;
+
+end:
+  free(bytes);
+
+  return r;
+}
diff --git a/573file/lz-file.h b/573file/lz-file.h
new file mode 100644
index 0000000..7ff8751
--- /dev/null
+++ b/573file/lz-file.h
@@ -0,0 +1,7 @@
+#pragma once
+
+#include <stddef.h>
+
+#include "util/iobuf.h"
+
+int lz_file_read(struct const_iobuf *src, void **out_bytes, size_t *out_nbytes);
diff --git a/573file/meson.build b/573file/meson.build
index 20b6dd0..5ffaa88 100644
--- a/573file/meson.build
+++ b/573file/meson.build
@@ -7,6 +7,8 @@ _573file_lib = static_library(
     'ifs.h',
     'lz.c',
     'lz.h',
+    'lz-file.c',
+    'lz-file.h',
     'prop-binary-reader.c',
     'prop-binary-reader.h',
     'prop-type.c',