xplist: Improve memory usage by estimating output buffer size
diff --git a/src/strbuf.h b/src/strbuf.h
index b805892..0d28edf 100644
--- a/src/strbuf.h
+++ b/src/strbuf.h
@@ -26,7 +26,7 @@
typedef struct bytearray_t strbuf_t;
-#define str_buf_new() byte_array_new(32768)
+#define str_buf_new(__sz) byte_array_new(__sz)
#define str_buf_free(__ba) byte_array_free(__ba)
#define str_buf_grow(__ba, __am) byte_array_grow(__ba, __am)
#define str_buf_append(__ba, __str, __len) byte_array_append(__ba, (void*)(__str), __len)
diff --git a/src/xplist.c b/src/xplist.c
index bb27f53..2eeccf9 100644
--- a/src/xplist.c
+++ b/src/xplist.c
@@ -37,6 +37,7 @@
#include <inttypes.h>
#include <math.h>
+#include <limits.h>
#include <node.h>
#include <node_list.h>
@@ -69,6 +70,8 @@
#define MAC_EPOCH 978307200
+#define MAX_DATA_BYTES_PER_LINE(__i) (((76 - (__i << 3)) >> 2) * 3)
+
static const char XML_PLIST_PROLOG[] = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n\
<!DOCTYPE plist PUBLIC \"-//Apple//DTD PLIST 1.0//EN\" \"http://www.apple.com/DTDs/PropertyList-1.0.dtd\">\n\
<plist version=\"1.0\">\n";
@@ -290,7 +293,7 @@
char *buf = malloc(80);
uint32_t j = 0;
uint32_t indent = (depth > 8) ? 8 : depth;
- uint32_t maxread = ((76 - indent*8) / 4) * 3;
+ uint32_t maxread = MAX_DATA_BYTES_PER_LINE(indent);
size_t count = 0;
size_t b64count = 0;
size_t amount = (node_data->length / 3 * 4) + 4 + (((node_data->length / maxread) + 1) * (indent+1));
@@ -400,9 +403,131 @@
btime->tm_isdst=0;
}
+#define PO10i_LIMIT (INT64_MAX/10)
+
+/* based on https://stackoverflow.com/a/4143288 */
+static int num_digits_i(int64_t i)
+{
+ int n;
+ int64_t po10;
+ n=1;
+ if (i < 0) {
+ i = -i;
+ n++;
+ }
+ po10=10;
+ while (i>=po10) {
+ n++;
+ if (po10 > PO10i_LIMIT) break;
+ po10*=10;
+ }
+ return n;
+}
+
+#define PO10u_LIMIT (UINT64_MAX/10)
+
+/* based on https://stackoverflow.com/a/4143288 */
+static int num_digits_u(uint64_t i)
+{
+ int n;
+ uint64_t po10;
+ n=1;
+ po10=10;
+ while (i>=po10) {
+ n++;
+ if (po10 > PO10u_LIMIT) break;
+ po10*=10;
+ }
+ return n;
+}
+
+static void node_estimate_size(node_t *node, uint64_t *size, uint32_t depth)
+{
+ plist_data_t data;
+ if (!node) {
+ return;
+ }
+ data = plist_get_data(node);
+ if (node->children) {
+ node_t *ch;
+ for (ch = node_first_child(node); ch; ch = node_next_sibling(ch)) {
+ node_estimate_size(ch, size, depth + 1);
+ }
+ switch (data->type) {
+ case PLIST_DICT:
+ *size += (XPLIST_DICT_LEN << 1) + 7;
+ break;
+ case PLIST_ARRAY:
+ *size += (XPLIST_ARRAY_LEN << 1) + 7;
+ break;
+ default:
+ break;
+ }
+ *size += (depth << 1);
+ } else {
+ uint32_t indent = (depth > 8) ? 8 : depth;
+ switch (data->type) {
+ case PLIST_DATA: {
+ uint32_t req_lines = (data->length / MAX_DATA_BYTES_PER_LINE(indent)) + 1;
+ uint32_t b64len = data->length + (data->length / 3);
+ b64len += b64len % 4;
+ *size += b64len;
+ *size += (XPLIST_DATA_LEN << 1) + 5 + (indent+1) * (req_lines+1) + 1;
+ } break;
+ case PLIST_STRING:
+ *size += data->length;
+ *size += (XPLIST_STRING_LEN << 1) + 6;
+ break;
+ case PLIST_KEY:
+ *size += data->length;
+ *size += (XPLIST_KEY_LEN << 1) + 6;
+ break;
+ case PLIST_UINT:
+ if (data->length == 16) {
+ *size += num_digits_u(data->intval);
+ } else {
+ *size += num_digits_i((int64_t)data->intval);
+ }
+ *size += (XPLIST_INT_LEN << 1) + 6;
+ break;
+ case PLIST_REAL:
+ *size += num_digits_i((int64_t)data->realval) + 7;
+ *size += (XPLIST_REAL_LEN << 1) + 6;
+ break;
+ case PLIST_DATE:
+ *size += 20; /* YYYY-MM-DDThh:mm:ssZ */
+ *size += (XPLIST_DATE_LEN << 1) + 6;
+ break;
+ case PLIST_BOOLEAN:
+ *size += ((data->boolval) ? XPLIST_TRUE_LEN : XPLIST_FALSE_LEN) + 4;
+ break;
+ case PLIST_DICT:
+ *size += XPLIST_DICT_LEN + 4; /* <dict/> */
+ break;
+ case PLIST_ARRAY:
+ *size += XPLIST_ARRAY_LEN + 4; /* <array/> */
+ break;
+ case PLIST_UID:
+ *size += num_digits_i((int64_t)data->intval);
+ *size += (XPLIST_DICT_LEN << 1) + 7;
+ *size += indent + ((indent+1) << 1);
+ *size += 18; /* <key>CF$UID</key> */
+ *size += (XPLIST_INT_LEN << 1) + 6;
+ break;
+ default:
+ break;
+ }
+ *size += indent;
+ }
+}
+
PLIST_API void plist_to_xml(plist_t plist, char **plist_xml, uint32_t * length)
{
- strbuf_t *outbuf = str_buf_new();
+ uint64_t size = 0;
+ node_estimate_size(plist, &size, 0);
+ size += sizeof(XML_PLIST_PROLOG) + sizeof(XML_PLIST_EPILOG) - 1;
+
+ strbuf_t *outbuf = str_buf_new(size);
str_buf_append(outbuf, XML_PLIST_PROLOG, sizeof(XML_PLIST_PROLOG)-1);
