Fix performance regression: cache dostime to time_t conversion results.

Closes issue #462

lib/zip_dirent.c

@@ -282,6 +282,7 @@ _zip_dirent_init(zip_dirent_t *de) {
     de->cloned = 0;
 
     de->crc_valid = true;
+    de->last_mod_mtime_valid = false;
     de->version_madeby = 63 | (ZIP_OPSYS_DEFAULT << 8);
     de->version_needed = 10; /* 1.0 */
     de->bitflags = 0;
@@ -1263,3 +1264,12 @@ zip_dirent_check_consistency(zip_dirent_t *dirent) {
     }
     return 0;
 }
+
+time_t zip_dirent_get_last_mod_mtime(zip_dirent_t *de) {
+    if (!de->last_mod_mtime_valid) {
+        de->last_mod_mtime = _zip_d2u_time(&de->last_mod);
+        de->last_mod_mtime_valid = true;
+    }
+
+    return de->last_mod_mtime;
+}

lib/zip_file_set_mtime.c

@@ -33,8 +33,7 @@
 
 #include "zipint.h"
 
-ZIP_EXTERN int
-zip_file_set_dostime(zip_t *za, zip_uint64_t idx, zip_uint16_t dtime, zip_uint16_t ddate, zip_flags_t flags) {
+static int zip_file_set_time(zip_t *za, zip_uint64_t idx, zip_uint16_t dtime, zip_uint16_t ddate, zip_flags_t flags, time_t *mtime) {
     zip_entry_t *e;
 
     if (_zip_get_dirent(za, idx, 0, NULL) == NULL) {
@@ -66,18 +65,29 @@ zip_file_set_dostime(zip_t *za, zip_uint64_t idx, zip_uint16_t dtime, zip_uint16
 
     e->changes->last_mod.time = dtime;
     e->changes->last_mod.date = ddate;
+    if (mtime != NULL) {
+        e->changes->last_mod_mtime = *mtime;
+        e->changes->last_mod_mtime_valid = true;
+    }
+    else {
+        e->changes->last_mod_mtime_valid = false;
+    }
     e->changes->changed |= ZIP_DIRENT_LAST_MOD;
 
     return 0;
 }
 
-ZIP_EXTERN int
-zip_file_set_mtime(zip_t *za, zip_uint64_t idx, time_t mtime, zip_flags_t flags) {
+ZIP_EXTERN int zip_file_set_dostime(zip_t *za, zip_uint64_t idx, zip_uint16_t dtime, zip_uint16_t ddate, zip_flags_t flags) {
+    return zip_file_set_time(za, idx, dtime, ddate, flags, NULL);
+}
+
+
+ZIP_EXTERN int zip_file_set_mtime(zip_t *za, zip_uint64_t idx, time_t mtime, zip_flags_t flags) {
     zip_dostime_t dostime;
 
     if (_zip_u2d_time(mtime, &dostime, &za->error) < 0) {
         return -1;
     }
 
-    return zip_file_set_dostime(za, idx, dostime.time, dostime.date, flags);
+    return zip_file_set_time(za, idx, dostime.time, dostime.date, flags, &mtime);
 }

lib/zip_new.c

@@ -68,6 +68,7 @@ _zip_new(zip_error_t *error) {
     za->nopen_source = za->nopen_source_alloc = 0;
     za->open_source = NULL;
     za->progress = NULL;
+    za->torrent_mtime = 0;
 
     return za;
 }

lib/zip_stat_index.c

@@ -77,7 +77,7 @@ zip_stat_index(zip_t *za, zip_uint64_t index, zip_flags_t flags, zip_stat_t *st)
         }
 
         if (entry->changes != NULL && entry->changes->changed & ZIP_DIRENT_LAST_MOD) {
-            st->mtime = _zip_d2u_time(&de->last_mod);
+            st->mtime = zip_dirent_get_last_mod_mtime(de);
             st->valid |= ZIP_STAT_MTIME;
         }
     }
@@ -86,7 +86,7 @@ zip_stat_index(zip_t *za, zip_uint64_t index, zip_flags_t flags, zip_stat_t *st)
 
         st->crc = de->crc;
         st->size = de->uncomp_size;
-        st->mtime = _zip_d2u_time(&de->last_mod);
+        st->mtime = zip_dirent_get_last_mod_mtime(de);
         st->comp_size = de->comp_size;
         st->comp_method = (zip_uint16_t)de->comp_method;
         st->encryption_method = de->encryption_method;
@@ -97,9 +97,12 @@ zip_stat_index(zip_t *za, zip_uint64_t index, zip_flags_t flags, zip_stat_t *st)
     }
 
     if ((za->ch_flags & ZIP_AFL_WANT_TORRENTZIP) && (flags & ZIP_FL_UNCHANGED) == 0) {
-        zip_dostime_t dostime = {0xbc00, 0x2198};
+        if (za->torrent_mtime == 0) {
+            zip_dostime_t dostime = {0xbc00, 0x2198};
+            za->torrent_mtime = _zip_d2u_time(&dostime);
+        }
         st->comp_method = ZIP_CM_DEFLATE;
-        st->mtime = _zip_d2u_time(&dostime);
+        st->mtime = za->torrent_mtime;
         st->valid |= ZIP_STAT_MTIME | ZIP_STAT_COMP_METHOD;
         st->valid &= ~ZIP_STAT_COMP_SIZE;
     }

lib/zipint.h

@@ -314,6 +314,7 @@ struct zip {
     zip_progress_t *progress; /* progress callback for zip_close() */
 
     zip_uint32_t* write_crc; /* have _zip_write() compute CRC */
+    time_t torrent_mtime;
 };
 
 /* file in zip archive, part of API */
@@ -346,6 +347,7 @@ struct zip_dirent {
     bool cloned;                  /*      whether this instance is cloned, and thus shares non-changed strings */
 
     bool crc_valid; /*      if CRC is valid (sometimes not for encrypted archives) */
+    bool last_mod_mtime_valid;
 
     zip_uint16_t version_madeby;     /* (c)  version of creator */
     zip_uint16_t version_needed;     /* (cl) version needed to extract */
@@ -366,6 +368,8 @@ struct zip_dirent {
     zip_uint32_t compression_level; /*      level of compression to use (never valid in orig) */
     zip_uint16_t encryption_method; /*      encryption method, computed from other fields */
     char *password;                 /*      file specific encryption password */
+
+    time_t last_mod_mtime;          /*      cached last_mod in Unix time format */
 };
 
 /* zip archive central directory */
@@ -553,6 +557,7 @@ int zip_dirent_check_consistency(zip_dirent_t *dirent);
 zip_dirent_t *_zip_dirent_clone(const zip_dirent_t *);
 void _zip_dirent_free(zip_dirent_t *);
 void _zip_dirent_finalize(zip_dirent_t *);
+time_t zip_dirent_get_last_mod_mtime(zip_dirent_t *de);
 void _zip_dirent_init(zip_dirent_t *);
 bool _zip_dirent_needs_zip64(const zip_dirent_t *, zip_flags_t);
 zip_dirent_t *_zip_dirent_new(void);