From a3d3cddeb38fd64d39d59e32be4b838d03cf353c Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Sun, 6 Nov 2022 11:51:03 +0100
Subject: [PATCH] Add functions to search for specific files or file types

---
 README.md | 18 +++++++++++++++++-
 minitar.h |  2 ++
 src/tar.c | 29 +++++++++++++++++++++++++++++
 3 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 464405e..0e1a2f5 100644
--- a/README.md
+++ b/README.md
@@ -57,13 +57,29 @@ This function returns NULL on end-of-file (when all entries have been read).
 ### minitar_free_entry
 `void minitar_free_entry(struct minitar_entry* entry)`
 
-Frees the heap-allocated `struct minitar_entry` and the file contents stored inside it. The pointer passed to `minitar_free_entry()` should be the return value of a previous call to `minitar_read_entry()`.
+Frees the heap-allocated `struct minitar_entry` and the file contents stored inside it. The pointer passed to `minitar_free_entry()` should be the return value of a previous call to `minitar_read_entry()`, `minitar_find_by_name()` or `minitar_find_any_of()`.
 
 ### minitar_rewind
 `void minitar_rewind(struct minitar* mp)`
 
 Rewinds the `struct minitar` back to the beginning of the archive file, which means that the next call to `minitar_read_entry()` will return the first entry instead of the entry after the last read entry.
 
+### minitar_find_by_name
+`struct minitar_entry* minitar_find_by_name(struct minitar* mp, const char* name)`
+
+Returns the first entry with a matching name, or NULL if none are found. The return value is a `struct minitar_entry`, which is heap-allocated and should be freed after use with `minitar_free_entry()`. This structure is already documented in the entry documenting `minitar_read_entry()`.
+
+This function starts searching from the current archive position, which means that to find a matching entry in the entire archive `minitar_rewind()` should be called on it first.
+
+The state of `mp` after `minitar_find_by_name()` returns is unspecified, but a successive call to `minitar_find_by_name()` will return the next matching entry, if there is one. (Calling `minitar_find_by_name()` in a loop until it returns NULL will return all matching entries.)
+
+In order to petform other minitar operations on the archive, `minitar_rewind()` should probably be called first, to get a known state.
+
+### minitar_find_any_of
+`struct minitar_entry* minitar_find_any_of(struct minitar* mp, enum minitar_file_type type)`
+
+Does the same thing as `minitar_find_by_name()`, but matches the file type instead of the name. As with `minitar_find_by_name()`, this function starts searching from the current archive position and calling it in a loop until it returns NULL will return all matching entries.
+
 ### minitar_close
 `int minitar_close(struct minitar* mp)`
 
diff --git a/minitar.h b/minitar.h
index e8ad393..dcaf38b 100644
--- a/minitar.h
+++ b/minitar.h
@@ -43,6 +43,8 @@ struct minitar* minitar_open(const char* pathname);
 struct minitar_entry* minitar_read_entry(struct minitar* mp);
 void minitar_free_entry(struct minitar_entry* entry);
 void minitar_rewind(struct minitar* mp);
+struct minitar_entry* minitar_find_by_name(struct minitar* mp, const char* name);
+struct minitar_entry* minitar_find_any_of(struct minitar* mp, enum minitar_file_type type);
 int minitar_close(struct minitar* mp);
 
 #endif
\ No newline at end of file
diff --git a/src/tar.c b/src/tar.c
index b7cb056..8e71332 100644
--- a/src/tar.c
+++ b/src/tar.c
@@ -2,6 +2,7 @@
 #include "tar.h"
 #include "minitar.h"
 #include <stdlib.h>
+#include <string.h>
 
 int minitar_read_header(struct minitar* mp, struct tar_header* hdr);
 int minitar_validate_header(struct tar_header* hdr);
@@ -72,4 +73,32 @@ void minitar_free_entry(struct minitar_entry* entry)
 {
     free(entry->ptr);
     free(entry);
+}
+
+struct minitar_entry* minitar_find_by_name(struct minitar* mp, const char* name)
+{
+    struct minitar_entry* entry;
+    do {
+        entry = minitar_read_entry(mp);
+        if (entry)
+        {
+            if (!strcmp(entry->metadata.name, name)) return entry;
+            minitar_free_entry(entry);
+        }
+    } while (entry);
+    return NULL;
+}
+
+struct minitar_entry* minitar_find_any_of(struct minitar* mp, enum minitar_file_type type)
+{
+    struct minitar_entry* entry;
+    do {
+        entry = minitar_read_entry(mp);
+        if (entry)
+        {
+            if (entry->metadata.type == type) return entry;
+            minitar_free_entry(entry);
+        }
+    } while (entry);
+    return NULL;
 }
\ No newline at end of file