From 679c4501846391539061e53fbb6573daf407f8ba Mon Sep 17 00:00:00 2001
From: Qiang Yu <yuq825@gmail.com>
Date: Mon, 9 Dec 2024 16:08:40 +0800
Subject: [PATCH] util/blake3: add _mesa_blake3_from_printed_string

To convert printed blake3 string back to blake3 hash.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32570>
---
 src/util/mesa-blake3.c | 27 ++++++++++++++++++++++++++-
 src/util/mesa-blake3.h |  5 ++++-
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/src/util/mesa-blake3.c b/src/util/mesa-blake3.c
index b813a288684..0f89f2da8a8 100644
--- a/src/util/mesa-blake3.c
+++ b/src/util/mesa-blake3.c
@@ -53,6 +53,13 @@ blake3_to_uint32(const blake3_hash blake3,
       out[i / 4] |= (uint32_t)blake3[i] << ((i % 4) * 8);
 }
 
+static void
+blake3_from_uint32(blake3_hash blake3, uint32_t in[BLAKE3_OUT_LEN32])
+{
+   for (unsigned i = 0; i < BLAKE3_OUT_LEN; i++)
+      blake3[i] = (in[i / 4] >> ((i % 4) * 8)) & 0xff;
+}
+
 void
 _mesa_blake3_print(FILE *f, const blake3_hash blake3)
 {
@@ -63,6 +70,24 @@ _mesa_blake3_print(FILE *f, const blake3_hash blake3)
    }
 }
 
+bool
+_mesa_blake3_from_printed_string(blake3_hash blake3, const char *printed)
+{
+   unsigned expected_len = BLAKE3_OUT_LEN32 * 12 - 2;
+   if (strlen(printed) != expected_len)
+      return false;
+
+   uint32_t u32[BLAKE3_OUT_LEN32];
+   for (unsigned i = 0; i < BLAKE3_OUT_LEN32; i++) {
+      int ret = sscanf(printed, i == BLAKE3_OUT_LEN32 - 1 ? "0x%08" PRIx32 : "0x%08" PRIx32 ", ", &u32[i]);
+      if (ret != 1)
+         return false;
+      printed += 12;
+   }
+   blake3_from_uint32(blake3, u32);
+   return true;
+}
+
 bool
 _mesa_printed_blake3_equal(const blake3_hash blake3,
                            const uint32_t printed_blake3[BLAKE3_OUT_LEN32])
@@ -71,4 +96,4 @@ _mesa_printed_blake3_equal(const blake3_hash blake3,
    blake3_to_uint32(blake3, u32);
 
    return memcmp(u32, printed_blake3, sizeof(u32)) == 0;
-}
\ No newline at end of file
+}
diff --git a/src/util/mesa-blake3.h b/src/util/mesa-blake3.h
index 10313a99672..504cad8911f 100644
--- a/src/util/mesa-blake3.h
+++ b/src/util/mesa-blake3.h
@@ -68,6 +68,9 @@ _mesa_blake3_compute(const void *data, size_t size, blake3_hash result);
 void
 _mesa_blake3_print(FILE *f, const blake3_hash blake3);
 
+bool
+_mesa_blake3_from_printed_string(blake3_hash blake3, const char *printed);
+
 bool
 _mesa_printed_blake3_equal(const blake3_hash blake3,
                            const uint32_t printed_blake3[BLAKE3_OUT_LEN32]);
@@ -76,4 +79,4 @@ _mesa_printed_blake3_equal(const blake3_hash blake3,
 } /* extern C */
 #endif
 
-#endif
\ No newline at end of file
+#endif