util: Add dedicated hex conversion functions and use it.

This deduplicate two identical bytes_to_hex implementation into one.

The intention is to ease the introduction of a new hash algorithm, which
will also have its formatting helper (to ensure seamless transition from
sha1).

Note that the new functions always take the size of the binary buffer,
unlike the old disk_cache_format_hex_id which took `binary * 2` which was
inconsistent (binary size is `binary` and string size is `binary * 2 + 1`).

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22527>

diff --git a/src/util/disk_cache.h b/src/util/disk_cache.h
index 026ca42..32f6380 100644 (file)
--- a/src/util/disk_cache.h
+++ b/src/util/disk_cache.h
@@ -33,6 +33,7 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <sys/stat.h>
+#include "util/hex.h"
 #include "util/mesa-sha1.h"
 #include "util/detect_os.h"
 
@@ -82,16 +83,7 @@ struct disk_cache;
 static inline char *
 disk_cache_format_hex_id(char *buf, const uint8_t *hex_id, unsigned size)
 {
-   static const char hex_digits[] = "0123456789abcdef";
-   unsigned i;
-
-   for (i = 0; i < size; i += 2) {
-      buf[i] = hex_digits[hex_id[i >> 1] >> 4];
-      buf[i + 1] = hex_digits[hex_id[i >> 1] & 0x0f];
-   }
-   buf[i] = '\0';
-
-   return buf;
+   return mesa_bytes_to_hex(buf, hex_id, size / 2);
 }
 
 #ifdef HAVE_DLADDR

diff --git a/src/util/hex.h b/src/util/hex.h
new file mode 100644 (file)
index 0000000..5bd6180
--- /dev/null
+++ b/src/util/hex.h
@@ -0,0 +1,69 @@
+/* Copyright © 2023 Valve Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef UTIL_HEX_H
+#define UTIL_HEX_H
+
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Convert a binary buffer of length `len` to a hexadecimal string of length
+ * `len * 2 + 1` (including NUL terminator).
+ */
+static inline char *mesa_bytes_to_hex(char *buf, const unsigned char *binary,
+                                      unsigned len) {
+  static const char hex_digits[] = "0123456789abcdef";
+  unsigned i;
+
+  for (i = 0; i < len * 2; i += 2) {
+    buf[i] = hex_digits[binary[i >> 1] >> 4];
+    buf[i + 1] = hex_digits[binary[i >> 1] & 0x0f];
+  }
+  buf[i] = '\0';
+
+  return buf;
+}
+
+/*
+ * Read `len` pairs of hexadecimal digits from `hex` and write the values to
+ * `binary` as `len` bytes.
+ */
+static inline void mesa_hex_to_bytes(unsigned char *buf, const char *hex,
+                                     unsigned len) {
+  for (unsigned i = 0; i < len; i++) {
+    char tmp[3];
+    tmp[0] = hex[i * 2];
+    tmp[1] = hex[(i * 2) + 1];
+    tmp[2] = '\0';
+    buf[i] = strtol(tmp, NULL, 16);
+  }
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
\ No newline at end of file

diff --git a/src/util/mesa-sha1.c b/src/util/mesa-sha1.c
index bdca123..eed6e34 100644 (file)
--- a/src/util/mesa-sha1.c
+++ b/src/util/mesa-sha1.c
@@ -26,6 +26,7 @@
 
 #include "sha1/sha1.h"
 #include "mesa-sha1.h"
+#include "hex.h"
 #include <string.h>
 #include <inttypes.h>
 
@@ -42,14 +43,7 @@ _mesa_sha1_compute(const void *data, size_t size, unsigned char result[20])
 void
 _mesa_sha1_format(char *buf, const unsigned char *sha1)
 {
-   static const char hex_digits[] = "0123456789abcdef";
-   int i;
-
-   for (i = 0; i < 40; i += 2) {
-      buf[i] = hex_digits[sha1[i >> 1] >> 4];
-      buf[i + 1] = hex_digits[sha1[i >> 1] & 0x0f];
-   }
-   buf[i] = '\0';
+   mesa_bytes_to_hex(buf, sha1, SHA1_DIGEST_LENGTH);
 }
 
 /* Convert a hashs string hexidecimal representation into its more compact
@@ -58,13 +52,7 @@ _mesa_sha1_format(char *buf, const unsigned char *sha1)
 void
 _mesa_sha1_hex_to_sha1(unsigned char *buf, const char *hex)
 {
-   for (unsigned i = 0; i < 20; i++) {
-      char tmp[3];
-      tmp[0] = hex[i * 2];
-      tmp[1] = hex[(i * 2) + 1];
-      tmp[2] = '\0';
-      buf[i] = strtol(tmp, NULL, 16);
-   }
+   mesa_hex_to_bytes(buf, hex, SHA1_DIGEST_LENGTH);
 }
 
 static void

diff --git a/src/util/meson.build b/src/util/meson.build
index e74b187..9b4864c 100644 (file)
--- a/src/util/meson.build
+++ b/src/util/meson.build
@@ -64,6 +64,7 @@ files_mesa_util = files(
   'half_float.h',
   'hash_table.c',
   'hash_table.h',
+  'hex.h',
   'u_idalloc.c',
   'u_idalloc.h',
   'list.h',