From 01ba4fb41ffbb6a5de7ca2637e5d06d439ba3ebe Mon Sep 17 00:00:00 2001
From: Alexandre Paillier <alexandre.paillier@ledger.fr>
Date: Tue, 26 Apr 2022 18:15:53 +0200
Subject: [PATCH] Small refactoring to the format uint memory utils function

---
 src_features/signMessageEIP712/encode_type.c |  6 ++--
 src_features/signMessageEIP712/encode_type.h |  1 +
 src_features/signMessageEIP712/mem_utils.c   | 32 ++++++++++++++------
 src_features/signMessageEIP712/mem_utils.h   |  7 +++--
 4 files changed, 30 insertions(+), 16 deletions(-)

diff --git a/src_features/signMessageEIP712/encode_type.c b/src_features/signMessageEIP712/encode_type.c
index e65a664..1422407 100644
--- a/src_features/signMessageEIP712/encode_type.c
+++ b/src_features/signMessageEIP712/encode_type.c
@@ -29,8 +29,7 @@ static bool format_field_type_array_levels_string(const void *lvl_ptr, uint8_t l
             case ARRAY_DYNAMIC:
                 break;
             case ARRAY_FIXED_SIZE:
-                // max value = 255, 3 characters max
-                mem_alloc_and_format_uint(array_size, 3);
+                mem_alloc_and_format_uint(array_size, NULL);
                 break;
             default:
                 // should not be in here :^)
@@ -81,8 +80,7 @@ static bool format_field_string(const void *field_ptr)
                 // should not be in here :^)
                 break;
         }
-        // max value = 256, 3 characters max
-        mem_alloc_and_format_uint(field_size, 3);
+        mem_alloc_and_format_uint(field_size, NULL);
     }
 
     // field type array levels
diff --git a/src_features/signMessageEIP712/encode_type.h b/src_features/signMessageEIP712/encode_type.h
index f7ed216..9271cd4 100644
--- a/src_features/signMessageEIP712/encode_type.h
+++ b/src_features/signMessageEIP712/encode_type.h
@@ -2,6 +2,7 @@
 #define ENCODE_TYPE_H_
 
 #include <stdint.h>
+#include <stdbool.h>
 
 const char  *encode_type(const void *const structs_array,
                         const char *const struct_name,
diff --git a/src_features/signMessageEIP712/mem_utils.c b/src_features/signMessageEIP712/mem_utils.c
index 0220fb0..0c5583f 100644
--- a/src_features/signMessageEIP712/mem_utils.c
+++ b/src_features/signMessageEIP712/mem_utils.c
@@ -24,20 +24,34 @@ char    *mem_alloc_and_copy_char(char c)
  * Format an unsigned number up to 32-bit into memory into an ASCII string.
  *
  * @param[in] value Value to write in memory
- * @param[in] max_chars Maximum number of characters that could be written
+ * @param[out] length number of characters written to memory
  *
- * @return how many characters have been written in memory, 0 in case of an allocation error
+ * @return pointer to memory area or \ref NULL if the allocated failed
  */
-uint8_t mem_alloc_and_format_uint(uint32_t value, const uint8_t max_chars)
+char *mem_alloc_and_format_uint(uint32_t value,
+                                uint8_t *const length)
 {
-    char        *ptr;
-    uint8_t     written_chars;
+    char        *mem_ptr;
+    uint32_t    value_copy;
+    uint8_t     size;
 
-    if ((ptr = mem_alloc(sizeof(char) * max_chars)) == NULL)
+    size = 1; // minimum size, even if 0
+    value_copy = value;
+    while (value_copy >= 10)
+    {
+        value_copy /= 10;
+        size += 1;
+    }
+    // +1 for the null character
+    if ((mem_ptr = mem_alloc(sizeof(char) * (size + 1))) == NULL)
     {
         return 0;
     }
-    written_chars = sprintf(ptr, "%u", value);
-    mem_dealloc(max_chars - written_chars); // in case it ended up being less
-    return written_chars;
+    snprintf(mem_ptr, (size + 1), "%u", value);
+    mem_dealloc(sizeof(char)); // to skip the null character
+    if (length != NULL)
+    {
+        *length = size;
+    }
+    return mem_ptr;
 }
diff --git a/src_features/signMessageEIP712/mem_utils.h b/src_features/signMessageEIP712/mem_utils.h
index dad38d6..a86684c 100644
--- a/src_features/signMessageEIP712/mem_utils.h
+++ b/src_features/signMessageEIP712/mem_utils.h
@@ -4,8 +4,9 @@
 #include <stdint.h>
 #include <stdbool.h>
 
-char    *mem_alloc_and_copy_char(char c);
-void    *mem_alloc_and_copy(const void *data, size_t size);
-uint8_t mem_alloc_and_format_uint(uint32_t value, const uint8_t max_chars);
+char *mem_alloc_and_copy_char(char c);
+void *mem_alloc_and_copy(const void *data, size_t size);
+char *mem_alloc_and_format_uint(uint32_t value,
+                                uint8_t *const written_chars);
 
 #endif // MEM_UTILS_H_