From deb54b8866e119f601fde91cb44a6ddf44f1552e Mon Sep 17 00:00:00 2001
From: winlin <winlin@vip.126.com>
Date: Mon, 13 Jul 2020 14:30:44 +0800
Subject: [PATCH] Core: Refine utility string/hex

---
 trunk/src/kernel/srs_kernel_utility.cpp | 16 ++++++++++++++++
 trunk/src/kernel/srs_kernel_utility.hpp | 13 +++++++++----
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/trunk/src/kernel/srs_kernel_utility.cpp b/trunk/src/kernel/srs_kernel_utility.cpp
index 72e2d705e..73ae0c75f 100644
--- a/trunk/src/kernel/srs_kernel_utility.cpp
+++ b/trunk/src/kernel/srs_kernel_utility.cpp
@@ -1078,6 +1078,22 @@ char* srs_data_to_hex(char* des, const u_int8_t* src, int len)
     return des;
 }
 
+char* srs_data_to_hex_lowercase(char* des, const u_int8_t* src, int len)
+{
+    if(src == NULL || len == 0 || des == NULL){
+        return NULL;
+    }
+
+    const char *hex_table = "0123456789abcdef";
+
+    for (int i=0; i<len; i++) {
+        des[i * 2]     = hex_table[src[i] >> 4];
+        des[i * 2 + 1] = hex_table[src[i] & 0x0F];
+    }
+
+    return des;
+}
+
 int srs_hex_to_data(uint8_t* data, const char* p, int size)
 {
     if (size <= 0 || (size%2) == 1) {
diff --git a/trunk/src/kernel/srs_kernel_utility.hpp b/trunk/src/kernel/srs_kernel_utility.hpp
index 8dc54894c..e6a2f3371 100644
--- a/trunk/src/kernel/srs_kernel_utility.hpp
+++ b/trunk/src/kernel/srs_kernel_utility.hpp
@@ -145,12 +145,17 @@ extern srs_error_t srs_av_base64_decode(std::string cipher, std::string& plainte
 // Calculate the output size needed to base64-encode x bytes to a null-terminated string.
 #define SRS_AV_BASE64_SIZE(x) (((x)+2) / 3 * 4 + 1)
 
-// Convert hex string to data, for example, p=config='139056E5A0'
-// The output data in hex {0x13, 0x90, 0x56, 0xe5, 0xa0} as such.
+// Covert hex string to uint8 data, for example:
+//      srs_hex_to_data(data, string("139056E5A0"))
+//      which outputs the data in hex {0x13, 0x90, 0x56, 0xe5, 0xa0}.
 extern int srs_hex_to_data(uint8_t* data, const char* p, int size);
 
-// Convert data string to hex.
-extern char *srs_data_to_hex(char *des, const uint8_t *src, int len);
+// Convert data string to hex, for example:
+//      srs_data_to_hex(des, {0xf3, 0x3f}, 2)
+//      which outputs the des is string("F33F").
+extern char* srs_data_to_hex(char* des, const uint8_t* src, int len);
+// Output in lowercase, such as string("f33f").
+extern char* srs_data_to_hex_lowercase(char* des, const uint8_t* src, int len);
 
 // Generate the c0 chunk header for msg.
 // @param cache, the cache to write header.