COMPMID-1817 Replace std::regex with POSIX C regex in runtime

Change-Id: I6066cfc8c1bc16e212171cc9eb4bd6a3ab003485
Reviewed-on: https://review.mlplatform.org/318
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Reviewed-by: Anthony Barbier <Anthony.barbier@arm.com>

1 files changed, 16 insertions, 28 deletions

diff --git a/src/runtime/MEMUtils.cpp b/src/runtime/MEMUtils.cpp
index be6a3b690d..5ae1c2abef 100644
--- a/src/runtime/MEMUtils.cpp
+++ b/src/runtime/MEMUtils.cpp
@@ -27,7 +27,7 @@
 
 #ifndef BARE_METAL
 #include <fstream>
-#include <regex>
+#include <iterator>
 #include <sstream>
 #endif // ifndef BARE_METAL
 
@@ -43,45 +43,33 @@ void parse_mem_info(size_t &total, size_t &free, size_t &buffer)
     size_t        memfree  = 0;
     std::ifstream meminfo_f;
     meminfo_f.open("/proc/meminfo", std::ios::in);
+
     if(meminfo_f.is_open())
     {
-        std::stringstream str_stream;
-        str_stream << meminfo_f.rdbuf();
-        const std::string str = str_stream.str();
-#ifndef ARM_COMPUTE_EXCEPTIONS_DISABLED
-        try
+        std::string line;
+        while(bool(getline(meminfo_f, line)))
         {
-#endif /* ARM_COMPUTE_EXCEPTIONS_DISABLED */
-            std::smatch match;
-            if(std::regex_search(str, match, std::regex("MemTotal: (.*)kB")) && match.size() > 1)
+            std::istringstream       iss(line);
+            std::vector<std::string> tokens((std::istream_iterator<std::string>(iss)),
+                                            std::istream_iterator<std::string>());
+            if(tokens[0] == "MemTotal:")
             {
-                const std::string result = match.str(1);
-                total                    = arm_compute::support::cpp11::stoul(result, nullptr);
+                total = arm_compute::support::cpp11::stoul(tokens[1], nullptr);
             }
-            if(std::regex_search(str, match, std::regex("MemFree: (.*)kB")) && match.size() > 1)
+            else if(tokens[0] == "MemFree:")
             {
-                const std::string result = match.str(1);
-                memfree                  = arm_compute::support::cpp11::stoul(result, nullptr);
+                memfree = arm_compute::support::cpp11::stoul(tokens[1], nullptr);
             }
-            if(std::regex_search(str, match, std::regex("Buffers: (.*)kB")) && match.size() > 1)
+            else if(tokens[0] == "Buffers:")
             {
-                const std::string result = match.str(1);
-                buffer                   = arm_compute::support::cpp11::stoul(result, nullptr);
+                buffer = arm_compute::support::cpp11::stoul(tokens[1], nullptr);
             }
-            if(std::regex_search(str, match, std::regex("Cached: (.*)kB")) && match.size() > 1)
+            else if(tokens[0] == "Cached:")
             {
-                const std::string result = match.str(1);
-                memcache                 = arm_compute::support::cpp11::stoul(result, nullptr);
+                memcache = arm_compute::support::cpp11::stoul(tokens[1], nullptr);
             }
-            free = memfree + (buffer + memcache);
-#ifndef ARM_COMPUTE_EXCEPTIONS_DISABLED
-        }
-        catch(std::regex_error &e)
-        {
-            // failed parsing /proc/meminfo
-            // return 0s on all fields
         }
-#endif /* ARM_COMPUTE_EXCEPTIONS_DISABLED */
+        free = memfree + (buffer + memcache);
     }
 #endif // ifndef BARE_METAL
 }