Don't Use StringStream When It's Overkill

(This is a merge of http://go/wvgerrit/76063)

Now that we have C++11, many places that do string formatting or parsing
can be replaced with std::to_string() or one of the std::sto*() family
of functions. This patch updates places that do simple stringifying or
parsing to use these functions. Some parts of the code are left
untouched because they were using StringStream to do more complex
actions, such as constructing more complex output or checking the status
of the parsing.

Bug: 120599938
Test: CE CDM Unit Tests
Test: Android Unit Tests
Change-Id: I482dc234ecd7c6014fa9b6874387ff51e04b772f

libwvdrmengine/cdm/core/src/cdm_session.cpp

@@ -7,8 +7,7 @@
 #include <assert.h>
 #include <stdlib.h>
 
-#include <iostream>
-#include <sstream>
+#include <string>
 
 #include "cdm_engine.h"
 #include "clock.h"
@@ -607,9 +606,8 @@ CdmResponseType CdmSession::QueryOemCryptoSessionId(
     return NOT_INITIALIZED_ERROR;
   }
 
-  std::stringstream ss;
-  ss << crypto_session_->oec_session_id();
-  (*query_response)[QUERY_KEY_OEMCRYPTO_SESSION_ID] = ss.str();
+  (*query_response)[QUERY_KEY_OEMCRYPTO_SESSION_ID] =
+      std::to_string(crypto_session_->oec_session_id());
   return NO_ERROR;
 }
 

libwvdrmengine/cdm/core/src/client_identification.cpp

@@ -4,7 +4,7 @@
 
 #include "client_identification.h"
 
-#include <sstream>
+#include <string>
 
 #include "crypto_session.h"
 #include "license_protocol.pb.h"
@@ -146,9 +146,8 @@ CdmResponseType ClientIdentification::Prepare(
   }
   client_info = client_id->add_client_info();
   client_info->set_name(kKeyOemCryptoSecurityPatchLevel);
-  std::stringstream ss;
-  ss << (uint32_t)crypto_session_->GetSecurityPatchLevel();
-  client_info->set_value(ss.str());
+  client_info->set_value(
+      std::to_string((uint32_t)crypto_session_->GetSecurityPatchLevel()));
 
   if (!provider_client_token.empty()) {
     client_id->set_provider_client_token(provider_client_token);

libwvdrmengine/cdm/core/src/initialization_data.cpp

@@ -5,7 +5,7 @@
 #include "initialization_data.h"
 
 #include <string.h>
-#include <sstream>
+#include <string>
 
 #include "buffer_reader.h"
 #include "cdm_engine.h"
@@ -721,13 +721,7 @@ bool InitializationData::DetectEntitlementPreference(
   if (oec_version_string.empty()) {
     return false;
   }
-
-  uint32_t oec_version_int = 0;
-  std::istringstream parse_int;
-  parse_int.str(oec_version_string);
-  parse_int >> oec_version_int;
-
-  return oec_version_int >= 14;
+  return std::stoul(oec_version_string) >= 14;
 }
 
 }  // namespace wvcdm

libwvdrmengine/cdm/core/src/policy_engine.cpp

@@ -5,7 +5,7 @@
 #include "policy_engine.h"
 
 #include <limits.h>
-#include <sstream>
+#include <string>
 
 #include "clock.h"
 #include "log.h"
@@ -271,7 +271,6 @@ void PolicyEngine::NotifySessionExpiration() {
 }
 
 CdmResponseType PolicyEngine::Query(CdmQueryMap* query_response) {
-  std::stringstream ss;
   int64_t current_time = GetCurrentTime();
 
   if (license_state_ == kLicenseStateInitial) {
@@ -288,11 +287,10 @@ CdmResponseType PolicyEngine::Query(CdmQueryMap* query_response) {
       policy_.can_persist() ? QUERY_VALUE_TRUE : QUERY_VALUE_FALSE;
   (*query_response)[QUERY_KEY_RENEW_ALLOWED] =
       policy_.can_renew() ? QUERY_VALUE_TRUE : QUERY_VALUE_FALSE;
-  ss << GetLicenseOrRentalDurationRemaining(current_time);
-  (*query_response)[QUERY_KEY_LICENSE_DURATION_REMAINING] = ss.str();
-  ss.str("");
-  ss << GetPlaybackDurationRemaining(current_time);
-  (*query_response)[QUERY_KEY_PLAYBACK_DURATION_REMAINING] = ss.str();
+  (*query_response)[QUERY_KEY_LICENSE_DURATION_REMAINING] =
+      std::to_string(GetLicenseOrRentalDurationRemaining(current_time));
+  (*query_response)[QUERY_KEY_PLAYBACK_DURATION_REMAINING] =
+      std::to_string(GetPlaybackDurationRemaining(current_time));
   (*query_response)[QUERY_KEY_RENEWAL_SERVER_URL] =
       policy_.renewal_server_url();