Extract ParseDescriptorRange

So as to be consistently informative when the checks fail, and
to protect against unintentional divergence among the checks.

1 files changed, 19 insertions, 1 deletions

diff --git a/src/rpc/util.cpp b/src/rpc/util.cpp
index 10979b43b0..8f8488bc5f 100644
--- a/src/rpc/util.cpp
+++ b/src/rpc/util.cpp
@@ -8,6 +8,8 @@
 #include <tinyformat.h>
 #include <util/strencodings.h>
 
+#include <tuple>
+
 InitInterfaces* g_rpc_interfaces = nullptr;
 
 // Converts a hex string to a public key if possible
@@ -529,7 +531,7 @@ std::string RPCArg::ToString(const bool oneline) const
     assert(false);
 }
 
-std::pair<int64_t, int64_t> ParseRange(const UniValue& value)
+static std::pair<int64_t, int64_t> ParseRange(const UniValue& value)
 {
     if (value.isNum()) {
         return {0, value.get_int64()};
@@ -542,3 +544,19 @@ std::pair<int64_t, int64_t> ParseRange(const UniValue& value)
     }
     throw JSONRPCError(RPC_INVALID_PARAMETER, "Range must be specified as end or as [begin,end]");
 }
+
+std::pair<int64_t, int64_t> ParseDescriptorRange(const UniValue& value)
+{
+    int64_t low, high;
+    std::tie(low, high) = ParseRange(value);
+    if (low < 0) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Range should be greater or equal than 0");
+    }
+    if ((high >> 31) != 0) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "End of range is too high");
+    }
+    if (high >= low + 1000000) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Range is too large");
+    }
+    return {low, high};
+}