server: Added support for n_predict values of -2

Author: N0rthHXD

examples/server/server.cpp

@@ -1321,17 +1321,29 @@ struct server_slot {
             && are_lora_equal(lora, other_slot.lora);
     }
 
-    bool has_budget(const common_params & global_params) {
+    bool has_budget(const common_params & global_params, int32_t slot_n_ctx) {
         if (params.n_predict == -1 && global_params.n_predict == -1) {
             return true; // limitless
         }
 
         n_remaining = -1;
-
-        if (params.n_predict != -1) {
-            n_remaining = params.n_predict - n_decoded;
-        } else if (global_params.n_predict != -1) {
-            n_remaining = global_params.n_predict - n_decoded;
+        if (global_params.n_predict == -1) {
+            if (params.n_predict == -2)
+                n_remaining = slot_n_ctx - n_decoded;
+            else
+                n_remaining = params.n_predict - n_decoded;
+        } else if (global_params.n_predict == -2) {
+            if (params.n_predict == -1 || params.n_predict == -2)
+                n_remaining = slot_n_ctx - n_decoded;
+            else
+                n_remaining = std::min(params.n_predict - n_decoded, slot_n_ctx - n_decoded);
+        } else {
+            if (params.n_predict == -1)
+                n_remaining = global_params.n_predict - n_decoded;
+            else if (params.n_predict == -2)
+                n_remaining = std::min(global_params.n_predict - n_decoded, slot_n_ctx - n_decoded);
+            else
+                n_remaining = std::min(params.n_predict - n_decoded, global_params.n_predict - n_decoded);
         }
 
         return n_remaining > 0; // no budget
@@ -2153,7 +2165,7 @@ struct server_context {
         }
 
         // check the limits
-        if (slot.n_decoded > 0 && slot.has_next_token && !slot.has_budget(params_base)) {
+        if (slot.n_decoded > 0 && slot.has_next_token && !slot.has_budget(params_base, slot.n_ctx)) {
             slot.stop           = STOP_TYPE_LIMIT;
             slot.has_next_token = false;