grammar: fix regression caused by ggml-org#17381 (ggml-org#17412)

* grammar: fix regression caused by ggml-org#17381

* more readable

Author: ngxson

src/llama-grammar.cpp

@@ -347,10 +347,10 @@ const char * llama_grammar_parser::parse_sequence(
     size_t last_sym_start = rule.size();
     const char * pos = src;
 
-    // use UINT64_MAX as the empty value because we aligned to the proper unsigned long type so -1 can't be used
+    // use UINT64_MAX as the empty value because we aligned to the proper uint64_t type so -1 can't be used
     // (though it's technically the same as -1 now)
-    auto handle_repetitions = [&](unsigned long min_times, unsigned long max_times) {
-
+    auto handle_repetitions = [&](uint64_t min_times, uint64_t max_times) {
+        bool no_max = max_times == UINT64_MAX;
         if (last_sym_start == rule.size()) {
             throw std::runtime_error(std::string("expecting preceding item to */+/?/{ at ") + pos);
         }
@@ -377,20 +377,20 @@ const char * llama_grammar_parser::parse_sequence(
             rule.resize(last_sym_start);
         } else {
             // Repeat the previous elements (min_times - 1) times
-            for (unsigned long i = 1; i < min_times; i++) {
+            for (uint64_t i = 1; i < min_times; i++) {
                 rule.insert(rule.end(), prev_rule.begin(), prev_rule.end());
             }
         }
 
         uint32_t last_rec_rule_id = 0;
-        auto n_opt = max_times == UINT64_MAX ? 1 : max_times - min_times;
+        auto n_opt = no_max ? 1 : max_times - min_times;
 
         llama_grammar_rule rec_rule(prev_rule);
-        for (unsigned long i = 0; i < n_opt; i++) {
+        for (uint64_t i = 0; i < n_opt; i++) {
             rec_rule.resize(prev_rule.size());
             uint32_t rec_rule_id = generate_symbol_id( rule_name);
-            if (i > 0 || max_times == UINT64_MAX) {
-                rec_rule.push_back({LLAMA_GRETYPE_RULE_REF, max_times == UINT64_MAX ? rec_rule_id : last_rec_rule_id});
+            if (i > 0 || no_max) {
+                rec_rule.push_back({LLAMA_GRETYPE_RULE_REF, no_max ? rec_rule_id : last_rec_rule_id});
             }
             rec_rule.push_back({LLAMA_GRETYPE_ALT, 0});
             rec_rule.push_back({LLAMA_GRETYPE_END, 0});
@@ -482,10 +482,10 @@ const char * llama_grammar_parser::parse_sequence(
                 throw std::runtime_error(std::string("expecting an int at ") + pos);
             }
             const char * int_end = parse_int(pos);
-            unsigned long min_times = std::stoul(std::string(pos, int_end - pos));
+            uint64_t min_times = std::stoul(std::string(pos, int_end - pos));
             pos = parse_space(int_end, is_nested);
 
-            unsigned long max_times = UINT64_MAX;
+            uint64_t max_times = UINT64_MAX; // default: no max limit
 
             if (*pos == '}') {
                 max_times = min_times;
@@ -506,7 +506,8 @@ const char * llama_grammar_parser::parse_sequence(
             } else {
                 throw std::runtime_error(std::string("expecting ',' at ") + pos);
             }
-            if (min_times > MAX_REPETITION_THRESHOLD || (max_times != UINT64_MAX && max_times > MAX_REPETITION_THRESHOLD)) {
+            bool has_max = max_times != UINT64_MAX;
+            if (min_times > MAX_REPETITION_THRESHOLD || (has_max && max_times > MAX_REPETITION_THRESHOLD)) {
                 throw std::runtime_error(std::string("number of repetitions exceeds sane defaults, please reduce the number of repetitions"));
             }
             handle_repetitions(min_times, max_times);