gguf : add gguf_find_key (#2438)

* gguf.cpp : find key example

* ggml.h : add gguf_find_key

* ggml.c : add gguf_find_key

Author: klosax

examples/gguf/gguf.cpp

@@ -253,6 +253,20 @@ bool gguf_ex_read_0(const std::string & fname) {
         }
     }
 
+    // find kv string
+    {
+        char findkey[32];
+        sprintf(findkey, "some.parameter.string");
+
+        int keyidx = gguf_find_key(ctx, findkey);
+        if (keyidx == -1) {
+            fprintf(stdout, "%s: find key: %s not found.\n", __func__, findkey);
+        } else {
+            const char * key_value = gguf_get_val_str(ctx, keyidx);
+            fprintf(stdout, "%s: find key: %s found, kv[%d] value = %s\n", __func__, findkey, keyidx, key_value);
+        }
+    }
+
     // tensor info
     {
         const int n_tensors = gguf_get_n_tensors(ctx);

ggml.c

@@ -18745,6 +18745,21 @@ int gguf_get_n_kv(struct gguf_context * ctx) {
     return ctx->header.n_kv;
 }
 
+int gguf_find_key(struct gguf_context * ctx, const char * key) {
+    // return -1 if key not found
+    const int n_kv = gguf_get_n_kv(ctx);
+    int keyfound   = -1;
+
+    for (int i = 0; i < n_kv; ++i) {
+        if (strcmp(key, gguf_get_key(ctx, i)) == 0) {
+            keyfound = i;
+            break;
+        }
+    }
+
+    return keyfound;
+}
+
 const char * gguf_get_key(struct gguf_context * ctx, int i) {
     return ctx->header.kv[i].key.data;
 }

ggml.h

@@ -1653,6 +1653,7 @@ extern "C" {
     GGML_API void * gguf_get_data       (struct gguf_context * ctx);
 
     GGML_API int          gguf_get_n_kv(struct gguf_context * ctx);
+    GGML_API int          gguf_find_key(struct gguf_context * ctx, const char * key);
     GGML_API const char * gguf_get_key (struct gguf_context * ctx, int i);
     GGML_API void         gguf_get_val (struct gguf_context * ctx, int i, void * val);