feat(ltm): initial instantiate function

ltm/src/_include/ltm/template_internal.h

@@ -93,14 +93,20 @@ typedef struct ltm_instance_block {
   struct ltm_instance_block *next;
 } ltm_instance_block;
 
+ltm_err ltm_instance_block_init(ltm_instance_block **out);
+
 struct ltm_instance {
+  const ltm_template *template;
   struct {
     ltm_instance_block *head;
     ltm_instance_block *tail;
     ltm_instance_block *current;
   } blocks;
+  ltm_instance_block ***vars;
   // How many bytes of the current block have been written
   size_t written;
 };
 
+ltm_err ltm_instance_init(ltm_instance **out);
+
 #endif

ltm/src/ltm_instance.c

@@ -0,0 +1,76 @@
+#include "ltm/template.h"
+#include "ltm/template_internal.h"
+
+ltm_err ltm_instance_block_init(ltm_instance_block **out) {
+  ltm_instance_block *block = calloc(1, sizeof(ltm_instance_block));
+
+  if (block == NULL) {
+    return ltm_err_failed_alloc;
+  }
+
+  *out = block;
+
+  return ltm_err_ok;
+}
+
+ltm_err ltm_instance_init(ltm_instance **out) {
+  ltm_instance *instance = calloc(1, sizeof(ltm_instance));
+
+  if (instance == NULL) {
+    return ltm_err_failed_alloc;
+  }
+
+  *out = instance;
+
+  return ltm_err_ok;
+}
+
+ltm_err ltm_template_instantiate(ltm_instance **out,
+                                 const ltm_template *template) {
+  ltm_instance *instance;
+  LTM_RES(ltm_instance_init(&instance));
+
+  instance->template = template;
+
+  ltm_instance_block ***vars =
+      malloc(template->names.len * sizeof(ltm_instance_block **));
+
+  if (vars == NULL) {
+    return ltm_err_failed_alloc;
+  }
+
+  instance->vars = vars;
+
+  for (size_t block_index = 0; block_index < template->blocks.len;
+       block_index++) {
+    ltm_template_block *template_block = &template->blocks.arr[block_index];
+
+    switch (template_block->type) {
+    case ltm_template_block_type_literal: {
+      ltm_instance_block *block;
+      LTM_RES(ltm_instance_block_init(&block));
+
+      block->type = ltm_instance_block_type_buf;
+      block->data.ptr = template_block->data.ptr;
+      block->data.len = template_block->data.len;
+
+      if (instance->blocks.head == NULL) {
+        instance->blocks.head = block;
+        instance->blocks.tail = block;
+        instance->blocks.current = block;
+      } else {
+        instance->blocks.tail->next = block;
+        instance->blocks.tail = block;
+      }
+    } break;
+    case ltm_template_block_type_var:
+    case ltm_template_block_type_nested:
+      *vars = &instance->blocks.tail->next;
+      vars++;
+    }
+  }
+
+  *out = instance;
+
+  return ltm_err_ok;
+}