/*
  tre-ast.c - Abstract syntax tree (AST) routines

  This software is released under a BSD-style license.
  See the file LICENSE for details and copyright.

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /* HAVE_CONFIG_H */
#include <assert.h>
#include <limits.h>

#include "tre-ast.h"
#include "tre-mem.h"

tre_ast_node_t *
tre_ast_new_node(tre_mem_t mem, tre_ast_type_t type, size_t size)
{
  tre_ast_node_t *node;

  node = tre_mem_calloc(mem, sizeof(*node));
  if (!node)
    return NULL;
  node->obj = tre_mem_calloc(mem, size);
  if (!node->obj)
    return NULL;
  node->type = type;
  node->nullable = -1;
  node->submatch_id = -1;

  return node;
}

tre_ast_node_t *
tre_ast_new_literal(tre_mem_t mem, int code_min, int code_max, int position)
{
  tre_ast_node_t *node;
  tre_literal_t *lit;

  node = tre_ast_new_node(mem, LITERAL, sizeof(tre_literal_t));
  if (!node)
    return NULL;
  lit = node->obj;
  lit->code_min = code_min;
  lit->code_max = code_max;
  lit->position = position;

  return node;
}

tre_ast_node_t *
tre_ast_new_iter(tre_mem_t mem, tre_ast_node_t *arg, int min, int max,
		 int minimal)
{
  tre_ast_node_t *node;
  tre_iteration_t *iter;

  node = tre_ast_new_node(mem, ITERATION, sizeof(tre_iteration_t));
  if (!node)
    return NULL;
  iter = node->obj;
  iter->arg = arg;
  iter->min = min;
  iter->max = max;
  iter->minimal = minimal;
  node->num_submatches = arg->num_submatches;

  return node;
}

tre_ast_node_t *
tre_ast_new_union(tre_mem_t mem, tre_ast_node_t *left, tre_ast_node_t *right)
{
  tre_ast_node_t *node;

  node = tre_ast_new_node(mem, UNION, sizeof(tre_union_t));
  if (node == NULL)
    return NULL;
  ((tre_union_t *)node->obj)->left = left;
  ((tre_union_t *)node->obj)->right = right;
  node->num_submatches = left->num_submatches + right->num_submatches;

  return node;
}

tre_ast_node_t *
tre_ast_new_catenation(tre_mem_t mem, tre_ast_node_t *left,
		       tre_ast_node_t *right)
{
  tre_ast_node_t *node;

  node = tre_ast_new_node(mem, CATENATION, sizeof(tre_catenation_t));
  if (node == NULL)
    return NULL;
  ((tre_catenation_t *)node->obj)->left = left;
  ((tre_catenation_t *)node->obj)->right = right;
  // UBSAN warning in clang 10: signed integer overflow
  double tmp = (double)left->num_submatches + (double)right->num_submatches;
  if (tmp >= INT_MIN && tmp <= INT_MAX)
      node->num_submatches = left->num_submatches + right->num_submatches;
  else node->num_submatches = 0;

  return node;
}

#ifdef TRE_DEBUG

static void
tre_findent(FILE *stream, int i)
{
  while (i-- > 0)
    fputc(' ', stream);
}

void
tre_print_params(int *params)
{
  int i;
  if (params)
    {
      DPRINT(("params ["));
      for (i = 0; i < TRE_PARAM_LAST; i++)
	{
	  if (params[i] == TRE_PARAM_UNSET)
	    DPRINT(("unset"));
	  else if (params[i] == TRE_PARAM_DEFAULT)
	    DPRINT(("default"));
	  else
	    DPRINT(("%d", params[i]));
	  if (i < TRE_PARAM_LAST - 1)
	    DPRINT((", "));
	}
      DPRINT(("]"));
    }
}

static void
tre_do_print(FILE *stream, tre_ast_node_t *ast, int indent)
{
  int code_min, code_max, pos;
  int num_tags = ast->num_tags;
  tre_literal_t *lit;
  tre_iteration_t *iter;

  tre_findent(stream, indent);
  switch (ast->type)
    {
    case LITERAL:
      lit = ast->obj;
      code_min = lit->code_min;
      code_max = lit->code_max;
      pos = lit->position;
      if (IS_EMPTY(lit))
	{
	  fprintf(stream, "literal empty\n");
	}
      else if (IS_ASSERTION(lit))
	{
	  int i;
	  char *assertions[] = { "bol", "eol", "ctype", "!ctype",
				 "bow", "eow", "wb", "!wb" };
	  if (code_max >= ASSERT_LAST << 1)
	    assert(0);
	  fprintf(stream, "assertions: ");
	  for (i = 0; (1 << i) <= ASSERT_LAST; i++)
	    if (code_max & (1 << i))
	      fprintf(stream, "%s ", assertions[i]);
	  fprintf(stream, "\n");
	}
      else if (IS_TAG(lit))
	{
	  fprintf(stream, "tag %d\n", code_max);
	}
      else if (IS_BACKREF(lit))
	{
	  fprintf(stream, "backref %d, pos %d\n", code_max, pos);
	}
      else if (IS_PARAMETER(lit))
	{
	  tre_print_params(lit->u.params);
	  fprintf(stream, "\n");
	}
      else
	{
	  fprintf(stream, "literal (%c, %c) (%d, %d), pos %d, sub %d, "
		  "%d tags\n", code_min, code_max, code_min, code_max, pos,
		  ast->submatch_id, num_tags);
	}
      break;
    case ITERATION:
      iter = ast->obj;
      fprintf(stream, "iteration {%d, %d}, sub %d, %d tags, %s\n",
	      iter->min, iter->max, ast->submatch_id, num_tags,
	      iter->minimal ? "minimal" : "greedy");
      tre_do_print(stream, iter->arg, indent + 2);
      break;
    case UNION:
      fprintf(stream, "union, sub %d, %d tags\n", ast->submatch_id, num_tags);
      tre_do_print(stream, ((tre_union_t *)ast->obj)->left, indent + 2);
      tre_do_print(stream, ((tre_union_t *)ast->obj)->right, indent + 2);
      break;
    case CATENATION:
      fprintf(stream, "catenation, sub %d, %d tags\n", ast->submatch_id,
	      num_tags);
      tre_do_print(stream, ((tre_catenation_t *)ast->obj)->left, indent + 2);
      tre_do_print(stream, ((tre_catenation_t *)ast->obj)->right, indent + 2);
      break;
    default:
      assert(0);
      break;
    }
}

static void
tre_ast_fprint(FILE *stream, tre_ast_node_t *ast)
{
  tre_do_print(stream, ast, 0);
}

void
tre_ast_print(tre_ast_node_t *tree)
{
  printf("AST:\n");
  tre_ast_fprint(stdout, tree);
}

#endif /* TRE_DEBUG */

/* EOF */
