/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: Details at https://graphviz.org
 *************************************************************************/

/*
 *  Code for main functions in gpr
 */

#include <ast/ast.h>
#include <ast/error.h>
#include <cgraph/agxbuf.h>
#include <cgraph/alloc.h>
#include <cgraph/strcasecmp.h>
#include <cgraph/unreachable.h>
#include <cgraph/unused.h>
#include <ctype.h>
#include <gvpr/actions.h>
#include <gvpr/compile.h>
#include <limits.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#define KINDS(p)                                                               \
  ((AGTYPE(p) == AGRAPH) ? "graph" : (AGTYPE(p) == AGNODE) ? "node" : "edge")

static int iofread(void *chan, char *buf, int bufsize) {
  FILE *fp = chan;

  return (int)read(fileno(fp), buf, bufsize);
}

static int ioputstr(void *chan, const char *str) { return fputs(str, chan); }

static int ioflush(void *chan) { return fflush(chan); }

static Agiodisc_t gprIoDisc = {iofread, ioputstr, ioflush};

/* sameG:
 * Return common root if objects belong to same root graph.
 * NULL otherwise
 */
Agraph_t *sameG(void *p1, void *p2, char *fn, char *msg) {
  Agobj_t *obj1 = OBJ(p1);
  Agobj_t *obj2 = OBJ(p2);
  Agraph_t *root;

  root = agroot(agraphof(obj1));
  if (root != agroot(agraphof(obj2))) {
    if (msg)
      error(ERROR_WARNING, "%s in %s() belong to different graphs", msg, fn);
    else
      error(ERROR_WARNING, "%s and %s in %s() belong to different graphs",
            KINDS(obj1), KINDS(obj2), fn);
    return 0;
  } else
    return root;
}

/* indexOf:
 * Return index of leftmost string s2 in string s1, or -1
 */
int indexOf(char *s1, char *s2) {
  char *s = strstr(s1, s2);
  return s == NULL ? -1 : (int)(s - s1);
}

/* rindexOf:
 * Return index of rightmost string s2 in string s1, or -1
 */
long rindexOf(char *s1, char *s2) {
  char c1 = *s2;
  char *p;
  size_t len1 = strlen(s1);
  size_t len2 = strlen(s2);

  if (c1 == '\0') {
    assert(len1 <= LONG_MAX);
    return (long)len1;
  }
  if (len2 > len1)
    return -1;
  p = s1 + (len1 - len2);
  while (true) {
    if (strncmp(p, s2, len2) == 0)
      return p - s1;
    if (p == s1)
      break;
    p--;
  }
  return -1;
}

/* match:
 * Return index of pattern pat in string str, or -1
 */
int match(char *str, char *pat) {
  int sub[2];

  if (strgrpmatch(str, pat, sub, 1, STR_MAXIMAL)) {
    return (sub[0]);
  } else
    return -1;
}

/* nodeInduce:
 * Add all edges in root graph connecting two nodes in
 * selected to selected.
 */
void nodeInduce(Agraph_t *selected) {
  Agnode_t *n;
  Agedge_t *e;
  Agraph_t *base;

  if (!selected)
    return;
  base = agroot(selected);
  if (base == selected)
    return;
  for (n = agfstnode(selected); n; n = agnxtnode(selected, n)) {
    for (e = agfstout(base, n); e; e = agnxtout(base, e)) {
      if (agsubnode(selected, aghead(e), 0))
        agsubedge(selected, e, 1);
    }
  }
}

/* copyAttr:
 * Copy attributes from src to tgt. Overrides currently
 * defined values.
 * FIX: we should probably use the default value of the source
 * graph when initializing the attribute, rather than "".
 * NOTE: We do not assume src and tgt have the same kind.
 */
int copyAttr(Agobj_t *src, Agobj_t *tgt) {
  Agraph_t *srcg;
  Agraph_t *tgtg;
  Agsym_t *sym = 0;
  Agsym_t *tsym = 0;
  int skind = AGTYPE(src);
  int tkind = AGTYPE(tgt);
  char *val;

  srcg = agraphof(src);
  tgtg = agraphof(tgt);
  while ((sym = agnxtattr(srcg, skind, sym))) {
    tsym = agattrsym(tgt, sym->name);
    if (!tsym)
      tsym = agattr(tgtg, tkind, sym->name, sym->defval);
    val = agxget(src, sym);
    if (aghtmlstr(val)) {
      val = agstrdup_html(tgtg, val);
      agxset(tgt, tsym, val);
      agstrfree(tgtg, val);
    } else
      agxset(tgt, tsym, val);
  }
  return 0;
}

/* copy:
 * Create new object of type AGTYPE(obj) with all of its
 * attributes.
 * If obj is an edge, only create end nodes if necessary.
 * If obj is a graph, if g is null, create a top-level
 * graph. Otherwise, create a subgraph of g.
 * Assume obj != NULL.
 */
Agobj_t *copy(Agraph_t *g, Agobj_t *obj) {
  Agobj_t *nobj = 0;
  Agedge_t *e;
  Agnode_t *h;
  Agnode_t *t;
  int kind = AGTYPE(obj);
  char *name;

  if (kind != AGRAPH && !g) {
    exerror("NULL graph with non-graph object in copy()");
    return 0;
  }

  switch (kind) {
  case AGNODE:
    name = agnameof(obj);
    nobj = (Agobj_t *)openNode(g, name);
    break;
  case AGRAPH:
    name = agnameof(obj);
    if (g)
      nobj = (Agobj_t *)openSubg(g, name);
    else
      nobj = (Agobj_t *)openG(name, ((Agraph_t *)obj)->desc);
    break;
  case AGINEDGE:
  case AGOUTEDGE:
    e = (Agedge_t *)obj;
    t = openNode(g, agnameof(agtail(e)));
    h = openNode(g, agnameof(aghead(e)));
    name = agnameof(AGMKOUT(e));
    nobj = (Agobj_t *)openEdge(g, t, h, name);
    break;
  default:
    UNREACHABLE();
  }
  if (nobj)
    copyAttr(obj, nobj);

  return nobj;
}

typedef struct {
  Dtlink_t link;
  Agedge_t *key;
  Agedge_t *val;
} edgepair_t;

static Agedge_t *mapEdge(Dt_t *emap, Agedge_t *e) {
  edgepair_t *ep = dtmatch(emap, &e);
  if (ep)
    return ep->val;
  else
    return NULL;
}

/* cloneSubg:
 * Clone subgraph sg in tgt.
 */
static Agraph_t *cloneSubg(Agraph_t *tgt, Agraph_t *g, Dt_t *emap) {
  Agraph_t *ng;
  Agraph_t *sg;
  Agnode_t *t;
  Agnode_t *newt;
  Agedge_t *e;
  Agedge_t *newe;
  char *name;

  ng = (Agraph_t *)copy(tgt, OBJ(g));
  if (!ng)
    return 0;
  for (t = agfstnode(g); t; t = agnxtnode(g, t)) {
    newt = agnode(tgt, agnameof(t), 0);
    if (!newt) {
      exerror("node %s not found in cloned graph %s", agnameof(t),
              agnameof(tgt));
      return 0;
    } else
      agsubnode(ng, newt, 1);
  }
  for (t = agfstnode(g); t; t = agnxtnode(g, t)) {
    for (e = agfstout(g, t); e; e = agnxtout(g, e)) {
      newe = mapEdge(emap, e);
      if (!newe) {
        name = agnameof(AGMKOUT(e));
        if (name)
          exerror("edge (%s,%s)[%s] not found in cloned graph %s",
                  agnameof(agtail(e)), agnameof(aghead(e)), name,
                  agnameof(tgt));
        else
          exerror("edge (%s,%s) not found in cloned graph %s",
                  agnameof(agtail(e)), agnameof(aghead(e)), agnameof(tgt));
        return 0;
      } else
        agsubedge(ng, newe, 1);
    }
  }
  for (sg = agfstsubg(g); sg; sg = agnxtsubg(sg)) {
    if (!cloneSubg(ng, sg, emap)) {
      exerror("error cloning subgraph %s from graph %s", agnameof(sg),
              agnameof(g));
      return 0;
    }
  }
  return ng;
}

static int cmppair(Dt_t *d, Agedge_t **key1, Agedge_t **key2, Dtdisc_t *disc) {
  (void)d;
  (void)disc;

  if (*key1 > *key2)
    return 1;
  else if (*key1 < *key2)
    return -1;
  else
    return 0;
}

static Dtdisc_t edgepair = {
    .key = offsetof(edgepair_t, key),
    .size = sizeof(Agedge_t *),
    .link = offsetof(edgepair_t, link),
    .comparf = (Dtcompar_f)cmppair,
};

/* cloneGraph:
 * Clone node, edge and subgraph structure from src to tgt.
 */
static void cloneGraph(Agraph_t *tgt, Agraph_t *src) {
  Agedge_t *e;
  Agedge_t *ne;
  Agnode_t *t;
  Agraph_t *sg;
  char *name;
  Dt_t *emap = dtopen(&edgepair, Dtoset);
  edgepair_t *data = malloc(sizeof(edgepair_t) * agnedges(src));
  edgepair_t *ep = data;

  for (t = agfstnode(src); t; t = agnxtnode(src, t)) {
    if (!copy(tgt, OBJ(t))) {
      exerror("error cloning node %s from graph %s", agnameof(t),
              agnameof(src));
    }
  }
  for (t = agfstnode(src); t; t = agnxtnode(src, t)) {
    for (e = agfstout(src, t); e; e = agnxtout(src, e)) {
      if (!(ne = (Agedge_t *)copy(tgt, OBJ(e)))) {
        name = agnameof(AGMKOUT(e));
        if (name)
          exerror("error cloning edge (%s,%s)[%s] from graph %s",
                  agnameof(agtail(e)), agnameof(aghead(e)), name,
                  agnameof(src));
        else
          exerror("error cloning edge (%s,%s) from graph %s",
                  agnameof(agtail(e)), agnameof(aghead(e)), agnameof(src));
        goto done;
      }
      ep->key = e;
      ep->val = ne;
      dtinsert(emap, ep++);
    }
  }
  for (sg = agfstsubg(src); sg; sg = agnxtsubg(sg)) {
    if (!cloneSubg(tgt, sg, emap)) {
      exerror("error cloning subgraph %s from graph %s", agnameof(sg),
              agnameof(src));
    }
  }

done:
  dtclose(emap);
  free(data);
}

/* cloneG:
 */
Agraph_t *cloneG(Agraph_t *g, char *name) {
  Agraph_t *ng;

  if (!name || *name == '\0')
    name = agnameof(g);
  ng = openG(name, g->desc);
  if (ng) {
    copyAttr((Agobj_t *)g, (Agobj_t *)ng);
    cloneGraph(ng, g);
  }
  return ng;
}

/* cloneO:
 * Create new object of type AGTYPE(obj) with all of its
 * attributes and substructure.
 * If obj is an edge, end nodes are cloned if necessary.
 * If obj is a graph, if g is null, create a clone top-level
 * graph. Otherwise, create a clone subgraph of g.
 * Assume obj != NULL.
 */
Agobj_t *cloneO(Agraph_t *g, Agobj_t *obj) {
  Agobj_t *nobj = 0;
  Agedge_t *e;
  Agnode_t *h;
  Agnode_t *t;
  int kind = AGTYPE(obj);
  char *name;

  if (kind != AGRAPH && !g) {
    exerror("NULL graph with non-graph object in clone()");
    return 0;
  }

  switch (kind) {
  case AGNODE: /* same as copy node */
    name = agnameof(obj);
    nobj = (Agobj_t *)openNode(g, name);
    if (nobj)
      copyAttr(obj, nobj);
    break;
  case AGRAPH:
    name = agnameof(obj);
    if (g)
      nobj = (Agobj_t *)openSubg(g, name);
    else
      nobj = (Agobj_t *)openG(name, ((Agraph_t *)obj)->desc);
    if (nobj) {
      copyAttr(obj, nobj);
      cloneGraph((Agraph_t *)nobj, (Agraph_t *)obj);
    }
    break;
  case AGINEDGE:
  case AGOUTEDGE:
    e = (Agedge_t *)obj;
    t = (Agnode_t *)cloneO(g, OBJ(agtail(e)));
    h = (Agnode_t *)cloneO(g, OBJ(aghead(e)));
    name = agnameof(AGMKOUT(e));
    nobj = (Agobj_t *)openEdge(g, t, h, name);
    if (nobj)
      copyAttr(obj, nobj);
    break;
  default:
    UNREACHABLE();
  }

  return nobj;
}

#define CCMARKED(n) (((nData(n))->iu.integer) & 2)
#define CCMARK(n) (((nData(n))->iu.integer) |= 2)
#define CCUNMARK(n) (((nData(n))->iu.integer) &= ~2)

static void cc_dfs(Agraph_t *g, Agraph_t *comp, Agnode_t *n) {
  Agedge_t *e;
  Agnode_t *other;

  CCMARK(n);
  agidnode(comp, AGID(n), 1);
  for (e = agfstedge(g, n); e; e = agnxtedge(g, e, n)) {
    if (agtail(e) == n)
      other = aghead(e);
    else
      other = agtail(e);
    if (!CCMARKED(other))
      cc_dfs(g, comp, other);
  }
}

/* compOf:
 * Return connected component of node.
 */
Agraph_t *compOf(Agraph_t *g, Agnode_t *n) {
  Agraph_t *cg;
  Agnode_t *np;
  static int id;
  char name[64];

  if (!(n = agidnode(g, AGID(n), 0)))
    return 0; /* n not in g */
  for (np = agfstnode(g); np; np = agnxtnode(g, np))
    CCUNMARK(np);

  snprintf(name, sizeof(name), "_cc_%d", id++);
  cg = openSubg(g, name);
  cc_dfs(g, cg, n);

  return cg;
}

/* isEdge:
 * Return edge, if any, between t and h with given key.
 * Edge is in g.
 */
Agedge_t *isEdge(Agraph_t *g, Agnode_t *t, Agnode_t *h, char *key) {
  Agraph_t *root;

  root = sameG(t, h, "isEdge", "tail and head node");
  if (!root)
    return 0;
  if (g) {
    if (root != agroot(g))
      return 0;
  } else
    g = root;

  return agedge(g, t, h, key, 0);
}

/* addNode:
 * Insert node n into subgraph g.
 * Return image of n
 */
Agnode_t *addNode(Agraph_t *gp, Agnode_t *np, int doAdd) {
  if (!sameG(gp, np, "addNode", 0))
    return 0;
  return agsubnode(gp, np, doAdd);
}

/* addEdge:
 * Insert edge e into subgraph g.
 * Return image of e
 */
Agedge_t *addEdge(Agraph_t *gp, Agedge_t *ep, int doAdd) {
  if (!sameG(gp, ep, "addEdge", 0))
    return 0;
  return agsubedge(gp, ep, doAdd);
}

/* lockGraph:
 * Set lock so that graph g will not be deleted.
 * g must be a root graph.
 * If v > 0, set lock
 * If v = 0, unset lock and delete graph is necessary.
 * If v < 0, no op
 * Always return previous lock state.
 * Return -1 on error.
 */
int lockGraph(Agraph_t *g, int v) {
  gdata *data;
  int oldv;

  if (g != agroot(g)) {
    error(ERROR_WARNING, "Graph argument to lock() is not a root graph");
    return -1;
  }
  data = gData(g);
  oldv = data->lock & 1;
  if (v > 0)
    data->lock |= 1;
  else if (v == 0 && oldv) {
    if (data->lock & 2)
      agclose(g);
    else
      data->lock = 0;
  }
  return oldv;
}

/* deleteObj:
 * Remove obj from g.
 * obj may belong to a subgraph of g, so we first must map
 * obj to its version in g.
 * If g is null, remove object from root graph.
 * If obj is a (sub)graph, close it. The g parameter is unused.
 * Return 0 on success, non-zero on failure.
 */
int deleteObj(Agraph_t *g, Agobj_t *obj) {
  gdata *data;
  if (AGTYPE(obj) == AGRAPH) {
    g = (Agraph_t *)obj;
    if (g != agroot(g))
      return agclose(g);
    data = gData(g);
    if (data->lock & 1) {
      error(ERROR_WARNING, "Cannot delete locked graph %s", agnameof(g));
      data->lock |= 2;
      return -1;
    } else
      return agclose(g);
  }

  /* node or edge */
  if (!g)
    g = agroot(agraphof(obj));
  if (obj)
    return agdelete(g, obj);
  else
    return -1;
}

/* sfioWrite:
 * If the graph is passed in from a library, its output discipline
 * might not use sfio. In this case, we push an sfio discipline on
 * the graph, write it, and then pop it off.
 */
int sfioWrite(Agraph_t *g, FILE *fp) {
  int rv;

  Agiodisc_t *saveio = g->clos->disc.io;
  g->clos->disc.io = &gprIoDisc;
  rv = agwrite(g, fp);
  g->clos->disc.io = saveio;
  return rv;
}

/* writeFile:
 * Write graph into file f.
 * Return 0 on success
 */
int writeFile(Agraph_t *g, char *f) {
  int rv;

  if (!f) {
    exerror("NULL string passed to writeG");
    return 1;
  }
  FILE *fp = fopen(f, "w");
  if (!fp) {
    exwarn("Could not open %s for writing in writeG", f);
    return 1;
  }
  rv = sfioWrite(g, fp);
  fclose(fp);
  return rv;
}

/* readFile:
 * Read graph from file f.
 * Return 0 on failure
 */
Agraph_t *readFile(char *f) {
  Agraph_t *gp;

  if (!f) {
    exerror("NULL string passed to readG");
    return 0;
  }
  FILE *fp = fopen(f, "r");
  if (!fp) {
    exwarn("Could not open %s for reading in readG", f);
    return 0;
  }
  gp = readG(fp);
  fclose(fp);

  return gp;
}

int fwriteFile(Expr_t *ex, Agraph_t *g, int fd) {
  FILE *sp;

  if (fd < 0 ||
      (elementsof(ex->file) <= INT_MAX && fd >= (int)elementsof(ex->file)) ||
      !((sp = ex->file[fd]))) {
    exerror("fwriteG: %d: invalid descriptor", fd);
    return 0;
  }
  return sfioWrite(g, sp);
}

Agraph_t *freadFile(Expr_t *ex, int fd) {
  FILE *sp;

  if (fd < 0 ||
      (elementsof(ex->file) <= INT_MAX && fd >= (int)elementsof(ex->file)) ||
      !((sp = ex->file[fd]))) {
    exerror("freadG: %d: invalid descriptor", fd);
    return 0;
  }
  return readG(sp);
}

int openFile(Expr_t *ex, const char *fname, const char *mode) {
  int idx;

  /* find open index */
  for (idx = 3; idx < elementsof(ex->file); idx++)
    if (!ex->file[idx])
      break;
  if (idx == elementsof(ex->file)) {
    exerror("openF: no available descriptors");
    return -1;
  }
  ex->file[idx] = fopen(fname, mode);
  if (ex->file[idx])
    return idx;
  else
    return -1;
}

int closeFile(Expr_t *ex, int fd) {
  int rv;

  if (0 <= fd && fd <= 2) {
    exerror("closeF: cannot close standard stream %d", fd);
    return -1;
  }
  if (fd < 0 ||
      (elementsof(ex->file) <= INT_MAX && fd >= (int)elementsof(ex->file))) {
    exerror("closeG: %d: invalid descriptor", fd);
    return -1;
  }
  if (!ex->file[fd]) {
    exerror("closeF: stream %d not open", fd);
    return -1;
  }
  rv = fclose(ex->file[fd]);
  if (!rv)
    ex->file[fd] = 0;
  return rv;
}

/*
 * Read single line from stream.
 * Return "" on EOF.
 */
char *readLine(Expr_t *ex, int fd) {
  FILE *sp;
  int c;
  char *line;

  if (fd < 0 || fd >= elementsof(ex->file) || !((sp = ex->file[fd]))) {
    exerror("readL: %d: invalid descriptor", fd);
    return "";
  }

  agxbuf tmps = {0};
  while ((c = getc(sp)) > 0 && c != '\n')
    agxbputc(&tmps, (char)c);
  if (c == '\n')
    agxbputc(&tmps, (char)c);
  line = exstring(ex, agxbuse(&tmps));
  agxbfree(&tmps);
  return line;
}

/* compare:
 * Lexicographic ordering of objects.
 */
int compare(Agobj_t *l, Agobj_t *r) {
  char lkind, rkind;
  if (l == NULL) {
    if (r == NULL)
      return 0;
    else
      return -1;
  } else if (r == NULL) {
    return 1;
  }
  if (AGID(l) < AGID(r))
    return -1;
  else if (AGID(l) > AGID(r))
    return 1;
  lkind = AGTYPE(l);
  rkind = AGTYPE(r);
  if (lkind == 3)
    lkind = 2;
  if (rkind == 3)
    rkind = 2;
  if (lkind == rkind)
    return 0;
  else if (lkind < rkind)
    return -1;
  else
    return 1;
}

/* toLower:
 * Convert characters to lowercase
 */
char *toLower(Expr_t *pgm, char *src) {

  const size_t len = strlen(src);
  char *dst = exstralloc(pgm, len + 1);
  if (dst == NULL) {
    return NULL;
  }

  for (size_t i = 0; i < len; ++i) {
    dst[i] = (char)tolower((int)src[i]);
  }

  dst[len] = '\0';
  return dst;
}

/* toUpper:
 * Convert characters to uppercase
 */
char *toUpper(Expr_t *pgm, char *src) {

  const size_t len = strlen(src);
  char *dst = exstralloc(pgm, len + 1);
  if (dst == NULL) {
    return NULL;
  }

  for (size_t i = 0; i < len; ++i) {
    dst[i] = (char)toupper((int)src[i]);
  }

  dst[len] = '\0';
  return dst;
}

/* toHtml:
 * Create a string marked as HTML
 */
char *toHtml(Agraph_t *g, char *arg) { return agstrdup_html(g, arg); }

/* canon:
 * Canonicalize a string for printing.
 */
char *canon(Expr_t *pgm, char *arg) {
  char *p;

  p = agcanonStr(arg);
  if (p != arg)
    p = exstring(pgm, p);

  return p;
}

#undef S

// force the upcoming ../common/colxlate.c functions to not be exported
#ifdef COLORPROCS_API
#undef COLORPROCS_API
#endif
#ifdef GVDLL
#undef GVDLL
#endif
#ifdef GVC_EXPORTS
#undef GVC_EXPORTS
#endif
#define COLORPROCS_API static UNUSED

#include "../common/colxlate.c"

/* colorx:
 * RGB, RGBA, HSV, HSVA, CMYK
 */
char *colorx(Expr_t *ex, char *incolor, char *fmt) {
  gvcolor_t color = {{{0}}, 0};
  color_type_t type;
  int rc;
  int alpha;

  if (*fmt == '\0' || *incolor == '\0')
    return "";
  if (*fmt == 'R') {
    type = RGBA_BYTE;
    if (!strcmp(fmt, "RGBA"))
      alpha = 1;
    else
      alpha = 0;
  } else if (*fmt == 'H') {
    type = HSVA_DOUBLE;
    if (!strcmp(fmt, "HSVA"))
      alpha = 1;
    else
      alpha = 0;
  } else if (*fmt == 'C') {
    type = CMYK_BYTE;
    alpha = 0;
  } else
    return "";

  rc = colorxlate(incolor, &color, type);
  if (rc != COLOR_OK)
    return "";

  agxbuf fp = {0};

  switch (type) {
  case HSVA_DOUBLE:
    agxbprint(&fp, "%.03f %.03f %.03f", color.u.HSVA[0], color.u.HSVA[1],
              color.u.HSVA[2]);
    if (alpha)
      agxbprint(&fp, " %.03f", color.u.HSVA[3]);
    break;
  case RGBA_BYTE:
    agxbprint(&fp, "#%02x%02x%02x", color.u.rgba[0], color.u.rgba[1],
              color.u.rgba[2]);
    if (alpha)
      agxbprint(&fp, "%02x", color.u.rgba[3]);
    break;
  case CMYK_BYTE:
    agxbprint(&fp, "#%02x%02x%02x%02x", color.u.cmyk[0], color.u.cmyk[1],
              color.u.cmyk[2], color.u.cmyk[3]);
    break;
  default:
    break;
  }

  char *result = exstring(ex, agxbuse(&fp));
  agxbfree(&fp);
  return result;
}

#ifndef _WIN32

#include <sys/param.h>
#include <sys/times.h>
#include <sys/types.h>
#include <unistd.h>

#ifndef HZ
#define HZ 60
#endif
typedef struct tms mytime_t;
#define GET_TIME(S) times(&(S))
#define DIFF_IN_SECS(S, T)                                                     \
  ((S.tms_utime + S.tms_stime - T.tms_utime - T.tms_stime) / (double)HZ)

#else

#include <time.h>

typedef clock_t mytime_t;
#define GET_TIME(S) S = clock()
#define DIFF_IN_SECS(S, T) ((S - T) / (double)CLOCKS_PER_SEC)

#endif

static mytime_t T;

void gvstart_timer(void) { GET_TIME(T); }

double gvelapsed_sec(void) {
  mytime_t S;
  double rv;

  GET_TIME(S);
  rv = DIFF_IN_SECS(S, T);
  return rv;
}
