src/gr_edge.c

   1 /*=========================================================================*\
   2  * LuaGRAPH toolkit
   3  * Graph support for Lua.
   4  * Herbert Leuwer
   5  * 30-7-2006, 01/2017
   6  *
   7  * Edge related functionality.
   8  *
   9 \*=========================================================================*/
  10
  11 /*=========================================================================*\
  12  * Includes
  13 \*=========================================================================*/
  14 #include <string.h>
  15 #include <stdlib.h>
  16
  17 #include "lua.h"
  18 #include "lauxlib.h"
  19
  20 #include "gr_graph.h"
  21
  22 /*=========================================================================*\
  23  * Defines
  24 \*=========================================================================*/
  25
  26 /*=========================================================================*\
  27  * Prototypes
  28 \*=========================================================================*/
  29 static int gr_equal(lua_State *L);
  30 static int gr_nameof(lua_State *L);
  31 static int gr_id(lua_State *L);
  32 static int gr_delete(lua_State *L);
  33 static int gr_head(lua_State *L);
  34 static int gr_tail(lua_State *L);
  35 static int gr_info(lua_State *L);
  36 static int gr_graphof(lua_State *L);
  37 static int gr_tostring(lua_State *L);
  38
  39 /*=========================================================================*\
  40  * Data
  41 \*=========================================================================*/
  42
  43 /*
  44  * Edge object methods
  45  */
  46 static const luaL_Reg reg_methods[] = {
  47   {"delete", gr_delete},
  48   {"type", get_object_type},
  49   {"rawget", getval},
  50   {"info", gr_info},
  51   {NULL, NULL}
  52 };
  53
  54 /*
  55  * Read-only members
  56  */
  57 static const luaL_Reg reg_rmembers[] = {
  58   {"head", gr_head},
  59   {"tail", gr_tail},
  60   {"name", gr_nameof},
  61   {"id", gr_id},
  62   {"graph", gr_graphof},
  63   {"status", gr_status},
  64   {NULL, NULL}
  65 };
  66
  67 /*
  68  * Standard metamethods
  69  */
  70 static const luaL_Reg reg_metamethods[] = {
  71   {"__gc", gr_collect},
  72   {"__eq", gr_equal},
  73   {"__newindex", object_newindex_handler},
  74   {"__tostring", gr_tostring},
  75   {NULL, NULL}
  76 };
  77
  78 /*=========================================================================*\
  79  * Functions
  80 \*=========================================================================*/
  81 /*-------------------------------------------------------------------------*\
  82  * Utility Functions
  83 \*-------------------------------------------------------------------------*/
  84 int new_edge(lua_State *L){
  85   return new_object(L, "edge", reg_rmembers, reg_methods, reg_metamethods,
  86                     object_index_handler);
  87 }
  88
  89 /*-------------------------------------------------------------------------*\
  90  * Metametho: __eq [boolean]
  91  * Compare two edges.
  92  * Example:
  93  * e1 == e2 or e1 ~= e2 with metamethods
  94 \*-------------------------------------------------------------------------*/
  95 static int gr_equal(lua_State *L)
  96 {
  97   gr_edge_t *ud1 = toedge(L, 1, STRICT);
  98   gr_edge_t *ud2 = toedge(L, 2, STRICT);
  99   lua_pushboolean(L, ageqedge(ud1->e, ud2->e));
 100   return 1;
 101 }
 102
 103 /*-------------------------------------------------------------------------*\
 104  * Property: name [string]
 105  * Provides the name of an edge.
 106  * Example:
 107  * name = e.name
 108 \*-------------------------------------------------------------------------*/
 109 static int gr_nameof(lua_State *L)
 110 {
 111   gr_edge_t *ud = toedge(L, 1, STRICT);
 112   if (ud->status != ALIVE)
 113     luaL_error(L, "deleted");
 114   lua_pushstring(L, ud->name);
 115   return 1;
 116 }
 117
 118 /*-------------------------------------------------------------------------*\
 119  * Property: id [number]
 120  * Get an edge's id.
 121  * Example:
 122  * n = e.id
 123 \*-------------------------------------------------------------------------*/
 124 static int gr_id(lua_State *L)
 125 {
 126   gr_edge_t *ud = toedge(L, 1, STRICT);
 127   lua_pushnumber(L, AGID(ud->e));
 128   return 1;
 129 }
 130
 131 /*-------------------------------------------------------------------------*\
 132  * Method: e.delete(self)
 133  * Delete an edge.
 134  * Returns non-nil on success.
 135  * Example:
 136  * rv, err = n:delete()
 137 \*-------------------------------------------------------------------------*/
 138 static int gr_delete(lua_State *L)
 139 {
 140   int rv = -1;
 141   gr_edge_t *ud = toedge(L, 1, NONSTRICT);
 142   Agraph_t *g;
 143   if (ud->e != NULL){
 144     g = agroot(ud->e);
 145     if (ud->status == ALIVE){
 146       TRACE("   e.delete(): deleting edge '%s' ud=%p id=0x%lx e=%p (%s %d)\n",
 147             agnameof(ud->e), (void *) ud, (unsigned long) AGID(ud->e), (void *)ud->e, __FILE__, __LINE__);
 148       agdeledge(g, ud->e);
 149     }
 150   } else {
 151     TRACE("   e.delete(): ud=%p already closed (%s %d)\n", (void *)ud, __FILE__, __LINE__);
 152   }
 153   lua_pushnumber(L, rv);
 154   return 1;
 155 }
 156
 157 /*
 158  * Provided for external access to gr_delete function.
 159  */
 160 int gr_delete_edge(lua_State *L)
 161 {
 162   return gr_delete(L);
 163 }
 164
 165 /*-------------------------------------------------------------------------*\
 166  * Print info about a node to stdout.
 167  * Example:
 168  * e:info()
 169 \*-------------------------------------------------------------------------*/
 170 static int gr_info(lua_State *L)
 171 {
 172   gr_edge_t *ud = toedge(L, 1, STRICT);
 173   Agnode_t *head = aghead(ud->e);
 174   Agnode_t *tail = agtail(ud->e);
 175   Agedge_t *cedge = agopp(ud->e);
 176   Agnode_t *chead = aghead(cedge);
 177   Agnode_t *ctail = agtail(cedge);
 178   printf("INFO EDGE:\n");
 179   printf("  label: '%s' '%s'\n", agnameof(ud->e), ud->name);
 180   printf("  ptr : %p\n", (void *)ud->e);
 181   printf("  name: %s\n", agnameof(ud->e));
 182   printf("  head: %s\n", agnameof(head));
 183   printf("  tail: %s\n", agnameof(tail));
 184   printf("  cptr: %p\n", (void*)cedge);
 185   printf("  cname: %s\n", agnameof(cedge));
 186   printf("  chead: %s\n", agnameof(chead));
 187   printf("  ctail: %s\n", agnameof(ctail));
 188   return 0;
 189 }
 190
 191 /*-------------------------------------------------------------------------* \
 192  * Methods: n, err = e.head(self) and n, err = e.tail(self)
 193  * Retrieves head and tail node of an edge.
 194  * Returns node userdata on success.
 195  * Example:
 196  * head, err = e:head()
 197  * tail ,err = e.tail()
 198 \*-------------------------------------------------------------------------*/
 199 static int gr_head(lua_State *L)
 200 {
 201   gr_edge_t *ud = toedge(L, 1, STRICT);
 202   Agnode_t *n = aghead(ud->e);
 203   if (n == NULL){
 204     lua_pushnil(L);
 205     return 1;
 206   } else
 207     return get_object(L, n);
 208 }
 209
 210 static int gr_tail(lua_State *L)
 211 {
 212   gr_edge_t *ud = toedge(L, 1, STRICT);
 213   Agnode_t *n = agtail(ud->e);
 214   if (n == NULL){
 215     lua_pushnil(L);
 216     return 1;
 217   } else
 218     return get_object(L, n);
 219 }
 220
 221 /*-------------------------------------------------------------------------*\
 222  * Determines the graph to which of a edge belongs.
 223  * Returns graph userdata.
 224  * Example:
 225  * rv = n.graph
 226  * Methods: n, err = e.head(self) and n, err = e.tail(self)
 227 \*-------------------------------------------------------------------------*/
 228 static int gr_graphof(lua_State *L)
 229 {
 230   gr_edge_t *ud = toedge(L, 1, STRICT);
 231   Agraph_t *g = agraphof(ud->e);
 232   if (g == NULL){
 233     lua_pushnil(L);
 234     lua_pushstring(L, "no graph");
 235     return 2;
 236   }
 237   return get_object(L, g);
 238 }
 239
 240 static int gr_tostring(lua_State *L)
 241 {
 242   gr_object_t *ud = toobject(L, 1, NULL, NONSTRICT);
 243   lua_pushfstring(L, "edge: %p (%s)", ud, ud->p.status == ALIVE ? "alive" : "dead");
 244   return 1;
 245 }