text: /*
   * Generic map implementation.
   */
  #include "hashmap.h"
  
  #include <stdlib.h>
  #include <stdio.h>
  #include <string.h>
  
  #define INITIAL_SIZE (256)
  #define MAX_CHAIN_LENGTH (8)
  
  /* We need to keep keys and values */
  typedef struct _hashmap_element{
  	char* key;
  	int in_use;
  	any_t data;
  } hashmap_element;
  
  /* A hashmap has some maximum size and current size,
   * as well as the data to hold. */
  typedef struct _hashmap_map{
  	int table_size;
  	int size;
  	hashmap_element *data;
  } hashmap_map;
  
  /*
   * Return an empty hashmap, or NULL on failure.
   */
  map_t hashmap_new() {
  	hashmap_map* m = (hashmap_map*)calloc(1, sizeof(hashmap_map));
  	if(!m) goto err;
  
  	m->data = (hashmap_element*) calloc(INITIAL_SIZE, sizeof(hashmap_element));
  	if(!m->data) goto err;
  
  	m->table_size = INITIAL_SIZE;
  	m->size = 0;
  
  	return m;
  	err:
  		if (m)
  			hashmap_free(m);
  		return NULL;
  }
  
  /* The implementation here was originally done by Gary S. Brown.  I have
     borrowed the tables directly, and made some minor changes to the
     crc32-function (including changing the interface). //ylo */
  
    /* ============================================================= */
    /*  COPYRIGHT (C) 1986 Gary S. Brown.  You may use this program, or       */
    /*  code or tables extracted from it, as desired without restriction.     */
    /*                                                                        */
    /*  First, the polynomial itself and its table of feedback terms.  The    */
    /*  polynomial is                                                         */
    /*  X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0   */
    /*                                                                        */
    /*  Note that we take it "backwards" and put the highest-order term in    */
    /*  the lowest-order bit.  The X^32 term is "implied"; the LSB is the     */
    /*  X^31 term, etc.  The X^0 term (usually shown as "+1") results in      */
    /*  the MSB being 1.                                                      */
    /*                                                                        */
    /*  Note that the usual hardware shift register implementation, which     */
    /*  is what we're using (we're merely optimizing it by doing eight-bit    */
    /*  chunks at a time) shifts bits into the lowest-order term.  In our     */
    /*  implementation, that means shifting towards the right.  Why do we     */
    /*  do it this way?  Because the calculated CRC must be transmitted in    */
    /*  order from highest-order term to lowest-order term.  UARTs transmit   */
    /*  characters in order from LSB to MSB.  By storing the CRC this way,    */
    /*  we hand it to the UART in the order low-byte to high-byte; the UART   */
    /*  sends each low-bit to hight-bit; and the result is transmission bit   */
    /*  by bit from highest- to lowest-order term without requiring any bit   */
    /*  shuffling on our part.  Reception works similarly.                    */
    /*                                                                        */
    /*  The feedback terms table consists of 256, 32-bit entries.  Notes:     */
    /*                                                                        */
    /*      The table can be generated at runtime if desired; code to do so   */
    /*      is shown later.  It might not be obvious, but the feedback        */
    /*      terms simply represent the results of eight shift/xor opera-      */
    /*      tions for all combinations of data and CRC register values.       */
    /*                                                                        */
    /*      The values must be right-shifted by eight bits by the "updcrc"    */
    /*      logic; the shift must be unsigned (bring in zeroes).  On some     */
    /*      hardware you could probably optimize the shift in assembler by    */
    /*      using byte-swap instructions.                                     */
    /*      polynomial $edb88320                                              */
    /*                                                                        */
    /*  --------------------------------------------------------------------  */
  
  static unsigned long crc32_tab[] = {
        0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
        0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
        0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
        0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
        0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
        0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
        0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
        0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
        0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
        0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
        0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
        0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
        0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
        0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
        0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
        0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
        0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
        0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
        0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
        0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
        0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
        0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
        0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
        0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
        0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
        0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
        0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
        0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
        0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
        0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
        0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
        0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
        0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
        0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
        0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
        0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
        0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
        0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
        0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
        0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
        0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
        0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
        0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
        0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
        0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
        0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
        0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
        0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
        0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
        0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
        0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
        0x2d02ef8dL
     };
  
  /* Return a 32-bit CRC of the contents of the buffer. */
  
  unsigned long crc32(const unsigned char *s, unsigned int len)
  {
    unsigned int i;
    unsigned long crc32val;
    
    crc32val = 0;
    for (i = 0;  i < len;  i ++)
      {
        crc32val =
  	crc32_tab[(crc32val ^ s[i]) & 0xff] ^
  	  (crc32val >> 8);
      }
    return crc32val;
  }
  
  /*
   * Hashing function for a string
   */
  unsigned int hashmap_hash_int(hashmap_map * m, char* keystring){
  
      unsigned long key = crc32((unsigned char*)(keystring), strlen(keystring));
  
  	/* Robert Jenkins' 32 bit Mix Function */
  	key += (key << 12);
  	key ^= (key >> 22);
  	key += (key << 4);
  	key ^= (key >> 9);
  	key += (key << 10);
  	key ^= (key >> 2);
  	key += (key << 7);
  	key ^= (key >> 12);
  
  	/* Knuth's Multiplicative Method */
  	key = (key >> 3) * 2654435761;
  
  	return key % m->table_size;
  }
  
  /*
   * Return the integer of the location in data
   * to store the point to the item, or MAP_FULL.
   */
  int hashmap_hash(map_t in, char* key){
  	int curr;
  	int i;
  
  	/* Cast the hashmap */
  	hashmap_map* m = (hashmap_map *) in;
  
  	/* If full, return immediately */
  	if(m->size >= (m->table_size/2)) return MAP_FULL;
  
  	/* Find the best index */
  	curr = hashmap_hash_int(m, key);
  
  	/* Linear probing */
  	for(i = 0; i< MAX_CHAIN_LENGTH; i++){
  		if(m->data[curr].in_use == 0)
  			return curr;
  
  		if(m->data[curr].in_use == 1 && (strcmp(m->data[curr].key,key)==0))
  			return curr;
  
  		curr = (curr + 1) % m->table_size;
  	}
  
  	return MAP_FULL;
  }
  
  /*
   * Doubles the size of the hashmap, and rehashes all the elements
   */
  int hashmap_rehash(map_t in){
  	int i;
  	int old_size;
  	hashmap_element* curr;
  
  	/* Setup the new elements */
  	hashmap_map *m = (hashmap_map *) in;
  	hashmap_element* temp = (hashmap_element *)
  		calloc(2 * m->table_size, sizeof(hashmap_element));
  	if(!temp) return MAP_OMEM;
  
  	/* Update the array */
  	curr = m->data;
  	m->data = temp;
  
  	/* Update the size */
  	old_size = m->table_size;
  	m->table_size = 2 * m->table_size;
  	m->size = 0;
  
  	/* Rehash the elements */
  	for(i = 0; i < old_size; i++){
          int status;
  
          if (curr[i].in_use == 0)
              continue;
              
  		status = hashmap_put(m, curr[i].key, curr[i].data);
  		if (status != MAP_OK)
  			return status;
  	}
  
  	free(curr);
  
  	return MAP_OK;
  }
  
  /*
   * Add a pointer to the hashmap with some key
   */
  int hashmap_put(map_t in, char* key, any_t value){
  	int index;
  	hashmap_map* m;
  
  	/* Cast the hashmap */
  	m = (hashmap_map *) in;
  
  	/* Find a place to put our value */
  	index = hashmap_hash(in, key);
  	while(index == MAP_FULL){
  		if (hashmap_rehash(in) == MAP_OMEM) {
  			return MAP_OMEM;
  		}
  		index = hashmap_hash(in, key);
  	}
  
  	/* Set the data */
  	m->data[index].data = value;
  	m->data[index].key = key;
  	m->data[index].in_use = 1;
  	m->size++; 
  
  	return MAP_OK;
  }
  
  /*
   * Get your pointer out of the hashmap with a key
   */
  int hashmap_get(map_t in, char* key, any_t *arg){
  	int curr;
  	int i;
  	hashmap_map* m;
  
  	/* Cast the hashmap */
  	m = (hashmap_map *) in;
  
  	/* Find data location */
  	curr = hashmap_hash_int(m, key);
  
  	/* Linear probing, if necessary */
  	for(i = 0; i<MAX_CHAIN_LENGTH; i++){
  
          int in_use = m->data[curr].in_use;
          if (in_use == 1){
              if (strcmp(m->data[curr].key,key)==0){
                  *arg = (m->data[curr].data);
                  return MAP_OK;
              }
  		}
  
  		curr = (curr + 1) % m->table_size;
  	}
  
  	*arg = NULL;
  
  	/* Not found */
  	return MAP_MISSING;
  }
  
  /*
   * Iterate the function parameter over each element in the hashmap.  The
   * additional any_t argument is passed to the function as its first
   * argument and the hashmap element is the second.
   */
  int hashmap_iterate(map_t in, PFany f, any_t item) {
  	int i;
  
  	/* Cast the hashmap */
  	hashmap_map* m = (hashmap_map*) in;
  
  	/* On empty hashmap, return immediately */
  	if (hashmap_length(m) <= 0)
  		return MAP_MISSING;	
  
  	/* Linear probing */
  	for(i = 0; i< m->table_size; i++)
  		if(m->data[i].in_use != 0) {
  			any_t data = (any_t) (m->data[i].data);
  			int status = f(item, data);
  			if (status != MAP_OK) {
  				return status;
  			}
  		}
  
      return MAP_OK;
  }
  
  /*
   * Remove an element with that key from the map
   */
  int hashmap_remove(map_t in, char* key){
  	int i;
  	int curr;
  	hashmap_map* m;
  
  	/* Cast the hashmap */
  	m = (hashmap_map *) in;
  
  	/* Find key */
  	curr = hashmap_hash_int(m, key);
  
  	/* Linear probing, if necessary */
  	for(i = 0; i<MAX_CHAIN_LENGTH; i++){
  
          int in_use = m->data[curr].in_use;
          if (in_use == 1){
              if (strcmp(m->data[curr].key,key)==0){
                  /* Blank out the fields */
                  m->data[curr].in_use = 0;
                  m->data[curr].data = NULL;
                  m->data[curr].key = NULL;
  
                  /* Reduce the size */
                  m->size--;
                  return MAP_OK;
              }
  		}
  		curr = (curr + 1) % m->table_size;
  	}
  
  	/* Data not found */
  	return MAP_MISSING;
  }
  
  /* Deallocate the hashmap */
  void hashmap_free(map_t in){
  	hashmap_map* m = (hashmap_map*) in;
  	free(m->data);
  	free(m);
  }
  
  /* Return the length of the hashmap */
  int hashmap_length(map_t in){
  	hashmap_map* m = (hashmap_map *) in;
  	if(m != NULL) return m->size;
  	else return 0;
  }