output/strtbl.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2017 The NASM Authors - All Rights Reserved
   4  *   See the file AUTHORS included with the NASM distribution for
   5  *   the specific copyright holders.
   6  *
   7  *   Redistribution and use in source and binary forms, with or without
   8  *   modification, are permitted provided that the following
   9  *   conditions are met:
  10  *
  11  *   * Redistributions of source code must retain the above copyright
  12  *     notice, this list of conditions and the following disclaimer.
  13  *   * Redistributions in binary form must reproduce the above
  14  *     copyright notice, this list of conditions and the following
  15  *     disclaimer in the documentation and/or other materials provided
  16  *     with the distribution.
  17  *
  18  *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  19  *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  20  *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  21  *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  22  *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  23  *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  25  *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  26  *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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  29  *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
  30  *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31  *
  32  * ----------------------------------------------------------------------- */
  33
  34 /*
  35  * Common string table handling
  36  *
  37  * A number of output formats use a "string table"; a container for
  38  * a number of strings which may be reused at will.  This implements
  39  * a string table which eliminates duplicates and returns the index
  40  * into the string table when queried.
  41  */
  42
  43 #include "compiler.h"
  44
  45 #include "nasm.h"
  46 #include "nasmlib.h"
  47 #include "error.h"
  48 #include "strtbl.h"
  49
  50 struct strtbl_entry {
  51     size_t index;
  52     size_t bytes;
  53     char str[1];
  54 };
  55
  56 void strtbl_init(struct nasm_strtbl *tbl)
  57 {
  58     tbl->size = 0;
  59     hash_init(&tbl->hash, HASH_LARGE);
  60     strtbl_add(tbl, "");       /* Index 0 is always an empty string */
  61 }
  62
  63 void strtbl_free(struct nasm_strtbl *tbl)
  64 {
  65     hash_free_all(&tbl->hash, false);
  66 }
  67
  68 size_t strtbl_add(struct nasm_strtbl *tbl, const char *str)
  69 {
  70     void **sep;
  71     struct strtbl_entry *se;
  72     struct hash_insert hi;
  73
  74     sep = hash_find(&tbl->hash, str, &hi);
  75     if (sep) {
  76         se = *sep;
  77     } else {
  78         size_t bytes = strlen(str) + 1;
  79
  80         se = nasm_malloc(sizeof(struct strtbl_entry)-1+bytes);
  81         se->index = tbl->size;
  82         tbl->size += bytes;
  83         se->bytes = bytes;
  84         memcpy(se->str, str, bytes);
  85
  86         hash_add(&hi, se->str, se);
  87     }
  88
  89     return se->index;
  90 }
  91
  92 size_t strtbl_find(struct nasm_strtbl *tbl, const char *str)
  93 {
  94     void **sep;
  95     struct strtbl_entry *se;
  96
  97     sep = hash_find(&tbl->hash, str, NULL);
  98     if (sep) {
  99         se = *sep;
 100         return se->index;
 101     } else {
 102         return STRTBL_NONE;
 103     }
 104 }
 105
 106 /* This create a linearized buffer containing the actual string table */
 107 void *strtbl_generate(const struct nasm_strtbl *tbl)
 108 {
 109     char *buf = nasm_malloc(strtbl_size(tbl));
 110     struct hash_tbl_node *iter = NULL;
 111     struct strtbl_entry *se;
 112
 113     while ((se = hash_iterate(&tbl->hash, &iter, NULL)))
 114         memcpy(buf + se->index, se->str, se->bytes);
 115
 116     return buf;
 117 }