nasm/output/strtbl.c

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/*
 * Common string table handling
 *
 * A number of output formats use a "string table"; a container for
 * a number of strings which may be reused at will.  This implements
 * a string table which eliminates duplicates and returns the index
 * into the string table when queried.
 */

#include "compiler.h"

#include "nasm.h"
#include "nasmlib.h"
#include "error.h"
#include "strtbl.h"

struct strtbl_entry {
    size_t index;
    size_t bytes;
    char str[1];
};

void strtbl_init(struct nasm_strtbl *tbl)
{
    tbl->size = 0;
    hash_init(&tbl->hash, HASH_LARGE);
    strtbl_find(tbl, "", true); /* Index 0 is always an empty string */
}

void strtbl_free(struct nasm_strtbl *tbl)
{
    struct hash_tbl_node *iter = NULL;
    struct strtbl_entry *se;

    while ((se = hash_iterate(&tbl->hash, &iter, NULL)))
        nasm_free(se);

    hash_free(&tbl->hash);
}

size_t strtbl_find(struct nasm_strtbl *tbl, const char *str, bool add)
{
    struct hash_insert hi;
    void **dp;
    struct strtbl_entry *se;

    dp = hash_find(&tbl->hash, str, &hi);
    if (dp) {
        se = *dp;
    } else if (add) {
        size_t bytes = strlen(str) + 1;

        se = nasm_malloc(sizeof(struct strtbl_entry)-1+bytes);
        se->index = tbl->size;
        tbl->size += bytes;
        se->bytes = bytes;
        memcpy(se->str, str, bytes);

        hash_add(&hi, se->str, se);
    } else {
        return STRTBL_NONE;
    }

    return se->index;
}

/* This create a linearized buffer containing the actual string table */
void *strtbl_generate(const struct nasm_strtbl *tbl)
{
    char *buf = nasm_malloc(strtbl_size(tbl));
    struct hash_tbl_node *iter = NULL;
    struct strtbl_entry *se;

    while ((se = hash_iterate(&tbl->hash, &iter, NULL)))
        memcpy(buf + se->index, se->str, se->bytes);

    return buf;
}