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/*
* Generator of Word Recognition Hash Tables
* (a.k.a. simple gperf replacement)
*
* (c) 1999 Martin Mares <mj@ucw.cz>
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <alloca.h>
struct word {
struct word *next;
char *w;
char *extra;
};
static unsigned int hash(char *c)
{
unsigned int h = 0;
while (*c)
h = (h * 37) + *c++;
return h;
}
static int /* Sequential search */
fast_isprime(unsigned x) /* We know x != 2 && x != 3 */
{
unsigned test = 5;
for(;;)
{
if (!(x % test))
return 0;
if (x / test <= test)
return 1;
test += 2; /* 6k+1 */
if (!(x % test))
return 0;
if (x / test <= test)
return 1;
test += 4; /* 6k-1 */
}
}
static unsigned int
nextprime(unsigned x) /* Returns some prime greater than X */
{
if (x <= 5)
return 5;
x += 5 - (x % 6); /* x is 6k-1 */
for(;;)
{
if (fast_isprime(x))
return x;
x += 2; /* 6k+1 */
if (fast_isprime(x))
return x;
x += 4; /* 6k-1 */
}
}
int main(int argc, char **argv)
{
FILE *fi, *fo;
struct word *words = NULL;
struct word *w, **ht;
char buf[1024], *c, namebuf[256];
int cnt = 0;
int skip, i, size;
if (argc != 4)
{
fprintf(stderr, "Usage: genhash <input> <output> <func_name>\n");
return 1;
}
fi = fopen(argv[1], "r");
if (!fi) { fprintf(stderr, "Cannot open input file: %m\n"); return 1; }
fo = fopen(argv[2], "w");
if (!fo) { fprintf(stderr, "Cannot open output file: %m\n"); return 1; }
buf[0] = 0;
fgets(buf, sizeof(buf)-1, fi);
if (strncmp(buf, "%{", 2)) { fprintf(stderr, "Syntax error at <%s>\n", buf); return 1; }
fputs(buf+2, fo);
while (fgets(buf, sizeof(buf)-1, fi) && strcmp(buf, "%}\n"))
fputs(buf, fo);
fgets(namebuf, sizeof(namebuf)-1, fi);
if (strncmp(namebuf, "struct ", 7) || !(c = strchr(namebuf+7, ' ')))
{ fprintf(stderr, "Syntax error at <%s>\n", namebuf); return 1; }
*c = 0;
while (fgets(buf, sizeof(buf)-1, fi) && strcmp(buf, "%%\n"))
;
while (fgets(buf, sizeof(buf)-1, fi))
{
c = strchr(buf, '\n');
if (c)
*c = 0;
c = strchr(buf, ',');
w = alloca(sizeof(struct word));
if (c)
*c++ = 0;
else
{ fprintf(stderr, "No comma?\n"); return 1; }
w->w = alloca(strlen(buf)+1);
strcpy(w->w, buf);
w->extra = alloca(strlen(c)+1);
strcpy(w->extra, c);
w->next = words;
words = w;
cnt++;
}
cnt = cnt*12/10;
size = 16;
while (size < cnt)
size += size;
skip = nextprime(size*3/4);
ht = alloca(size * sizeof(struct word *));
bzero(ht, size * sizeof(struct word *));
for(w=words; w; w=w->next)
{
int h = hash(w->w) & (size - 1);
while (ht[h])
h = (h + skip) & (size - 1);
ht[h] = w;
}
fprintf(fo, "static %s htable[] = {\n", namebuf);
for(i=0; i<size; i++)
if (ht[i])
fprintf(fo, "{ \"%s\", %s },\n", ht[i]->w, ht[i]->extra);
else
fprintf(fo, "{ NULL },\n");
fprintf(fo, "};\n\nconst %s *%s(const char *x, unsigned int len)\n\
{\n\
const char *c = x;\n\
unsigned int h = 0;\n\
while (*c)\n\
h = (h * 37) + *c++;\n\
h = h & %d;\n\
while (htable[h].name)\n\
{\n\
if (!strcmp(htable[h].name, x))\n\
return &htable[h];\n\
h = (h + %d) & %d;\n\
}\n\
return NULL;\n\
}\n", namebuf, argv[3], size-1, skip, size-1);
return 0;
}