/*
  binaries.c: code to save loaded LPC objects to binary files (in order
  to speed loading during subsequent runs of the driver).

  This is mostly original code by Darin Johnson.  Ideas came from CD,
  including crdir_fopen().  Feel free to use this code but please keep
  credits intact.
*/

#include "config.h"

#ifdef SAVE_BINARIES

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "lint.h"
#include "interpret.h"
#include "object.h"
#include "exec.h"
#include "opcodes.h"
#include "incralloc.h"
#include "switch.h"

extern int comp_flag;
extern struct program *prog;
extern char *inherit_file;
extern struct object *master_ob;
extern int total_prog_block_size, total_num_prog_blocks;
extern int num_parse_error;

char *magic_id = "MUDB";
time_t driver_id;
time_t config_id;

#define MAXSHORT ((1 << (sizeof(short)*8)) - 1)

int get_id_number();

static void patch_out(), patch_in();
static int check_times();
static FILE *crdir_fopen();

void
save_binary(prog, includes, patches)
    struct program *prog;
    struct mem_block *includes, *patches;
{
    char file_name_buf[200];
    char *file_name = file_name_buf;
    FILE *f;
    int i, tmp;
    short len;
    struct program *p;
    struct stat st;

    /* See if we can save the binary.  If master_ob doesn't exist,
     * assume it's ok (so that simul_efun.c and master.c can be saved)
     */
    if (master_ob) {
	struct svalue *ret;
	char *nm;
	nm = add_slash(prog->name);
	push_string(nm, STRING_MALLOC);
	free(nm);
	ret = safe_apply_master_ob("valid_save_binary", 1);
	if (IS_ZERO(ret))
	    return;
    }
    
    if (prog->p.i.total_size > (int)MAXSHORT ||
        includes->current_size > (int)MAXSHORT)
	/* assume all other sizes ok */
	return;

    strcpy(file_name, SAVE_BINARIES);
    if (file_name[0] == '/') file_name++;
    if (stat(file_name, &st) == -1)
	return;
    strcat(file_name, "/");
    strcat(file_name, prog->name);
    len = strlen(file_name);
    file_name[len-1] = 'b';   /* change .c ending to .b */

    if (!(f = crdir_fopen(file_name)))
	return;

    if (comp_flag)
	fprintf(stderr," saving binary ...");

    /*
     * Write out preamble.  Includes magic number, etc,
     * all of which must match while loading.
     */
    if (fwrite(magic_id, strlen(magic_id), 1, f) != 1 ||
	fwrite((char *)&driver_id, sizeof driver_id, 1, f) != 1 ||
	fwrite((char *)&config_id, sizeof config_id, 1, f) != 1)
    {
	debug_message("I/O error in save_binary.\n");
	fclose(f);
	unlink(file_name);
	return;
    }
    
    /*
     * Write out list of include files.
     */
    len = includes->current_size;
    fwrite((char *)&len, sizeof len, 1, f);
    fwrite(includes->block, includes->current_size, 1, f);

    /*
     * copy and patch program
     */
    p = (struct program *)DXALLOC(prog->p.i.total_size, 56, "save_binary");
    /* convert to relative pointers, copy, then convert back */
    locate_out(prog);
    memcpy(p, prog, prog->p.i.total_size);
    locate_in(prog);
    if (patches->current_size) {
	locate_in(p);
	patch_out(p, (short *)patches->block,
		  patches->current_size / sizeof(short));
	locate_out(p);
    }
    
    /*
     * write out prog.  The prog structure is mostly setup,
     * but strings will have to be stored specially.
     */
    len = strlen(p->name);
    fwrite((char *)&len, sizeof len, 1, f);
    fwrite(p->name, sizeof(char), len, f);

    fwrite((char *)&p->p.i.total_size, sizeof p->p.i.total_size, 1, f);
    fwrite((char *)p, p->p.i.total_size, 1, f);
    FREE(p);
    p = prog;
    
    /* inherit names */
    for (i=0; i<(int)p->p.i.num_inherited; i++) {
	len = strlen(p->p.i.inherit[i].prog->name);
	fwrite((char *)&len, sizeof len, 1, f);
	fwrite(p->p.i.inherit[i].prog->name, sizeof(char), len, f);
    }

    /* string table */
    for (i=0; i<(int)p->p.i.num_strings; i++) {
	tmp = strlen(p->p.i.strings[i]);
	if (tmp > (int)MAXSHORT) {  /* possible? */
	    fclose(f);
	    unlink(file_name);
	    error("String to long for save_binary.\n");
	    return;
	}
	len = tmp;
	fwrite((char *)&len, sizeof len, 1, f);
	fwrite(p->p.i.strings[i], sizeof(char), len, f);
    }

    /* var names */
    for (i=0; i<(int)p->p.i.num_variables; i++) {
	len = strlen(p->p.i.variable_names[i].name);
	fwrite((char *)&len, sizeof len, 1, f);
	fwrite(p->p.i.variable_names[i].name, sizeof(char), len, f);
    }

    /* function names */
    for (i=0; i<(int)p->p.i.num_functions; i++) {
    	len = strlen(p->p.i.functions[i].name);
	fwrite((char *)&len, sizeof len, 1, f);
	fwrite(p->p.i.functions[i].name, sizeof(char), len, f);
    }

    /* line_numbers */
    if (p->p.i.line_numbers)
	len = p->p.i.line_numbers[0] * sizeof(short);
    else
	len = 0;
    fwrite((char *)&len, sizeof len, 1, f);
    fwrite((char *)p->p.i.line_numbers, len, 1, f);
    
    /*
     * patches
     */
    len = patches->current_size;
    fwrite((char *)&len, sizeof len, 1, f);
    fwrite(patches->block, patches->current_size, 1, f);

    fclose(f);
}

#define ALLOC_BUF(size) \
    if ((size) > buf_size) { FREE(buf); buf = XALLOC(size); }

int
load_binary(name)
    char *name;
{
    char file_name_buf[200];
    char *buf, *iname, *file_name = file_name_buf;
    FILE *f;
    int i, buf_size, ilen;
    time_t mtime;
    short len;
    struct program *p;
    struct object *ob;
    struct stat st;

    /* stuff from prolog() */
    prog = 0; num_parse_error = 0;
    
    sprintf(file_name, "%s/%s", SAVE_BINARIES, name);
    if (file_name[0] == '/') file_name++;
    len = strlen(file_name);
    file_name[len-1] = 'b';   /* change .c ending to .b */

    if (stat(file_name, &st) != -1)
	mtime = st.st_mtime;
    else
	return 0;

    if (!(f = fopen(file_name, "r")))
	return 0;

    if (comp_flag)
	fprintf(stderr," loading binary %s ...", name);

    /* see if we're out of date with source */
    if (check_times(mtime, name) <= 0) {
	if (comp_flag)
	    fprintf(stderr, "out of date.\n");
	fclose(f);
	return 0;
    }
    
    buf = XALLOC(buf_size = SMALL_STRING_SIZE);
    
    /*
     * Read preamble.  This must match, or we assume a different
     * driver or configuration.
     */
    if (fread(buf, strlen(magic_id), 1, f) != 1 ||
	strncmp(buf, magic_id, strlen(magic_id)) != 0 ||
	fread((char *)&i, sizeof i, 1, f) != 1 || driver_id != i ||
	fread((char *)&i, sizeof i, 1, f) != 1 || config_id != i)
    {
	if (comp_flag)
	    fprintf(stderr, "out of date.\n");
        fclose(f);
        FREE(buf);
	return 0;
    }
    
    /*
     * read list of includes and check times
     */
    fread((char *)&len, sizeof len, 1, f);
    ALLOC_BUF(len);
    fread(buf, sizeof(char), len, f);
    for (iname = buf; iname < buf + len; iname += strlen(iname)+1) {
	if (check_times(mtime, iname) <= 0) {
	    if (comp_flag)
		fprintf(stderr, "out of date.\n");
	    fclose(f);
	    FREE(buf);
	    return 0;
	}
    }
    
    /* check program name */
    fread((char *)&len, sizeof len, 1, f);
    ALLOC_BUF(len+1);
    fread(buf, sizeof(char), len, f);
    buf[len] = '\0';
    if (strcmp(name, buf) != 0) {
	if (comp_flag)
	    fprintf(stderr, "binary name inconsistent with file.\n");
        fclose(f);
        FREE(buf);
        return 0;
    }
	
    /*
     * Read program structure.
     */
    fread((char *)&ilen, sizeof ilen, 1, f);
    p = (struct program *)DXALLOC(ilen, 56, "load_binary");
    fread((char *)p, ilen, 1, f);
    locate_in(p);  /* from swap.c */
    p->name = string_copy(name);

    /* Read inherit names and find prog.  Check mod times also. */
    for (i=0; i<(int)p->p.i.num_inherited; i++) {
	fread((char *)&len, sizeof len, 1, f);
	ALLOC_BUF(len+1);
	fread(buf, sizeof(char), len, f);
	buf[len] = '\0';

	/*
	 * Check times against inherited source.  If saved
	 * binary if inherited prog exists, check against
	 * it also.
	 */
	sprintf(file_name, "%s/%s", SAVE_BINARIES, buf);
	len = strlen(file_name);
	file_name[len-1] = 'b';
	if (check_times(mtime, buf) <= 0 ||
	    check_times(mtime, file_name) == 0)  /* ok if -1 */
	{
	    
	    if (comp_flag)
		fprintf(stderr, "out of date.\n");
	    fclose(f);
	FREE(p->name);
	FREE(p);
	    FREE(buf);
	    return 0;
	}

	/* find inherited program (maybe load it here?) */
	ob = find_object2(buf);
	if (!ob) {
	    if (comp_flag)
		fprintf(stderr, "missing inherited prog.\n");
	    fclose(f);
		FREE(p->name);
	    FREE(p);
	    inherit_file = buf;  /* freed elsewhere */
	    return 1;  /* not 0 */
	}
	p->p.i.inherit[i].prog = ob->prog;
    }

    /* Read string table */
    for (i=0; i<(int)p->p.i.num_strings; i++) {
	fread((char *)&len, sizeof len, 1, f);
	ALLOC_BUF(len+1);
	fread(buf, sizeof(char), len, f);
	buf[len] = '\0';
	p->p.i.strings[i] = make_shared_string(buf);
    }

    /* var names */
    for (i=0; i<(int)p->p.i.num_variables; i++) {
	fread((char *)&len, sizeof len, 1, f);
	ALLOC_BUF(len+1);
	fread(buf, sizeof(char), len, f);
	buf[len] = '\0';
	p->p.i.variable_names[i].name = make_shared_string(buf);
    }

    /* function names */
    for (i=0; i<(int)p->p.i.num_functions; i++) {
	fread((char *)&len, sizeof len, 1, f);
	ALLOC_BUF(len+1);
	fread(buf, sizeof(char), len, f);
	buf[len] = '\0';
	p->p.i.functions[i].name = make_shared_string(buf);
    }

    /* line numbers */
    fread((char *)&len, sizeof len, 1, f);
    p->p.i.line_numbers = (unsigned short *)XALLOC(len);
    fread((char *)p->p.i.line_numbers, len, 1, f);

    /* patches */
    fread((char *)&len, sizeof len, 1, f);
    ALLOC_BUF(len);
    fread(buf, len, 1, f);
    /* fix up some stuff */
    patch_in(p, (short *)buf, len / sizeof(short));

    fclose(f);
    FREE(buf);

    /*
     * Now finish everything up.  (stuff from epilog())
     */
    prog = p;
    prog->p.i.id_number = get_id_number();

    total_prog_block_size += prog->p.i.total_size;
    total_num_prog_blocks += 1;
    
    swap_line_numbers(prog);
    reference_prog (prog, "load_binary");
    for (i = 0; (unsigned)i < prog->p.i.num_inherited; i++) {
        reference_prog (prog->p.i.inherit[i].prog, "inheritance");
    }

    if (comp_flag)
	fprintf(stderr, "done.\n");
    return 1;
}

void
init_binaries(argc, argv)
    int argc;
    char **argv;
{
    extern int current_time;
    struct stat st;
    int arg_id, i;

    if (stat(argv[0], &st) != -1)
	driver_id = st.st_mtime;
    else {
	driver_id = current_time;
	fprintf(stderr, "Can't stat <%s>, ignoring old binaries.\n", argv[0]);
	fprintf(stderr, "Try invoking the driver using the full pathname.\n");
    }

    arg_id = 0;
    for (i=1; i<argc; i++) {
	if (argv[i][0] != '-') {
	    if (config_id) continue;
	    if (stat(argv[i], &st) != -1)
		config_id = st.st_mtime;
	    else
		config_id = current_time;
	} else if (argv[i][1] == 'D' || argv[i][1] == 'm') {
	    arg_id = (arg_id << 1) ^ whashstr(argv[i]+2, 32);
	}
    }

    config_id ^= (arg_id << (sizeof(short)*8));
}

/*
 * Test against modification times.  -1 if file doesn't exist,
 * 0 if out of date, and 1 if it's ok.
 */
static int
check_times(mtime, nm)
    time_t mtime;
    char *nm;
{
    struct stat st;
    if (stat(nm, &st) == -1)
	return -1;
    if (st.st_mtime > mtime) {
	return 0;
    }
    return 1;
}

/*
 * open file for writing, creating intermediate directories if needed.
 */
static FILE*
crdir_fopen(file_name)
    char *file_name;
{
    char *p;
    struct stat st;
    
    p = file_name;
    while (*p && (p = (char *)strchr(p, '/'))) {
	*p = '\0';
	if (stat(file_name, &st) == -1) {
	    /* make this dir */
	    if (mkdir(file_name, 0770) == -1) {
		*p = '/';
		return (FILE *)0;
	    }
	}
	*p = '/';
	p++;
    }

    return fopen(file_name, "w");
}

/*
 * Routines to do some hacking on the program being saved/loaded.
 * Basically to fix up string switch tables, since the alternative
 * would probably need a linear search in f_switch().
 * I set things up so these routines can be used with other things
 * that might need patching.
 *
 * I don't think the patch_out/patch_in will work on 64 bit machines,
 * however in that case, I don't think switches with strings will either...
 */
static void
patch_out(prog, patches, len)
    struct program *prog;
    short *patches;
    int len;
{
    int i;
    char *p;
    
    p = prog->p.i.program;
    while (len > 0) {
	i = patches[--len];
	if (p[i] == F_SWITCH && p[i+1] >> 4 != 0xf) {  /* string switch */
	    short offset, break_addr;
	    int s;
	    /* replace strings in table with string table indices */
	    ((char *)&offset)[0] = p[i+2];
	    ((char *)&offset)[1] = p[i+3];
	    ((char *)&break_addr)[0] = p[i+4];
	    ((char *)&break_addr)[1] = p[i+5];

	    while (offset < break_addr) {
		((char *)&s)[0] = p[offset+0];
		((char *)&s)[1] = p[offset+1];
		((char *)&s)[2] = p[offset+2];
		((char *)&s)[3] = p[offset+3];
		/*
		 * take advantage of fact that s is in strings table
		 * to find it's index.
		 */
		if (s == (int)ZERO_AS_STR_CASE_LABEL)
		    s = -1;
		else
		    s = store_prog_string((char *)s);
		p[offset+0] = ((char *)&s)[0];
		p[offset+1] = ((char *)&s)[1];
		p[offset+2] = ((char *)&s)[2];
		p[offset+3] = ((char *)&s)[3];
		offset += 6;
	    }
	}
    }
}

static
int str_case_cmp(a, b)
    char *a, *b;
{
    char *s1, *s2;
    ((char *)&s1)[0] = a[0];
    ((char *)&s1)[1] = a[1];
    ((char *)&s1)[2] = a[2];
    ((char *)&s1)[3] = a[3];
    
    ((char *)&s2)[0] = b[0];
    ((char *)&s2)[1] = b[1];
    ((char *)&s2)[2] = b[2];
    ((char *)&s2)[3] = b[3];

    return s1 - s2;
}

/* todo: this function contains non-portable code.  It assumes the size of
   a pointer is the same as the size as an integer (not true on DEC Alpha)
*/

static void
patch_in(prog, patches, len)
    struct program *prog;
    short *patches;
    int len;
{
    int i;
    char *p;
    
    p = prog->p.i.program;
    while (len > 0) {
	i = patches[--len];
	if (p[i] == F_SWITCH && p[i+1] >> 4 != 0xf) {  /* string switch */
	    short offset, start, break_addr;
	    int s;

	    /* replace string indices with string pointers */
	    ((char *)&offset)[0] = p[i+2];
	    ((char *)&offset)[1] = p[i+3];
	    ((char *)&break_addr)[0] = p[i+4];
	    ((char *)&break_addr)[1] = p[i+5];

	    start = offset;
	    while (offset < break_addr) {
		((char *)&s)[0] = p[offset+0];
		((char *)&s)[1] = p[offset+1];
		((char *)&s)[2] = p[offset+2];
		((char *)&s)[3] = p[offset+3];
		/*
		 * get real pointer from strings table
		 */
		if (s == -1)
		    s = (int)ZERO_AS_STR_CASE_LABEL;
		else
		    s = (int)prog->p.i.strings[s];
		p[offset+0] = ((char *)&s)[0];
		p[offset+1] = ((char *)&s)[1];
		p[offset+2] = ((char *)&s)[2];
		p[offset+3] = ((char *)&s)[3];
		offset += 6;
	    }
	    /* sort so binary search still works */
	    quickSort(&p[start], (break_addr-start)/6, 6, str_case_cmp);
	}
    }
}

#endif