/* sim_frontpanel.c: simulator frontpanel API

   Copyright (c) 2015, Mark Pizzolato

   Permission is hereby granted, free of charge, to any person obtaining a
   copy of this software and associated documentation files (the "Software"),
   to deal in the Software without restriction, including without limitation
   the rights to use, copy, modify, merge, publish, distribute, sublicense,
   and/or sell copies of the Software, and to permit persons to whom the
   Software is furnished to do so, subject to the following conditions:

   The above copyright notice and this permission notice shall be included in
   all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   MARK PIZZOLATO BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
   IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

   Except as contained in this notice, the name of Mark Pizzolato shall not be
   used in advertising or otherwise to promote the sale, use or other dealings
   in this Software without prior written authorization from Mark Pizzolato.

   05-Feb-15    MP      Initial implementation

   This module provides interface between a front panel application and a simh
   simulator.  Facilities provide ways to gather information from and to 
   observe and control the state of a simulator.

*/

#include "sim_frontpanel.h"

#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <errno.h>
#include <signal.h>
#include <pthread.h>

#if defined(_WIN32)
#include <process.h>
#define sleep(n) Sleep(n*1000)
#define msleep(n) Sleep(n)
#define strtoull _strtoui64
#else
#include <unistd.h>
#define msleep(n) usleep(1000*n)
#include <sys/wait.h>
#endif

#ifdef  __cplusplus
extern "C" {
#endif

#include "sim_sock.h"

typedef struct {
    char *name;
    void *addr;
    size_t size;
    } REG;

struct sim_frontpanel {
    char                *path;
    char                *config;
    char                *temp_config;
    char                hostport[64];
    SOCKET              sock;
    int                 reg_count;
    REG                 *regs;
    OperationalState    State;
    pthread_mutex_t     lock;
    pthread_t           io_thread;
    int                 io_thread_running;
    pthread_mutex_t     io_lock;
    pthread_mutex_t     io_send_lock;
    pthread_cond_t      io_done;
    pthread_cond_t      startup_cond;
    PANEL_DISPLAY_PCALLBACK callback;
    pthread_t           callback_thread;
    int                 callback_thread_running;
    void                *callback_context;
    int                 callbacks_per_second;
#if defined(_WIN32)
    HANDLE              hProcess;
#else
    pid_t               pidProcess;
#endif
    };

static char *sim_prompt = "sim> ";
static int little_endian;
static void *_panel_reader(void *arg);
static void *_panel_callback(void *arg);

#define TN_IAC          0xFFu /* -1 */                  /* protocol delim */
#define TN_DONT         0xFEu /* -2 */                  /* dont */
#define TN_DO           0xFDu /* -3 */                  /* do */
#define TN_WONT         0xFCu /* -4 */                  /* wont */
#define TN_WILL         0xFBu /* -5 */                  /* will */

#define TN_BIN            0                             /* bin */
#define TN_ECHO           1                             /* echo */
#define TN_SGA            3                             /* sga */
#define TN_LINE          34                             /* line mode */

static unsigned char mantra[] = {
    TN_IAC, TN_WILL, TN_LINE,
    TN_IAC, TN_WILL, TN_SGA,
    TN_IAC, TN_WILL, TN_ECHO,
    TN_IAC, TN_WILL, TN_BIN,
    TN_IAC, TN_DO, TN_BIN
    };


static void *
_panel_malloc (size_t size)
{
void *p = malloc (size);

if (p == NULL)
    sim_panel_set_error ("Out of Memory");
return p;
}

static int
_panel_send (PANEL *p, const char *msg, int len)
{
int sent = 0;

if (p->sock == INVALID_SOCKET) {
    sim_panel_set_error ("Invalid Socket for write");
    return -1;
    }
pthread_mutex_lock (&p->io_send_lock);
while (len) {
    int bsent = sim_write_sock (p->sock, msg, len);
    if (bsent < 0) {
        sim_panel_set_error ("%s", sim_get_err_sock("Error writing to socket"));
        pthread_mutex_unlock (&p->io_send_lock);
        return bsent;
        }
    len -= bsent;
    msg += bsent;
    sent += bsent;
    }
pthread_mutex_unlock (&p->io_send_lock);
return sent;
}

static int
_panel_sendf (PANEL *p, const char *fmt, ...);

static int
_panel_register_query_string (PANEL *panel, char **buf, int *buf_size)
{
int i, buf_data, buf_needed = 0;

for (i=0; i<panel->reg_count; i++)
    buf_needed += 7 + strlen (panel->regs[i].name);
buf_needed += 20; /* # REGISTERS-DONE */
if (buf_needed > *buf_size) {
    free (*buf);
    *buf = (char *)_panel_malloc (buf_needed);
    if (!*buf)
        return -1;
    *buf_size = buf_needed;
    }
buf_data = 0;
#if SEPARATE_REGISTERS
for (i=0; i<panel->reg_count; i++) {
    sprintf (*buf + buf_data, "E -H %s\r", panel->regs[i].name);
    buf_data += strlen (*buf + buf_data);
    }
#else
sprintf (*buf + buf_data, "E -H ");
buf_data += strlen (*buf + buf_data);
for (i=0; i<panel->reg_count; i++) {
    sprintf (*buf + buf_data, "%s%s", (i>0) ? "," : "", panel->regs[i].name);
    buf_data += strlen (*buf + buf_data);
    }
sprintf (*buf + buf_data, "\r");
buf_data += strlen (*buf + buf_data);
#endif
sprintf (*buf + buf_data, "# REGISTERS-DONE\r");
buf_data += strlen (*buf + buf_data);
*buf_size = buf_data;
return 0;
}

static PANEL **panels = NULL;
static int panel_count = 0;

static void
_panel_cleanup (void)
{
while (panel_count)
    sim_panel_stop_simulator (*panels);
}

static void
_panel_register_panel (PANEL *p)
{
++panel_count;
panels = realloc (panels, sizeof(*panels)*panel_count);
panels[panel_count-1] = p;
if (panel_count == 1)
    atexit (&_panel_cleanup);
}

static void
_panel_deregister_panel (PANEL *p)
{
int i;

for (i=0; i<panel_count; i++) {
    if (panels[i] == p) {
        int j;
        for (j=i+1; j<panel_count; j++) 
            panels[j-1] = panels[j];
        --panel_count;
        if (panel_count == 0) {
            free (panels);
            panels = NULL;
            }
        break;
        }
    }
}


PANEL *
sim_panel_start_simulator (const char *sim_path,
                           const char *sim_config)
{
PANEL *p = NULL;
FILE *f = NULL;
struct stat statb;
char *buf = NULL;
int port;
char hostport[64];
union {int i; char c[sizeof (int)]; } end_test;

end_test.i = 1;                             /* test endian-ness */
little_endian = (end_test.c[0] != 0);
sim_init_sock ();
for (port=1024; port < 2048; port++) {
    SOCKET sock;

    sprintf (hostport, "%d", port);
    sock = sim_connect_sock_ex (NULL, hostport, NULL, NULL, SIM_SOCK_OPT_NODELAY | SIM_SOCK_OPT_BLOCKING);
    if (sock != INVALID_SOCKET) {
        int sta = 0;
        while (!sta) {
            msleep (10);
            sta = sim_check_conn (sock, 1);
            }
        sim_close_sock (sock);
        if (sta == -1)
            break;
        }
    else
        break;
    
    }
if (stat (sim_path, &statb) < 0) {
    sim_panel_set_error ("Can't stat simulator '%s': %s", sim_path, strerror(errno));
    goto Error_Return;
    }
if (stat (sim_config, &statb) < 0) {
    sim_panel_set_error ("Can't stat simulator configuration '%s': %s", sim_config, strerror(errno));
    goto Error_Return;
    }
f = fopen (sim_config, "rb");
if (NULL == f) {
    sim_panel_set_error ("Can't open simulator configuration '%s': %s", sim_config, strerror(errno));
    goto Error_Return;
    }
buf = (char *)_panel_malloc (statb.st_size+1);
if (buf == NULL)
    goto Error_Return;
buf[statb.st_size] = '\0';
p = (PANEL *)_panel_malloc (sizeof(*p));
if (p == NULL)
    goto Error_Return;
memset (p, 0, sizeof(*p));
p->sock = INVALID_SOCKET;
p->path = (char *)_panel_malloc (strlen (sim_path) + 1);
if (p->path == NULL)
    goto Error_Return;
strcpy (p->path, sim_path);
p->config = (char *)_panel_malloc (strlen (sim_config) + 1);
if (p->config == NULL)
    goto Error_Return;
strcpy (p->config, sim_config);
f = fopen (sim_config, "rb");
if (f == NULL) {
    sim_panel_set_error ("Can't open configuration file '%s': %s", sim_config, strerror(errno));
    goto Error_Return;
    }
if (statb.st_size != fread (buf, 1, statb.st_size, f)) {
    sim_panel_set_error ("Can't read complete configuration file '%s': %s", sim_config, strerror(errno));
    goto Error_Return;
    }
fclose (f);
f = NULL;
p->temp_config = (char *)_panel_malloc (strlen (sim_config) + 40);
if (p->temp_config == NULL)
    goto Error_Return;
sprintf (p->temp_config, "%s-Panel-%d", sim_config, getpid());
f = fopen (p->temp_config, "w");
if (f == NULL) {
    sim_panel_set_error ("Can't create temporary configuration file '%s': %s", p->temp_config, strerror(errno));
    goto Error_Return;
    }
fprintf (f, "# Temporary FrontPanel generated simh configuration file\n");
fprintf (f, "# Original Configuration File: %s\n", p->config);
fprintf (f, "# Simulator Path: %s\n", p->path);
fprintf (f, "%s\n", buf);
free (buf);
buf = NULL;
fprintf (f, "set remote telnet=%s\n", hostport);
fprintf (f, "set remote master\n");
fclose (f);
f = NULL;
if (1) {
#if defined(_WIN32)
    char cmd[1024];

    sprintf(cmd, "%s%s%s %s%s%s", strchr (p->path, ' ') ? "\"" : "", p->path, strchr (p->path, ' ') ? "\"" : "", strchr (p->temp_config, ' ') ? "\"" : "", p->temp_config, strchr (p->temp_config, ' ') ? "\"" : "");
    if (1) {
        PROCESS_INFORMATION ProcessInfo;
        STARTUPINFO StartupInfo;

        memset (&ProcessInfo, 0, sizeof(ProcessInfo));
        memset (&StartupInfo, 0, sizeof(StartupInfo));
        StartupInfo.dwFlags = STARTF_USESTDHANDLES;
        StartupInfo.hStdInput = INVALID_HANDLE_VALUE;
        StartupInfo.hStdOutput = INVALID_HANDLE_VALUE;
        StartupInfo.hStdError = INVALID_HANDLE_VALUE;
        if (CreateProcessA(p->path, cmd, NULL, NULL, FALSE, CREATE_NO_WINDOW, NULL, NULL, &StartupInfo, &ProcessInfo)) {
            CloseHandle (ProcessInfo.hThread);
            p->hProcess = ProcessInfo.hProcess;
            Sleep (500);
            }
        else { /* Creation Problem */
            sim_panel_set_error ("CreateProcess Error: %d", GetLastError());
            goto Error_Return;
            }
        }
#else
    p->pidProcess = fork();
    if (p->pidProcess == 0) {
        close (0);
        close (1);
        close (2);
        if (execl (p->path, p->path, p->temp_config, NULL)) {
            perror ("execl");
            exit(errno);
            }
        }
    if (p->pidProcess < 0) {
        p->pidProcess = 0;
        sim_panel_set_error ("vfork() Error: %s", strerror(errno));
        goto Error_Return;
        }
    msleep (500);
#endif
    }
p->sock = sim_connect_sock_ex (NULL, hostport, NULL, NULL, SIM_SOCK_OPT_NODELAY | SIM_SOCK_OPT_BLOCKING);
if (p->sock == INVALID_SOCKET) {
    sim_panel_set_error ("Can't connect to simulator Remote Console on port %s", hostport);
    goto Error_Return;
    }
if (1) {
    pthread_attr_t attr;

    pthread_mutex_init (&p->io_lock, NULL);
    pthread_mutex_init (&p->io_send_lock, NULL);
    pthread_cond_init (&p->io_done, NULL);
    pthread_cond_init (&p->startup_cond, NULL);
    pthread_attr_init(&attr);
    pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
    pthread_mutex_lock (&p->io_lock);
    pthread_create (&p->io_thread, &attr, _panel_reader, (void *)p);
    pthread_attr_destroy(&attr);
    while (!p->io_thread_running)
        pthread_cond_wait (&p->startup_cond, &p->io_lock); /* Wait for thread to stabilize */
    pthread_mutex_unlock (&p->io_lock);
    pthread_cond_destroy (&p->startup_cond);
    }
if (sizeof(mantra) != _panel_send (p, (char *)mantra, sizeof(mantra))) {
    sim_panel_set_error ("Error sending Telnet mantra (options): %s", sim_get_err_sock ("send"));
    goto Error_Return;
    }
_panel_register_panel (p);
return p;

Error_Return:
if (f)
    fclose (f);
if (buf)
    free (buf);
sim_panel_stop_simulator (p);
return NULL;
}

int
sim_panel_stop_simulator (PANEL *panel)
{
REG *reg;

if (panel) {
    _panel_deregister_panel (panel);
    free (panel->path);
    free (panel->config);
    if (panel->sock != INVALID_SOCKET) {
        SOCKET sock = panel->sock;
        int wait_count;

        /* First, wind down the automatic register queries */
        sim_panel_set_display_callback (panel, NULL, NULL, 0);
        /* Next, attempt a simulator shutdown */
        _panel_send (panel, "\005\rEXIT\r", 7);
        /* Wait for up to 2 seconds for a graceful shutdown */
        for (wait_count=0; panel->io_thread_running && (wait_count<20); ++wait_count)
            msleep (100);
        /* Now close the socket which should stop a pending read which hasn't completed */
        panel->sock = INVALID_SOCKET;
        sim_close_sock (sock);
        pthread_join (panel->io_thread, NULL);
        pthread_mutex_destroy (&panel->io_lock);
        pthread_mutex_destroy (&panel->io_send_lock);
        pthread_cond_destroy (&panel->io_done);
        }
#if defined(_WIN32)
    if (panel->hProcess) {
        TerminateProcess (panel->hProcess, 0);
        WaitForSingleObject (panel->hProcess, INFINITE);
        CloseHandle (panel->hProcess);
        }
#else
    if (panel->pidProcess) {
        int status;

        if (!kill (panel->pidProcess, 0)) {
            kill (panel->pidProcess, SIGTERM);
            msleep (200);
            if (!kill (panel->pidProcess, 0))
                kill (panel->pidProcess, SIGKILL);
            }
        waitpid (panel->pidProcess, &status, 0);
        }
#endif
    if (panel->temp_config)
        remove (panel->temp_config);
    free (panel->temp_config);
    reg = panel->regs;
    while (panel->reg_count--) {
        free (reg->name);
        reg++;
        }
    free (panel->regs);
    }
sim_cleanup_sock ();
free (panel);
return 0;
}

OperationalState
sim_panel_get_state (PANEL *panel)
{
if (!panel) {
    sim_panel_set_error ("Invalid Panel");
    return -1;
    }
return panel->State;
}

int
sim_panel_add_register (PANEL *panel,
                        const char *name,
                        size_t size,
                        void *addr)
{
REG *regs, *reg;

if (!panel) {
    sim_panel_set_error ("Invalid Panel");
    return -1;
    }
regs = (REG *)_panel_malloc ((1 + panel->reg_count)*sizeof(*regs));
if (regs == NULL)
    return -1;
memcpy (regs, panel->regs, panel->reg_count*sizeof(*regs));
reg = &regs[panel->reg_count];
memset (reg, 0, sizeof(*regs));
reg->name = (char *)_panel_malloc (1 + strlen (name));
if (reg->name == NULL) {
    free (regs);
    return -1;
    }
strcpy (reg->name, name);
reg->addr = addr;
reg->size = size;
++panel->reg_count;
free (panel->regs);
panel->regs = regs;
return 0;
}

int
sim_panel_get_registers (PANEL *panel)
{
char *buf = NULL;
int buf_data;

if (!panel) {
    sim_panel_set_error ("Invalid Panel");
    return -1;
    }
if (panel->callback) {
    sim_panel_set_error ("Callback provides register data");
    return -1;
    }
buf_data = 0;
if (_panel_register_query_string (panel, &buf, &buf_data))
    return -1;
pthread_mutex_lock (&panel->io_lock);
if (buf_data != _panel_send (panel, buf, buf_data))
    return -1;
pthread_cond_wait (&panel->io_done, &panel->io_lock);
pthread_mutex_unlock (&panel->io_lock);
return 0;
}

int
sim_panel_set_display_callback (PANEL *panel, 
                                PANEL_DISPLAY_PCALLBACK callback, 
                                void *context, 
                                int callbacks_per_second)
{
if (!panel) {
    sim_panel_set_error ("Invalid Panel");
    return -1;
    }
pthread_mutex_lock (&panel->io_lock);
panel->callback = callback;
panel->callback_context = context;
if (callbacks_per_second && (0 == panel->callbacks_per_second)) { /* Need to start callbacks */
    pthread_attr_t attr;

    panel->callbacks_per_second = callbacks_per_second;
    pthread_cond_init (&panel->startup_cond, NULL);
    pthread_attr_init(&attr);
    pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
    pthread_create (&panel->callback_thread, &attr, _panel_callback, (void *)panel);
    pthread_attr_destroy(&attr);
    while (!panel->callback_thread_running)
        pthread_cond_wait (&panel->startup_cond, &panel->io_lock); /* Wait for thread to stabilize */
    pthread_cond_destroy (&panel->startup_cond);
    }
if ((callbacks_per_second == 0) && panel->callbacks_per_second) { /* Need to stop callbacks */
    panel->callbacks_per_second = 0;
    pthread_mutex_unlock (&panel->io_lock);
    pthread_join (panel->callback_thread, NULL);
    pthread_mutex_lock (&panel->io_lock);
    }
pthread_mutex_unlock (&panel->io_lock);
return 0;
}

int
sim_panel_exec_halt (PANEL *panel)
{
if (!panel) {
    sim_panel_set_error ("Invalid Panel");
    return -1;
    }
if (panel->State == Run) {
    if (1 != _panel_send (panel, "\005", 1))
        return -1;
    }
return 0;
}

int
sim_panel_exec_boot (PANEL *panel, const char *device)
{
if (!panel) {
    sim_panel_set_error ("Invalid Panel");
    return -1;
    }
if (panel->State == Run) {
    sim_panel_set_error ("Not Halted");
    return -1;
    }
if (_panel_sendf (panel, "BOOT %s\r", device))
    return -1;
panel->State = Run;
return 0;
}

int
sim_panel_exec_run (PANEL *panel)
{
if (!panel) {
    sim_panel_set_error ("Invalid Panel");
    return -1;
    }
if (panel->State == Run) {
    sim_panel_set_error ("Not Halted");
    return -1;
    }
if (5 != _panel_send (panel, "CONT\r", 5))
    return -1;
panel->State = Run;
return 0;
}

int
sim_panel_exec_step (PANEL *panel)
{
if (!panel) {
    sim_panel_set_error ("Invalid Panel");
    return -1;
    }
if (panel->State == Run) {
    sim_panel_set_error ("Not Halted");
    return -1;
    }
    
if (5 != _panel_send (panel, "STEP\r", 5))
    return -1;
panel->State = Run;
return 0;
}

static void *
_panel_reader(void *arg)
{
PANEL *p = (PANEL*)arg;
int sched_policy;
struct sched_param sched_priority;
char buf[4096];
int buf_data = 0;

/* 
   Boost Priority for this response processing thread to quickly digest 
   arriving data.
 */
pthread_getschedparam (pthread_self(), &sched_policy, &sched_priority);
++sched_priority.sched_priority;
pthread_setschedparam (pthread_self(), sched_policy, &sched_priority);

pthread_mutex_lock (&p->io_lock);
p->io_thread_running = 1;
pthread_cond_signal (&p->startup_cond);   /* Signal we're ready to go */
while (p->sock != INVALID_SOCKET) {
    int new_data;
    char *s, *e, *eol;

    pthread_mutex_unlock (&p->io_lock);
    new_data = sim_read_sock (p->sock, &buf[buf_data], sizeof(buf)-(buf_data+1));
    if (new_data <= 0)
        break;
    buf_data += new_data;
    buf[buf_data] = '\0';
    s = buf;
    while ((eol = strchr (s, '\r'))) {
        /* Line to process */
        *eol++ = '\0';
        e = strchr (s, ':');
        if (e) {
            int i;

            *e++ = '\0';
            for (i=0; i<p->reg_count; i++) {
                if (!strcmp(p->regs[i].name, s)) {
                    unsigned long long data;

                    data = strtoull (e, NULL, 16);
                    if (little_endian)
                        memcpy (p->regs[i].addr, &data, p->regs[i].size);
                    else
                        memcpy (p->regs[i].addr, ((char *)&data) + sizeof(data)-p->regs[i].size, p->regs[i].size);
                    break;
                    }
                }
            if (i == p->reg_count) {
                /* Unexpected Register Data Found */
                }
            }
        else {
            if (!strcmp (s + strlen (sim_prompt), "# REGISTERS-DONE"))
                if (p->callback) {
                    p->callback (p, p->callback_context);
                    }
                else {
                    pthread_mutex_lock (&p->io_lock);
                    pthread_cond_signal (&p->io_done);
                    pthread_mutex_unlock (&p->io_lock);
                    }
            else {
                /* Non Register Data Found (echo of EXAMINE or other commands) */
                }
            }
        s = eol;
        while (isspace(*s))
            ++s;
        }
    pthread_mutex_lock (&p->io_lock);
    if ((p->State == Run) && (!strcmp (s, sim_prompt))) {
        p->State = Halt;
        }
    memmove (buf, s, strlen (s)+1);
    buf_data = strlen (buf);
    if (!strcmp("Simulator Running", buf)) {
        p->State = Run;
        buf_data = 0;
        buf[0] = '\0';
        }
    }
p->io_thread_running = 0;
pthread_mutex_unlock (&p->io_lock);
return NULL;
}

static void *
_panel_callback(void *arg)
{
PANEL *p = (PANEL*)arg;
int sched_policy;
struct sched_param sched_priority;
char *buf = NULL;
int buf_data = 0;
unsigned int callback_count = 0;

/* 
   Boost Priority for timer thread so it doesn't compete 
   with compute bound activities.
 */
pthread_getschedparam (pthread_self(), &sched_policy, &sched_priority);
++sched_priority.sched_priority;
pthread_setschedparam (pthread_self(), sched_policy, &sched_priority);

pthread_mutex_lock (&p->io_lock);
p->callback_thread_running = 1;
pthread_cond_signal (&p->startup_cond);   /* Signal we're ready to go */
while ((p->sock != INVALID_SOCKET) && 
       (p->callbacks_per_second)) {
    int rate = p->callbacks_per_second;
    pthread_mutex_unlock (&p->io_lock);

    ++callback_count;
    if (1 == callback_count%rate)
        _panel_register_query_string (p, &buf, &buf_data);
    msleep (1000/rate);
    if ((p->State == Run) || (0 == callback_count%(5*rate)))
        if (buf_data != _panel_send (p, buf, buf_data)) {
            break;
            }
    pthread_mutex_lock (&p->io_lock);
    }
p->callback_thread_running = 0;
pthread_mutex_unlock (&p->io_lock);
free (buf);
return NULL;
}

static char *sim_panel_error_buf = NULL;
static size_t sim_panel_error_bufsize = 0;

const char *sim_panel_get_error (void)
{
return (sim_panel_error_buf ? sim_panel_error_buf : "");
}

void sim_panel_clear_error (void)
{
if (sim_panel_error_bufsize)
    free (sim_panel_error_buf);
sim_panel_error_buf = NULL;
sim_panel_error_bufsize = 0;
}

#if defined (_WIN32)
#define vsnprintf _vsnprintf
#endif

void sim_panel_set_error (const char *fmt, ...)
{
va_list arglist;
int len;

if (sim_panel_error_bufsize == 0) {
    sim_panel_error_bufsize = 2048;
    sim_panel_error_buf = (char *) malloc (sim_panel_error_bufsize);
    if (sim_panel_error_buf == NULL) {          /* out of memory */
        sim_panel_error_buf = "sim_panel_set_error(): Out of Memory\n";
        sim_panel_error_bufsize = 0;
        return;
        }
    }
sim_panel_error_buf[sim_panel_error_bufsize-1] = '\0';

while (1) {                                         /* format passed string, args */
    va_start (arglist, fmt);
    len = vsnprintf (sim_panel_error_buf, sim_panel_error_bufsize-1, fmt, arglist);
    va_end (arglist);

/* If the formatted result didn't fit into the buffer, then grow the buffer and try again */

    if ((len < 0) || (len >= (int)(sim_panel_error_bufsize-1))) {
        free (sim_panel_error_buf);
        sim_panel_error_bufsize = sim_panel_error_bufsize * 2;
        while ((int)sim_panel_error_bufsize < len + 1)
            sim_panel_error_bufsize = sim_panel_error_bufsize * 2;
        sim_panel_error_buf = (char *) malloc (sim_panel_error_bufsize);
        if (sim_panel_error_buf == NULL) {          /* out of memory */
            sim_panel_error_buf = "sim_panel_set_error(): Out of Memory\n";
            sim_panel_error_bufsize = 0;
            return;
            }
        sim_panel_error_buf[sim_panel_error_bufsize-1] = '\0';
        continue;
        }
    break;
    }

return;
}

static int
_panel_sendf (PANEL *p, const char *fmt, ...)
{
char stackbuf[1024];
int bufsize = sizeof(stackbuf);
char *buf = stackbuf;
int len;
va_list arglist;
int ret;

while (1) {                                         /* format passed string, args */
    va_start (arglist, fmt);
    len = vsnprintf (buf, bufsize-1, fmt, arglist);
    va_end (arglist);

/* If the formatted result didn't fit into the buffer, then grow the buffer and try again */

    if ((len < 0) || (len >= bufsize-1)) {
        if (buf != stackbuf)
            free (buf);
        bufsize = bufsize * 2;
        buf = (char *) _panel_malloc (bufsize);
        if (buf == NULL)                            /* out of memory */
            return -1;
        buf[bufsize-1] = '\0';
        continue;
        }
    break;
    }

ret = (strlen (buf) == _panel_send (p, buf, strlen (buf))) ? 0 : -1;

if (buf != stackbuf)
    free (buf);
return ret;
}


#ifdef  __cplusplus
}
#endif