src/config.c (7d31e7e) - libetherpix · BlinkenArea

config.c

/*
 * EtherPix library
 *
 * Copyright 2010-2017 Stefan Schuermans <stefan schuermans info>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 3 of the License.
 *
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <etherpix/msg.h>
#include <etherpix/types.h>
#include <intern/const_data.h>
#include <intern/constants.h>
#include <intern/config.h>
#include <intern/mapping.h>
#include <intern/missing.h>
#include <intern/net.h>
#include <intern/parse.h>
#include <intern/strtod_noloc.h>
#include <intern/types.h>

/**
 * \brief process distributor from config file
 *
 * \param[in,out] p_ctx context information
 * \param[in] p_setting_part2 second half of setting to process
 * \param[in] p_value value of setting
 * \return 0 in case of success, -1 in case of error
 */
int etp_config_proc_distri(etp_config_ctx_t *p_ctx, char *p_setting_part2,
                           char *p_value)
{
  char *ptr;
  unsigned long val;
  unsigned int distri, out, pix, i;
  etp_distri_t *p_distri;

/* get distributor number */
  val = strtoul(p_setting_part2, &ptr, 0);
  if (ptr == p_setting_part2 || *ptr != 0 || val >= ETP_DISTRI_MAX_CNT) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid distributor number \"%s\""
                        " in line %u of config file\n",
                        p_setting_part2, p_ctx->line_no);
    return -1;
  }
  distri = (unsigned int)val;

/* get number of outputs and pixels */
  if (etp_parse_two_nos(p_value, &out, &pix, &ptr) || *ptr != 0) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid distributor size \"%s\""
                        " in line %u of config file\n",
                        p_value, p_ctx->line_no);
    return -1;
  }
  if (out >= ETP_OUTPUT_MAX_CNT) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid number of outputs \"%u\""
                        " in line %u of config file\n",
                        out, p_ctx->line_no);
    return -1;
  }
  if (pix >= ETP_PIXEL_MAX_CNT) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid number of pixels \"%u\""
                        " in line %u of config file\n",
                        pix, p_ctx->line_no);
    return -1;
  }

/* check if distributor is already present */
  if (p_ctx->p_display->distri_ptrs[distri]) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "duplicate definition of distributor \"%u\""
                        " in line %u of config file\n",
                        distri, p_ctx->line_no);
    return -1;
  }

/* create a new distributor */
  p_distri = (etp_distri_t *)malloc(sizeof (etp_distri_t));
  if (!p_distri) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err, "out of memory\n");
    return -1;
  }
  p_distri->distri = distri;
  p_distri->output_cnt = out;
  p_distri->pixel_cnt = pix;
  /* no network address yet */
  p_distri->addr_cnt = 0;
  /* initialize mapping information */
  for (i = 0; i < 3; i++) {
    p_distri->mapping[i].base = 0.0;
    p_distri->mapping[i].gamma = 1.0;
    p_distri->mapping[i].factor = 1.0;
    etp_mapping_precalc(&p_distri->mapping[i]);
  }
  /* create and initialize pixel array */
  p_distri->p_pixels =
    (etp_pixel_t *)malloc(out * pix * sizeof (etp_pixel_t));
  if (!p_distri->p_pixels) {
    free(p_distri);
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err, "out of memory\n");
    return -1;
  }
  for (i = 0; i < out * pix; i++) {
    p_distri->p_pixels[i].x = -1;
    p_distri->p_pixels[i].y = -1;
  }
  /* create and initialize message buffer */
  p_distri->msg_len = ETP_MCUF_HDR_LEN + out * pix * 3;
  p_distri->p_msg_buf = (etp_u8_t *)malloc(p_distri->msg_len);
  if (!p_distri->p_msg_buf) {
    free(p_distri->p_pixels);
    free(p_distri);
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err, "out of memory\n");
    return -1;
  }
  memset(p_distri->p_msg_buf, 0, p_distri->msg_len);
  memcpy(p_distri->p_msg_buf, etp_mcuf_hdr, ETP_MCUF_HDR_LEN);
  p_distri->p_msg_buf[ETP_MCUF_HDR_OFS_OUTPUTS_U16 + 0] = (etp_u8_t)(out >> 8);
  p_distri->p_msg_buf[ETP_MCUF_HDR_OFS_OUTPUTS_U16 + 1] = (etp_u8_t)out;
  p_distri->p_msg_buf[ETP_MCUF_HDR_OFS_PIXELS_U16 + 0] = (etp_u8_t)(pix >> 8);
  p_distri->p_msg_buf[ETP_MCUF_HDR_OFS_PIXELS_U16 + 1] = (etp_u8_t)pix;
  /* store pointer to distributor */
  p_ctx->p_display->distri_ptrs[distri] = p_distri;

/* count distributors */
  p_ctx->p_display->distri_cnt++;

return 0;
}

/**
 * \brief process distributor address from config file
 *
 * \param[in,out] p_ctx context information
 * \param[in] p_setting_part2 second half of setting to process
 * \param[in] p_value value of setting
 * \return 0 in case of success, -1 in case of error
 */
int etp_config_proc_distri_addr(etp_config_ctx_t *p_ctx, char *p_setting_part2,
                                char *p_value)
{
  char *ptr;
  unsigned long val;
  unsigned int distri;
  etp_distri_t *p_distri;

/* get distributor number */
  val = strtoul(p_setting_part2, &ptr, 0);
  if (ptr == p_setting_part2 || *ptr != 0) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid mapping specifier \"%s\""
                        " in line %u of config file\n",
                        p_setting_part2, p_ctx->line_no);
    return -1;
  }
  distri = (unsigned int)val;
  if (distri >= ETP_DISTRI_MAX_CNT) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid distributor number \"%u\""
                        " in line %u of config file\n",
                        distri, p_ctx->line_no);
    return -1;
  }

/* check if maximum number of addresses reached */
  if (p_distri->addr_cnt >= ETP_DISTRI_MAX_ADDRS) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "too many addresses (\"%s\") for distributor with"
                        " number \"%u\" in line %u of config file\n",
                        p_value, distri, p_ctx->line_no);
    return -1;
  }

/* get address and add it to distributor */
  if (etp_parse_addr(p_value, &p_distri->addrs[p_distri->addr_cnt])) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid address \"%s\" for distributor with number"
                        " \"%u\" in line %u of config file\n",
                        p_value, distri, p_ctx->line_no);
    return -1;
  }
  ++p_distri->addr_cnt;

return 0;
}

/**
 * \brief process mapping from config file
 *
 * \param[in,out] p_ctx context information
 * \param[in] p_setting_part2 second half of setting to process
 * \param[in] p_value value of setting
 * \return 0 in case of success, -1 in case of error
 */
int etp_config_proc_mapping(etp_config_ctx_t *p_ctx, char *p_setting_part2,
                            char *p_value)
{
  char *ptr, *ptr2;
  unsigned long val;
  unsigned int distri, chan;
  etp_distri_t *p_distri;
  double base, factor, gamma;

/* get distributor number */
  val = strtoul(p_setting_part2, &ptr, 0);
  if (ptr == p_setting_part2
      || (*ptr != 0 && *ptr != ' ' && *ptr != '\t'
          && *ptr != '\r' && *ptr != '\n')) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid mapping specifier \"%s\""
                        " in line %u of config file\n",
                        p_setting_part2, p_ctx->line_no);
    return -1;
  }
  distri = (unsigned int)val;
  if (distri >= ETP_DISTRI_MAX_CNT) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid distributor number \"%u\""
                        " in line %u of config file\n",
                        distri, p_ctx->line_no);
    return -1;
  }

/* get channel */
  while (*ptr == ' ' || *ptr == '\t' || *ptr == '\r' || *ptr == '\n')
    ptr++;
  if (!strcmp(ptr, "red"))
    chan = 0;
  else if (!strcmp(ptr, "green"))
    chan = 1;
  else if (!strcmp(ptr, "blue"))
    chan = 2;
  else {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid channel \"%s\""
                        " in line %u of config file\n", ptr,
                        p_ctx->line_no);
    return -1;
  }

/* get mapping parameters: base, factor, gamma */
  base = etp_strtod_noloc(p_value, &ptr);
  if (ptr == p_value
      || (*ptr != 0 && *ptr != ' ' && *ptr != '\t'
          && *ptr != '\r' && *ptr != '\n')) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid mapping parameters \"%s\""
                        " in line %u of config file\n",
                        p_value, p_ctx->line_no);
    return -1;
  }
  factor = etp_strtod_noloc(ptr, &ptr2);
  if (ptr2 == ptr
      || (*ptr2 != 0 && *ptr2 != ' ' && *ptr2 != '\t'
          && *ptr2 != '\r' && *ptr2 != '\n')) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid mapping parameters \"%s\""
                        " in line %u of config file\n",
                        p_value, p_ctx->line_no);
    return -1;
  }
  gamma = etp_strtod_noloc(ptr2, &ptr);
  if (ptr == ptr2
      || (*ptr != 0 && *ptr != ' ' && *ptr != '\t'
          && *ptr != '\r' && *ptr != '\n')) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid mapping parameters \"%s\""
                        " in line %u of config file\n",
                        p_value, p_ctx->line_no);
    return -1;
  }
  if (gamma <= 0.0) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid gamma value \"%f\""
                        " in line %u of config file\n",
                        gamma, p_ctx->line_no);
    return -1;
  }

/* store new mapping parameters and re-calculate mapping table */
  p_distri->mapping[chan].base = base;
  p_distri->mapping[chan].factor = factor;
  p_distri->mapping[chan].gamma = gamma;
  etp_mapping_precalc(&p_distri->mapping[chan]);

return 0;
}

/**
 * \brief process pixel from config file
 *
 * \param[in,out] p_ctx context information
 * \param[in] sz_pixel text of pixel to process
 * \param[in] distri number of distributor
 * \param[in] out number of output
 * \param[in] pix number of pixel
 * \return 0 in case of success, -1 in case of error
 */
int etp_config_proc_pixel(etp_config_ctx_t *p_ctx, char *sz_pixel,
                          unsigned int distri, unsigned int out,
                          unsigned int pix)
{
  etp_distri_t *p_distri = p_ctx->p_display->distri_ptrs[distri];
  char *ptr;
  unsigned int x, y, idx;

/* get coordinates of pixel */
  if (etp_parse_two_nos(sz_pixel, &x, &y, &ptr) || *ptr != 0
      || (int)x < 0 || (int)x >= p_ctx->p_display->size.x
      || (int)y < 0 || (int)y >= p_ctx->p_display->size.y) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid pixel \"%s\""
                        " in line %u of config file\n",
                        sz_pixel, p_ctx->line_no);
    return -1;
  }

/* check pixel number */
  if (pix >= ETP_PIXEL_MAX_CNT || pix >= p_distri->pixel_cnt) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "too many pixels (more than %u)"
                        " in line %u of config file\n",
                        p_distri->pixel_cnt, p_ctx->line_no);
    return -1;
  }

/* check that pixel is not yet set */
  idx = out * p_distri->pixel_cnt + pix;
  if (p_distri->p_pixels[idx].x >= 0
      && p_distri->p_pixels[idx].y >= 0) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "pixel %u of output %u of distributor %u already set"
                        " to pixel %u,%u in line %u of config file\n",
                        pix, out, distri, p_distri->p_pixels[idx].x,
                 p_distri->p_pixels[idx].y, p_ctx->line_no);
    return -1;
  }

/* set pixel coordinates */
  p_distri->p_pixels[idx].x = x;
  p_distri->p_pixels[idx].y = y;

/* count pixels in total */
  p_ctx->p_display->pixel_cnt++;

return 0;
}

/**
 * \brief process output from config file
 *
 * \param[in,out] p_ctx context information
 * \param[in] p_setting_part2 second half of setting to process
 * \param[in] p_value value of setting
 * \return 0 in case of success, -1 in case of error
 */
int etp_config_proc_output(etp_config_ctx_t *p_ctx, char *p_setting_part2,
                           char *p_value)
{
  char *ptr, *p_pos, *p_white, white;
  unsigned int distri, out, pix;
  etp_distri_t *p_distri;
  int err;

/* get number of distributor and output */
  if (etp_parse_two_nos(p_setting_part2, &distri, &out, &ptr) || *ptr != 0) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid output specifier \"%s\""
                        " in line %u of config file\n",
                        p_setting_part2, p_ctx->line_no);
    return -1;
  }
  if (distri >= ETP_DISTRI_MAX_CNT) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid distributor number \"%u\""
                        " in line %u of config file\n",
                        distri, p_ctx->line_no);
    return -1;
  }
  if (out >= ETP_OUTPUT_MAX_CNT) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "invalid output number \"%u\""
                        " in line %u of config file\n",
                        out, p_ctx->line_no);
    return -1;
  }

/* get distributor */
  p_distri = p_ctx->p_display->distri_ptrs[distri];
  if (!p_distri) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "no distributor with number \"%u\""
                        " in line %u of config file\n",
                        distri, p_ctx->line_no);
    return -1;
  }
  /* check output number */
  if (out >= p_distri->output_cnt) {
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                        "no output with output number \"%u\""
                        " in line %u of config file\n",
                        out, p_ctx->line_no);
    return -1;
  }

/* count outputs */
  p_ctx->p_display->output_cnt++;

/* process pixels */

/* process all parts separated by whitespace */
  p_pos = p_value;
  err = 0;
  pix = 0;
  while (*p_pos != 0) {

/* get end of item (first whitespace) */
    for (p_white = p_pos;
         *p_white && *p_white != ' ' && *p_white != '\t'
         && *p_white != '\r' && *p_white != '\n'; p_white++);

/* process item: a pixel */
    white = *p_white; /* terminate item */
    *p_white = 0;
    if (etp_config_proc_pixel(p_ctx, p_pos, distri, out, pix)) /* process */
      err = -1;       /* remember errors */
    pix++;            /* count pixels */
    *p_white = white; /* undo termination */

/* skip whitespace and continue after it */
    for (;
         *p_white == ' ' || *p_white == '\t'
         || *p_white == '\r' || *p_white == '\n'; p_white++);
    p_pos = p_white;

} /* while (*p_pos != 0) */

return err;
}

/**
 * \brief process setting from config file
 *
 * \param[in,out] p_ctx context information
 * \param[in] p_setting setting to process
 * \param[in] p_value value of setting
 * \return 0 in case of success, -1 in case of error
 */
int etp_config_proc_setting(etp_config_ctx_t *p_ctx, char *p_setting,
                            char *p_value)
{
  char *ptr;
  unsigned int x, y;

/* replace all whitespace with spaces in setting */
  while ((ptr = strchr(p_setting, '\t')))
    *ptr = ' ';
  while ((ptr = strchr(p_setting, '\r')))
    *ptr = ' ';
  while ((ptr = strchr(p_setting, '\n')))
    *ptr = ' ';

/* bind address for UDP output */
  if (!strcmp(p_setting, "bindAddr")) {
    if (etp_parse_addr(p_value, &p_ctx->p_display->bind_addr)) {
      if (p_ctx->p_msg_func)
        p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                          "invalid address \"%s\" for \"%s\""
                          " in line %u of config file\n",
                          p_value, p_setting, p_ctx->line_no);
      return -1;
    }
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_info, "bind address: %s\n", p_value);
    return 0;
  }

/* size of display */
  if (!strcmp(p_setting, "size")) {
    if (etp_parse_two_nos(p_value, &x, &y, &ptr)
        || (int)x <= 0 || (int)y <= 0) {
      if (p_ctx->p_msg_func)
        p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_err,
                          "invalid value \"%s\" for \"%s\""
                          " in line %u of config file\n",
                          p_value, p_setting, p_ctx->line_no);
      return -1;
    }
    p_ctx->p_display->size.x = x;
    p_ctx->p_display->size.y = y;
    return 0;
  }

/* distributor */
  if (!strncmp(p_setting, "distributor ", 12))
    return etp_config_proc_distri(p_ctx, p_setting + 12, p_value);

/* distributor address */
  if (!strncmp(p_setting, "distributorAddr ", 16))
    return etp_config_proc_distri_addr(p_ctx, p_setting + 16, p_value);

/* mapping */
  if (!strncmp(p_setting, "mapping ", 8))
    return etp_config_proc_mapping(p_ctx, p_setting + 8, p_value);

/* output */
  if (!strncmp(p_setting, "output ", 7))
    return etp_config_proc_output(p_ctx, p_setting + 7, p_value);

/* unknown setting */
  if (p_ctx->p_msg_func)
    p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_warn,
                      "unknown setting \"%s\""
                      " in line %u of config file, ignored\n",
                      p_setting, p_ctx->line_no);
  return 0;
}

/**
 * \brief process line from config file
 *
 * \param[in,out] p_ctx context information
 * \param[in] p_line line to process
 * \return 0 in case of success, -1 in case of error
 */
int etp_config_proc_line(etp_config_ctx_t *p_ctx, char *p_line)
{
  char *p_hash, *p_equal, *p_setting, *p_value;
  int i;

/* remove comment */
  p_hash = strchr(p_line, '#');
  if (p_hash)
    *p_hash = 0;

/* remove trailing whitespace */
  for (i = strlen(p_line) - 1;
       i >= 0 && (p_line[i] == ' ' || p_line[i] == '\t'
                  || p_line[i] == '\r' || p_line[i] == '\n'); i--)
    p_line[i] = 0;

/* remove leading whitespace */
  for (; *p_line == ' ' || *p_line == '\t'
         || *p_line == '\r' || *p_line == '\n'; p_line++);

/* ignore empty line */
  if (!p_line[0])
    return 0;

/* find equal sign */
  p_equal = strchr(p_line, '=');
  if (!p_equal) {               /* no equal sign found */
    if (p_ctx->p_msg_func)
      p_ctx->p_msg_func(p_ctx->p_msg_ctx, etp_msg_type_warn,
                        "invalid line %u in config file, ignored\n",
                        p_ctx->line_no);
    return 0;
  }

/* split string at equal sign */
  *p_equal = 0;
  p_setting = p_line;
  p_value = p_equal + 1;

/* remove trailing whitespaces in setting name */
  for (i = strlen(p_setting) - 1;
       i >= 0 && (p_setting[i] == ' ' || p_setting[i] == '\t'
                  || p_setting[i] == '\r' || p_setting[i] == '\n'); i--)
    p_setting[i] = 0;

/* remove leading whitespaces in value */
  for (; *p_value == ' ' || *p_value == '\t'
         || *p_value == '\r' || *p_value == '\n'; p_value++);

/* process setting */
  return etp_config_proc_setting(p_ctx, p_setting, p_value);
}

/**
 * \brief set default addresses of distributors
 * \param[in,out] p_ctx context information
 */
static void etp_config_set_def_distri_addrs(etp_config_ctx_t *p_ctx)
{
  unsigned int distri;
  etp_distri_t *p_distri;

/* set default addresses of distributors */
  for (distri = 0; distri < ETP_DISTRI_MAX_CNT; distri++) {
    p_distri = p_ctx->p_display->distri_ptrs[distri];
    if (p_distri) {

/* no address yet -> use default */
      if (p_distri->addr_cnt == 0) {
        p_distri->addr_cnt = 1;
        p_distri->addrs[0].sin_family = AF_INET;
        p_distri->addrs[0].sin_addr.s_addr =
            htonl(ETP_DEST_IP_BASE + p_distri->distri * ETP_DEST_IP_STEP);
        p_distri->addrs[0].sin_port = htons(ETP_DEST_PORT);
      }

}  // if (p_distri)
  } // for (distri ...)
}

/**
 * \brief process config file
 *
 * \param[in,out] p_display display to configure
 * \param[in] sz_config_file name of config file to read
 * \param[in] p_msg_func message callback function or NULL
 * \param[in] p_msg_ctx user context for message callback
 * \return 0 in case of success, -1 in case of error
 */
int etp_config_proc_file(etp_display_t *p_display,
                         const char *sz_config_file,
                         etp_msg_func_p_t p_msg_func, void *p_msg_ctx)
{
  etp_config_ctx_t ctx;
  FILE *file;

/* set up context */
  ctx.p_display = p_display;
  ctx.p_msg_func = p_msg_func;
  ctx.p_msg_ctx = p_msg_ctx;

/* check if file is present */
  if (!sz_config_file || !sz_config_file[0]) {
    if (p_msg_func)
      p_msg_func(p_msg_ctx, etp_msg_type_err,
                 "no config file specified\n");
    return -1;
  }

if (p_msg_func)
    p_msg_func(p_msg_ctx, etp_msg_type_info,
               "using config file \"%s\"\n",
               sz_config_file);

/* open file */
  file = fopen(sz_config_file, "rt");
  if (!file) {
    if (p_msg_func) {
      char errmsg[256];
      strerror_r(errno, errmsg, sizeof(errmsg));
      p_msg_func(p_msg_ctx, etp_msg_type_err,
                 "cannot open config file \"%s\" for reading: %s\n",
                 sz_config_file, errmsg);
    }
    return -1;
  }

/* process lines in file */
  ctx.line_no = 1;
  while (!feof(file)) {
    char line[4096], *p_lf;

/* read a line */
    line[0] = 0;
    if (fgets(line, sizeof (line), file) == NULL)
      break;
    p_lf = strchr(line, '\n'); /* find LF in line in replace it with 0 */
    if (p_lf)
      *p_lf = 0;
    else {                     /* no LF in line */
      if (!feof(file)) {       /* not at end of file */
        char dummy[4096];
        if (p_msg_func)
          p_msg_func(p_msg_ctx, etp_msg_type_warn,
                     "line %u too long in config file, truncated\n",
                     ctx.line_no);
        /* jump over in rest of line */
        dummy[0] = 0;
        while (!feof(file) && !strchr(dummy, '\n'))
          if (fgets(dummy, sizeof (dummy), file) == NULL)
            break;
      }
    }

/* process line from file */
    if (etp_config_proc_line(&ctx, line))
      return -1;

ctx.line_no++;
  }

/* close file */
  fclose(file);

/* set default addresses of distributors */
  etp_config_set_def_distri_addrs(&ctx);

if (p_msg_func)
    p_msg_func(p_msg_ctx, etp_msg_type_info,
               "%ux%u input format, %u distributors, %u outputs, %lu pixels\n",
               p_display->size.x, p_display->size.y,
               p_display->distri_cnt, p_display->output_cnt,
               p_display->pixel_cnt);
  return 0;
}

libetherpix

support multiple addresses per distributor