lwdouble_to_dms()

static char* lwdouble_to_dms ( double  val, const char *  pos_dir_symbol, const char *  neg_dir_symbol, const char *  format  )

static

Definition at line 76 of file lwprint.c.

{
        /* 3 numbers, 1 sign or compass dir, and 5 possible strings (degree signs, spaces, misc text, etc) between or around them.*/
#       define NUM_PIECES 9
#       define WORK_SIZE 1024
        char pieces[NUM_PIECES][WORK_SIZE];
        int current_piece = 0;
        int is_negative = 0;
 
        double degrees = 0.0;
        double minutes = 0.0;
        double seconds = 0.0;
 
        int compass_dir_piece = -1;
 
        int reading_deg = 0;
        int deg_digits = 0;
        int deg_has_decpoint = 0;
        int deg_dec_digits = 0;
        int deg_piece = -1;
 
        int reading_min = 0;
        int min_digits = 0;
        int min_has_decpoint = 0;
        int min_dec_digits = 0;
        int min_piece = -1;
 
        int reading_sec = 0;
        int sec_digits = 0;
        int sec_has_decpoint = 0;
        int sec_dec_digits = 0;
        int sec_piece = -1;
 
        int round_pow = 0;
 
        int format_length = ((NULL == format) ? 0 : strlen(format));
 
        char * result;
 
        int index, following_byte_index;
        int multibyte_char_width = 1;
 
        /* Initialize the working strs to blank.  We may not populate all of them, and
         * this allows us to concat them all at the end without worrying about how many
         * we actually needed. */
        for (index = 0; index < NUM_PIECES; index++)
        {
                pieces[index][0] = '\0';
        }
 
        /* If no format is provided, use a default. */
        if (0 == format_length)
        {
                /* C2B0 is UTF-8 for the degree symbol. */
                format = "D\xC2\xB0""M'S.SSS\"C";
                format_length = strlen(format);
        }
        else if (format_length > WORK_SIZE)
        {
                /* Sanity check, we don't want to overwrite an entire piece of work and no one should need a 1K-sized
                * format string anyway. */
                lwerror("Bad format, exceeds maximum length (%d).", WORK_SIZE);
        }
 
        for (index = 0; index < format_length; index++)
        {
                char next_char = format[index];
                switch (next_char)
                {
                case 'D':
                        if (reading_deg)
                        {
                                /* If we're reading degrees, add another digit. */
                                deg_has_decpoint ? deg_dec_digits++ : deg_digits++;
                        }
                        else
                        {
                                /* If we're not reading degrees, we are now. */
                                current_piece++;
                                deg_piece = current_piece;
                                if (deg_digits > 0)
                                {
                                        lwerror("Bad format, cannot include degrees (DD.DDD) more than once.");
                                }
                                reading_deg = 1;
                                reading_min = 0;
                                reading_sec = 0;
                                deg_digits++;
                        }
                        break;
                case 'M':
                        if (reading_min)
                        {
                                /* If we're reading minutes, add another digit. */
                                min_has_decpoint ? min_dec_digits++ : min_digits++;
                        }
                        else
                        {
                                /* If we're not reading minutes, we are now. */
                                current_piece++;
                                min_piece = current_piece;
                                if (min_digits > 0)
                                {
                                        lwerror("Bad format, cannot include minutes (MM.MMM) more than once.");
                                }
                                reading_deg = 0;
                                reading_min = 1;
                                reading_sec = 0;
                                min_digits++;
                        }
                        break;
                case 'S':
                        if (reading_sec)
                        {
                                /* If we're reading seconds, add another digit. */
                                sec_has_decpoint ? sec_dec_digits++ : sec_digits++;
                        }
                        else
                        {
                                /* If we're not reading seconds, we are now. */
                                current_piece++;
                                sec_piece = current_piece;
                                if (sec_digits > 0)
                                {
                                        lwerror("Bad format, cannot include seconds (SS.SSS) more than once.");
                                }
                                reading_deg = 0;
                                reading_min = 0;
                                reading_sec = 1;
                                sec_digits++;
                        }
                        break;
                case 'C':
                        /* We're done reading anything else we might have been reading. */
                        if (reading_deg || reading_min || reading_sec)
                        {
                                /* We were reading something, that means this is the next piece. */
                                reading_deg = 0;
                                reading_min = 0;
                                reading_sec = 0;
                        }
                        current_piece++;
 
                        if (compass_dir_piece >= 0)
                        {
                                lwerror("Bad format, cannot include compass dir (C) more than once.");
                        }
                        /* The compass dir is a piece all by itself.  */
                        compass_dir_piece = current_piece;
                        current_piece++;
                        break;
                case '.':
                        /* If we're reading deg, min, or sec, we want a decimal point for it. */
                        if (reading_deg)
                        {
                                deg_has_decpoint = 1;
                        }
                        else if (reading_min)
                        {
                                min_has_decpoint = 1;
                        }
                        else if (reading_sec)
                        {
                                sec_has_decpoint = 1;
                        }
                        else
                        {
                                /* Not reading anything, just pass through the '.' */
                                strncat(pieces[current_piece], &next_char, 1);
                        }
                        break;
                default:
                        /* Any other char is just passed through unchanged.  But it does mean we are done reading D, M, or S.*/
                        if (reading_deg || reading_min || reading_sec)
                        {
                                /* We were reading something, that means this is the next piece. */
                                current_piece++;
                                reading_deg = 0;
                                reading_min = 0;
                                reading_sec = 0;
                        }
 
                        /* Check if this is a multi-byte UTF-8 character.  If so go ahead and read the rest of the bytes as well. */
                        multibyte_char_width = 1;
                        if (next_char & 0x80)
                        {
                                if ((next_char & 0xF8) == 0xF0)
                                {
                                        multibyte_char_width += 3;
                                }
                                else if ((next_char & 0xF0) == 0xE0)
                                {
                                        multibyte_char_width += 2;
                                }
                                else if ((next_char & 0xE0) == 0xC0)
                                {
                                        multibyte_char_width += 1;
                                }
                                else
                                {
                                        lwerror("Bad format, invalid high-order byte found first, format string may not be UTF-8.");
                                }
                        }
                        if (multibyte_char_width > 1)
                        {
                                if (index + multibyte_char_width >= format_length)
                                {
                                        lwerror("Bad format, UTF-8 character first byte found with insufficient following bytes, format string may not be UTF-8.");
                                }
                                for (following_byte_index = (index + 1); following_byte_index < (index + multibyte_char_width); following_byte_index++)
                                {
                                        if ((format[following_byte_index] & 0xC0) != 0x80)
                                        {
                                                lwerror("Bad format, invalid byte found following leading byte of multibyte character, format string may not be UTF-8.");
                                        }
                                }
                        }
                        /* Copy all the character's bytes into the current piece. */
                        strncat(pieces[current_piece], &(format[index]), multibyte_char_width);
                        /* Now increment index past the rest of those bytes. */
                        index += multibyte_char_width - 1;
                        break;
                }
                if (current_piece >= NUM_PIECES)
                {
                        lwerror("Internal error, somehow needed more pieces than it should.");
                }
        }
        if (deg_piece < 0)
        {
                lwerror("Bad format, degrees (DD.DDD) must be included.");
        }
 
        /* Divvy the number up into D, DM, or DMS */
        if (val < 0)
        {
                val *= -1;
                is_negative = 1;
        }
        degrees = val;
        if (min_digits > 0)
        {
                /* Break degrees to integer and use fraction for minutes */
                minutes = modf(val, &degrees) * 60;
        }
        if (sec_digits > 0)
        {
                if (0 == min_digits)
                {
                        lwerror("Bad format, cannot include seconds (SS.SSS) without including minutes (MM.MMM).");
                }
                seconds = modf(minutes, &minutes) * 60;
                if (sec_piece >= 0)
                {
                        /* See if the formatted seconds round up to 60. If so, increment minutes and reset seconds. */
                        round_pow = pow(10, sec_dec_digits);
                        if (floorf(seconds * round_pow) / round_pow >= 60)
                        {
                                minutes += 1;
                                seconds = 0;
                        }
                }
        }
 
        /* Handle the compass direction.  If not using compass dir, display degrees as a positive/negative number. */
        if (compass_dir_piece >= 0)
        {
                strcpy(pieces[compass_dir_piece], is_negative ? neg_dir_symbol : pos_dir_symbol);
        }
        else if (is_negative)
        {
                degrees *= -1;
        }
 
        /* Format the degrees into their string piece. */
        if (deg_digits + deg_dec_digits + 2 > WORK_SIZE)
        {
                lwerror("Bad format, degrees (DD.DDD) number of digits was greater than our working limit.");
        }
        if(deg_piece >= 0)
        {
                sprintf(pieces[deg_piece], "%*.*f", deg_digits, deg_dec_digits, degrees);
        }
 
        if (min_piece >= 0)
        {
                /* Format the minutes into their string piece. */
                if (min_digits + min_dec_digits + 2 > WORK_SIZE)
                {
                        lwerror("Bad format, minutes (MM.MMM) number of digits was greater than our working limit.");
                }
                sprintf(pieces[min_piece], "%*.*f", min_digits, min_dec_digits, minutes);
        }
        if (sec_piece >= 0)
        {
                /* Format the seconds into their string piece. */
                if (sec_digits + sec_dec_digits + 2 > WORK_SIZE)
                {
                        lwerror("Bad format, seconds (SS.SSS) number of digits was greater than our working limit.");
                }
                sprintf(pieces[sec_piece], "%*.*f", sec_digits, sec_dec_digits, seconds);
        }
 
        /* Allocate space for the result.  Leave plenty of room for excess digits, negative sign, etc.*/
        result = (char*)lwalloc(format_length + WORK_SIZE);
        memset(result, 0, format_length + WORK_SIZE);
 
        /* Append all the pieces together. There may be less than 9, but in that case the rest will be blank. */
        strcpy(result, pieces[0]);
        for (index = 1; index < NUM_PIECES; index++)
        {
                strcat(result, pieces[index]);
        }
 
        return result;
}

References lwalloc(), lwerror(), NUM_PIECES, and WORK_SIZE.

Referenced by lwdoubles_to_latlon().

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