libxlsxwriter/src/utility.c

/*****************************************************************************
 * utility - Utility functions for libxlsxwriter.
 *
 * Used in conjunction with the libxlsxwriter library.
 *
 * Copyright 2014-2021, John McNamara, jmcnamara@cpan.org. See LICENSE.txt.
 *
 */

#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <stdlib.h>
#include "xlsxwriter.h"
#include "xlsxwriter/common.h"
#include "xlsxwriter/third_party/tmpfileplus.h"

#ifdef USE_DTOA_LIBRARY
#include "xlsxwriter/third_party/emyg_dtoa.h"
#endif

char *error_strings[LXW_MAX_ERRNO + 1] = {
    "No error.",
    "Memory error, failed to malloc() required memory.",
    "Error creating output xlsx file. Usually a permissions error.",
    "Error encountered when creating a tmpfile during file assembly.",
    "Error reading a tmpfile.",
    "Zip generic error ZIP_ERRNO while creating the xlsx file.",
    "Zip error ZIP_PARAMERROR while creating the xlsx file.",
    "Zip error ZIP_BADZIPFILE (use_zip64 option may be required).",
    "Zip error ZIP_INTERNALERROR while creating the xlsx file.",
    "File error or unknown zip error when adding sub file to xlsx file.",
    "Unknown zip error when closing xlsx file.",
    "Feature is not currently supported in this configuration.",
    "NULL function parameter ignored.",
    "Function parameter validation error.",
    "Worksheet name exceeds Excel's limit of 31 characters.",
    "Worksheet name cannot contain invalid characters: '[ ] : * ? / \\'",
    "Worksheet name cannot start or end with an apostrophe.",
    "Worksheet name is already in use.",
    "Parameter exceeds Excel's limit of 32 characters.",
    "Parameter exceeds Excel's limit of 128 characters.",
    "Parameter exceeds Excel's limit of 255 characters.",
    "String exceeds Excel's limit of 32,767 characters.",
    "Error finding internal string index.",
    "Worksheet row or column index out of range.",
    "Maximum hyperlink length (2079) exceeded.",
    "Maximum number of worksheet URLs (65530) exceeded.",
    "Couldn't read image dimensions or DPI.",
    "Unknown error number."
};

char *
lxw_strerror(lxw_error error_num)
{
    if (error_num > LXW_MAX_ERRNO)
        error_num = LXW_MAX_ERRNO;

    return error_strings[error_num];
}

/*
 * Convert Excel A-XFD style column name to zero based number.
 */
void
lxw_col_to_name(char *col_name, lxw_col_t col_num, uint8_t absolute)
{
    uint8_t pos = 0;
    size_t len;
    size_t i;

    /* Change from 0 index to 1 index. */
    col_num++;

    /* Convert the column number to a string in reverse order. */
    while (col_num) {

        /* Get the remainder in base 26. */
        int remainder = col_num % 26;

        if (remainder == 0)
            remainder = 26;

        /* Convert the remainder value to a character. */
        col_name[pos++] = 'A' + remainder - 1;
        col_name[pos] = '\0';

        /* Get the next order of magnitude. */
        col_num = (col_num - 1) / 26;
    }

    if (absolute) {
        col_name[pos] = '$';
        col_name[pos + 1] = '\0';
    }

    /* Reverse the column name string. */
    len = strlen(col_name);
    for (i = 0; i < (len / 2); i++) {
        char tmp = col_name[i];
        col_name[i] = col_name[len - i - 1];
        col_name[len - i - 1] = tmp;
    }
}

/*
 * Convert zero indexed row and column to an Excel style A1 cell reference.
 */
void
lxw_rowcol_to_cell(char *cell_name, lxw_row_t row, lxw_col_t col)
{
    size_t pos;

    /* Add the column to the cell. */
    lxw_col_to_name(cell_name, col, 0);

    /* Get the end of the cell. */
    pos = strlen(cell_name);

    /* Add the row to the cell. */
    lxw_snprintf(&cell_name[pos], LXW_MAX_ROW_NAME_LENGTH, "%d", ++row);
}

/*
 * Convert zero indexed row and column to an Excel style $A$1 cell with
 * an absolute reference.
 */
void
lxw_rowcol_to_cell_abs(char *cell_name, lxw_row_t row, lxw_col_t col,
                       uint8_t abs_row, uint8_t abs_col)
{
    size_t pos;

    /* Add the column to the cell. */
    lxw_col_to_name(cell_name, col, abs_col);

    /* Get the end of the cell. */
    pos = strlen(cell_name);

    if (abs_row)
        cell_name[pos++] = '$';

    /* Add the row to the cell. */
    lxw_snprintf(&cell_name[pos], LXW_MAX_ROW_NAME_LENGTH, "%d", ++row);
}

/*
 * Convert zero indexed row and column pair to an Excel style A1:C5
 * range reference.
 */
void
lxw_rowcol_to_range(char *range,
                    lxw_row_t first_row, lxw_col_t first_col,
                    lxw_row_t last_row, lxw_col_t last_col)
{
    size_t pos;

    /* Add the first cell to the range. */
    lxw_rowcol_to_cell(range, first_row, first_col);

    /* If the start and end cells are the same just return a single cell. */
    if (first_row == last_row && first_col == last_col)
        return;

    /* Get the end of the cell. */
    pos = strlen(range);

    /* Add the range separator. */
    range[pos++] = ':';

    /* Add the first cell to the range. */
    lxw_rowcol_to_cell(&range[pos], last_row, last_col);
}

/*
 * Convert zero indexed row and column pairs to an Excel style $A$1:$C$5
 * range reference with absolute values.
 */
void
lxw_rowcol_to_range_abs(char *range,
                        lxw_row_t first_row, lxw_col_t first_col,
                        lxw_row_t last_row, lxw_col_t last_col)
{
    size_t pos;

    /* Add the first cell to the range. */
    lxw_rowcol_to_cell_abs(range, first_row, first_col, 1, 1);

    /* If the start and end cells are the same just return a single cell. */
    if (first_row == last_row && first_col == last_col)
        return;

    /* Get the end of the cell. */
    pos = strlen(range);

    /* Add the range separator. */
    range[pos++] = ':';

    /* Add the first cell to the range. */
    lxw_rowcol_to_cell_abs(&range[pos], last_row, last_col, 1, 1);
}

/*
 * Convert sheetname and zero indexed row and column pairs to an Excel style
 * Sheet1!$A$1:$C$5 formula reference with absolute values.
 */
void
lxw_rowcol_to_formula_abs(char *formula, const char *sheetname,
                          lxw_row_t first_row, lxw_col_t first_col,
                          lxw_row_t last_row, lxw_col_t last_col)
{
    size_t pos;
    char *quoted_name = lxw_quote_sheetname(sheetname);

    strncpy(formula, quoted_name, LXW_MAX_FORMULA_RANGE_LENGTH - 1);
    free(quoted_name);

    /* Get the end of the sheetname. */
    pos = strlen(formula);

    /* Add the range separator. */
    formula[pos++] = '!';

    /* Add the first cell to the range. */
    lxw_rowcol_to_cell_abs(&formula[pos], first_row, first_col, 1, 1);

    /* If the start and end cells are the same just return a single cell. */
    if (first_row == last_row && first_col == last_col)
        return;

    /* Get the end of the cell. */
    pos = strlen(formula);

    /* Add the range separator. */
    formula[pos++] = ':';

    /* Add the first cell to the range. */
    lxw_rowcol_to_cell_abs(&formula[pos], last_row, last_col, 1, 1);
}

/*
 * Convert an Excel style A1 cell reference to a zero indexed row number.
 */
lxw_row_t
lxw_name_to_row(const char *row_str)
{
    lxw_row_t row_num = 0;
    const char *p = row_str;

    /* Skip the column letters and absolute symbol of the A1 cell. */
    while (p && !isdigit((unsigned char) *p))
        p++;

    /* Convert the row part of the A1 cell to a number. */
    if (p)
        row_num = atoi(p);

    if (row_num)
        return row_num - 1;
    else
        return 0;
}

/*
 * Convert an Excel style A1 cell reference to a zero indexed column number.
 */
lxw_col_t
lxw_name_to_col(const char *col_str)
{
    lxw_col_t col_num = 0;
    const char *p = col_str;

    /* Convert leading column letters of A1 cell. Ignore absolute $ marker. */
    while (p && (isupper((unsigned char) *p) || *p == '$')) {
        if (*p != '$')
            col_num = (col_num * 26) + (*p - 'A' + 1);
        p++;
    }

    return col_num - 1;
}

/*
 * Convert the second row of an Excel range ref to a zero indexed number.
 */
uint32_t
lxw_name_to_row_2(const char *row_str)
{
    const char *p = row_str;

    /* Find the : separator in the range. */
    while (p && *p != ':')
        p++;

    if (p)
        return lxw_name_to_row(++p);
    else
        return -1;
}

/*
 * Convert the second column of an Excel range ref to a zero indexed number.
 */
uint16_t
lxw_name_to_col_2(const char *col_str)
{
    const char *p = col_str;

    /* Find the : separator in the range. */
    while (p && *p != ':')
        p++;

    if (p)
        return lxw_name_to_col(++p);
    else
        return -1;
}

/*
 * Convert a lxw_datetime struct to an Excel serial date, with a 1900
 * or 1904 epoch.
 */
double
lxw_datetime_to_excel_date_epoch(lxw_datetime *datetime, uint8_t date_1904)
{
    int year = datetime->year;
    int month = datetime->month;
    int day = datetime->day;
    int hour = datetime->hour;
    int min = datetime->min;
    double sec = datetime->sec;
    double seconds;
    int epoch = date_1904 ? 1904 : 1900;
    int offset = date_1904 ? 4 : 0;
    int norm = 300;
    int range;
    /* Set month days and check for leap year. */
    int mdays[] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
    int leap = 0;
    int days = 0;
    int i;

    /* For times without dates set the default date for the epoch. */
    if (!year) {
        if (!date_1904) {
            year = 1899;
            month = 12;
            day = 31;
        }
        else {
            year = 1904;
            month = 1;
            day = 1;
        }
    }

    /* Convert the Excel seconds to a fraction of the seconds in 24 hours. */
    seconds = (hour * 60 * 60 + min * 60 + sec) / (24 * 60 * 60.0);

    /* Special cases for Excel dates in the 1900 epoch. */
    if (!date_1904) {
        /* Excel 1900 epoch. */
        if (year == 1899 && month == 12 && day == 31)
            return seconds;

        /* Excel 1900 epoch. */
        if (year == 1900 && month == 1 && day == 0)
            return seconds;

        /* Excel false leapday */
        if (year == 1900 && month == 2 && day == 29)
            return 60 + seconds;
    }

    /* We calculate the date by calculating the number of days since the */
    /* epoch and adjust for the number of leap days. We calculate the */
    /* number of leap days by normalizing the year in relation to the */
    /* epoch. Thus the year 2000 becomes 100 for 4-year and 100-year */
    /* leapdays and 400 for 400-year leapdays. */
    range = year - epoch;

    if (year % 4 == 0 && (year % 100 > 0 || year % 400 == 0)) {
        leap = 1;
        mdays[2] = 29;
    }

    /*
     * Calculate the serial date by accumulating the number of days
     * since the epoch.
     */

    /* Add days for previous months. */
    for (i = 0; i < month; i++) {
        days += mdays[i];
    }
    /* Add days for current month. */
    days += day;
    /* Add days for all previous years.  */
    days += range * 365;
    /* Add 4 year leapdays. */
    days += range / 4;
    /* Remove 100 year leapdays. */
    days -= (range + offset) / 100;
    /* Add 400 year leapdays. */
    days += (range + offset + norm) / 400;
    /* Remove leap days already counted. */
    days -= leap;

    /* Adjust for Excel erroneously treating 1900 as a leap year. */
    if (!date_1904 && days > 59)
        days++;

    return days + seconds;
}

/*
 * Convert a lxw_datetime struct to an Excel serial date, for the 1900 epoch.
 */
double
lxw_datetime_to_excel_datetime(lxw_datetime *datetime)
{
    return lxw_datetime_to_excel_date_epoch(datetime, LXW_FALSE);
}

/*
 * Convert a unix datetime (1970/01/01 epoch) to an Excel serial date, with a
 * 1900 epoch.
 */
double
lxw_unixtime_to_excel_date(time_t unixtime)
{
    return lxw_unixtime_to_excel_date_epoch(unixtime, LXW_FALSE);
}

/*
 * Convert a unix datetime (1970/01/01 epoch) to an Excel serial date, with a
 * 1900 or 1904 epoch.
 */
double
lxw_unixtime_to_excel_date_epoch(time_t unixtime, uint8_t date_1904)
{
    double excel_datetime = 0.0;
    int epoch = date_1904 ? 24107.0 : 25568.0;

    excel_datetime = epoch + (unixtime / (24 * 60 * 60.0));

    if (!date_1904 && excel_datetime >= 60.0)
        excel_datetime = excel_datetime + 1.0;

    return excel_datetime;
}

/* Simple strdup() implementation since it isn't ANSI C. */
char *
lxw_strdup(const char *str)
{
    size_t len;
    char *copy;

    if (!str)
        return NULL;

    len = strlen(str) + 1;
    copy = malloc(len);

    if (copy)
        memcpy(copy, str, len);

    return copy;
}

/* Simple function to strdup() a formula string without the leading "=". */
char *
lxw_strdup_formula(const char *formula)
{
    if (!formula)
        return NULL;

    if (formula[0] == '=')
        return lxw_strdup(formula + 1);
    else
        return lxw_strdup(formula);
}

/* Simple strlen that counts UTF-8 characters. Assumes well formed UTF-8. */
size_t
lxw_utf8_strlen(const char *str)
{
    size_t byte_count = 0;
    size_t char_count = 0;

    while (str[byte_count]) {
        if ((str[byte_count] & 0xc0) != 0x80)
            char_count++;

        byte_count++;
    }

    return char_count;
}

/* Simple tolower() for strings. */
void
lxw_str_tolower(char *str)
{
    int i;

    for (i = 0; str[i]; i++)
        str[i] = tolower(str[i]);
}

/* Create a quoted version of the worksheet name, or return an unmodified
 * copy if it doesn't required quoting. */
char *
lxw_quote_sheetname(const char *str)
{

    uint8_t needs_quoting = 0;
    size_t number_of_quotes = 2;
    size_t i, j;
    size_t len = strlen(str);

    /* Don't quote the sheetname if it is already quoted. */
    if (str[0] == '\'')
        return lxw_strdup(str);

    /* Check if the sheetname contains any characters that require it
     * to be quoted. Also check for single quotes within the string. */
    for (i = 0; i < len; i++) {
        if (!isalnum((unsigned char) str[i]) && str[i] != '_'
            && str[i] != '.')
            needs_quoting = 1;

        if (str[i] == '\'') {
            needs_quoting = 1;
            number_of_quotes++;
        }
    }

    if (!needs_quoting) {
        return lxw_strdup(str);
    }
    else {
        /* Add single quotes to the start and end of the string. */
        char *quoted_name = calloc(1, len + number_of_quotes + 1);
        RETURN_ON_MEM_ERROR(quoted_name, NULL);

        quoted_name[0] = '\'';

        for (i = 0, j = 1; i < len; i++, j++) {
            quoted_name[j] = str[i];

            /* Double quote inline single quotes. */
            if (str[i] == '\'') {
                quoted_name[++j] = '\'';
            }
        }
        quoted_name[j++] = '\'';
        quoted_name[j++] = '\0';

        return quoted_name;
    }
}

/*
 * Thin wrapper for tmpfile() so it can be over-ridden with a user defined
 * version if required for safety or portability.
 */
FILE *
lxw_tmpfile(char *tmpdir)
{
#ifndef USE_STANDARD_TMPFILE
    return tmpfileplus(tmpdir, NULL, NULL, 0);
#else
    (void) tmpdir;
    return tmpfile();
#endif
}

/*
 * Use third party function to handle sprintf of doubles for locale portable
 * code.
 */
#ifdef USE_DTOA_LIBRARY
int
lxw_sprintf_dbl(char *data, double number)
{
    emyg_dtoa(number, data);
    return 0;
}
#endif

/*
 * Retrieve runtime library version.
 */
const char *
lxw_version(void)
{
    return LXW_VERSION;
}

/*
 * Retrieve runtime library version ID.
 */
uint16_t
lxw_version_id(void)
{
    return LXW_VERSION_ID;
}

/*
 * Hash a worksheet password. Based on the algorithm provided by Daniel Rentz
 * of OpenOffice.
 */
uint16_t
lxw_hash_password(const char *password)
{
    size_t count;
    size_t i;
    uint16_t hash = 0x0000;

    count = strlen(password);

    for (i = 0; i < (uint8_t) count; i++) {
        uint32_t low_15;
        uint32_t high_15;
        uint32_t letter = password[i] << (i + 1);

        low_15 = letter & 0x7fff;
        high_15 = letter & (0x7fff << 15);
        high_15 = high_15 >> 15;
        letter = low_15 | high_15;

        hash ^= letter;
    }

    hash ^= count;
    hash ^= 0xCE4B;

    return hash;
}

/* Make a simple portable version of fopen() for Windows. */
#ifdef __MINGW32__
#undef _WIN32
#endif

#ifdef _WIN32

#include <windows.h>

FILE *
lxw_fopen(const char *filename, const char *mode)
{
    int n;
    wchar_t wide_filename[_MAX_PATH + 1] = L"";
    wchar_t wide_mode[_MAX_PATH + 1] = L"";

    n = MultiByteToWideChar(CP_UTF8, 0, filename, (int) strlen(filename),
                            wide_filename, _MAX_PATH);

    if (n == 0) {
        LXW_ERROR("MultiByteToWideChar error: filename");
        return NULL;
    }

    n = MultiByteToWideChar(CP_UTF8, 0, mode, (int) strlen(mode),
                            wide_mode, _MAX_PATH);

    if (n == 0) {
        LXW_ERROR("MultiByteToWideChar error: mode");
        return NULL;
    }

    return _wfopen(wide_filename, wide_mode);
}
#else
FILE *
lxw_fopen(const char *filename, const char *mode)
{
    return fopen(filename, mode);
}
#endif