[easytag] Reimplement Roman numeral detection
- From: David King <davidk src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [easytag] Reimplement Roman numeral detection
- Date: Fri, 4 Apr 2014 08:25:09 +0000 (UTC)
commit a6b44d7abbf150235bcdc3233fe1161c3191c0b5
Author: Santtu Lakkala <inz inz fi>
Date: Fri Apr 4 08:06:35 2014 +0300
Reimplement Roman numeral detection
Roman numeral detection code used complicated process of check, parse,
build, compare to detect if a string was a valid Roman numeral.
Reimplemented as a single step, that only checks for the validity (and
well-formedness) of the string, without computing its value.
It uses the same modern Roman numeral notation, including subtractive
notation.
src/scan.c | 441 +++++++-----------------------------------------------------
1 files changed, 50 insertions(+), 391 deletions(-)
---
diff --git a/src/scan.c b/src/scan.c
index a926ddc..831b4aa 100644
--- a/src/scan.c
+++ b/src/scan.c
@@ -263,10 +263,6 @@ static void Mask_Editor_Clean_Up_Masks_List (void);
static void Scanner_Option_Menu_Activate_Item (GtkWidget *widget, gpointer data);
-static int roman2int (const char *str);
-static const char *int2roman (int num);
-static char *int2roman_r (int num, char * str, size_t len);
-
static void Scan_Convert_Character (gchar **string);
static GList *Scan_Generate_New_Tag_From_Mask (ET_File *ETFile, gchar *mask);
static void Scan_Set_Scanner_Window_Init_Position (void);
@@ -1831,417 +1827,80 @@ handle_error:
goto out;
}
-/*
- * Quick roman numeral check (non-roman numerals may also return true)
- * Patch from Slash Bunny (2007.08.12)
- * (http://home.hiwaay.net/~lkseitz/math/roman/numerals.shtml)
- * I = 1 (one)
- * V = 5 (five)
- * X = 10 (ten)
- * L = 50 (fifty)
- * C = 100 (one hundred)
- * D = 500 (five hundred)
- * M = 1000 (one thousand)
- */
static gint
Scan_Word_Is_Roman_Numeral (const gchar *text)
{
- const gchar *tmp;
- gint len;
- gchar *buf = NULL;
- gint rn_int;
- gchar *rn_char;
+ /* No need for caseless strchr. */
+ static const gchar romans[] = "MmDdCcLlXxVvIi";
- if (!ScannerWindow
- || !ProcessFieldsDetectRomanNumerals
- || !gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(ProcessFieldsDetectRomanNumerals)))
- return 0;
-
- tmp = text;
- len = 0;
+ gsize next_allowed = 0;
+ gsize prev = 0;
+ gsize count = 0;
- while (*tmp)
- {
- if (*tmp == (gunichar)'i'
- || *tmp == (gunichar)'v'
- || *tmp == (gunichar)'x'
- || *tmp == (gunichar)'l'
- || *tmp == (gunichar)'c'
- || *tmp == (gunichar)'d'
- || *tmp == (gunichar)'m')
- {
- // Found a roman numeral => continue
- tmp++;
- len++;
- } else if (*tmp == ' '
- || *tmp == '_'
- || *tmp == '.'
- || *tmp == ','
- || *tmp == '-')
- {
- // A separator was found => end of word
- // Check if it is a valid roman numeral
- goto roman_numeral_found;
-
- } else
- {
- return 0;
- }
- }
+ const gchar *i;
- // Found in last word of the string
-
-roman_numeral_found:
- // Check if it is a valid roman numeral
- buf = g_strndup(text,len);
- rn_int = roman2int(buf); // Convert the Roman numeral string to integer
-
- if (rn_int >= 0 )
- {
- // Some strings as "IIIII" or "CCCCC" are returned as valid, which is not correct...
- // Same problem with: IC MIC IM MIM IL CIL XM MXM VC MVC VM MVM VL MVL LC MLC LD MLD LM MLM MDM
- // So we convert it again to a string, and compare to the initial one.
- rn_char = (gchar *)int2roman(rn_int); // Convert the Roman numeral integer to string
- if (rn_char
- && strcasecmp(buf,rn_char)==0)
- {
- g_free(buf);
- g_free(rn_char);
- return len; // Roman numeral valid
- }else
- {
- g_free(buf);
- g_free(rn_char);
- return 0;
- }
- }else
+ if (!ScannerWindow || !ProcessFieldsDetectRomanNumerals
+ || !gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON (ProcessFieldsDetectRomanNumerals)))
{
- g_free(buf);
return 0;
}
-}
-
-
-/*
- * Taken from :
- * Roman Numeral Conversion API (http://sourceforge.net/project/showfiles.php?group_id=211070)
- * Copyright (c) 2007 David M. Syzdek <roman-project syzdek net>
- */
-/* Convert Roman numeral from integer to string */
-static const char *
-int2roman (int num)
-{
- #define ROMAN_BUFF_LEN 512
-
- /* buffer for storing conversions */
- char roman_string[ROMAN_BUFF_LEN];
-
- /* wrap long2roman_r() with library buffer */
- char *result = int2roman_r(num, roman_string, ROMAN_BUFF_LEN);
-
- if (!result)
- return NULL;
- return g_strdup(roman_string);
-}
+ for (i = text; *i; i++)
+ {
+ const char *s = strchr (romans, *i);
-static char *
-int2roman_r (int num, char * str, size_t len)
-{
- // local variables
- unsigned pos;
- unsigned u;
- unsigned dividend;
-
- g_return_val_if_fail (str != NULL, NULL);
-
- // verify that number is withing boundaries
- if ((num > 5000) || (num < 0))
- {
- return NULL;
- };
-
- // sets initial values
- pos = 0;
- memset(str, 0, len);
- len--;
-
- // checks for nullae
- if (!(num))
- {
- str[0] = 'N';
- return str;
- };
-
- // calculates thousands
- dividend = num/1000;
- if (dividend > (len-1))
- {
- return NULL;
- };
- for (u = 0; u < dividend; u++)
- str[pos+u] = 'M';
- num %= 1000;
- pos += u;
-
- // calculates hundreds
- dividend = num/100;
- if (dividend > (len-1-pos))
- {
- return NULL;
- };
- if (dividend == 9)
- {
- str[pos+0] = 'C';
- str[pos+1] = 'M';
- pos += 2;
- dividend = 0;
- };
- if (dividend >= 5)
- {
- str[pos] = 'D';
- dividend -= 5;
- pos++;
- };
- if (dividend == 4)
- {
- str[pos+0] = 'C';
- str[pos+1] = 'D';
- dividend -= 4;
- pos += 2;
- };
- for(u = 0; u < dividend; u++)
- str[pos+u] = 'C';
- pos += u;
- num %= 100;
-
- // calculates tens
- dividend = num/10;
- if (dividend > (len-1-pos))
- {
- return NULL;
- };
- if (dividend == 9)
- {
- str[pos+0] = 'X';
- str[pos+1] = 'C';
- dividend = 0;
- pos += 2;
- };
- if (dividend >= 5)
- {
- str[pos+0] = 'L';
- dividend -= 5;
- pos++;
- };
- if (dividend == 4)
- {
- str[pos+0] = 'X';
- str[pos+1] = 'L';
- pos += 2;
- dividend -= 4;
- };
- for (u = 0; u < dividend; u++)
- str[pos+u] = 'X';
- pos += u;
- num %= 10;
-
- // calculates ones
- dividend = num;
- if (dividend > (len-1-pos))
- {
- return NULL;
- };
- if (dividend == 9)
- {
- str[pos+0] = 'I';
- str[pos+1] = 'X';
- dividend = 0;
- pos += 2;
- };
- if (dividend >= 5)
- {
- str[pos+0] = 'V';
- dividend -= 5;
- pos++;
- };
- if (dividend == 4)
- {
- str[pos+0] = 'I';
- str[pos+1] = 'V';
- pos += 2;
- dividend -= 4;
- };
- for(u = 0; u < dividend; u++)
- str[pos+u] = 'I';
-
- /* ends function */
- return str;
-}
+ if (s)
+ {
+ gsize c = (s - romans) / 2;
-/* Convert Roman numeral from string to integer */
-static int
-roman2int (const char *str)
-{
- // declares local vars
- int num;
- unsigned i;
- unsigned len;
- unsigned last;
- unsigned prevlast;
-
- // checks args
- if (!(str))
- {
- return(0);
- };
-
- // sets initial values
- num = 0;
- len = strlen(str);
- last = 1000;
- prevlast = 1000;
-
- // loops through characters
- for(i = 0; i < len; i++)
- {
- switch(str[i])
- {
- case 'n':
- case 'N':
- if (strlen(str) > 1)
- {
- return(-1);
- };
- return(0);
- break;
- case 'i':
- case 'I':
- num += 1;
- // prevent patterns like IXI
- if ((prevlast == 1) && (last != 1))
- {
- return(-1);
- };
- // prevent patterns like IIIII and VIIIII
- if ((!(num%5)) || (!(num%10)))
+ if (c < next_allowed)
{
- return(-1);
- };
- // rotates value into history
- prevlast = last;
- last = 1;
- break;
- case 'v':
- case 'V':
- num += 5;
- // tests for invalid syntax
- if ( ((last <= 5) && (last != 1)) || (prevlast <= 5) )
- {
- return(-1);
+ return 0;
}
- // applies subtraction method & rotates value into history
- if (last < 5)
- num -= (last * 2);
- prevlast = last;
- last = 5;
- break;
- case 'x':
- case 'X':
- num += 10;
- // tests for invalid syntax
- if ( ((prevlast < 10) && (last <= 10)) || ((last < 10) && (last != 1)) )
- {
- return(-1);
- };
- // prevent patterns like XXXXX and VXXXXX
- if ((!(num%50)) || (!(num%100)))
- {
- return(-1);
- };
- // applies subtraction method & rotates value into history
- if (last == 1)
- num -= (last * 2);
- prevlast = last;
- last = 10;
- break;
- case 'l':
- case 'L':
- num += 50;
- // tests for invalid syntax
- if ( ((last <= 50) && (last != 10)) || (prevlast <= 50) )
+
+ if (c < prev)
{
- return(-1);
+ /* After subtraction, no more subtracted chars allowed. */
+ next_allowed = prev + 1;
}
- // applies subtraction method & rotates value into history
- if (last < 50)
- num -= (last * 2);
- prevlast = last;
- last = 50;
- break;
- case 'c':
- case 'C':
- num += 100;
- // tests for invalid syntax
- if ( ((prevlast < 100) && (last <= 100)) || ((last < 100) && (last != 10)) )
- {
- return(-1);
- };
- // prevent patterns like CCCCC and VCCCCC
- if ((!(num%500)) || (!(num%1000)))
- {
- return(-1);
- };
- // applies subtraction method & rotates value into history
- if (last == 10)
- num -= (last * 2);
- prevlast = last;
- last = 100;
- break;
- case 'd':
- case 'D':
- num += 500;
- // tests for invalid syntax
- if ( ((last <= 500) && (last != 100)) || (prevlast <= 500) )
+ else if (c == prev)
{
- return(-1);
+ /* Allow indefinite repetition for m; three for c, x and i; and
+ * none for d, l and v. */
+ if ((c && ++count > 3) || (c & 1))
+ {
+ return 0;
+ }
+
+ /* No more subtraction. */
+ next_allowed = c;
}
- // applies subtraction method & rotates value into history
- if (last < 500)
- num -= (last * 2);
- prevlast = last;
- last = 500;
- break;
- case 'm':
- case 'M':
- num += 1000;
- // tests for invalid syntax
- if ( ((prevlast < 1000) && (last <= 1000)) || ((last < 1000) && (last != 100)) )
+ else if (c && !(c & 1))
{
- return(-1);
- };
- // prevent patterns like MMMMM and VMMMMM
- if ((!(num%5000)) || (!(num%10000)))
+ /* For first occurrence of c, x and i, allow "subtraction" from
+ * 10 and 5 times self, reset counting. */
+ next_allowed = c - 2;
+ count = 1;
+ }
+
+ prev = c;
+ }
+ else
+ {
+ if (g_unichar_isalnum (g_utf8_get_char (i)))
{
- return(-1);
- };
- // applies subtraction method & rotates value into history
- if (last == 100)
- num -= (last * 2);
- prevlast = last;
- last = 1000;
+ return 0;
+ }
+
break;
- default:
- return(-1);
- };
- };
+ }
+ }
- // ends function
- return(num);
+ /* Return length of found Roman numeral. */
+ return i - text;
}
-
/*
* Return the field of a 'File_Tag' structure corresponding to the mask code
*/
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