NAME
Image::Leptonica::Func::sarray
VERSION
version 0.04
sarray.c
sarray.c
Create/Destroy/Copy
SARRAY *sarrayCreate()
SARRAY *sarrayCreateInitialized()
SARRAY *sarrayCreateWordsFromString()
SARRAY *sarrayCreateLinesFromString()
void *sarrayDestroy()
SARRAY *sarrayCopy()
SARRAY *sarrayClone()
Add/Remove string
l_int32 sarrayAddString()
static l_int32 sarrayExtendArray()
char *sarrayRemoveString()
l_int32 sarrayReplaceString()
l_int32 sarrayClear()
Accessors
l_int32 sarrayGetCount()
char **sarrayGetArray()
char *sarrayGetString()
l_int32 sarrayGetRefcount()
l_int32 sarrayChangeRefcount()
Conversion back to string
char *sarrayToString()
char *sarrayToStringRange()
Concatenate 2 sarrays
l_int32 sarrayConcatenate()
l_int32 sarrayAppendRange()
Pad an sarray to be the same size as another sarray
l_int32 sarrayPadToSameSize()
Convert word sarray to (formatted) line sarray
SARRAY *sarrayConvertWordsToLines()
Split string on separator list
SARRAY *sarraySplitString()
Filter sarray
SARRAY *sarraySelectBySubstring()
SARRAY *sarraySelectByRange()
l_int32 sarrayParseRange()
Sort
SARRAY *sarraySort()
SARRAY *sarraySortByIndex()
l_int32 stringCompareLexical()
Serialize for I/O
SARRAY *sarrayRead()
SARRAY *sarrayReadStream()
l_int32 sarrayWrite()
l_int32 sarrayWriteStream()
l_int32 sarrayAppend()
Directory filenames
SARRAY *getNumberedPathnamesInDirectory()
SARRAY *getSortedPathnamesInDirectory()
SARRAY *convertSortedToNumberedPathnames()
SARRAY *getFilenamesInDirectory()
These functions are important for efficient manipulation
of string data, and they have found widespread use in
leptonica. For example:
(1) to generate text files: e.g., PostScript and PDF
wrappers around sets of images
(2) to parse text files: e.g., extracting prototypes
from the source to generate allheaders.h
(3) to generate code for compilation: e.g., the fast
dwa code for arbitrary structuring elements.
Comments on usage:
The user is responsible for correctly disposing of strings
that have been extracted from sarrays:
- When you want a string from an Sarray to inspect it, or
plan to make a copy of it later, use sarrayGetString()
with copyflag = 0. In this case, you must neither free
the string nor put it directly in another array.
We provide the copyflag constant L_NOCOPY, which is 0,
for this purpose:
str-not-owned = sarrayGetString(sa, index, L_NOCOPY);
To extract a copy of a string, use:
str-owned = sarrayGetString(sa, index, L_COPY);
- When you want to insert a string that is in one
array into another array (always leaving the first
array intact), you have two options:
(1) use copyflag = L_COPY to make an immediate copy,
which you must then add to the second array
by insertion; namely,
str-owned = sarrayGetString(sa, index, L_COPY);
sarrayAddString(sa, str-owned, L_INSERT);
(2) use copyflag = L_NOCOPY to get another handle to
the string, in which case you must add
a copy of it to the second string array:
str-not-owned = sarrayGetString(sa, index, L_NOCOPY);
sarrayAddString(sa, str-not-owned, L_COPY).
In all cases, when you use copyflag = L_COPY to extract
a string from an array, you must either free it
or insert it in an array that will be freed later.FUNCTIONS
convertSortedToNumberedPathnames
SARRAY * convertSortedToNumberedPathnames ( SARRAY *sa, l_int32 numpre, l_int32 numpost, l_int32 maxnum )
convertSortedToNumberedPathnames()
Input: sorted pathnames (including zero-padded integers)
numpre (number of characters in name before number)
numpost (number of characters in name after the number,
up to a dot before an extension)
maxnum (only consider page numbers up to this value)
Return: sarray of numbered pathnames, or NULL on error
Notes:
(1) Typically, numpre = numpost = 0; e.g., when the filename
just has a number followed by an optional extension.getFilenamesInDirectory
SARRAY * getFilenamesInDirectory ( const char *dirname )
getFilenamesInDirectory()
Input: directory name
Return: sarray of file names, or NULL on error
Notes:
(1) The versions compiled under unix and cygwin use the POSIX C
library commands for handling directories. For windows,
there is a separate implementation.
(2) It returns an array of filename tails; i.e., only the part of
the path after the last slash.
(3) Use of the d_type field of dirent is not portable:
"According to POSIX, the dirent structure contains a field
char d_name[] of unspecified size, with at most NAME_MAX
characters preceding the terminating null character. Use
of other fields will harm the portability of your programs."
(4) As a consequence of (3), we note several things:
- MINGW doesn't have a d_type member.
- Older versions of gcc (e.g., 2.95.3) return DT_UNKNOWN
for d_type from all files.
On these systems, this function will return directories
(except for '.' and '..', which are eliminated using
the d_name field).getNumberedPathnamesInDirectory
SARRAY * getNumberedPathnamesInDirectory ( const char *dirname, const char *substr, l_int32 numpre, l_int32 numpost, l_int32 maxnum )
getNumberedPathnamesInDirectory()
Input: directory name
substr (<optional> substring filter on filenames; can be NULL)
numpre (number of characters in name before number)
numpost (number of characters in name after the number,
up to a dot before an extension)
maxnum (only consider page numbers up to this value)
Return: sarray of numbered pathnames, or NULL on error
Notes:
(1) Returns the full pathnames of the numbered filenames in
the directory. The number in the filename is the index
into the sarray. For indices for which there are no filenames,
an empty string ("") is placed into the sarray.
This makes reading numbered files very simple. For example,
the image whose filename includes number N can be retrieved using
pixReadIndexed(sa, N);
(2) If @substr is not NULL, only filenames that contain
the substring can be included. If @substr is NULL,
all matching filenames are used.
(3) If no numbered files are found, it returns an empty sarray,
with no initialized strings.
(4) It is assumed that the page number is contained within
the basename (the filename without directory or extension).
@numpre is the number of characters in the basename
preceeding the actual page number; @numpost is the number
following the page number, up to either the end of the
basename or a ".", whichever comes first.
(5) This is useful when all filenames contain numbers that are
not necessarily consecutive. 0-padding is not required.
(6) To use a O(n) matching algorithm, the largest page number
is found and two internal arrays of this size are created.
This maximum is constrained not to exceed @maxsum,
to make sure that an unrealistically large number is not
accidentally used to determine the array sizes.getSortedPathnamesInDirectory
SARRAY * getSortedPathnamesInDirectory ( const char *dirname, const char *substr, l_int32 first, l_int32 nfiles )
getSortedPathnamesInDirectory()
Input: directory name
substr (<optional> substring filter on filenames; can be NULL)
first (0-based)
nfiles (use 0 for all to the end)
Return: sarray of sorted pathnames, or NULL on error
Notes:
(1) Use @substr to filter filenames in the directory. If
@substr == NULL, this takes all files.
(2) The files in the directory, after optional filtering by
the substring, are lexically sorted in increasing order.
Use @first and @nfiles to select a contiguous set of files.
(3) The full pathnames are returned for the requested sequence.
If no files are found after filtering, returns an empty sarray.sarrayAddString
l_int32 sarrayAddString ( SARRAY *sa, char *string, l_int32 copyflag )
sarrayAddString()
Input: sarray
string (string to be added)
copyflag (L_INSERT, L_COPY)
Return: 0 if OK, 1 on error
Notes:
(1) Legacy usage decrees that we always use 0 to insert a string
directly and 1 to insert a copy of the string. The
enums for L_INSERT and L_COPY agree with this convention,
and will not change in the future.
(2) See usage comments at the top of this file.sarrayAppend
l_int32 sarrayAppend ( const char *filename, SARRAY *sa )
sarrayAppend()
Input: filename
sarray
Return: 0 if OK; 1 on errorsarrayAppendRange
l_int32 sarrayAppendRange ( SARRAY *sa1, SARRAY *sa2, l_int32 start, l_int32 end )
sarrayAppendRange()
Input: sa1 (to be added to)
sa2 (append specified range of strings in sa2 to sa1)
start (index of first string of sa2 to append)
end (index of last string of sa2 to append; -1 to end of array)
Return: 0 if OK, 1 on error
Notes:
(1) Copies of the strings in sarray2 are added to sarray1.
(2) The [start ... end] range is truncated if necessary.
(3) Use end == -1 to append to the end of sa2.sarrayChangeRefcount
l_int32 sarrayChangeRefcount ( SARRAY *sa, l_int32 delta )
sarrayChangeRefcount()
Input: sarray
delta (change to be applied)
Return: 0 if OK, 1 on errorsarrayClear
l_int32 sarrayClear ( SARRAY *sa )
sarrayClear()
Input: sarray
Return: 0 if OK; 1 on errorsarrayClone
SARRAY * sarrayClone ( SARRAY *sa )
sarrayClone()
Input: sarray
Return: ptr to same sarray, or null on errorsarrayConcatenate
l_int32 sarrayConcatenate ( SARRAY *sa1, SARRAY *sa2 )
sarrayConcatenate()
Input: sa1 (to be added to)
sa2 (append to sa1)
Return: 0 if OK, 1 on error
Notes:
(1) Copies of the strings in sarray2 are added to sarray1.sarrayConvertWordsToLines
SARRAY * sarrayConvertWordsToLines ( SARRAY *sa, l_int32 linesize )
sarrayConvertWordsToLines()
Input: sa (sa of individual words)
linesize (max num of chars in each line)
Return: saout (sa of formatted lines), or null on error
This is useful for re-typesetting text to a specific maximum
line length. The individual words in the input sarray
are concatenated into textlines. An input word string of zero
length is taken to be a paragraph separator. Each time
such a string is found, the current line is ended and
a new line is also produced that contains just the
string of zero length (""). When the output sarray
of lines is eventually converted to a string with newlines
(typically) appended to each line string, the empty
strings are just converted to newlines, producing the visible
paragraph separation.
What happens when a word is larger than linesize?
We write it out as a single line anyway! Words preceding
or following this long word are placed on lines preceding
or following the line with the long word. Why this choice?
Long "words" found in text documents are typically URLs, and
it's often desirable not to put newlines in the middle of a URL.
The text display program (e.g., text editor) will typically
wrap the long "word" to fit in the window.sarrayCopy
SARRAY * sarrayCopy ( SARRAY *sa )
sarrayCopy()
Input: sarray
Return: copy of sarray, or null on errorsarrayCreate
SARRAY * sarrayCreate ( l_int32 n )
sarrayCreate()
Input: size of string ptr array to be alloc'd
(use 0 for default)
Return: sarray, or null on errorsarrayCreateInitialized
SARRAY * sarrayCreateInitialized ( l_int32 n, char *initstr )
sarrayCreateInitialized()
Input: n (size of string ptr array to be alloc'd)
initstr (string to be initialized on the full array)
Return: sarray, or null on errorsarrayCreateLinesFromString
SARRAY * sarrayCreateLinesFromString ( char *string, l_int32 blankflag )
sarrayCreateLinesFromString()
Input: string
blankflag (0 to exclude blank lines; 1 to include)
Return: sarray, or null on error
Notes:
(1) This finds the number of line substrings, each of which
ends with a newline, and puts a copy of each substring
in a new sarray.
(2) The newline characters are removed from each substring.sarrayCreateWordsFromString
SARRAY * sarrayCreateWordsFromString ( const char *string )
sarrayCreateWordsFromString()
Input: string
Return: sarray, or null on error
Notes:
(1) This finds the number of word substrings, creates an sarray
of this size, and puts copies of each substring into the sarray.sarrayDestroy
void sarrayDestroy ( SARRAY **psa )
sarrayDestroy()
Input: &sarray <to be nulled>
Return: void
Notes:
(1) Decrements the ref count and, if 0, destroys the sarray.
(2) Always nulls the input ptr.sarrayGetCount
l_int32 sarrayGetCount ( SARRAY *sa )
sarrayGetCount()
Input: sarray
Return: count, or 0 if no strings or on errorsarrayGetRefcount
l_int32 sarrayGetRefcount ( SARRAY *sa )
sarrayGetRefcount()
Input: sarray
Return: refcount, or UNDEF on errorsarrayGetString
char * sarrayGetString ( SARRAY *sa, l_int32 index, l_int32 copyflag )
sarrayGetString()
Input: sarray
index (to the index-th string)
copyflag (L_NOCOPY or L_COPY)
Return: string, or null on error
Notes:
(1) Legacy usage decrees that we always use 0 to get the
pointer to the string itself, and 1 to get a copy of
the string.
(2) See usage comments at the top of this file.
(3) To get a pointer to the string itself, use for copyflag:
L_NOCOPY or 0 or FALSE
To get a copy of the string, use for copyflag:
L_COPY or 1 or TRUE
The const values of L_NOCOPY and L_COPY are guaranteed not
to change.sarrayPadToSameSize
l_int32 sarrayPadToSameSize ( SARRAY *sa1, SARRAY *sa2, char *padstring )
sarrayPadToSameSize()
Input: sa1, sa2
padstring
Return: 0 if OK, 1 on error
Notes:
(1) If two sarrays have different size, this adds enough
instances of @padstring to the smaller so that they are
the same size. It is useful when two or more sarrays
are being sequenced in parallel, and it is necessary to
find a valid string at each index.sarrayParseRange
l_int32 sarrayParseRange ( SARRAY *sa, l_int32 start, l_int32 *pactualstart, l_int32 *pend, l_int32 *pnewstart, const char *substr, l_int32 loc )
sarrayParseRange()
Input: sa (input sarray)
start (index to start range search)
&actualstart (<return> index of actual start; may be > 'start')
&end (<return> index of end)
&newstart (<return> index of start of next range)
substr (substring for matching at beginning of string)
loc (byte offset within the string for the pattern; use
-1 if the location does not matter);
Return: 0 if valid range found; 1 otherwise
Notes:
(1) This finds the range of the next set of strings in SA,
beginning the search at 'start', that does NOT have
the substring 'substr' either at the indicated location
in the string or anywhere in the string. The input
variable 'loc' is the specified offset within the string;
use -1 to indicate 'anywhere in the string'.
(2) Always check the return value to verify that a valid range
was found.
(3) If a valid range is not found, the values of actstart,
end and newstart are all set to the size of sa.
(4) If this is the last valid range, newstart returns the value n.
In use, this should be tested before calling the function.
(5) Usage example. To find all the valid ranges in a file
where the invalid lines begin with two dashes, copy each
line in the file to a string in an sarray, and do:
start = 0;
while (!sarrayParseRange(sa, start, &actstart, &end, &start,
"--", 0))
fprintf(stderr, "start = %d, end = %d\n", actstart, end);sarrayRead
SARRAY * sarrayRead ( const char *filename )
sarrayRead()
Input: filename
Return: sarray, or null on errorsarrayReadStream
SARRAY * sarrayReadStream ( FILE *fp )
sarrayReadStream()
Input: stream
Return: sarray, or null on error
Notes:
(1) We store the size of each string along with the string.
(2) This allows a string to have embedded newlines. By reading
the entire string, as determined by its size, we are
not affected by any number of embedded newlines.sarrayRemoveString
char * sarrayRemoveString ( SARRAY *sa, l_int32 index )
sarrayRemoveString()
Input: sarray
index (of string within sarray)
Return: removed string, or null on errorsarrayReplaceString
l_int32 sarrayReplaceString ( SARRAY *sa, l_int32 index, char *newstr, l_int32 copyflag )
sarrayReplaceString()
Input: sarray
index (of string within sarray to be replaced)
newstr (string to replace existing one)
copyflag (L_INSERT, L_COPY)
Return: 0 if OK, 1 on error
Notes:
(1) This destroys an existing string and replaces it with
the new string or a copy of it.
(2) By design, an sarray is always compacted, so there are
never any holes (null ptrs) in the ptr array up to the
current count.sarraySelectByRange
SARRAY * sarraySelectByRange ( SARRAY *sain, l_int32 first, l_int32 last )
sarraySelectByRange()
Input: sain (input sarray)
first (index of first string to be selected)
last (index of last string to be selected; use 0 to go to the
end of the sarray)
Return: saout (output sarray), or null on error
Notes:
(1) This makes @saout consisting of copies of all strings in @sain
in the index set [first ... last]. Use @last == 0 to get all
strings from @first to the last string in the sarray.sarraySelectBySubstring
SARRAY * sarraySelectBySubstring ( SARRAY *sain, const char *substr )
sarraySelectBySubstring()
Input: sain (input sarray)
substr (<optional> substring for matching; can be NULL)
Return: saout (output sarray, filtered with substring) or null on error
Notes:
(1) This selects all strings in sain that have substr as a substring.
Note that we can't use strncmp() because we're looking for
a match to the substring anywhere within each filename.
(2) If substr == NULL, returns a copy of the sarray.sarraySort
SARRAY * sarraySort ( SARRAY *saout, SARRAY *sain, l_int32 sortorder )
sarraySort()
Input: saout (output sarray; can be NULL or equal to sain)
sain (input sarray)
sortorder (L_SORT_INCREASING or L_SORT_DECREASING)
Return: saout (output sarray, sorted by ascii value), or null on error
Notes:
(1) Set saout = sain for in-place; otherwise, set naout = NULL.
(2) Shell sort, modified from K&R, 2nd edition, p.62.
Slow but simple O(n logn) sort.sarraySortByIndex
SARRAY * sarraySortByIndex ( SARRAY *sain, NUMA *naindex )
sarraySortByIndex()
Input: sain
naindex (na that maps from the new sarray to the input sarray)
Return: saout (sorted), or null on errorsarraySplitString
l_int32 sarraySplitString ( SARRAY *sa, const char *str, const char *separators )
sarraySplitString()
Input: sa (to append to; typically empty initially)
str (string to split; not changed)
separators (characters that split input string)
Return: 0 if OK, 1 on error.
Notes:
(1) This uses strtokSafe(). See the notes there in utils.c.sarrayToString
char * sarrayToString ( SARRAY *sa, l_int32 addnlflag )
sarrayToString()
Input: sarray
addnlflag (flag: 0 adds nothing to each substring
1 adds '\n' to each substring
2 adds ' ' to each substring)
Return: dest string, or null on error
Notes:
(1) Concatenates all the strings in the sarray, preserving
all white space.
(2) If addnlflag != 0, adds either a '\n' or a ' ' after
each substring.
(3) This function was NOT implemented as:
for (i = 0; i < n; i++)
strcat(dest, sarrayGetString(sa, i, L_NOCOPY));
Do you see why?sarrayToStringRange
char * sarrayToStringRange ( SARRAY *sa, l_int32 first, l_int32 nstrings, l_int32 addnlflag )
sarrayToStringRange()
Input: sarray
first (index of first string to use; starts with 0)
nstrings (number of strings to append into the result; use
0 to append to the end of the sarray)
addnlflag (flag: 0 adds nothing to each substring
1 adds '\n' to each substring
2 adds ' ' to each substring)
Return: dest string, or null on error
Notes:
(1) Concatenates the specified strings inthe sarray, preserving
all white space.
(2) If addnlflag != 0, adds either a '\n' or a ' ' after
each substring.
(3) If the sarray is empty, this returns a string with just
the character corresponding to @addnlflag.sarrayWrite
l_int32 sarrayWrite ( const char *filename, SARRAY *sa )
sarrayWrite()
Input: filename
sarray
Return: 0 if OK; 1 on errorsarrayWriteStream
l_int32 sarrayWriteStream ( FILE *fp, SARRAY *sa )
sarrayWriteStream()
Input: stream
sarray
Returns 0 if OK; 1 on error
Notes:
(1) This appends a '\n' to each string, which is stripped
off by sarrayReadStream().stringCompareLexical
l_int32 stringCompareLexical ( const char *str1, const char *str2 )
stringCompareLexical()
Input: str1
str2
Return: 1 if str1 > str2 (lexically); 0 otherwise
Notes:
(1) If the lexical values are identical, return a 0, to
indicate that no swapping is required to sort the strings.AUTHOR
Zakariyya Mughal <zmughal@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2014 by Zakariyya Mughal.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.