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Feature #836 » strscan.c

apeiros (Stefan Rusterholz), 12/08/2008 11:27 AM

 
/*
$Id: strscan.c 11708 2007-02-12 23:01:19Z shyouhei $

Copyright (c) 1999-2006 Minero Aoki

This program is free software.
You can distribute/modify this program under the terms of
the Ruby License. For details, see the file COPYING.
*/

#include "ruby.h"
#include "re.h"

#define STRSCAN_VERSION "0.7.0"

/* =======================================================================
Data Type Definitions
======================================================================= */

static VALUE StringScanner;
static VALUE ScanError;

struct strscanner
{
/* multi-purpose flags */
unsigned long flags;
#define FLAG_MATCHED (1 << 0)

/* the string to scan */
VALUE str;
/* scan pointers */
long prev; /* legal only when MATCHED_P(s) */
long curr; /* always legal */

/* the regexp register; legal only when MATCHED_P(s) */
struct re_registers regs;
};

#define MATCHED_P(s) ((s)->flags & FLAG_MATCHED)
#define MATCHED(s) (s)->flags |= FLAG_MATCHED
#define CLEAR_MATCH_STATUS(s) (s)->flags &= ~FLAG_MATCHED

#define S_PBEG(s) (RSTRING((s)->str)->ptr)
#define S_LEN(s) (RSTRING((s)->str)->len)
#define S_PEND(s) (S_PBEG(s) + S_LEN(s))
#define CURPTR(s) (S_PBEG(s) + (s)->curr)
#define S_RESTLEN(s) (S_LEN(s) - (s)->curr)

#define EOS_P(s) ((s)->curr >= RSTRING(p->str)->len)

#define GET_SCANNER(obj,var) do {\
Data_Get_Struct(obj, struct strscanner, var);\
if (NIL_P(var->str)) rb_raise(rb_eArgError, "uninitialized StringScanner object");\
} while (0)

/* =======================================================================
Function Prototypes
======================================================================= */

static VALUE infect _((VALUE str, struct strscanner *p));
static VALUE extract_range _((struct strscanner *p, long beg_i, long end_i));
static VALUE extract_beg_len _((struct strscanner *p, long beg_i, long len));

static void check_strscan _((VALUE obj));
static void strscan_mark _((struct strscanner *p));
static void strscan_free _((struct strscanner *p));
static VALUE strscan_s_allocate _((VALUE klass));
static VALUE strscan_initialize _((int argc, VALUE *argv, VALUE self));
static VALUE strscan_init_copy _((VALUE vself, VALUE vorig));

static VALUE strscan_s_mustc _((VALUE self));
static VALUE strscan_terminate _((VALUE self));
static VALUE strscan_clear _((VALUE self));
static VALUE strscan_get_string _((VALUE self));
static VALUE strscan_set_string _((VALUE self, VALUE str));
static VALUE strscan_concat _((VALUE self, VALUE str));
static VALUE strscan_get_pos _((VALUE self));
static VALUE strscan_set_pos _((VALUE self, VALUE pos));
static VALUE strscan_do_scan _((VALUE self, VALUE regex,
int succptr, int getstr, int headonly));
static VALUE strscan_scan _((VALUE self, VALUE re));
static VALUE strscan_match_p _((VALUE self, VALUE re));
static VALUE strscan_skip _((VALUE self, VALUE re));
static VALUE strscan_check _((VALUE self, VALUE re));
static VALUE strscan_scan_full _((VALUE self, VALUE re,
VALUE succp, VALUE getp));
static VALUE strscan_scan_until _((VALUE self, VALUE re));
static VALUE strscan_skip_until _((VALUE self, VALUE re));
static VALUE strscan_check_until _((VALUE self, VALUE re));
static VALUE strscan_search_full _((VALUE self, VALUE re,
VALUE succp, VALUE getp));
static void adjust_registers_to_matched _((struct strscanner *p));
static VALUE strscan_getch _((VALUE self));
static VALUE strscan_get_byte _((VALUE self));
static VALUE strscan_getbyte _((VALUE self));
static VALUE strscan_peek _((VALUE self, VALUE len));
static VALUE strscan_peep _((VALUE self, VALUE len));
static VALUE strscan_unscan _((VALUE self));
static VALUE strscan_bol_p _((VALUE self));
static VALUE strscan_eos_p _((VALUE self));
static VALUE strscan_empty_p _((VALUE self));
static VALUE strscan_rest_p _((VALUE self));
static VALUE strscan_matched_p _((VALUE self));
static VALUE strscan_matched _((VALUE self));
static VALUE strscan_matched_size _((VALUE self));
static VALUE strscan_aref _((VALUE self, VALUE idx));
static VALUE strscan_pre_match _((VALUE self));
static VALUE strscan_post_match _((VALUE self));
static VALUE strscan_rest _((VALUE self));
static VALUE strscan_rest_size _((VALUE self));

static VALUE strscan_inspect _((VALUE self));
static VALUE inspect1 _((struct strscanner *p));
static VALUE inspect2 _((struct strscanner *p));

/* =======================================================================
Utils
======================================================================= */

static VALUE
infect(VALUE str, struct strscanner *p)
{
OBJ_INFECT(str, p->str);
return str;
}

static VALUE
extract_range(struct strscanner *p, long beg_i, long end_i)
{
if (beg_i > S_LEN(p)) return Qnil;
if (end_i > S_LEN(p))
end_i = S_LEN(p);
return infect(rb_str_new(S_PBEG(p) + beg_i, end_i - beg_i), p);
}

static VALUE
extract_beg_len(struct strscanner *p, long beg_i, long len)
{
if (beg_i > S_LEN(p)) return Qnil;
if (beg_i + len > S_LEN(p))
len = S_LEN(p) - beg_i;
return infect(rb_str_new(S_PBEG(p) + beg_i, len), p);
}

/* =======================================================================
Constructor
======================================================================= */

static void
strscan_mark(struct strscanner *p)
{
rb_gc_mark(p->str);
}

static void
strscan_free(struct strscanner *p)
{
re_free_registers(&(p->regs));
free(p);
}

static VALUE
strscan_s_allocate(VALUE klass)
{
struct strscanner *p;
p = ALLOC(struct strscanner);
MEMZERO(p, struct strscanner, 1);
CLEAR_MATCH_STATUS(p);
MEMZERO(&(p->regs), struct re_registers, 1);
p->str = Qnil;
return Data_Wrap_Struct(klass, strscan_mark, strscan_free, p);
}

/*
* call-seq: StringScanner.new(string, dup = false)
*
* Creates a new StringScanner object to scan over the given +string+.
* +dup+ argument is obsolete and not used now.
*/
static VALUE
strscan_initialize(int argc, VALUE *argv, VALUE self)
{
struct strscanner *p;
VALUE str, need_dup;

Data_Get_Struct(self, struct strscanner, p);
rb_scan_args(argc, argv, "11", &str, &need_dup);
StringValue(str);
p->str = str;

return self;
}

static void
check_strscan(VALUE obj)
{
if (TYPE(obj) != T_DATA || RDATA(obj)->dmark != (RUBY_DATA_FUNC)strscan_mark) {
rb_raise(rb_eTypeError,
"wrong argument type %s (expected StringScanner)",
rb_obj_classname(obj));
}
}

/*
* call-seq:
* dup
* clone
*
* Duplicates a StringScanner object.
*/
static VALUE
strscan_init_copy(VALUE vself, VALUE vorig)
{
struct strscanner *self, *orig;

Data_Get_Struct(vself, struct strscanner, self);
check_strscan(vorig);
Data_Get_Struct(vorig, struct strscanner, orig);
if (self != orig) {
self->flags = orig->flags;
self->str = orig->str;
self->prev = orig->prev;
self->curr = orig->curr;
re_copy_registers(&self->regs, &orig->regs);
}
return vself;
}

/* =======================================================================
Instance Methods
======================================================================= */

/*
* call-seq: StringScanner.must_C_version
*
* This method is defined for backward compatibility.
*/
static VALUE
strscan_s_mustc(VALUE self)
{
return self;
}

/*
* Reset the scan pointer (index 0) and clear matching data.
*/
static VALUE
strscan_reset(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
p->curr = 0;
CLEAR_MATCH_STATUS(p);
return self;
}

/*
* call-seq:
* terminate
* clear
*
* Set the scan pointer to the end of the string and clear matching data.
*/
static VALUE
strscan_terminate(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
p->curr = S_LEN(p);
CLEAR_MATCH_STATUS(p);
return self;
}

/*
* Equivalent to #terminate.
* This method is obsolete; use #terminate instead.
*/
static VALUE
strscan_clear(VALUE self)
{
rb_warning("StringScanner#clear is obsolete; use #terminate instead");
return strscan_terminate(self);
}

/*
* Returns the string being scanned.
*/
static VALUE
strscan_get_string(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
return p->str;
}

/*
* call-seq: string=(str)
*
* Changes the string being scanned to +str+ and resets the scanner.
* Returns +str+.
*/
static VALUE
strscan_set_string(VALUE self, VALUE str)
{
struct strscanner *p;

Data_Get_Struct(self, struct strscanner, p);
StringValue(str);
p->str = rb_str_dup(str);
rb_obj_freeze(p->str);
p->curr = 0;
CLEAR_MATCH_STATUS(p);
return str;
}

/*
* call-seq:
* concat(str)
* <<(str)
*
* Appends +str+ to the string being scanned.
* This method does not affect scan pointer.
*
* s = StringScanner.new("Fri Dec 12 1975 14:39")
* s.scan(/Fri /)
* s << " +1000 GMT"
* s.string # -> "Fri Dec 12 1975 14:39 +1000 GMT"
* s.scan(/Dec/) # -> "Dec"
*/
static VALUE
strscan_concat(VALUE self, VALUE str)
{
struct strscanner *p;

GET_SCANNER(self, p);
StringValue(str);
rb_str_append(p->str, str);
return self;
}

/*
* Returns the position of the scan pointer. In the 'reset' position, this
* value is zero. In the 'terminated' position (i.e. the string is exhausted),
* this value is the length of the string.
*
* In short, it's a 0-based index into the string.
*
* s = StringScanner.new('test string')
* s.pos # -> 0
* s.scan_until /str/ # -> "test str"
* s.pos # -> 8
* s.terminate # -> #<StringScanner fin>
* s.pos # -> 11
*/
static VALUE
strscan_get_pos(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
return INT2FIX(p->curr);
}

/*
* call-seq: pos=(n)
*
* Modify the scan pointer.
*
* s = StringScanner.new('test string')
* s.pos = 7 # -> 7
* s.rest # -> "ring"
*/
static VALUE
strscan_set_pos(VALUE self, VALUE v)
{
struct strscanner *p;
long i;

GET_SCANNER(self, p);
i = NUM2INT(v);
if (i < 0) i += S_LEN(p);
if (i < 0) rb_raise(rb_eRangeError, "index out of range");
if (i > S_LEN(p)) rb_raise(rb_eRangeError, "index out of range");
p->curr = i;
return INT2NUM(i);
}

static VALUE
strscan_do_scan(VALUE self, VALUE regex, int succptr, int getstr, int headonly)
{
struct strscanner *p;
int ret;

Check_Type(regex, T_REGEXP);
GET_SCANNER(self, p);

CLEAR_MATCH_STATUS(p);
if (S_RESTLEN(p) < 0) {
return Qnil;
}
rb_kcode_set_option(regex);
if (headonly) {
ret = re_match(RREGEXP(regex)->ptr,
CURPTR(p), S_RESTLEN(p),
0,
&(p->regs));
}
else {
ret = re_search(RREGEXP(regex)->ptr,
CURPTR(p), S_RESTLEN(p),
0,
S_RESTLEN(p),
&(p->regs));
}
rb_kcode_reset_option();

if (ret == -2) rb_raise(ScanError, "regexp buffer overflow");
if (ret < 0) {
/* not matched */
return Qnil;
}

MATCHED(p);
p->prev = p->curr;
if (succptr) {
p->curr += p->regs.end[0];
}
if (getstr) {
return extract_beg_len(p, p->prev, p->regs.end[0]);
}
else {
return INT2FIX(p->regs.end[0]);
}
}

/*
* call-seq: scan(pattern) => String
*
* Tries to match with +pattern+ at the current position. If there's a match,
* the scanner advances the "scan pointer" and returns the matched string.
* Otherwise, the scanner returns +nil+.
*
* s = StringScanner.new('test string')
* p s.scan(/\w+/) # -> "test"
* p s.scan(/\w+/) # -> nil
* p s.scan(/\s+/) # -> " "
* p s.scan(/\w+/) # -> "string"
* p s.scan(/./) # -> nil
*
*/
static VALUE
strscan_scan(VALUE self, VALUE re)
{
return strscan_do_scan(self, re, 1, 1, 1);
}

/*
* call-seq: match?(pattern)
*
* Tests whether the given +pattern+ is matched from the current scan pointer.
* Returns the length of the match, or +nil+. The scan pointer is not advanced.
*
* s = StringScanner.new('test string')
* p s.match?(/\w+/) # -> 4
* p s.match?(/\w+/) # -> 4
* p s.match?(/\s+/) # -> nil
*/
static VALUE
strscan_match_p(VALUE self, VALUE re)
{
return strscan_do_scan(self, re, 0, 0, 1);
}

/*
* call-seq: skip(pattern)
*
* Attempts to skip over the given +pattern+ beginning with the scan pointer.
* If it matches, the scan pointer is advanced to the end of the match, and the
* length of the match is returned. Otherwise, +nil+ is returned.
*
* It's similar to #scan, but without returning the matched string.
*
* s = StringScanner.new('test string')
* p s.skip(/\w+/) # -> 4
* p s.skip(/\w+/) # -> nil
* p s.skip(/\s+/) # -> 1
* p s.skip(/\w+/) # -> 6
* p s.skip(/./) # -> nil
*
*/
static VALUE
strscan_skip(VALUE self, VALUE re)
{
return strscan_do_scan(self, re, 1, 0, 1);
}

/*
* call-seq: check(pattern)
*
* This returns the value that #scan would return, without advancing the scan
* pointer. The match register is affected, though.
*
* s = StringScanner.new("Fri Dec 12 1975 14:39")
* s.check /Fri/ # -> "Fri"
* s.pos # -> 0
* s.matched # -> "Fri"
* s.check /12/ # -> nil
* s.matched # -> nil
*
* Mnemonic: it "checks" to see whether a #scan will return a value.
*/
static VALUE
strscan_check(VALUE self, VALUE re)
{
return strscan_do_scan(self, re, 0, 1, 1);
}

/*
* call-seq: scan_full(pattern, return_string_p, advance_pointer_p)
*
* Tests whether the given +pattern+ is matched from the current scan pointer.
* Returns the matched string if +return_string_p+ is true.
* Advances the scan pointer if +advance_pointer_p+ is true.
* The match register is affected.
*
* "full" means "#scan with full parameters".
*/
static VALUE
strscan_scan_full(VALUE self, VALUE re, VALUE s, VALUE f)
{
return strscan_do_scan(self, re, RTEST(s), RTEST(f), 1);
}


/*
* call-seq: scan_until(pattern)
*
* Scans the string _until_ the +pattern+ is matched. Returns the substring up
* to and including the end of the match, advancing the scan pointer to that
* location. If there is no match, +nil+ is returned.
*
* s = StringScanner.new("Fri Dec 12 1975 14:39")
* s.scan_until(/1/) # -> "Fri Dec 1"
* s.pre_match # -> "Fri Dec "
* s.scan_until(/XYZ/) # -> nil
*/
static VALUE
strscan_scan_until(VALUE self, VALUE re)
{
return strscan_do_scan(self, re, 1, 1, 0);
}

/*
* call-seq: exist?(pattern)
*
* Looks _ahead_ to see if the +pattern+ exists _anywhere_ in the string,
* without advancing the scan pointer. This predicates whether a #scan_until
* will return a value.
*
* s = StringScanner.new('test string')
* s.exist? /s/ # -> 3
* s.scan /test/ # -> "test"
* s.exist? /s/ # -> 6
* s.exist? /e/ # -> nil
*/
static VALUE
strscan_exist_p(VALUE self, VALUE re)
{
return strscan_do_scan(self, re, 0, 0, 0);
}

/*
* call-seq: skip_until(pattern)
*
* Advances the scan pointer until +pattern+ is matched and consumed. Returns
* the number of bytes advanced, or +nil+ if no match was found.
*
* Look ahead to match +pattern+, and advance the scan pointer to the _end_
* of the match. Return the number of characters advanced, or +nil+ if the
* match was unsuccessful.
*
* It's similar to #scan_until, but without returning the intervening string.
*
* s = StringScanner.new("Fri Dec 12 1975 14:39")
* s.skip_until /12/ # -> 10
* s #
*/
static VALUE
strscan_skip_until(VALUE self, VALUE re)
{
return strscan_do_scan(self, re, 1, 0, 0);
}

/*
* call-seq: check_until(pattern)
*
* This returns the value that #scan_until would return, without advancing the
* scan pointer. The match register is affected, though.
*
* s = StringScanner.new("Fri Dec 12 1975 14:39")
* s.check_until /12/ # -> "Fri Dec 12"
* s.pos # -> 0
* s.matched # -> 12
*
* Mnemonic: it "checks" to see whether a #scan_until will return a value.
*/
static VALUE
strscan_check_until(VALUE self, VALUE re)
{
return strscan_do_scan(self, re, 0, 1, 0);
}

/*
* call-seq: search_full(pattern, return_string_p, advance_pointer_p)
*
* Scans the string _until_ the +pattern+ is matched.
* Returns the matched string if +return_string_p+ is true, otherwise
* returns the number of bytes advanced.
* Advances the scan pointer if +advance_pointer_p+, otherwise not.
* This method does affect the match register.
*/
static VALUE
strscan_search_full(VALUE self, VALUE re, VALUE s, VALUE f)
{
return strscan_do_scan(self, re, RTEST(s), RTEST(f), 0);
}

/* DANGEROUS; need to synchronize with regex.c */
static void
adjust_registers_to_matched(struct strscanner *p)
{
if (p->regs.allocated == 0) {
p->regs.beg = ALLOC_N(int, RE_NREGS);
p->regs.end = ALLOC_N(int, RE_NREGS);
p->regs.allocated = RE_NREGS;
}
p->regs.num_regs = 1;
p->regs.beg[0] = 0;
p->regs.end[0] = p->curr - p->prev;
}

/*
* Scans one character and returns it.
* This method is multi-byte character sensitive.
* See also #get_byte.
*
* s = StringScanner.new('ab')
* s.getch # => "a"
* s.getch # => "b"
* s.getch # => nil
*
* $KCODE = 'EUC'
* s = StringScanner.new("\244\242")
* s.getch # => "\244\242" # Japanese hira-kana "A" in EUC-JP
* s.getch # => nil
*/
static VALUE
strscan_getch(VALUE self)
{
struct strscanner *p;
long len;

GET_SCANNER(self, p);
CLEAR_MATCH_STATUS(p);
if (EOS_P(p))
return Qnil;
len = mbclen(*CURPTR(p));
if (p->curr + len > S_LEN(p)) {
len = S_LEN(p) - p->curr;
}
p->prev = p->curr;
p->curr += len;
MATCHED(p);
adjust_registers_to_matched(p);
return extract_range(p, p->prev + p->regs.beg[0],
p->prev + p->regs.end[0]);
}

/*
* Scans one byte and returns it.
* This method is NOT multi-byte character sensitive.
* See also #getch.
*
* s = StringScanner.new('ab')
* s.get_byte # => "a"
* s.get_byte # => "b"
* s.get_byte # => nil
*
* s = StringScanner.new("\244\242")
* s.get_byte # => "\244"
* s.get_byte # => "\242"
* s.get_byte # => nil
*/
static VALUE
strscan_get_byte(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
CLEAR_MATCH_STATUS(p);
if (EOS_P(p)) {
return Qnil;
}
p->prev = p->curr;
p->curr++;
MATCHED(p);
adjust_registers_to_matched(p);
return extract_range(p, p->prev + p->regs.beg[0],
p->prev + p->regs.end[0]);
}

/*
* Equivalent to #get_byte.
* This method is obsolete; use #get_byte instead.
*/
static VALUE
strscan_getbyte(VALUE self)
{
rb_warning("StringScanner#getbyte is obsolete; use #get_byte instead");
return strscan_get_byte(self);
}

/*
* call-seq: peek(len)
*
* Extracts a string corresponding to <tt>string[pos,len]</tt>, without
* advancing the scan pointer.
*
* s = StringScanner.new('test string')
* s.peek(7) # => "test st"
* s.peek(7) # => "test st"
*
*/
static VALUE
strscan_peek(VALUE self, VALUE vlen)
{
struct strscanner *p;
long len;

GET_SCANNER(self, p);
len = NUM2LONG(vlen);
if (EOS_P(p)) {
return infect(rb_str_new("", 0), p);
}
if (p->curr + len > S_LEN(p)) {
len = S_LEN(p) - p->curr;
}
return extract_beg_len(p, p->curr, len);
}

/*
* Equivalent to #peek.
* This method is obsolete; use #peek instead.
*/
static VALUE
strscan_peep(VALUE self, VALUE vlen)
{
rb_warning("StringScanner#peep is obsolete; use #peek instead");
return strscan_peek(self, vlen);
}

/*
* Set the scan pointer to the previous position. Only one previous position is
* remembered, and it changes with each scanning operation.
*
* s = StringScanner.new('test string')
* s.scan(/\w+/) # => "test"
* s.unscan
* s.scan(/../) # => "te"
* s.scan(/\d/) # => nil
* s.unscan # ScanError: unscan failed: previous match had failed
*/
static VALUE
strscan_unscan(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
if (! MATCHED_P(p)) {
rb_raise(ScanError, "unscan failed: previous match had failed");
}
p->curr = p->prev;
CLEAR_MATCH_STATUS(p);
return self;
}

/*
* Returns +true+ iff the scan pointer is at the beginning of the line.
*
* s = StringScanner.new("test\ntest\n")
* s.bol? # => true
* s.scan(/te/)
* s.bol? # => false
* s.scan(/st\n/)
* s.bol? # => true
* s.terminate
* s.bol? # => true
*/
static VALUE
strscan_bol_p(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
if (CURPTR(p) > S_PEND(p)) return Qnil;
if (p->curr == 0) return Qtrue;
return (*(CURPTR(p) - 1) == '\n') ? Qtrue : Qfalse;
}

/*
* Returns +true+ if the scan pointer is at the end of the string.
*
* s = StringScanner.new('test string')
* p s.eos? # => false
* s.scan(/test/)
* p s.eos? # => false
* s.terminate
* p s.eos? # => true
*/
static VALUE
strscan_eos_p(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
return EOS_P(p) ? Qtrue : Qfalse;
}

/*
* Equivalent to #eos?.
* This method is obsolete, use #eos? instead.
*/
static VALUE
strscan_empty_p(VALUE self)
{
rb_warning("StringScanner#empty? is obsolete; use #eos? instead");
return strscan_eos_p(self);
}

/*
* Returns true iff there is more data in the string. See #eos?.
* This method is obsolete; use #eos? instead.
*
* s = StringScanner.new('test string')
* s.eos? # These two
* s.rest? # are opposites.
*/
static VALUE
strscan_rest_p(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
return EOS_P(p) ? Qfalse : Qtrue;
}

/*
* Returns +true+ iff the last match was successful.
*
* s = StringScanner.new('test string')
* s.match?(/\w+/) # => 4
* s.matched? # => true
* s.match?(/\d+/) # => nil
* s.matched? # => false
*/
static VALUE
strscan_matched_p(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
return MATCHED_P(p) ? Qtrue : Qfalse;
}

/*
* Returns the last matched string.
*
* s = StringScanner.new('test string')
* s.match?(/\w+/) # -> 4
* s.matched # -> "test"
*/
static VALUE
strscan_matched(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
if (! MATCHED_P(p)) return Qnil;

return extract_range(p, p->prev + p->regs.beg[0],
p->prev + p->regs.end[0]);
}

/*
* Returns the size of the most recent match (see #matched), or +nil+ if there
* was no recent match.
*
* s = StringScanner.new('test string')
* s.check /\w+/ # -> "test"
* s.matched_size # -> 4
* s.check /\d+/ # -> nil
* s.matched_size # -> nil
*/
static VALUE
strscan_matched_size(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
if (! MATCHED_P(p)) return Qnil;

return INT2NUM(p->regs.end[0] - p->regs.beg[0]);
}

/*
* Equivalent to #matched_size.
* This method is obsolete; use #matched_size instead.
*/
static VALUE
strscan_matchedsize(VALUE self)
{
rb_warning("StringScanner#matchedsize is obsolete; use #matched_size instead");
return strscan_matched_size(self);
}

/*
* call-seq: [](n)
*
* Return the n-th subgroup in the most recent match.
*
* s = StringScanner.new("Fri Dec 12 1975 14:39")
* s.scan(/(\w+) (\w+) (\d+) /) # -> "Fri Dec 12 "
* s[0] # -> "Fri Dec 12 "
* s[1] # -> "Fri"
* s[2] # -> "Dec"
* s[3] # -> "12"
* s.post_match # -> "1975 14:39"
* s.pre_match # -> ""
*/
static VALUE
strscan_aref(VALUE self, VALUE idx)
{
struct strscanner *p;
long i;

GET_SCANNER(self, p);
if (! MATCHED_P(p)) return Qnil;
i = NUM2LONG(idx);
if (i < 0)
i += p->regs.num_regs;
if (i < 0) return Qnil;
if (i >= p->regs.num_regs) return Qnil;
if (p->regs.beg[i] == -1) return Qnil;

return extract_range(p, p->prev + p->regs.beg[i],
p->prev + p->regs.end[i]);
}

/*
* call-seq: size
*
* Return the amount of subgroups in the most recent match.
* The full match counts as a subgroup.
*
* s = StringScanner.new("Fri Dec 12 1975 14:39")
* s.scan(/(\w+) (\w+) (\d+) /) # -> "Fri Dec 12 "
* s.size # -> 4
*/
static VALUE
strscan_size(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
if (! MATCHED_P(p)) return Qnil;
return INT2FIX(p->regs.num_regs);
}

/*
* call-seq: size
*
* Returns the subgroups in the most recent match (not including the full match).
* If nothing was priorly matched, it returns nil.
*
* s = StringScanner.new("Fri Dec 12 1975 14:39")
* s.scan(/(\w+) (\w+) (\d+) /) # -> "Fri Dec 12 "
* s.captures # -> ["Fri", "Dec", "12"]
* s.scan(/(\w+) (\w+) (\d+) /) # -> nil
* s.captures # -> nil
*/
static VALUE
strscan_captures(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
if (! MATCHED_P(p)) return Qnil;
int i;
int num_regs = p->regs.num_regs;
VALUE result = rb_ary_new2(num_regs);

for(i=1; i<num_regs; i++) {
rb_ary_push(
result,
extract_range(p, p->prev + p->regs.beg[i], p->prev + p->regs.end[i])
);
}
return result;
}

/*
* call-seq:
* scanner.values_at( i1, i2, ... iN ) -> an_array
*
* Returns the subgroups in the most recent match at the given indices.
* If nothing was priorly matched, it returns nil.
*
* s = StringScanner.new("Fri Dec 12 1975 14:39")
* s.scan(/(\w+) (\w+) (\d+) /) # -> "Fri Dec 12 "
* s.values_at 0, -1, 5, 2 # -> ["Fri Dec 12 ", "12", nil, "Dec"]
* s.scan(/(\w+) (\w+) (\d+) /) # -> nil
* s.captures # -> nil
*/

static VALUE
strscan_values_at(int argc, VALUE *argv, VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
if (! MATCHED_P(p)) return Qnil;

long i;
VALUE new_ary = rb_ary_new2(argc);

for (i=0; i<argc; i++) {
rb_ary_push(new_ary, strscan_aref(self, argv[i]));
}

return new_ary;
}

/*
* Return the <i><b>pre</b>-match</i> (in the regular expression sense) of the last scan.
*
* s = StringScanner.new('test string')
* s.scan(/\w+/) # -> "test"
* s.scan(/\s+/) # -> " "
* s.pre_match # -> "test"
* s.post_match # -> "string"
*/
static VALUE
strscan_pre_match(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
if (! MATCHED_P(p)) return Qnil;

return extract_range(p, 0, p->prev + p->regs.beg[0]);
}

/*
* Return the <i><b>post</b>-match</i> (in the regular expression sense) of the last scan.
*
* s = StringScanner.new('test string')
* s.scan(/\w+/) # -> "test"
* s.scan(/\s+/) # -> " "
* s.pre_match # -> "test"
* s.post_match # -> "string"
*/
static VALUE
strscan_post_match(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
if (! MATCHED_P(p)) return Qnil;

return extract_range(p, p->prev + p->regs.end[0], S_LEN(p));
}

/*
* Returns the "rest" of the string (i.e. everything after the scan pointer).
* If there is no more data (eos? = true), it returns <tt>""</tt>.
*/
static VALUE
strscan_rest(VALUE self)
{
struct strscanner *p;

GET_SCANNER(self, p);
if (EOS_P(p)) {
return infect(rb_str_new("", 0), p);
}
return extract_range(p, p->curr, S_LEN(p));
}

/*
* <tt>s.rest_size</tt> is equivalent to <tt>s.rest.size</tt>.
*/
static VALUE
strscan_rest_size(VALUE self)
{
struct strscanner *p;
long i;

GET_SCANNER(self, p);
if (EOS_P(p)) {
return INT2FIX(0);
}

i = S_LEN(p) - p->curr;
return INT2FIX(i);
}

/*
* <tt>s.restsize</tt> is equivalent to <tt>s.rest_size</tt>.
* This method is obsolete; use #rest_size instead.
*/
static VALUE
strscan_restsize(VALUE self)
{
rb_warning("StringScanner#restsize is obsolete; use #rest_size instead");
return strscan_rest_size(self);
}

#define INSPECT_LENGTH 5
#define BUFSIZE 256

/*
* Returns a string that represents the StringScanner object, showing:
* - the current position
* - the size of the string
* - the characters surrounding the scan pointer
*
* s = StringScanner.new("Fri Dec 12 1975 14:39")
* s.inspect # -> '#<StringScanner 0/21 @ "Fri D...">'
* s.scan_until /12/ # -> "Fri Dec 12"
* s.inspect # -> '#<StringScanner 10/21 "...ec 12" @ " 1975...">'
*/
static VALUE
strscan_inspect(VALUE self)
{
struct strscanner *p;
char buf[BUFSIZE];
long len;
VALUE a, b;

Data_Get_Struct(self, struct strscanner, p);
if (NIL_P(p->str)) {
len = snprintf(buf, BUFSIZE, "#<%s (uninitialized)>",
rb_class2name(CLASS_OF(self)));
return infect(rb_str_new(buf, len), p);
}
if (EOS_P(p)) {
len = snprintf(buf, BUFSIZE, "#<%s fin>",
rb_class2name(CLASS_OF(self)));
return infect(rb_str_new(buf, len), p);
}
if (p->curr == 0) {
b = inspect2(p);
len = snprintf(buf, BUFSIZE, "#<%s %ld/%ld @ %s>",
rb_class2name(CLASS_OF(self)),
p->curr, S_LEN(p),
RSTRING(b)->ptr);
return infect(rb_str_new(buf, len), p);
}
a = inspect1(p);
b = inspect2(p);
len = snprintf(buf, BUFSIZE, "#<%s %ld/%ld %s @ %s>",
rb_class2name(CLASS_OF(self)),
p->curr, S_LEN(p),
RSTRING(a)->ptr,
RSTRING(b)->ptr);
return infect(rb_str_new(buf, len), p);
}

static VALUE
inspect1(struct strscanner *p)
{
char buf[BUFSIZE];
char *bp = buf;
long len;

if (p->curr == 0) return rb_str_new2("");
if (p->curr > INSPECT_LENGTH) {
strcpy(bp, "..."); bp += 3;
len = INSPECT_LENGTH;
}
else {
len = p->curr;
}
memcpy(bp, CURPTR(p) - len, len); bp += len;
return rb_str_dump(rb_str_new(buf, bp - buf));
}

static VALUE
inspect2(struct strscanner *p)
{
char buf[BUFSIZE];
char *bp = buf;
long len;

if (EOS_P(p)) return rb_str_new2("");
len = S_LEN(p) - p->curr;
if (len > INSPECT_LENGTH) {
len = INSPECT_LENGTH;
memcpy(bp, CURPTR(p), len); bp += len;
strcpy(bp, "..."); bp += 3;
}
else {
memcpy(bp, CURPTR(p), len); bp += len;
}
return rb_str_dump(rb_str_new(buf, bp - buf));
}

/* =======================================================================
Ruby Interface
======================================================================= */

/*
* Document-class: StringScanner
*
* StringScanner provides for lexical scanning operations on a String. Here is
* an example of its usage:
*
* s = StringScanner.new('This is an example string')
* s.eos? # -> false
*
* p s.scan(/\w+/) # -> "This"
* p s.scan(/\w+/) # -> nil
* p s.scan(/\s+/) # -> " "
* p s.scan(/\s+/) # -> nil
* p s.scan(/\w+/) # -> "is"
* s.eos? # -> false
*
* p s.scan(/\s+/) # -> " "
* p s.scan(/\w+/) # -> "an"
* p s.scan(/\s+/) # -> " "
* p s.scan(/\w+/) # -> "example"
* p s.scan(/\s+/) # -> " "
* p s.scan(/\w+/) # -> "string"
* s.eos? # -> true
*
* p s.scan(/\s+/) # -> nil
* p s.scan(/\w+/) # -> nil
*
* Scanning a string means remembering the position of a <i>scan pointer</i>,
* which is just an index. The point of scanning is to move forward a bit at
* a time, so matches are sought after the scan pointer; usually immediately
* after it.
*
* Given the string "test string", here are the pertinent scan pointer
* positions:
*
* t e s t s t r i n g
* 0 1 2 ... 1
* 0
*
* When you #scan for a pattern (a regular expression), the match must occur
* at the character after the scan pointer. If you use #scan_until, then the
* match can occur anywhere after the scan pointer. In both cases, the scan
* pointer moves <i>just beyond</i> the last character of the match, ready to
* scan again from the next character onwards. This is demonstrated by the
* example above.
*
* == Method Categories
*
* There are other methods besides the plain scanners. You can look ahead in
* the string without actually scanning. You can access the most recent match.
* You can modify the string being scanned, reset or terminate the scanner,
* find out or change the position of the scan pointer, skip ahead, and so on.
*
* === Advancing the Scan Pointer
*
* - #getch
* - #get_byte
* - #scan
* - #scan_until
* - #skip
* - #skip_until
*
* === Looking Ahead
*
* - #check
* - #check_until
* - #exist?
* - #match?
* - #peek
*
* === Finding Where we Are
*
* - #beginning_of_line? (#bol?)
* - #eos?
* - #rest?
* - #rest_size
* - #pos
*
* === Setting Where we Are
*
* - #reset
* - #terminate
* - #pos=
*
* === Match Data
*
* - #matched
* - #matched?
* - #matched_size
* - []
* - #pre_match
* - #post_match
*
* === Miscellaneous
*
* - <<
* - #concat
* - #string
* - #string=
* - #unscan
*
* There are aliases to several of the methods.
*/
void
Init_strscan(void)
{
ID id_scanerr = rb_intern("ScanError");
VALUE tmp;

StringScanner = rb_define_class("StringScanner", rb_cObject);
ScanError = rb_define_class_under(StringScanner, "Error", rb_eStandardError);
if (!rb_const_defined(rb_cObject, id_scanerr)) {
rb_const_set(rb_cObject, id_scanerr, ScanError);
}
tmp = rb_str_new2(STRSCAN_VERSION);
rb_obj_freeze(tmp);
rb_const_set(StringScanner, rb_intern("Version"), tmp);
tmp = rb_str_new2("$Id: strscan.c 11708 2007-02-12 23:01:19Z shyouhei $");
rb_obj_freeze(tmp);
rb_const_set(StringScanner, rb_intern("Id"), tmp);
rb_define_alloc_func(StringScanner, strscan_s_allocate);
rb_define_private_method(StringScanner, "initialize", strscan_initialize, -1);
rb_define_private_method(StringScanner, "initialize_copy", strscan_init_copy, 1);
rb_define_singleton_method(StringScanner, "must_C_version", strscan_s_mustc, 0);
rb_define_method(StringScanner, "reset", strscan_reset, 0);
rb_define_method(StringScanner, "terminate", strscan_terminate, 0);
rb_define_method(StringScanner, "clear", strscan_clear, 0);
rb_define_method(StringScanner, "string", strscan_get_string, 0);
rb_define_method(StringScanner, "string=", strscan_set_string, 1);
rb_define_method(StringScanner, "concat", strscan_concat, 1);
rb_define_method(StringScanner, "<<", strscan_concat, 1);
rb_define_method(StringScanner, "pos", strscan_get_pos, 0);
rb_define_method(StringScanner, "pos=", strscan_set_pos, 1);
rb_define_method(StringScanner, "pointer", strscan_get_pos, 0);
rb_define_method(StringScanner, "pointer=", strscan_set_pos, 1);

rb_define_method(StringScanner, "scan", strscan_scan, 1);
rb_define_method(StringScanner, "skip", strscan_skip, 1);
rb_define_method(StringScanner, "match?", strscan_match_p, 1);
rb_define_method(StringScanner, "check", strscan_check, 1);
rb_define_method(StringScanner, "scan_full", strscan_scan_full, 3);

rb_define_method(StringScanner, "scan_until", strscan_scan_until, 1);
rb_define_method(StringScanner, "skip_until", strscan_skip_until, 1);
rb_define_method(StringScanner, "exist?", strscan_exist_p, 1);
rb_define_method(StringScanner, "check_until", strscan_check_until, 1);
rb_define_method(StringScanner, "search_full", strscan_search_full, 3);

rb_define_method(StringScanner, "getch", strscan_getch, 0);
rb_define_method(StringScanner, "get_byte", strscan_get_byte, 0);
rb_define_method(StringScanner, "getbyte", strscan_getbyte, 0);
rb_define_method(StringScanner, "peek", strscan_peek, 1);
rb_define_method(StringScanner, "peep", strscan_peep, 1);

rb_define_method(StringScanner, "unscan", strscan_unscan, 0);

rb_define_method(StringScanner, "beginning_of_line?", strscan_bol_p, 0);
rb_alias(StringScanner, rb_intern("bol?"), rb_intern("beginning_of_line?"));
rb_define_method(StringScanner, "eos?", strscan_eos_p, 0);
rb_define_method(StringScanner, "empty?", strscan_empty_p, 0);
rb_define_method(StringScanner, "rest?", strscan_rest_p, 0);

rb_define_method(StringScanner, "matched?", strscan_matched_p, 0);
rb_define_method(StringScanner, "matched", strscan_matched, 0);
rb_define_method(StringScanner, "matched_size", strscan_matched_size, 0);
rb_define_method(StringScanner, "matchedsize", strscan_matchedsize, 0);
rb_define_method(StringScanner, "[]", strscan_aref, 1);
rb_define_method(StringScanner, "pre_match", strscan_pre_match, 0);
rb_define_method(StringScanner, "post_match", strscan_post_match, 0);
rb_define_method(StringScanner, "size", strscan_size, 0);
rb_define_method(StringScanner, "captures", strscan_captures, 0);
rb_define_method(StringScanner, "values_at", strscan_values_at, -1);

rb_define_method(StringScanner, "rest", strscan_rest, 0);
rb_define_method(StringScanner, "rest_size", strscan_rest_size, 0);
rb_define_method(StringScanner, "restsize", strscan_restsize, 0);

rb_define_method(StringScanner, "inspect", strscan_inspect, 0);
}
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