NAME

src/string.c - Parrot Strings

DESCRIPTION

This file implements the non-ICU parts of the Parrot string subsystem.

Note that bufstart and buflen are used by the memory subsystem. The string functions may only use buflen to determine, if there is some space left beyond bufused. This is the only valid usage of these two data members, beside setting bufstart/buflen for external strings.

Functions

Parrot_unmake_COW: If the specified Parrot string is copy-on-write then the memory is copied over and the copy-on-write flag is cleared.
Parrot_make_COW_reference: Creates a copy-on-write string by cloning a string header without allocating a new buffer.
Parrot_reuse_COW_reference: Creates a copy-on-write string by cloning a string header without allocating a new buffer. Doesn't allocate a new string header, instead using the one passed in and returns it.
string_set: Makes the contents of first Parrot string a copy of the contents of second.

Basic String Functions

Creation, enlargement, etc.

string_init: Initializes the Parrot string subsystem.
string_deinit: De-Initializes the Parrot string subsystem.
string_capacity: Returns the capacity of the specified Parrot string in bytes, that is how many bytes can be appended onto strstart.
string_make_empty: Creates and returns an empty Parrot string.
string_rep_compatible: Find the "lowest" possible charset and encoding for the given string. E.g.; Returs NULL, if no compatible string representation can be found.
string_append: Take in two Parrot strings and append the second to the first. NOTE THAT RETURN VALUE MAY NOT BE THE FIRST STRING, if the first string is COW'd or read-only. So make sure to _use_ the return value.
string_from_cstring: Make a Parrot string from a specified C string.
string_primary_encoding_for_representation: Returns the primary encoding for the specified representation.; This is needed for packfile unpacking, unless we just always use UTF-8 or BOCU.
const_string: Creates and returns a constant Parrot string.
string_make: Creates and returns a new Parrot string using len bytes of string data read from buffer.; The value of charset_name specifies the string's representation. The currently recognised values are:; The encoding is implicitly guessed; unicode implies the utf-8 encoding, and the other three assume fixed-8 encoding.; If charset is unspecified the default charset 'ascii' will be used.; The value of flags is optionally one or more PObj_* flags OR-ed together.
string_grow: Grows the Parrot string's buffer by the specified number of characters.

Ordinary user-visible string operations

string_length: Returns the number of characters in the specified Parrot string.
string_index: Returns the character (or glyph, depending upon the string's encoding) This is to abstract the process of finding the Nth character in a (possibly unicode or JIS-encoded) string, the idea being that once the encoding functions are fleshed out, this function can do the right thing.; Note that this is not range-checked.
string_str_index: Returns the character position of the second Parrot string in the first at or after start. The return value is a (0 based) offset in characters, not bytes. If second string is not specified, then return -1.
string_ord: Returns the codepoint at a given index into a string. Negative indexes are treated as counting from the end of the string.
string_chr: Returns a single character Parrot string.; TODO - Allow this to take an array of characters?
string_copy: Creates and returns a copy of the specified Parrot string.

Vtable Dispatch Functions

string_compute_strlen: Calculates and returns the number of characters in the specified Parrot string.
string_max_bytes: Returns the number of bytes required to safely contain the specified number of characters in the specified Parrot string's representation.
string_concat: Concatenates two Parrot strings. If necessary, converts the second string's encoding and/or type to match those of the first string. If either string is NULL, then a copy of the non-NULL string is returned. If both strings are NULL, then a new zero-length string is created and returned.
string_repeat: Repeats the specified Parrot string num times and stores the result in the second string, and returns it. The second string is created if necessary.
string_substr: Copies the substring of length length from offset from the specified Parrot string and stores it in **d, allocating memory if necessary. The substring is also returned.
string_replace: This should follow the Perl semantics for:; Replaces a sequence of length characters from offset in the first Parrot string with the second Parrot string, returning what was replaced.; Replacing a sequence of characters with a longer string grows the string; a shorter string shrinks it.; Replacing 2 past the end of the string is undefined. However replacing 1 past the end of the string concatenates the two strings.; A negative offset is allowed to replace from the end.
string_chopn: Chops off the last n characters of the specified Parrot string. If n is negative, cuts the string after +n characters. The returned string is a copy of the one passed in.
string_chopn_inplace: Chops off the last n characters of the specified Parrot string. If n is negative, cuts the string after +n characters. The string passed in is modified and returned.
string_equal: Compares two Parrot strings, performing type and encoding conversions if necessary.; Note that this function returns 0 if the strings are equal and 1 otherwise.
make_writable: Makes the specified Parrot string writable with minimum length len. The representation argument is required in case a new Parrot string has to be created.
nonnull_encoding_name(STRING *s): Returns the string's encoding name if the string pointer is non-null, if the string pointer is null it simply returns the string "null string". This function prevents problems whereby the string used in real_exception to print the exception message could potentially be null.
string_bitwise_and: Performs a bitwise AND on two Parrot string, performing type and encoding conversions if necessary. If the second string is not NULL then it is reused, otherwise a new Parrot string is created.
string_bitwise_or: Performs a bitwise OR on two Parrot strings, performing type and encoding conversions if necessary. If the third string is not NULL then it is reused, otherwise a new Parrot string is created.
string_bitwise_xor: Performs a bitwise XOR on two Parrot strings, performing type and encoding conversions if necessary. If the second string is not NULL then it is reused, otherwise a new Parrot string is created.
string_bitwise_not: Performs a bitwise NOT on a Parrot string. If the second string is not NULL then it is reused, otherwise a new Parrot string is created.
string_bool: Returns whether the specified Parrot string is true. A string is true if it is equal to anything other than 0, "" or "0".
string_nprintf: This is like Parrot_snprintf() except that it writes to and returns a Parrot string.; Note that bytelen does not include space for a (non-existent) trailing '\0'. dest may be a NULL pointer, in which case a new native string will be created. If bytelen is 0, the behaviour becomes more sprintf-ish than snprintf-like. bytelen is measured in the encoding of *dest.
string_printf: Writes and returns a Parrot string.
string_to_int: Converts a numeric Parrot string to an integer value.; A number is such that:; The integer value is the appropriate integer representation of such a number, rounding towards zero.
string_to_num: Same as string_to_int() except that a floating-point value is returned.
string_from_int: Returns a Parrot string representation of the specified integer value.
string_from_num: Returns a Parrot string representation of the specified floating-point value.
string_to_cstring: Returns a C string for the specified Parrot string. Use string_cstring_free() to free the string. Failure to do this will result in a memory leak.
string_cstring_free: Free a string created by string_to_cstring().; TODO - Hopefully this can go away at some point, as it's got all sorts of leak potential otherwise.
string_pin: Replace the specified Parrot string's managed buffer memory by system memory.
string_unpin: Undo a string_pin() so that the string once again uses managed memory.
string_hash: Returns the hash value for the specified Parrot string, caching it in s->hashval.
string_escape_string: Escape all non-ascii chars to backslash sequences. Control chars that string_unescape_cstring can handle are esacped as \x, as well as a double quote character. Other control chars and codepoints < 0x100 are escaped as \xhh, codepoints up to 0xffff, as \uhhhh, and codepoints greater than this as \x{hh...hh}.
string_escape_string_delimited: Like above but limit output to len chars (used for trace output of strings).
string_unescape_cstring: Unescapes the specified C string. These sequences are covered:
string_upcase: Returns a copy of the specified Parrot string converted to upper case. Non-caseable characters are left unchanged.; TODO - implemented only for ASCII.
string_upcase_inplace: Converts the specified Parrot string to upper case.
string_downcase: Returns a copy of the specified Parrot string converted to lower case. Non-caseable characters are left unchanged.
string_downcase_inplace: Converts the specified Parrot string to lower case.
string_titlecase: Returns a copy of the specified Parrot string converted to title case. Non-caseable characters are left unchanged.
string_titlecase_inplace: Converts the specified Parrot string to title case.
string_increment: Perl5ish increment the string. Currently single char only.
Parrot_string_cstring: Returns a C string from a Parrot string. Both sides are treated as constants -- i.e. do not resize the result.
Parrot_string_is_cclass: Returns 1 if the codepoint of string s at given offset is in the given character class flags. See also include/parrot/cclass.h for possible character classes. Returns 0 otherwise, or if the string is empty or NULL.
Parrot_string_trans_charset: If dest == NULL, converts src to the given charset or encoding inplace, else returns a copy of src with the charset/encoding in dest.
Parrot_string_trans_encoding: If dest == NULL, converts src to the given charset or encoding inplace, else returns a copy of src with the charset/encoding in dest.
uint_to_str: Returns num converted to a Parrot STRING.; Note that base must be defined, a default of 10 is not assumed. The caller has to verify that base >= 2 && base <= 36 The buffer tc must be at least sizeof (UHUGEINTVAL)*8 + 1 chars big.; If minus is true then - is prepended to the string representation.
int_to_str: Returns num converted to a Parrot STRING.; Note that base must be defined, a default of 10 is not assumed.; If num < 0 then - is prepended to the string representation.