69 lines
3.3 KiB
Plaintext
69 lines
3.3 KiB
Plaintext
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ICONV - Charset Conversion Library. Version 2.0
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-----------------------------------------------
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This distribution provides:
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* the library (libiconv.a and .so) for conversion between
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various charsets (character encoding schemes);
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* and the command line utility (iconv), providing
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conversion of a file, standard input or its argument
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line from one charset to another;
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* a set of coded character set tables (binary files) and
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character encoding schemes (dynamically loaded modules)
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for use by the library;
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* a utility for creating character set tables from Unicode
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conversion tables and RFC1345-style charset descriptions.
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Syntax of the library functions (iconv_open, iconv, iconv_close)
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and the utility is described in the man pages.
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Features of the library:
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- Coded character set (CCS) tables are binary files containing
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pairs of tables for converting characters from some charset to
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Unicode (UCS-2 in host byte order) and vice versa. There are 4
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types of tables supported in iconv-2.0: for 7-bit, 8-bit, 14-bit
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and 16-bit charsets. The library uses memory mapping (in
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read-only mode) to access the table data.
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- Character encoding schemes (CES) are small sets of C structures
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and functions. The functions implement virtual methods for
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converting a sequence of characters in some charset to a Unicode
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character (UCS-4 in host byte order). Each encoding scheme is
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located in a separate C file and can be compiled to a dynamically
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loaded shared module.
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- A universal CES for all table driven charsets is compiled into
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the library and used for all CCS tables.
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- Both CCS tables and CES C code can be built into the library by
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specifying the corresponding charset name in the
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ICONV_BUILTIN_CHARSETS make variable. By default us-ascii, utf-8
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and ucs-4-internal are built in (plus the CES for all CCS
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tables). All the CES modules are included to a static version of
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the library (libiconv.a).
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- Multiple aliases for every charset are supported. All aliases are
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listed in the charset.aliases file(s). The library uses memory
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mapping to parse alias information and find a canonical name
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of a charset before looking it up in the internal list or
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external table or shared module. Alias information can also be
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compiled into the library (which is useful for compiled-in
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charsets ;-)
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- ISO/IEC 10646 conformance of the internal representation of
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characters; conversion is done in two steps:
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(1) a sequence of zero or more bytes from input buffer coded in
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the source charset is converted to exactly one valid UCS-4
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character and
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(2) the UCS-4 character is converted to a sequence of zero or
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more bytes in the target charset to the output buffer.
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In the case when two charset names are found to be aliases
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of the same charset, conversion is done via a simplified
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converter by copying the data from the input buffer to the
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output one.
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- Open module API: adding new modules is easy. API has only been
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documented via iconv.h file comments so far. A perl utility is
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provided for conversion of Unicode charset tables
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(http://www.unicode.org/Public/MAPPINGS/) and RFC1345-style
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charset tables into the CCS format recognized by the library.
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- API conformance to Unix98 specification.
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- BSD-style copyright.
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Konstantin Chuguev
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<Konstantin.Chuguev@dante.org.uk>
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November 2000.
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