58 lines
2.2 KiB
C
58 lines
2.2 KiB
C
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#ifndef __INCLUDE_TAILER_H__
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#define __INCLUDE_TAILER_H__
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/* Functions for managing a "tailer file", which is similar to a tar
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* archive but, in order to support ordinary unadorned files
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* - stores metainformation after each archived file
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* - stores a single magic number at the very end.
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*/
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/* Magic number, occurs only once at the end of tailer file. Should it
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* change, be sure to update TAIL_MAGIC_LEN
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*/
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#define TAIL_MAGIC "#TAIL_GUARD#"
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#define TAIL_MAGIC_LEN 12
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/* Maximum length of title associated with a stored file. Arbitrary, but
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* should it increase, metainfo size (currently 1 byte) must change
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* accordingly
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*/
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#define TAIL_MAX_TITLE_LENGTH 255
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/* Each file's metainfo entry comprises (version 1,0):
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* - offset where actual contents start: 4-byte big-endian
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* - size of contents in bytes: 4-byte big-endian
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* - title, up to TAIL_MAX_TITLE_LENGTH bytes, non 0-terminated
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* - title length, 1 byte
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* - major/minor version number, 1 byte each
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*
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* A tailer file is either an unadorned one or a linked list of content+
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* metainfo entries which goes backwards from the magic number.
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*/
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/* Functions for handling tailer data as memory buffers */
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/* If a memory buffer <p> with <size> given ends with the tailer magic
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* suffix, returns its offset, else returns -1
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*/
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extern long defex_tailerp_has_suffix(const unsigned char *p, long size);
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/* Given buffer <p> of <size> given, returns address of last occurrence
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* of contents of given <title> (and if <sizep> sets *<sizep> to
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* contents size), or 0 if <p> is unadorned has no such
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* occurrences
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*/
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extern const unsigned char *defex_tailerp_find(const unsigned char *p, long size,
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const char *title, long *sizep);
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/* Given buffer <p> with <size> bytes, returns 0 if unadorned. Else,
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* executes <task> for each entry, from last to first, passing arguments
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* <title> (unterminated), title length, absolute <start> address and
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* <size> in bytes, plus <data>. Terminates immediately if <task> returns
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* negative. Returns last result of <task>.
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*/
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extern int defex_tailerp_iterate(const unsigned char *p, long size,
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int (*task)(const char *title, int titleLen,
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const unsigned char *start,
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long size, void *data),
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void *data);
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#endif
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