zzip_disk_mmap(3)

💖 zzip_disk_mmap(3) — zziplib Function List 💖

okay bestie, buckle up, this is the one where you take a plain old filehandle and turn it into a whole mmapped zip disk archive handle ✨ it's giving main character energy for real.

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🌸 NAME 🌸

zzip_disk_mmap, zzip_disk_init, zzip_disk_new, zzip_disk_munmap, zzip_disk_open, zzip_disk_buffer, zzip_disk_close — turn a filehandle into a mmapped zip disk archive handle 🫶

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✨ SYNOPSIS ✨

#include <zzip/mmapped.h>

zzip__new__ ZZIP_DISK *
zzip_disk_mmap(int fd)

int
zzip_disk_init(ZZIP_DISK * disk, void *buffer, zzip_size_t buflen)

zzip__new__ ZZIP_DISK *
zzip_disk_new(void)

int
zzip_disk_munmap(ZZIP_DISK * disk)

zzip__new__ ZZIP_DISK *
zzip_disk_open(char *filename)

zzip__new__ ZZIP_DISK *
zzip_disk_buffer(void *buffer, size_t buflen)
int
zzip_disk_close(ZZIP_DISK * disk)

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💅 DESCRIPTION 💅

So zzip_disk_mmap takes the file-descriptor you hand it, peeks at how long the file actually is, and then calls the system mmap(2) to yeet it into main memory. And if that works? Congrats babes 🎀 you get a brand-new allocated ZZIP_DISK* back, with disk->buffer pointing right at the mapview of the zipdisk content. iconic.

And just so we're clear — zzip_disk_mmap may return null on errors (errno). that's the vibe check.

The zzip_disk_init function does primary initialization of a disk-buffer struct. that's it, that's the job 💜

And zzip_disk_init always returns 0 as success. always. no drama, no notes.

The zzip_disk_new function allocates a new disk-buffer with malloc(3) 🌈

The zzip_disk_new function may return null on errors (errno). 😭

The zzip_disk_munmap function is the inverse of zzip_disk_mmap — it uses the system munmap(2) on the buffer area and free(3) on the ZZIP_DISK structure. it's the breakup era, everything gets released ✨

The zzip_disk_open function opens the given archive by name and turns the filehandle over to zzip_disk_mmap to bring it into main memory. And if it can't be mmap(2)'ed? no worries, we slurp the whole file into a newly malloc(2)'ed memory block instead 🍓 only if that fails too do we return null. fr fr, two chances.

⚠️ lowkey important: since handling of disk->buffer is ambiguous it should not be snatched away please. hands off, bestie 🙈

And yes — zzip_disk_open may return null on errors (errno).

The zzip_disk_buffer function will attach a buffer with a zip image that was acquired from another source than a file. And heads up: if zzip_disk_mmap fails then zzip_disk_open will fall back and try to read the full file to memory, wrapping a ZZIP_DISK around the memory buffer — just as the zzip_disk_buffer function will do. 🦋

💀 another one: the zzip_disk_buffer function will not own the buffer — it will neither be written nor free()d. not your buffer, not your problem, don't touch it.

The zzip_disk_buffer function may return null (errno).

The zzip_disk_close function will release all data needed to access a (mmapped) zip archive, including any malloc()ed blocks, sharedmem mappings — and it dumps the handle struct as well. full cleanup, no crumbs left behind 👑

And zzip_disk_close returns 0 on success (or whatever munmap says). periodt.

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👑 AUTHOR 👑

Guido Draheim <guidod@gmx.de>

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🎀 COPYRIGHT 🎀

Copyright (c)Guido Draheim, use under copyleft (LGPL,MPL)

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okay that's the whole page bestie, and this was the zziplib 0.13.72 era of zzip_disk_mmap(3) — mwah, go mmap something and slay 💖✨🦋