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cc65/libsrc/apple2/readdir.c

91 lines
3.9 KiB
C

/*****************************************************************************/
/* */
/* readdir.c */
/* */
/* Read directory entry */
/* */
/* */
/* */
/* (C) 2005 Oliver Schmidt, <ol.sc@web.de> */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* warranty. In no event will the authors be held liable for any damages */
/* arising from the use of this software. */
/* */
/* Permission is granted to anyone to use this software for any purpose, */
/* including commercial applications, and to alter it and redistribute it */
/* freely, subject to the following restrictions: */
/* */
/* 1. The origin of this software must not be misrepresented; you must not */
/* claim that you wrote the original software. If you use this software */
/* in a product, an acknowledgment in the product documentation would be */
/* appreciated but is not required. */
/* 2. Altered source versions must be plainly marked as such, and must not */
/* be misrepresented as being the original software. */
/* 3. This notice may not be removed or altered from any source */
/* distribution. */
/* */
/*****************************************************************************/
#include <stddef.h>
#include <unistd.h>
#include <dirent.h>
#include "dir.h"
/*****************************************************************************/
/* Code */
/*****************************************************************************/
struct dirent* __fastcall__ readdir (register DIR* dir)
{
register unsigned char* entry;
/* Search for the next active directory entry */
do {
/* Read next directory block if necessary */
if (dir->current_entry == dir->entries_per_block) {
if (read (dir->fd,
dir->block.bytes,
sizeof (dir->block)) != sizeof (dir->block)) {
/* Just return failure as read() has */
/* set errno if (and only if) no EOF */
return NULL;
}
/* Start with first entry in next block */
dir->current_entry = 0;
}
/* Compute pointer to current entry */
entry = dir->block.content.entries +
dir->current_entry * dir->entry_length;
/* Switch to next entry */
++dir->current_entry;
} while (entry[0x00] == 0);
/* Move creation date/time to allow for next step below */
*(unsigned long*)&entry[0x1A] = *(unsigned long*)&entry[0x18];
/* Feature unsigned long access to EOF by extension from 3 to 4 bytes */
entry[0x18] = 0;
/* Move file type to allow for next step below */
entry[0x19] = entry[0x10];
/* Zero-terminate file name */
entry[0x01 + (entry[0x00] & 0x0F)] = 0;
/* Return success */
return (struct dirent*)&entry[0x01];
}