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rainmeter-studio/Installer/lzma/7zMemInStream.c

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/* 7zMemInStream.c -- Memory input stream
** 2012 - Birunthan Mohanathas
**
** This file is public domain.
*/
#include "7zMemInStream.h"
static SRes MemInStream_Look(void *pp, const void **buf, size_t *size)
{
CMemInStream *p = (CMemInStream *)pp;
size_t remaining = p->end - p->pos;
if (remaining == 0 && *size > 0)
{
// Restart stream.
p->pos = 0;
remaining = *size;
}
if (remaining < *size)
{
*size = remaining;
}
*buf = p->pos;
return SZ_OK;
}
static SRes MemInStream_Skip(void *pp, size_t offset)
{
CMemInStream *p = (CMemInStream *)pp;
p->pos += offset;
return SZ_OK;
}
static SRes MemInStream_Read(void *pp, void *buf, size_t *size)
{
CMemInStream *p = (CMemInStream *)pp;
size_t remaining = p->end - p->pos;
if (remaining == 0)
{
// End of stream.
*size = 0;
}
else
{
if (remaining > *size)
{
remaining = *size;
}
memcpy(buf, p->pos, remaining);
p->pos += remaining;
*size = remaining;
}
return SZ_OK;
}
static SRes MemInStream_Seek(void *pp, Int64 *pos, ESzSeek origin)
{
CMemInStream *p = (CMemInStream *)pp;
switch (origin)
{
case SZ_SEEK_SET: p->pos = p->begin + *pos; break;
case SZ_SEEK_CUR: p->pos += *pos; break;
case SZ_SEEK_END: p->pos = p->end - *pos; break;
default: return 1;
}
*pos = p->pos - p->begin;
return SZ_OK;
}
void MemInStream_Init(CMemInStream *p, const void *begin, size_t length)
{
p->begin = p->pos = (Byte *)begin;
p->end = p->begin + length;
p->s.Look = MemInStream_Look;
p->s.Skip = MemInStream_Skip;
p->s.Read = MemInStream_Read;
p->s.Seek = MemInStream_Seek;
}