Mesen/SevenZip/7zStream.c

172 lines
3.9 KiB
C

/* 7zStream.c -- 7z Stream functions
2013-11-12 : Igor Pavlov : Public domain */
#include "Precomp.h"
#include <string.h>
#include "7zTypes.h"
SRes SeqInStream_Read2(ISeqInStream *stream, void *buf, size_t size, SRes errorType)
{
while (size != 0)
{
size_t processed = size;
RINOK(stream->Read(stream, buf, &processed));
if (processed == 0)
return errorType;
buf = (void *)((Byte *)buf + processed);
size -= processed;
}
return SZ_OK;
}
SRes SeqInStream_Read(ISeqInStream *stream, void *buf, size_t size)
{
return SeqInStream_Read2(stream, buf, size, SZ_ERROR_INPUT_EOF);
}
SRes SeqInStream_ReadByte(ISeqInStream *stream, Byte *buf)
{
size_t processed = 1;
RINOK(stream->Read(stream, buf, &processed));
return (processed == 1) ? SZ_OK : SZ_ERROR_INPUT_EOF;
}
SRes LookInStream_SeekTo(ILookInStream *stream, UInt64 offset)
{
Int64 t = offset;
return stream->Seek(stream, &t, SZ_SEEK_SET);
}
SRes LookInStream_LookRead(ILookInStream *stream, void *buf, size_t *size)
{
const void *lookBuf;
if (*size == 0)
return SZ_OK;
RINOK(stream->Look(stream, &lookBuf, size));
memcpy(buf, lookBuf, *size);
return stream->Skip(stream, *size);
}
SRes LookInStream_Read2(ILookInStream *stream, void *buf, size_t size, SRes errorType)
{
while (size != 0)
{
size_t processed = size;
RINOK(stream->Read(stream, buf, &processed));
if (processed == 0)
return errorType;
buf = (void *)((Byte *)buf + processed);
size -= processed;
}
return SZ_OK;
}
SRes LookInStream_Read(ILookInStream *stream, void *buf, size_t size)
{
return LookInStream_Read2(stream, buf, size, SZ_ERROR_INPUT_EOF);
}
static SRes LookToRead_Look_Lookahead(void *pp, const void **buf, size_t *size)
{
SRes res = SZ_OK;
CLookToRead *p = (CLookToRead *)pp;
size_t size2 = p->size - p->pos;
if (size2 == 0 && *size > 0)
{
p->pos = 0;
size2 = LookToRead_BUF_SIZE;
res = p->realStream->Read(p->realStream, p->buf, &size2);
p->size = size2;
}
if (size2 < *size)
*size = size2;
*buf = p->buf + p->pos;
return res;
}
static SRes LookToRead_Look_Exact(void *pp, const void **buf, size_t *size)
{
SRes res = SZ_OK;
CLookToRead *p = (CLookToRead *)pp;
size_t size2 = p->size - p->pos;
if (size2 == 0 && *size > 0)
{
p->pos = 0;
if (*size > LookToRead_BUF_SIZE)
*size = LookToRead_BUF_SIZE;
res = p->realStream->Read(p->realStream, p->buf, size);
size2 = p->size = *size;
}
if (size2 < *size)
*size = size2;
*buf = p->buf + p->pos;
return res;
}
static SRes LookToRead_Skip(void *pp, size_t offset)
{
CLookToRead *p = (CLookToRead *)pp;
p->pos += offset;
return SZ_OK;
}
static SRes LookToRead_Read(void *pp, void *buf, size_t *size)
{
CLookToRead *p = (CLookToRead *)pp;
size_t rem = p->size - p->pos;
if (rem == 0)
return p->realStream->Read(p->realStream, buf, size);
if (rem > *size)
rem = *size;
memcpy(buf, p->buf + p->pos, rem);
p->pos += rem;
*size = rem;
return SZ_OK;
}
static SRes LookToRead_Seek(void *pp, Int64 *pos, ESzSeek origin)
{
CLookToRead *p = (CLookToRead *)pp;
p->pos = p->size = 0;
return p->realStream->Seek(p->realStream, pos, origin);
}
void LookToRead_CreateVTable(CLookToRead *p, int lookahead)
{
p->s.Look = lookahead ?
LookToRead_Look_Lookahead :
LookToRead_Look_Exact;
p->s.Skip = LookToRead_Skip;
p->s.Read = LookToRead_Read;
p->s.Seek = LookToRead_Seek;
}
void LookToRead_Init(CLookToRead *p)
{
p->pos = p->size = 0;
}
static SRes SecToLook_Read(void *pp, void *buf, size_t *size)
{
CSecToLook *p = (CSecToLook *)pp;
return LookInStream_LookRead(p->realStream, buf, size);
}
void SecToLook_CreateVTable(CSecToLook *p)
{
p->s.Read = SecToLook_Read;
}
static SRes SecToRead_Read(void *pp, void *buf, size_t *size)
{
CSecToRead *p = (CSecToRead *)pp;
return p->realStream->Read(p->realStream, buf, size);
}
void SecToRead_CreateVTable(CSecToRead *p)
{
p->s.Read = SecToRead_Read;
}