7zStream.c revision baa3858d3f5d128a5c8466b700098109edcad5f2 
1/* 7zStream.c -- 7z Stream functions
22010-03-11 : Igor Pavlov : Public domain */
3
4#include <string.h>
5
6#include "Types.h"
7
8SRes SeqInStream_Read2(ISeqInStream *stream, void *buf, size_t size, SRes errorType)
9{
10  while (size != 0)
11  {
12    size_t processed = size;
13    RINOK(stream->Read(stream, buf, &processed));
14    if (processed == 0)
15      return errorType;
16    buf = (void *)((Byte *)buf + processed);
17    size -= processed;
18  }
19  return SZ_OK;
20}
21
22SRes SeqInStream_Read(ISeqInStream *stream, void *buf, size_t size)
23{
24  return SeqInStream_Read2(stream, buf, size, SZ_ERROR_INPUT_EOF);
25}
26
27SRes SeqInStream_ReadByte(ISeqInStream *stream, Byte *buf)
28{
29  size_t processed = 1;
30  RINOK(stream->Read(stream, buf, &processed));
31  return (processed == 1) ? SZ_OK : SZ_ERROR_INPUT_EOF;
32}
33
34SRes LookInStream_SeekTo(ILookInStream *stream, UInt64 offset)
35{
36  Int64 t = offset;
37  return stream->Seek(stream, &t, SZ_SEEK_SET);
38}
39
40SRes LookInStream_LookRead(ILookInStream *stream, void *buf, size_t *size)
41{
42  const void *lookBuf;
43  if (*size == 0)
44    return SZ_OK;
45  RINOK(stream->Look(stream, &lookBuf, size));
46  memcpy(buf, lookBuf, *size);
47  return stream->Skip(stream, *size);
48}
49
50SRes LookInStream_Read2(ILookInStream *stream, void *buf, size_t size, SRes errorType)
51{
52  while (size != 0)
53  {
54    size_t processed = size;
55    RINOK(stream->Read(stream, buf, &processed));
56    if (processed == 0)
57      return errorType;
58    buf = (void *)((Byte *)buf + processed);
59    size -= processed;
60  }
61  return SZ_OK;
62}
63
64SRes LookInStream_Read(ILookInStream *stream, void *buf, size_t size)
65{
66  return LookInStream_Read2(stream, buf, size, SZ_ERROR_INPUT_EOF);
67}
68
69static SRes LookToRead_Look_Lookahead(void *pp, const void **buf, size_t *size)
70{
71  SRes res = SZ_OK;
72  CLookToRead *p = (CLookToRead *)pp;
73  size_t size2 = p->size - p->pos;
74  if (size2 == 0 && *size > 0)
75  {
76    p->pos = 0;
77    size2 = LookToRead_BUF_SIZE;
78    res = p->realStream->Read(p->realStream, p->buf, &size2);
79    p->size = size2;
80  }
81  if (size2 < *size)
82    *size = size2;
83  *buf = p->buf + p->pos;
84  return res;
85}
86
87static SRes LookToRead_Look_Exact(void *pp, const void **buf, size_t *size)
88{
89  SRes res = SZ_OK;
90  CLookToRead *p = (CLookToRead *)pp;
91  size_t size2 = p->size - p->pos;
92  if (size2 == 0 && *size > 0)
93  {
94    p->pos = 0;
95    if (*size > LookToRead_BUF_SIZE)
96      *size = LookToRead_BUF_SIZE;
97    res = p->realStream->Read(p->realStream, p->buf, size);
98    size2 = p->size = *size;
99  }
100  if (size2 < *size)
101    *size = size2;
102  *buf = p->buf + p->pos;
103  return res;
104}
105
106static SRes LookToRead_Skip(void *pp, size_t offset)
107{
108  CLookToRead *p = (CLookToRead *)pp;
109  p->pos += offset;
110  return SZ_OK;
111}
112
113static SRes LookToRead_Read(void *pp, void *buf, size_t *size)
114{
115  CLookToRead *p = (CLookToRead *)pp;
116  size_t rem = p->size - p->pos;
117  if (rem == 0)
118    return p->realStream->Read(p->realStream, buf, size);
119  if (rem > *size)
120    rem = *size;
121  memcpy(buf, p->buf + p->pos, rem);
122  p->pos += rem;
123  *size = rem;
124  return SZ_OK;
125}
126
127static SRes LookToRead_Seek(void *pp, Int64 *pos, ESzSeek origin)
128{
129  CLookToRead *p = (CLookToRead *)pp;
130  p->pos = p->size = 0;
131  return p->realStream->Seek(p->realStream, pos, origin);
132}
133
134void LookToRead_CreateVTable(CLookToRead *p, int lookahead)
135{
136  p->s.Look = lookahead ?
137      LookToRead_Look_Lookahead :
138      LookToRead_Look_Exact;
139  p->s.Skip = LookToRead_Skip;
140  p->s.Read = LookToRead_Read;
141  p->s.Seek = LookToRead_Seek;
142}
143
144void LookToRead_Init(CLookToRead *p)
145{
146  p->pos = p->size = 0;
147}
148
149static SRes SecToLook_Read(void *pp, void *buf, size_t *size)
150{
151  CSecToLook *p = (CSecToLook *)pp;
152  return LookInStream_LookRead(p->realStream, buf, size);
153}
154
155void SecToLook_CreateVTable(CSecToLook *p)
156{
157  p->s.Read = SecToLook_Read;
158}
159
160static SRes SecToRead_Read(void *pp, void *buf, size_t *size)
161{
162  CSecToRead *p = (CSecToRead *)pp;
163  return p->realStream->Read(p->realStream, buf, size);
164}
165
166void SecToRead_CreateVTable(CSecToRead *p)
167{
168  p->s.Read = SecToRead_Read;
169}
170