media/libmkv/EbmlBufferWriter.c@97036ab72558 (annotated)
media/libmkv/EbmlBufferWriter.c
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
| michael@0 | 1 | // #include <strmif.h> |
| michael@0 | 2 | #include "EbmlBufferWriter.h" |
| michael@0 | 3 | #include "EbmlWriter.h" |
| michael@0 | 4 | // #include <cassert> |
| michael@0 | 5 | // #include <limits> |
| michael@0 | 6 | // #include <malloc.h> //_alloca |
| michael@0 | 7 | #include <stdlib.h> |
| michael@0 | 8 | #include <wchar.h> |
| michael@0 | 9 | #include <string.h> |
| michael@0 | 10 | |
| michael@0 | 11 | void |
| michael@0 | 12 | Ebml_Serialize(EbmlGlobal *glob, const void *buffer_in, int buffer_size, unsigned long len) |
| michael@0 | 13 | { |
| michael@0 | 14 | /* buffer_size: |
| michael@0 | 15 | * 1 - int8_t; |
| michael@0 | 16 | * 2 - int16_t; |
| michael@0 | 17 | * 3 - int32_t; |
| michael@0 | 18 | * 4 - int64_t; |
| michael@0 | 19 | */ |
| michael@0 | 20 | long i; |
| michael@0 | 21 | for(i = len-1; i >= 0; i--) { |
| michael@0 | 22 | unsigned char x; |
| michael@0 | 23 | if (buffer_size == 1) { |
| michael@0 | 24 | x = (char)(*(const int8_t *)buffer_in >> (i * 8)); |
| michael@0 | 25 | } else if (buffer_size == 2) { |
| michael@0 | 26 | x = (char)(*(const int16_t *)buffer_in >> (i * 8)); |
| michael@0 | 27 | } else if (buffer_size == 4) { |
| michael@0 | 28 | x = (char)(*(const int32_t *)buffer_in >> (i * 8)); |
| michael@0 | 29 | } else if (buffer_size == 8) { |
| michael@0 | 30 | x = (char)(*(const int64_t *)buffer_in >> (i * 8)); |
| michael@0 | 31 | } |
| michael@0 | 32 | Ebml_Write(glob, &x, 1); |
| michael@0 | 33 | } |
| michael@0 | 34 | } |
| michael@0 | 35 | |
| michael@0 | 36 | void Ebml_Write(EbmlGlobal *glob, const void *buffer_in, unsigned long len) { |
| michael@0 | 37 | unsigned char *src = glob->buf; |
| michael@0 | 38 | src += glob->offset; |
| michael@0 | 39 | memcpy(src, buffer_in, len); |
| michael@0 | 40 | glob->offset += len; |
| michael@0 | 41 | } |
| michael@0 | 42 | |
| michael@0 | 43 | static void _Serialize(EbmlGlobal *glob, const unsigned char *p, const unsigned char *q) { |
| michael@0 | 44 | while (q != p) { |
| michael@0 | 45 | --q; |
| michael@0 | 46 | |
| michael@0 | 47 | memcpy(&(glob->buf[glob->offset]), q, 1); |
| michael@0 | 48 | glob->offset++; |
| michael@0 | 49 | } |
| michael@0 | 50 | } |
| michael@0 | 51 | |
| michael@0 | 52 | /* |
| michael@0 | 53 | void Ebml_Serialize(EbmlGlobal *glob, const void *buffer_in, unsigned long len) { |
| michael@0 | 54 | // assert(buf); |
| michael@0 | 55 | |
| michael@0 | 56 | const unsigned char *const p = (const unsigned char *)(buffer_in); |
| michael@0 | 57 | const unsigned char *const q = p + len; |
| michael@0 | 58 | |
| michael@0 | 59 | _Serialize(glob, p, q); |
| michael@0 | 60 | } |
| michael@0 | 61 | */ |
| michael@0 | 62 | |
| michael@0 | 63 | void Ebml_StartSubElement(EbmlGlobal *glob, EbmlLoc *ebmlLoc, unsigned long class_id) { |
| michael@0 | 64 | unsigned long long unknownLen = 0x01FFFFFFFFFFFFFFLL; |
| michael@0 | 65 | Ebml_WriteID(glob, class_id); |
| michael@0 | 66 | ebmlLoc->offset = glob->offset; |
| michael@0 | 67 | // todo this is always taking 8 bytes, this may need later optimization |
| michael@0 | 68 | Ebml_Serialize(glob, (void *)&unknownLen,sizeof(unknownLen), 8); // this is a key that says lenght unknown |
| michael@0 | 69 | } |
| michael@0 | 70 | |
| michael@0 | 71 | void Ebml_EndSubElement(EbmlGlobal *glob, EbmlLoc *ebmlLoc) { |
| michael@0 | 72 | unsigned long long size = glob->offset - ebmlLoc->offset - 8; |
| michael@0 | 73 | unsigned long long curOffset = glob->offset; |
| michael@0 | 74 | glob->offset = ebmlLoc->offset; |
| michael@0 | 75 | size |= 0x0100000000000000LL; |
| michael@0 | 76 | Ebml_Serialize(glob, &size,sizeof(size), 8); |
| michael@0 | 77 | glob->offset = curOffset; |
| michael@0 | 78 | } |
| michael@0 | 79 |
