54 lines
1.5 KiB
C++
54 lines
1.5 KiB
C++
|
#include "read.h"
|
||
|
|
|
||
|
|
|
||
|
|
/* helper macro to do a read, check error code and number of bytes read, and return from the function if necessary
|
||
|
|
has to be a macro because of the return */
|
||
|
|
|
||
|
|
#define NSAVI_READ(reader, buffer, size, bytes_read) { int ret = reader->Read(buffer, size, &bytes_read); if (ret) return ret; if (bytes_read != size) return READ_EOF; }
|
||
|
|
|
||
|
|
int nsavi::read_riff_chunk(nsavi::avi_reader *reader, nsavi::riff_chunk *chunk, uint32_t *out_bytes_read)
|
||
|
|
{
|
||
|
|
uint32_t total_bytes_read=0;
|
||
|
|
uint32_t bytes_read;
|
||
|
|
NSAVI_READ(reader, chunk, 8, bytes_read); // read id and size
|
||
|
|
total_bytes_read += bytes_read;
|
||
|
|
|
||
|
|
if (chunk->id == 'FFIR' || chunk->id == 'TSIL')
|
||
|
|
{
|
||
|
|
if (chunk->size < 4)
|
||
|
|
return READ_INVALID_DATA;
|
||
|
|
NSAVI_READ(reader, &chunk->type, 4, bytes_read);
|
||
|
|
total_bytes_read += bytes_read;
|
||
|
|
chunk->size -= 4;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
chunk->type = 0;
|
||
|
|
|
||
|
|
if (out_bytes_read)
|
||
|
|
*out_bytes_read = total_bytes_read;
|
||
|
|
return READ_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
// we pass riff_chunk instead of size
|
||
|
|
// to avoid any confusion about who is responsible for adding the padding byte
|
||
|
|
// (this function is responsible)
|
||
|
|
int nsavi::skip_chunk(nsavi::avi_reader *reader, const nsavi::riff_chunk *chunk, uint32_t *out_bytes_read)
|
||
|
|
{
|
||
|
|
uint32_t chunk_size = chunk->size;
|
||
|
|
if (chunk_size & 1)
|
||
|
|
{
|
||
|
|
chunk_size ++; // odd chunk sizes must be padded by one
|
||
|
|
if (chunk_size == 0) // check for overflow
|
||
|
|
return READ_INVALID_DATA;
|
||
|
|
}
|
||
|
|
|
||
|
|
int ret = reader->Skip(chunk_size);
|
||
|
|
if (ret)
|
||
|
|
return ret;
|
||
|
|
|
||
|
|
if (out_bytes_read)
|
||
|
|
*out_bytes_read = chunk_size;
|
||
|
|
return READ_OK;
|
||
|
|
}
|
||
|
|
|