Re: [sqlite] BLOB question
good idea!! i didn't think in this!!
On 23/02/07, Martin Jenkins <[EMAIL PROTECTED]> wrote:
Cesar Rodas wrote:
>while ( (n=fread(buff,Buffsize,1,file)) > 0)
>{
>if (i>0)
>*value = realloc(*value, (i+1) * Buffsize);
>memcpy(*value + (i * Buffsize), buff, Buffsize);
>*len += n;
>i++;
>}
An afterthought, why don't you just stat the file and malloc the right
sized buffer from the outset? Much easier.
Martin
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http://www.sf.net/projects/fastfs ( The Fast File System)
Mobile Phone: 595 961 974165
Phone: 595 21 645590
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Re: [sqlite] BLOB question
I would make your routine more like this. It avoids the needless buffer
shadowing you get by using fopen and also avoids unecessary mallocs.
I haven't tested the code, it just presents the method.
unsigned char *bp;
int fd;
long fsize;
fd = open(path, O_RDWR); /*Get handle to file.*/
if (fd < 0) return E_IO_COULDNT_OPEN;
fsize = lseek(fd, 0, SEEK_END); /*Gives file size.*/
madvise(bp, fsize, MADV_SEQUENTIAL); /*May make it run better.*/
/*Map file into local addressing space.*/
bp = mmap(NULL, fsize, PROT_READ, MAP_SHARED, fd, 0);
close(fd); /*Don't need the handle noe.*/
/*Place bind of bp to BLOB here usinjg sqlite3_bind_blob.*/
/**/
/*Execute SQL here using sqlite3_step.*/
/**/
/*Reset sql statement.*/
/**/
unmap(bp); /*Release file from local addressing space.*/
>
> uchar * value;
> char *query;
> long len;
>
> if ( LoadFileContent("file.jpeg",, ) != 0)
> exit();
>
> query = sqlite3_mprintf("INSERT INTO blob VALUES('%Q') ", value); /*
here i
> have a segmentation fault! */
>
Cesar Rodas wrote:
#define E_IO_COULDNT_OPEN - 1
#define E_IO_ERRO -2
#define uchar unsigned char *
int LoadFileContent(uchar *path, uchar ** value, long * len)
{
#define Buffsize 1024*4
int n;
long i=0;
FILE *file;
unsigned char buff[Buffsize];
if ( (file=fopen(path,"rb"))==0)
{
return E_IO_COULDNT_OPEN;
}
*value = malloc(Buffsize);
*len = 0;
fseek(file,0L,SEEK_SET);
while ( (n=fread(buff,Buffsize,1,file)) > 0)
{
if (i>0)
*value = realloc(*value, (i+1) * Buffsize);
memcpy(*value + (i * Buffsize), buff, Buffsize);
*len += n;
i++;
}
if (n==-1)
{
fclose(file);
return E_IO_ERRO;
}
fclose(file);
return 0;
}
uchar * value;
char *query;
long len;
if ( LoadFileContent("file.jpeg",, ) != 0)
exit();
query = sqlite3_mprintf("INSERT INTO blob VALUES('%Q') ", value); /* here i
have a segmentation fault! */
/** Here I compile in debug mode there segmentation
fault is
here */
sqlite3/printf.c LINE 608
for(i=n=0; (ch=escarg[i])!=0; i++){
escarg is NULL;
I know that is not an SQLite bug. I know that that is my fault.
Thanks.
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Re: [sqlite] BLOB question
Cesar Rodas wrote:
while ( (n=fread(buff,Buffsize,1,file)) > 0)
{
if (i>0)
*value = realloc(*value, (i+1) * Buffsize);
memcpy(*value + (i * Buffsize), buff, Buffsize);
*len += n;
i++;
}
An afterthought, why don't you just stat the file and malloc the right
sized buffer from the outset? Much easier.
Martin
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Re: [sqlite] BLOB question
Sorry I copy bad when I wanted to write "#define uchar unsigned char" but I did "#define uchar unsigned char *" On 23/02/07, Martin Jenkins <[EMAIL PROTECTED]> wrote: Cesar Rodas wrote: > #define uchar unsigned char * suggests it's a char but is in fact a pointer to a char so the signature of LoadFileContent is actually int LoadFileContent(unsigned char **path, unsigned char ***value, ... and that triggers my "three levels of indirection is usually an error" alarm. You want > #define uchar unsigned char /* no asterisk here */ or even better typedef unsigned char uchar; Martin - To unsubscribe, send email to [EMAIL PROTECTED] - -- Cesar Rodas http://www.sf.net/projects/pagerank (The PageRank made easy...) http://www.sf.net/projects/fastfs ( The Fast File System) Mobile Phone: 595 961 974165 Phone: 595 21 645590 [EMAIL PROTECTED] [EMAIL PROTECTED] - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] BLOB question
I found the answer!! http://www.sqlite.org/cvstrac/wiki?p=BlobExample
thanks for you help too Wesley
On 23/02/07, Cesar Rodas <[EMAIL PROTECTED]> wrote:
#define E_IO_COULDNT_OPEN - 1
#define E_IO_ERRO -2
#define uchar unsigned char *
int LoadFileContent(uchar *path, uchar ** value, long * len)
{
#define Buffsize 1024*4
int n;
long i=0;
FILE *file;
unsigned char buff[Buffsize];
if ( (file=fopen(path,"rb"))==0)
{
return E_IO_COULDNT_OPEN;
}
*value = malloc(Buffsize);
*len = 0;
fseek(file,0L,SEEK_SET);
while ( (n=fread(buff,Buffsize,1,file)) > 0)
{
if (i>0)
*value = realloc(*value, (i+1) * Buffsize);
memcpy(*value + (i * Buffsize), buff, Buffsize);
*len += n;
i++;
}
if (n==-1)
{
fclose(file);
return E_IO_ERRO;
}
fclose(file);
return 0;
}
uchar * value;
char *query;
long len;
if ( LoadFileContent("file.jpeg",, ) != 0)
exit();
query = sqlite3_mprintf("INSERT INTO blob VALUES('%Q') ", value); /* here
i have a segmentation fault! */
/** Here I compile in debug mode there segmentation fault
is here */
sqlite3/printf.c LINE 608
for(i=n=0; (ch=escarg[i])!=0; i++){
escarg is NULL;
I know that is not an SQLite bug. I know that that is my fault.
Thanks.
--
Cesar Rodas
http://www.sf.net/projects/pagerank (The PageRank made easy...)
http://www.sf.net/projects/fastfs ( The Fast File System)
Mobile Phone: 595 961 974165
Phone: 595 21 645590
[EMAIL PROTECTED]
[EMAIL PROTECTED]
--
Cesar Rodas
http://www.sf.net/projects/pagerank (The PageRank made easy...)
http://www.sf.net/projects/fastfs ( The Fast File System)
Mobile Phone: 595 961 974165
Phone: 595 21 645590
[EMAIL PROTECTED]
[EMAIL PROTECTED]
Re: [sqlite] BLOB question
Cesar Rodas wrote: > #define uchar unsigned char * suggests it's a char but is in fact a pointer to a char so the signature of LoadFileContent is actually int LoadFileContent(unsigned char **path, unsigned char ***value, ... and that triggers my "three levels of indirection is usually an error" alarm. You want > #define uchar unsigned char /* no asterisk here */ or even better typedef unsigned char uchar; Martin - To unsubscribe, send email to [EMAIL PROTECTED] -
Re: [sqlite] BLOB question
A couple of comments.
On Feb 23, 2007, at 3:03 PM, Cesar Rodas wrote:
while ( (n=fread(buff,Buffsize,1,file)) > 0)
{
if (i>0)
*value = realloc(*value, (i+1) * Buffsize);
memcpy(*value + (i * Buffsize), buff, Buffsize);
*len += n;
i++;
}
You are growing the array in size at each append. This is usually a
bad idea; it leads to n^2 complexity. The standard approach is to
double the buffer each time it fills up. This is 2*n complexity.
However, it's not your bug.
query = sqlite3_mprintf("INSERT INTO blob VALUES('%Q') ", value);
This segfaults because there is no null terminator on the value
string. The way SQLite3 reads 'value' is by scanning it until it
finds a '\0'. If there is no such character, it scans past the end of
the array, leading to the crash you are seeing.
A simple solution is to append this character to the end of the
string. However, it the file itself contains a '\0' character, this
will lead to the file being truncated in the database. A better
solution would be:
file_content = ... your loading code, allocated by malloc ...
file_length = ... length of the file ...;
query = "INSERT INTO blob VALUES(?);";
sqlite3_prepare_v2(db, query, -1, , );
sqlite3_bind_block(qhandle, 1, file_content, file_length, free);
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Re: [sqlite] BLOB question
#define E_IO_COULDNT_OPEN - 1
#define E_IO_ERRO -2
#define uchar unsigned char *
int LoadFileContent(uchar *path, uchar ** value, long * len)
{
#define Buffsize 1024*4
int n;
long i=0;
FILE *file;
unsigned char buff[Buffsize];
if ( (file=fopen(path,"rb"))==0)
{
return E_IO_COULDNT_OPEN;
}
*value = malloc(Buffsize);
*len = 0;
fseek(file,0L,SEEK_SET);
while ( (n=fread(buff,Buffsize,1,file)) > 0)
{
if (i>0)
*value = realloc(*value, (i+1) * Buffsize);
memcpy(*value + (i * Buffsize), buff, Buffsize);
*len += n;
i++;
}
if (n==-1)
{
fclose(file);
return E_IO_ERRO;
}
fclose(file);
return 0;
}
uchar * value;
char *query;
long len;
if ( LoadFileContent("file.jpeg",, ) != 0)
exit();
query = sqlite3_mprintf("INSERT INTO blob VALUES('%Q') ", value); /* here i
have a segmentation fault! */
/** Here I compile in debug mode there segmentation fault is
here */
sqlite3/printf.c LINE 608
for(i=n=0; (ch=escarg[i])!=0; i++){
escarg is NULL;
I know that is not an SQLite bug. I know that that is my fault.
Thanks.
--
Cesar Rodas
http://www.sf.net/projects/pagerank (The PageRank made easy...)
http://www.sf.net/projects/fastfs ( The Fast File System)
Mobile Phone: 595 961 974165
Phone: 595 21 645590
[EMAIL PROTECTED]
[EMAIL PROTECTED]
