</row>
<row>
<entry>
- <literal><function>pg_read_file(<parameter>filename</> <type>text</>, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</>)</function></literal>
+ <literal><function>pg_read_file(<parameter>filename</> <type>text</> [, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</>])</function></literal>
</entry>
<entry><type>text</type></entry>
<entry>Return the contents of a text file</entry>
</row>
+ <row>
+ <entry>
+ <literal><function>pg_read_binary_file(<parameter>filename</> <type>text</> [, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</>])</function></literal>
+ </entry>
+ <entry><type>bytea</type></entry>
+ <entry>Return the contents of a file</entry>
+ </row>
<row>
<entry>
<literal><function>pg_stat_file(<parameter>filename</> <type>text</>)</function></literal>
at the given <parameter>offset</>, returning at most <parameter>length</>
bytes (less if the end of file is reached first). If <parameter>offset</>
is negative, it is relative to the end of the file.
+ When <parameter>offset</> and <parameter>length</> parameters are omitted,
+ it returns the whole of the file.
+ The part of a file must be a valid text in the server encoding.
+ </para>
+
+ <indexterm>
+ <primary>pg_read_binary_file</primary>
+ </indexterm>
+ <para>
+ <function>pg_read_binary_file</> returns part of a file as like as
+ <function>pg_read_file</>, but the result is a bytea value.
+ One of the usages is to read a file in the specified encoding combined with
+ <function>convert_from</> function:
+<programlisting>
+SELECT convert_from(pg_read_binary_file('file_in_utf8.txt'), 'UTF8');
+</programlisting>
</para>
<indexterm>
/*
- * Read a section of a file, returning it as text
+ * Read a section of a file, returning it as bytea
+ *
+ * We read the whole of the file when bytes_to_read is nagative.
*/
-Datum
-pg_read_file(PG_FUNCTION_ARGS)
+static bytea *
+read_binary_file(text *filename_t, int64 seek_offset, int64 bytes_to_read)
{
- text *filename_t = PG_GETARG_TEXT_P(0);
- int64 seek_offset = PG_GETARG_INT64(1);
- int64 bytes_to_read = PG_GETARG_INT64(2);
- char *buf;
+ bytea *buf;
size_t nbytes;
FILE *file;
char *filename;
filename = convert_and_check_filename(filename_t);
+ if (bytes_to_read < 0)
+ {
+ if (seek_offset < 0)
+ bytes_to_read = -seek_offset;
+ else
+ {
+ struct stat fst;
+
+ if (stat(filename, &fst) < 0)
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not stat file \"%s\": %m", filename)));
+
+ bytes_to_read = fst.st_size - seek_offset;
+ }
+ }
+
+ /* not sure why anyone thought that int64 length was a good idea */
+ if (bytes_to_read > (MaxAllocSize - VARHDRSZ))
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("requested length too large")));
+
if ((file = AllocateFile(filename, PG_BINARY_R)) == NULL)
ereport(ERROR,
(errcode_for_file_access(),
(errcode_for_file_access(),
errmsg("could not seek in file \"%s\": %m", filename)));
- if (bytes_to_read < 0)
- ereport(ERROR,
- (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
- errmsg("requested length cannot be negative")));
-
- /* not sure why anyone thought that int64 length was a good idea */
- if (bytes_to_read > (MaxAllocSize - VARHDRSZ))
- ereport(ERROR,
- (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
- errmsg("requested length too large")));
-
- buf = palloc((Size) bytes_to_read + VARHDRSZ);
+ buf = (bytea *) palloc((Size) bytes_to_read + VARHDRSZ);
nbytes = fread(VARDATA(buf), 1, (size_t) bytes_to_read, file);
(errcode_for_file_access(),
errmsg("could not read file \"%s\": %m", filename)));
- /* Make sure the input is valid */
- pg_verifymbstr(VARDATA(buf), nbytes, false);
-
SET_VARSIZE(buf, nbytes + VARHDRSZ);
FreeFile(file);
pfree(filename);
- PG_RETURN_TEXT_P(buf);
+ return buf;
+}
+
+/*
+ * In addition to read_binary_file, verify whether the contents are encoded
+ * in the database encoding.
+ */
+static text *
+read_text_file(text *filename, int64 seek_offset, int64 bytes_to_read)
+{
+ bytea *buf = read_binary_file(filename, seek_offset, bytes_to_read);
+
+ /* Make sure the input is valid */
+ pg_verifymbstr(VARDATA(buf), VARSIZE(buf) - VARHDRSZ, false);
+
+ /* OK, we can cast it as text safely */
+ return (text *) buf;
+}
+
+/*
+ * Read a section of a file, returning it as text
+ */
+Datum
+pg_read_file(PG_FUNCTION_ARGS)
+{
+ text *filename_t = PG_GETARG_TEXT_P(0);
+ int64 seek_offset = PG_GETARG_INT64(1);
+ int64 bytes_to_read = PG_GETARG_INT64(2);
+
+ if (bytes_to_read < 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("requested length cannot be negative")));
+
+ PG_RETURN_TEXT_P(read_text_file(filename_t, seek_offset, bytes_to_read));
+}
+
+/*
+ * Read the whole of a file, returning it as text
+ */
+Datum
+pg_read_file_all(PG_FUNCTION_ARGS)
+{
+ text *filename_t = PG_GETARG_TEXT_P(0);
+
+ PG_RETURN_TEXT_P(read_text_file(filename_t, 0, -1));
+}
+
+/*
+ * Read a section of a file, returning it as bytea
+ */
+Datum
+pg_read_binary_file(PG_FUNCTION_ARGS)
+{
+ text *filename_t = PG_GETARG_TEXT_P(0);
+ int64 seek_offset = PG_GETARG_INT64(1);
+ int64 bytes_to_read = PG_GETARG_INT64(2);
+
+ if (bytes_to_read < 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("requested length cannot be negative")));
+
+ PG_RETURN_BYTEA_P(read_binary_file(filename_t, seek_offset, bytes_to_read));
+}
+
+/*
+ * Read the whole of a file, returning it as bytea
+ */
+Datum
+pg_read_binary_file_all(PG_FUNCTION_ARGS)
+{
+ text *filename_t = PG_GETARG_TEXT_P(0);
+
+ PG_RETURN_BYTEA_P(read_binary_file(filename_t, 0, -1));
}
/*
projects / users / hanada / postgres.git / commitdiff