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51 lines
1.6 KiB
51 lines
1.6 KiB
-- https://stackoverflow.com/questions/19539408/error-when-decoding-base-64-to-blob
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CREATE OR REPLACE FUNCTION base64_decode(p_content CLOB) RETURN BLOB
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IS
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C_CHUNK_SIZE CONSTANT INTEGER := 4000; -- should be a multiple of 4
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C_NON_BASE64_SYM_PATTERN CONSTANT VARCHAR2(20) := '[^A-Za-z0-9+/]';
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l_chunk_buf VARCHAR2(4000);
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l_chunk_b64_buf RAW(3000);
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l_chunk_offset INTEGER := 1;
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l_chunk_size INTEGER;
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l_res BLOB;
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FUNCTION get_next_full_base64_chunk(l_data CLOB, p_cur_pos IN OUT INTEGER, p_desired_size INTEGER, p_cur_size IN OUT INTEGER) RETURN VARCHAR2 IS
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l_res VARCHAR2(4000);
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l_tail_desired_size INTEGER;
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BEGIN
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l_res := dbms_lob.substr(l_data, p_desired_size, p_cur_pos);
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p_cur_pos := p_cur_pos + p_desired_size;
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IF l_res IS NULL THEN
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RETURN NULL;
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END IF;
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l_res := regexp_replace(l_res, C_NON_BASE64_SYM_PATTERN, '');
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p_cur_size := p_cur_size + length(l_res);
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l_tail_desired_size := 4 - mod(p_cur_size, 4);
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IF l_tail_desired_size = 4 THEN
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RETURN l_res;
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ELSE
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RETURN l_res || get_next_full_base64_chunk(l_data, p_cur_pos, l_tail_desired_size, p_cur_size);
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END IF;
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END;
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BEGIN
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dbms_lob.createtemporary(l_res, false);
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WHILE true
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LOOP
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l_chunk_size := 0;
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l_chunk_buf := get_next_full_base64_chunk(p_content, l_chunk_offset, C_CHUNK_SIZE, l_chunk_size);
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EXIT WHEN l_chunk_buf IS NULL;
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l_chunk_b64_buf := utl_encode.base64_decode(utl_raw.cast_to_raw(l_chunk_buf));
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dbms_lob.writeappend(l_res, utl_raw.length(l_chunk_b64_buf), l_chunk_b64_buf);
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END LOOP;
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RETURN l_res;
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END;
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/
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DECLARE
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l_clob CLOB;
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BEGIN
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