copyfromparse.c

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/*-------------------------------------------------------------------------
 *
 * copyfromparse.c
 *      Parse CSV/text/binary format for COPY FROM.
 *
 * This file contains routines to parse the text, CSV and binary input
 * formats.  The main entry point is NextCopyFrom(), which parses the
 * next input line and returns it as Datums.
 *
 * In text/CSV mode, the parsing happens in multiple stages:
 *
 * [data source] --> raw_buf --> input_buf --> line_buf --> attribute_buf
 *                1.          2.            3.           4.
 *
 * 1. CopyLoadRawBuf() reads raw data from the input file or client, and
 *    places it into 'raw_buf'.
 *
 * 2. CopyConvertBuf() calls the encoding conversion function to convert
 *    the data in 'raw_buf' from client to server encoding, placing the
 *    converted result in 'input_buf'.
 *
 * 3. CopyReadLine() parses the data in 'input_buf', one line at a time.
 *    It is responsible for finding the next newline marker, taking quote and
 *    escape characters into account according to the COPY options.  The line
 *    is copied into 'line_buf', with quotes and escape characters still
 *    intact.
 *
 * 4. CopyReadAttributesText/CSV() function takes the input line from
 *    'line_buf', and splits it into fields, unescaping the data as required.
 *    The fields are stored in 'attribute_buf', and 'raw_fields' array holds
 *    pointers to each field.
 *
 * If encoding conversion is not required, a shortcut is taken in step 2 to
 * avoid copying the data unnecessarily.  The 'input_buf' pointer is set to
 * point directly to 'raw_buf', so that CopyLoadRawBuf() loads the raw data
 * directly into 'input_buf'.  CopyConvertBuf() then merely validates that
 * the data is valid in the current encoding.
 *
 * In binary mode, the pipeline is much simpler.  Input is loaded into
 * 'raw_buf', and encoding conversion is done in the datatype-specific
 * receive functions, if required.  'input_buf' and 'line_buf' are not used,
 * but 'attribute_buf' is used as a temporary buffer to hold one attribute's
 * data when it's passed the receive function.
 *
 * 'raw_buf' is always 64 kB in size (RAW_BUF_SIZE).  'input_buf' is also
 * 64 kB (INPUT_BUF_SIZE), if encoding conversion is required.  'line_buf'
 * and 'attribute_buf' are expanded on demand, to hold the longest line
 * encountered so far.
 *
 * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/backend/commands/copyfromparse.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"
 
#include <ctype.h>
#include <unistd.h>
#include <sys/stat.h>
 
#include "commands/copy.h"
#include "commands/copyfrom_internal.h"
#include "commands/progress.h"
#include "executor/executor.h"
#include "libpq/libpq.h"
#include "libpq/pqformat.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "port/pg_bswap.h"
#include "utils/builtins.h"
#include "utils/memutils.h"
#include "utils/rel.h"
 
#define ISOCTAL(c) (((c) >= '0') && ((c) <= '7'))
#define OCTVALUE(c) ((c) - '0')
 
/*
 * These macros centralize code used to process line_buf and input_buf buffers.
 * They are macros because they often do continue/break control and to avoid
 * function call overhead in tight COPY loops.
 *
 * We must use "if (1)" because the usual "do {...} while(0)" wrapper would
 * prevent the continue/break processing from working.  We end the "if (1)"
 * with "else ((void) 0)" to ensure the "if" does not unintentionally match
 * any "else" in the calling code, and to avoid any compiler warnings about
 * empty statements.  See http://www.cit.gu.edu.au/~anthony/info/C/C.macros.
 */
 
/*
 * This keeps the character read at the top of the loop in the buffer
 * even if there is more than one read-ahead.
 */
#define IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(extralen) \
if (1) \
{ \
    if (input_buf_ptr + (extralen) >= copy_buf_len && !hit_eof) \
    { \
        input_buf_ptr = prev_raw_ptr; /* undo fetch */ \
        need_data = true; \
        continue; \
    } \
} else ((void) 0)
 
/* This consumes the remainder of the buffer and breaks */
#define IF_NEED_REFILL_AND_EOF_BREAK(extralen) \
if (1) \
{ \
    if (input_buf_ptr + (extralen) >= copy_buf_len && hit_eof) \
    { \
        if (extralen) \
            input_buf_ptr = copy_buf_len; /* consume the partial character */ \
        /* backslash just before EOF, treat as data char */ \
        result = true; \
        break; \
    } \
} else ((void) 0)
 
/*
 * Transfer any approved data to line_buf; must do this to be sure
 * there is some room in input_buf.
 */
#define REFILL_LINEBUF \
if (1) \
{ \
    if (input_buf_ptr > cstate->input_buf_index) \
    { \
        appendBinaryStringInfo(&cstate->line_buf, \
                             cstate->input_buf + cstate->input_buf_index, \
                               input_buf_ptr - cstate->input_buf_index); \
        cstate->input_buf_index = input_buf_ptr; \
    } \
} else ((void) 0)
 
/* Undo any read-ahead and jump out of the block. */
#define NO_END_OF_COPY_GOTO \
if (1) \
{ \
    input_buf_ptr = prev_raw_ptr + 1; \
    goto not_end_of_copy; \
} else ((void) 0)
 
/* NOTE: there's a copy of this in copyto.c */
static const char BinarySignature[11] = "PGCOPY\n\377\r\n\0";
 
 
/* non-export function prototypes */
static bool CopyReadLine(CopyFromState cstate);
static bool CopyReadLineText(CopyFromState cstate);
static int  CopyReadAttributesText(CopyFromState cstate);
static int  CopyReadAttributesCSV(CopyFromState cstate);
static Datum CopyReadBinaryAttribute(CopyFromState cstate, FmgrInfo *flinfo,
                                     Oid typioparam, int32 typmod,
                                     bool *isnull);
 
 
/* Low-level communications functions */
static int  CopyGetData(CopyFromState cstate, void *databuf,
                        int minread, int maxread);
static inline bool CopyGetInt32(CopyFromState cstate, int32 *val);
static inline bool CopyGetInt16(CopyFromState cstate, int16 *val);
static void CopyLoadInputBuf(CopyFromState cstate);
static int  CopyReadBinaryData(CopyFromState cstate, char *dest, int nbytes);
 
void
ReceiveCopyBegin(CopyFromState cstate)
{
    StringInfoData buf;
    int         natts = list_length(cstate->attnumlist);
    int16       format = (cstate->opts.binary ? 1 : 0);
    int         i;
 
    pq_beginmessage(&buf, 'G');
    pq_sendbyte(&buf, format);  /* overall format */
    pq_sendint16(&buf, natts);
    for (i = 0; i < natts; i++)
        pq_sendint16(&buf, format); /* per-column formats */
    pq_endmessage(&buf);
    cstate->copy_src = COPY_FRONTEND;
    cstate->fe_msgbuf = makeStringInfo();
    /* We *must* flush here to ensure FE knows it can send. */
    pq_flush();
}
 
void
ReceiveCopyBinaryHeader(CopyFromState cstate)
{
    char        readSig[11];
    int32       tmp;
 
    /* Signature */
    if (CopyReadBinaryData(cstate, readSig, 11) != 11 ||
        memcmp(readSig, BinarySignature, 11) != 0)
        ereport(ERROR,
                (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                 errmsg("COPY file signature not recognized")));
    /* Flags field */
    if (!CopyGetInt32(cstate, &tmp))
        ereport(ERROR,
                (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                 errmsg("invalid COPY file header (missing flags)")));
    if ((tmp & (1 << 16)) != 0)
        ereport(ERROR,
                (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                 errmsg("invalid COPY file header (WITH OIDS)")));
    tmp &= ~(1 << 16);
    if ((tmp >> 16) != 0)
        ereport(ERROR,
                (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                 errmsg("unrecognized critical flags in COPY file header")));
    /* Header extension length */
    if (!CopyGetInt32(cstate, &tmp) ||
        tmp < 0)
        ereport(ERROR,
                (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                 errmsg("invalid COPY file header (missing length)")));
    /* Skip extension header, if present */
    while (tmp-- > 0)
    {
        if (CopyReadBinaryData(cstate, readSig, 1) != 1)
            ereport(ERROR,
                    (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                     errmsg("invalid COPY file header (wrong length)")));
    }
}
 
/*
 * CopyGetData reads data from the source (file or frontend)
 *
 * We attempt to read at least minread, and at most maxread, bytes from
 * the source.  The actual number of bytes read is returned; if this is
 * less than minread, EOF was detected.
 *
 * Note: when copying from the frontend, we expect a proper EOF mark per
 * protocol; if the frontend simply drops the connection, we raise error.
 * It seems unwise to allow the COPY IN to complete normally in that case.
 *
 * NB: no data conversion is applied here.
 */
static int
CopyGetData(CopyFromState cstate, void *databuf, int minread, int maxread)
{
    int         bytesread = 0;
 
    switch (cstate->copy_src)
    {
        case COPY_FILE:
            bytesread = fread(databuf, 1, maxread, cstate->copy_file);
            if (ferror(cstate->copy_file))
                ereport(ERROR,
                        (errcode_for_file_access(),
                         errmsg("could not read from COPY file: %m")));
            if (bytesread == 0)
                cstate->raw_reached_eof = true;
            break;
        case COPY_FRONTEND:
            while (maxread > 0 && bytesread < minread && !cstate->raw_reached_eof)
            {
                int         avail;
 
                while (cstate->fe_msgbuf->cursor >= cstate->fe_msgbuf->len)
                {
                    /* Try to receive another message */
                    int         mtype;
                    int         maxmsglen;
 
            readmessage:
                    HOLD_CANCEL_INTERRUPTS();
                    pq_startmsgread();
                    mtype = pq_getbyte();
                    if (mtype == EOF)
                        ereport(ERROR,
                                (errcode(ERRCODE_CONNECTION_FAILURE),
                                 errmsg("unexpected EOF on client connection with an open transaction")));
                    /* Validate message type and set packet size limit */
                    switch (mtype)
                    {
                        case 'd':   /* CopyData */
                            maxmsglen = PQ_LARGE_MESSAGE_LIMIT;
                            break;
                        case 'c':   /* CopyDone */
                        case 'f':   /* CopyFail */
                        case 'H':   /* Flush */
                        case 'S':   /* Sync */
                            maxmsglen = PQ_SMALL_MESSAGE_LIMIT;
                            break;
                        default:
                            ereport(ERROR,
                                    (errcode(ERRCODE_PROTOCOL_VIOLATION),
                                     errmsg("unexpected message type 0x%02X during COPY from stdin",
                                            mtype)));
                            maxmsglen = 0;  /* keep compiler quiet */
                            break;
                    }
                    /* Now collect the message body */
                    if (pq_getmessage(cstate->fe_msgbuf, maxmsglen))
                        ereport(ERROR,
                                (errcode(ERRCODE_CONNECTION_FAILURE),
                                 errmsg("unexpected EOF on client connection with an open transaction")));
                    RESUME_CANCEL_INTERRUPTS();
                    /* ... and process it */
                    switch (mtype)
                    {
                        case 'd':   /* CopyData */
                            break;
                        case 'c':   /* CopyDone */
                            /* COPY IN correctly terminated by frontend */
                            cstate->raw_reached_eof = true;
                            return bytesread;
                        case 'f':   /* CopyFail */
                            ereport(ERROR,
                                    (errcode(ERRCODE_QUERY_CANCELED),
                                     errmsg("COPY from stdin failed: %s",
                                            pq_getmsgstring(cstate->fe_msgbuf))));
                            break;
                        case 'H':   /* Flush */
                        case 'S':   /* Sync */
 
                            /*
                             * Ignore Flush/Sync for the convenience of client
                             * libraries (such as libpq) that may send those
                             * without noticing that the command they just
                             * sent was COPY.
                             */
                            goto readmessage;
                        default:
                            Assert(false);  /* NOT REACHED */
                    }
                }
                avail = cstate->fe_msgbuf->len - cstate->fe_msgbuf->cursor;
                if (avail > maxread)
                    avail = maxread;
                pq_copymsgbytes(cstate->fe_msgbuf, databuf, avail);
                databuf = (void *) ((char *) databuf + avail);
                maxread -= avail;
                bytesread += avail;
            }
            break;
        case COPY_CALLBACK:
            bytesread = cstate->data_source_cb(databuf, minread, maxread);
            break;
    }
 
    return bytesread;
}
 
 
/*
 * These functions do apply some data conversion
 */
 
/*
 * CopyGetInt32 reads an int32 that appears in network byte order
 *
 * Returns true if OK, false if EOF
 */
static inline bool
CopyGetInt32(CopyFromState cstate, int32 *val)
{
    uint32      buf;
 
    if (CopyReadBinaryData(cstate, (char *) &buf, sizeof(buf)) != sizeof(buf))
    {
        *val = 0;               /* suppress compiler warning */
        return false;
    }
    *val = (int32) pg_ntoh32(buf);
    return true;
}
 
/*
 * CopyGetInt16 reads an int16 that appears in network byte order
 */
static inline bool
CopyGetInt16(CopyFromState cstate, int16 *val)
{
    uint16      buf;
 
    if (CopyReadBinaryData(cstate, (char *) &buf, sizeof(buf)) != sizeof(buf))
    {
        *val = 0;               /* suppress compiler warning */
        return false;
    }
    *val = (int16) pg_ntoh16(buf);
    return true;
}
 
 
/*
 * Perform encoding conversion on data in 'raw_buf', writing the converted
 * data into 'input_buf'.
 *
 * On entry, there must be some data to convert in 'raw_buf'.
 */
static void
CopyConvertBuf(CopyFromState cstate)
{
    /*
     * If the file and server encoding are the same, no encoding conversion is
     * required.  However, we still need to verify that the input is valid for
     * the encoding.
     */
    if (!cstate->need_transcoding)
    {
        /*
         * When conversion is not required, input_buf and raw_buf are the
         * same.  raw_buf_len is the total number of bytes in the buffer, and
         * input_buf_len tracks how many of those bytes have already been
         * verified.
         */
        int         preverifiedlen = cstate->input_buf_len;
        int         unverifiedlen = cstate->raw_buf_len - cstate->input_buf_len;
        int         nverified;
 
        if (unverifiedlen == 0)
        {
            /*
             * If no more raw data is coming, report the EOF to the caller.
             */
            if (cstate->raw_reached_eof)
                cstate->input_reached_eof = true;
            return;
        }
 
        /*
         * Verify the new data, including any residual unverified bytes from
         * previous round.
         */
        nverified = pg_encoding_verifymbstr(cstate->file_encoding,
                                            cstate->raw_buf + preverifiedlen,
                                            unverifiedlen);
        if (nverified == 0)
        {
            /*
             * Could not verify anything.
             *
             * If there is no more raw input data coming, it means that there
             * was an incomplete multi-byte sequence at the end.  Also, if
             * there's "enough" input left, we should be able to verify at
             * least one character, and a failure to do so means that we've
             * hit an invalid byte sequence.
             */
            if (cstate->raw_reached_eof || unverifiedlen >= pg_database_encoding_max_length())
                cstate->input_reached_error = true;
            return;
        }
        cstate->input_buf_len += nverified;
    }
    else
    {
        /*
         * Encoding conversion is needed.
         */
        int         nbytes;
        unsigned char *src;
        int         srclen;
        unsigned char *dst;
        int         dstlen;
        int         convertedlen;
 
        if (RAW_BUF_BYTES(cstate) == 0)
        {
            /*
             * If no more raw data is coming, report the EOF to the caller.
             */
            if (cstate->raw_reached_eof)
                cstate->input_reached_eof = true;
            return;
        }
 
        /*
         * First, copy down any unprocessed data.
         */
        nbytes = INPUT_BUF_BYTES(cstate);
        if (nbytes > 0 && cstate->input_buf_index > 0)
            memmove(cstate->input_buf, cstate->input_buf + cstate->input_buf_index,
                    nbytes);
        cstate->input_buf_index = 0;
        cstate->input_buf_len = nbytes;
        cstate->input_buf[nbytes] = '\0';
 
        src = (unsigned char *) cstate->raw_buf + cstate->raw_buf_index;
        srclen = cstate->raw_buf_len - cstate->raw_buf_index;
        dst = (unsigned char *) cstate->input_buf + cstate->input_buf_len;
        dstlen = INPUT_BUF_SIZE - cstate->input_buf_len + 1;
 
        /*
         * Do the conversion.  This might stop short, if there is an invalid
         * byte sequence in the input.  We'll convert as much as we can in
         * that case.
         *
         * Note: Even if we hit an invalid byte sequence, we don't report the
         * error until all the valid bytes have been consumed.  The input
         * might contain an end-of-input marker (\.), and we don't want to
         * report an error if the invalid byte sequence is after the
         * end-of-input marker.  We might unnecessarily convert some data
         * after the end-of-input marker as long as it's valid for the
         * encoding, but that's harmless.
         */
        convertedlen = pg_do_encoding_conversion_buf(cstate->conversion_proc,
                                                     cstate->file_encoding,
                                                     GetDatabaseEncoding(),
                                                     src, srclen,
                                                     dst, dstlen,
                                                     true);
        if (convertedlen == 0)
        {
            /*
             * Could not convert anything.  If there is no more raw input data
             * coming, it means that there was an incomplete multi-byte
             * sequence at the end.  Also, if there is plenty of input left,
             * we should be able to convert at least one character, so a
             * failure to do so must mean that we've hit a byte sequence
             * that's invalid.
             */
            if (cstate->raw_reached_eof || srclen >= MAX_CONVERSION_INPUT_LENGTH)
                cstate->input_reached_error = true;
            return;
        }
        cstate->raw_buf_index += convertedlen;
        cstate->input_buf_len += strlen((char *) dst);
    }
}
 
/*
 * Report an encoding or conversion error.
 */
static void
CopyConversionError(CopyFromState cstate)
{
    Assert(cstate->raw_buf_len > 0);
    Assert(cstate->input_reached_error);
 
    if (!cstate->need_transcoding)
    {
        /*
         * Everything up to input_buf_len was successfully verified, and
         * input_buf_len points to the invalid or incomplete character.
         */
        report_invalid_encoding(cstate->file_encoding,
                                cstate->raw_buf + cstate->input_buf_len,
                                cstate->raw_buf_len - cstate->input_buf_len);
    }
    else
    {
        /*
         * raw_buf_index points to the invalid or untranslatable character. We
         * let the conversion routine report the error, because it can provide
         * a more specific error message than we could here.  An earlier call
         * to the conversion routine in CopyConvertBuf() detected that there
         * is an error, now we call the conversion routine again with
         * noError=false, to have it throw the error.
         */
        unsigned char *src;
        int         srclen;
        unsigned char *dst;
        int         dstlen;
 
        src = (unsigned char *) cstate->raw_buf + cstate->raw_buf_index;
        srclen = cstate->raw_buf_len - cstate->raw_buf_index;
        dst = (unsigned char *) cstate->input_buf + cstate->input_buf_len;
        dstlen = INPUT_BUF_SIZE - cstate->input_buf_len + 1;
 
        (void) pg_do_encoding_conversion_buf(cstate->conversion_proc,
                                             cstate->file_encoding,
                                             GetDatabaseEncoding(),
                                             src, srclen,
                                             dst, dstlen,
                                             false);
 
        /*
         * The conversion routine should have reported an error, so this
         * should not be reached.
         */
        elog(ERROR, "encoding conversion failed without error");
    }
}
 
/*
 * Load more data from data source to raw_buf.
 *
 * If RAW_BUF_BYTES(cstate) > 0, the unprocessed bytes are moved to the
 * beginning of the buffer, and we load new data after that.
 */
static void
CopyLoadRawBuf(CopyFromState cstate)
{
    int         nbytes;
    int         inbytes;
 
    /*
     * In text mode, if encoding conversion is not required, raw_buf and
     * input_buf point to the same buffer.  Their len/index better agree, too.
     */
    if (cstate->raw_buf == cstate->input_buf)
    {
        Assert(!cstate->need_transcoding);
        Assert(cstate->raw_buf_index == cstate->input_buf_index);
        Assert(cstate->input_buf_len <= cstate->raw_buf_len);
    }
 
    /*
     * Copy down the unprocessed data if any.
     */
    nbytes = RAW_BUF_BYTES(cstate);
    if (nbytes > 0 && cstate->raw_buf_index > 0)
        memmove(cstate->raw_buf, cstate->raw_buf + cstate->raw_buf_index,
                nbytes);
    cstate->raw_buf_len -= cstate->raw_buf_index;
    cstate->raw_buf_index = 0;
 
    /*
     * If raw_buf and input_buf are in fact the same buffer, adjust the
     * input_buf variables, too.
     */
    if (cstate->raw_buf == cstate->input_buf)
    {
        cstate->input_buf_len -= cstate->input_buf_index;
        cstate->input_buf_index = 0;
    }
 
    /* Load more data */
    inbytes = CopyGetData(cstate, cstate->raw_buf + cstate->raw_buf_len,
                          1, RAW_BUF_SIZE - cstate->raw_buf_len);
    nbytes += inbytes;
    cstate->raw_buf[nbytes] = '\0';
    cstate->raw_buf_len = nbytes;
 
    cstate->bytes_processed += inbytes;
    pgstat_progress_update_param(PROGRESS_COPY_BYTES_PROCESSED, cstate->bytes_processed);
 
    if (inbytes == 0)
        cstate->raw_reached_eof = true;
}
 
/*
 * CopyLoadInputBuf loads some more data into input_buf
 *
 * On return, at least one more input character is loaded into
 * input_buf, or input_reached_eof is set.
 *
 * If INPUT_BUF_BYTES(cstate) > 0, the unprocessed bytes are moved to the start
 * of the buffer and then we load more data after that.
 */
static void
CopyLoadInputBuf(CopyFromState cstate)
{
    int         nbytes = INPUT_BUF_BYTES(cstate);
 
    /*
     * The caller has updated input_buf_index to indicate how much of the
     * input has been consumed and isn't needed anymore.  If input_buf is the
     * same physical area as raw_buf, update raw_buf_index accordingly.
     */
    if (cstate->raw_buf == cstate->input_buf)
    {
        Assert(!cstate->need_transcoding);
        Assert(cstate->input_buf_index >= cstate->raw_buf_index);
        cstate->raw_buf_index = cstate->input_buf_index;
    }
 
    for (;;)
    {
        /* If we now have some unconverted data, try to convert it */
        CopyConvertBuf(cstate);
 
        /* If we now have some more input bytes ready, return them */
        if (INPUT_BUF_BYTES(cstate) > nbytes)
            return;
 
        /*
         * If we reached an invalid byte sequence, or we're at an incomplete
         * multi-byte character but there is no more raw input data, report
         * conversion error.
         */
        if (cstate->input_reached_error)
            CopyConversionError(cstate);
 
        /* no more input, and everything has been converted */
        if (cstate->input_reached_eof)
            break;
 
        /* Try to load more raw data */
        Assert(!cstate->raw_reached_eof);
        CopyLoadRawBuf(cstate);
    }
}
 
/*
 * CopyReadBinaryData
 *
 * Reads up to 'nbytes' bytes from cstate->copy_file via cstate->raw_buf
 * and writes them to 'dest'.  Returns the number of bytes read (which
 * would be less than 'nbytes' only if we reach EOF).
 */
static int
CopyReadBinaryData(CopyFromState cstate, char *dest, int nbytes)
{
    int         copied_bytes = 0;
 
    if (RAW_BUF_BYTES(cstate) >= nbytes)
    {
        /* Enough bytes are present in the buffer. */
        memcpy(dest, cstate->raw_buf + cstate->raw_buf_index, nbytes);
        cstate->raw_buf_index += nbytes;
        copied_bytes = nbytes;
    }
    else
    {
        /*
         * Not enough bytes in the buffer, so must read from the file.  Need
         * to loop since 'nbytes' could be larger than the buffer size.
         */
        do
        {
            int         copy_bytes;
 
            /* Load more data if buffer is empty. */
            if (RAW_BUF_BYTES(cstate) == 0)
            {
                CopyLoadRawBuf(cstate);
                if (cstate->raw_reached_eof)
                    break;      /* EOF */
            }
 
            /* Transfer some bytes. */
            copy_bytes = Min(nbytes - copied_bytes, RAW_BUF_BYTES(cstate));
            memcpy(dest, cstate->raw_buf + cstate->raw_buf_index, copy_bytes);
            cstate->raw_buf_index += copy_bytes;
            dest += copy_bytes;
            copied_bytes += copy_bytes;
        } while (copied_bytes < nbytes);
    }
 
    return copied_bytes;
}
 
/*
 * Read raw fields in the next line for COPY FROM in text or csv mode.
 * Return false if no more lines.
 *
 * An internal temporary buffer is returned via 'fields'. It is valid until
 * the next call of the function. Since the function returns all raw fields
 * in the input file, 'nfields' could be different from the number of columns
 * in the relation.
 *
 * NOTE: force_not_null option are not applied to the returned fields.
 */
bool
NextCopyFromRawFields(CopyFromState cstate, char ***fields, int *nfields)
{
    int         fldct;
    bool        done;
 
    /* only available for text or csv input */
    Assert(!cstate->opts.binary);
 
    /* on input check that the header line is correct if needed */
    if (cstate->cur_lineno == 0 && cstate->opts.header_line)
    {
        ListCell   *cur;
        TupleDesc   tupDesc;
 
        tupDesc = RelationGetDescr(cstate->rel);
 
        cstate->cur_lineno++;
        done = CopyReadLine(cstate);
 
        if (cstate->opts.header_line == COPY_HEADER_MATCH)
        {
            int         fldnum;
 
            if (cstate->opts.csv_mode)
                fldct = CopyReadAttributesCSV(cstate);
            else
                fldct = CopyReadAttributesText(cstate);
 
            if (fldct != list_length(cstate->attnumlist))
                ereport(ERROR,
                        (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                         errmsg("wrong number of fields in header line: field count is %d, expected %d",
                                fldct, list_length(cstate->attnumlist))));
 
            fldnum = 0;
            foreach(cur, cstate->attnumlist)
            {
                int         attnum = lfirst_int(cur);
                char       *colName = cstate->raw_fields[attnum - 1];
                Form_pg_attribute attr = TupleDescAttr(tupDesc, attnum - 1);
 
                fldnum++;
 
                if (colName == NULL)
                    ereport(ERROR,
                            (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                             errmsg("column name mismatch in header line field %d: got null value (\"%s\"), expected \"%s\"",
                                    fldnum, cstate->opts.null_print, NameStr(attr->attname))));
 
                if (namestrcmp(&attr->attname, colName) != 0)
                {
                    ereport(ERROR,
                            (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                             errmsg("column name mismatch in header line field %d: got \"%s\", expected \"%s\"",
                                    fldnum, colName, NameStr(attr->attname))));
                }
            }
        }
 
        if (done)
            return false;
    }
 
    cstate->cur_lineno++;
 
    /* Actually read the line into memory here */
    done = CopyReadLine(cstate);
 
    /*
     * EOF at start of line means we're done.  If we see EOF after some
     * characters, we act as though it was newline followed by EOF, ie,
     * process the line and then exit loop on next iteration.
     */
    if (done && cstate->line_buf.len == 0)
        return false;
 
    /* Parse the line into de-escaped field values */
    if (cstate->opts.csv_mode)
        fldct = CopyReadAttributesCSV(cstate);
    else
        fldct = CopyReadAttributesText(cstate);
 
    *fields = cstate->raw_fields;
    *nfields = fldct;
    return true;
}
 
/*
 * Read next tuple from file for COPY FROM. Return false if no more tuples.
 *
 * 'econtext' is used to evaluate default expression for each columns not
 * read from the file. It can be NULL when no default values are used, i.e.
 * when all columns are read from the file.
 *
 * 'values' and 'nulls' arrays must be the same length as columns of the
 * relation passed to BeginCopyFrom. This function fills the arrays.
 */
bool
NextCopyFrom(CopyFromState cstate, ExprContext *econtext,
             Datum *values, bool *nulls)
{
    TupleDesc   tupDesc;
    AttrNumber  num_phys_attrs,
                attr_count,
                num_defaults = cstate->num_defaults;
    FmgrInfo   *in_functions = cstate->in_functions;
    Oid        *typioparams = cstate->typioparams;
    int         i;
    int        *defmap = cstate->defmap;
    ExprState **defexprs = cstate->defexprs;
 
    tupDesc = RelationGetDescr(cstate->rel);
    num_phys_attrs = tupDesc->natts;
    attr_count = list_length(cstate->attnumlist);
 
    /* Initialize all values for row to NULL */
    MemSet(values, 0, num_phys_attrs * sizeof(Datum));
    MemSet(nulls, true, num_phys_attrs * sizeof(bool));
 
    if (!cstate->opts.binary)
    {
        char      **field_strings;
        ListCell   *cur;
        int         fldct;
        int         fieldno;
        char       *string;
 
        /* read raw fields in the next line */
        if (!NextCopyFromRawFields(cstate, &field_strings, &fldct))
            return false;
 
        /* check for overflowing fields */
        if (attr_count > 0 && fldct > attr_count)
            ereport(ERROR,
                    (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                     errmsg("extra data after last expected column")));
 
        fieldno = 0;
 
        /* Loop to read the user attributes on the line. */
        foreach(cur, cstate->attnumlist)
        {
            int         attnum = lfirst_int(cur);
            int         m = attnum - 1;
            Form_pg_attribute att = TupleDescAttr(tupDesc, m);
 
            if (fieldno >= fldct)
                ereport(ERROR,
                        (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                         errmsg("missing data for column \"%s\"",
                                NameStr(att->attname))));
            string = field_strings[fieldno++];
 
            if (cstate->convert_select_flags &&
                !cstate->convert_select_flags[m])
            {
                /* ignore input field, leaving column as NULL */
                continue;
            }
 
            if (cstate->opts.csv_mode)
            {
                if (string == NULL &&
                    cstate->opts.force_notnull_flags[m])
                {
                    /*
                     * FORCE_NOT_NULL option is set and column is NULL -
                     * convert it to the NULL string.
                     */
                    string = cstate->opts.null_print;
                }
                else if (string != NULL && cstate->opts.force_null_flags[m]
                         && strcmp(string, cstate->opts.null_print) == 0)
                {
                    /*
                     * FORCE_NULL option is set and column matches the NULL
                     * string. It must have been quoted, or otherwise the
                     * string would already have been set to NULL. Convert it
                     * to NULL as specified.
                     */
                    string = NULL;
                }
            }
 
            cstate->cur_attname = NameStr(att->attname);
            cstate->cur_attval = string;
            values[m] = InputFunctionCall(&in_functions[m],
                                          string,
                                          typioparams[m],
                                          att->atttypmod);
            if (string != NULL)
                nulls[m] = false;
            cstate->cur_attname = NULL;
            cstate->cur_attval = NULL;
        }
 
        Assert(fieldno == attr_count);
    }
    else
    {
        /* binary */
        int16       fld_count;
        ListCell   *cur;
 
        cstate->cur_lineno++;
 
        if (!CopyGetInt16(cstate, &fld_count))
        {
            /* EOF detected (end of file, or protocol-level EOF) */
            return false;
        }
 
        if (fld_count == -1)
        {
            /*
             * Received EOF marker.  Wait for the protocol-level EOF, and
             * complain if it doesn't come immediately.  In COPY FROM STDIN,
             * this ensures that we correctly handle CopyFail, if client
             * chooses to send that now.  When copying from file, we could
             * ignore the rest of the file like in text mode, but we choose to
             * be consistent with the COPY FROM STDIN case.
             */
            char        dummy;
 
            if (CopyReadBinaryData(cstate, &dummy, 1) > 0)
                ereport(ERROR,
                        (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                         errmsg("received copy data after EOF marker")));
            return false;
        }
 
        if (fld_count != attr_count)
            ereport(ERROR,
                    (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                     errmsg("row field count is %d, expected %d",
                            (int) fld_count, attr_count)));
 
        foreach(cur, cstate->attnumlist)
        {
            int         attnum = lfirst_int(cur);
            int         m = attnum - 1;
            Form_pg_attribute att = TupleDescAttr(tupDesc, m);
 
            cstate->cur_attname = NameStr(att->attname);
            values[m] = CopyReadBinaryAttribute(cstate,
                                                &in_functions[m],
                                                typioparams[m],
                                                att->atttypmod,
                                                &nulls[m]);
            cstate->cur_attname = NULL;
        }
    }
 
    /*
     * Now compute and insert any defaults available for the columns not
     * provided by the input data.  Anything not processed here or above will
     * remain NULL.
     */
    for (i = 0; i < num_defaults; i++)
    {
        /*
         * The caller must supply econtext and have switched into the
         * per-tuple memory context in it.
         */
        Assert(econtext != NULL);
        Assert(CurrentMemoryContext == econtext->ecxt_per_tuple_memory);
 
        values[defmap[i]] = ExecEvalExpr(defexprs[i], econtext,
                                         &nulls[defmap[i]]);
    }
 
    return true;
}
 
/*
 * Read the next input line and stash it in line_buf.
 *
 * Result is true if read was terminated by EOF, false if terminated
 * by newline.  The terminating newline or EOF marker is not included
 * in the final value of line_buf.
 */
static bool
CopyReadLine(CopyFromState cstate)
{
    bool        result;
 
    resetStringInfo(&cstate->line_buf);
    cstate->line_buf_valid = false;
 
    /* Parse data and transfer into line_buf */
    result = CopyReadLineText(cstate);
 
    if (result)
    {
        /*
         * Reached EOF.  In protocol version 3, we should ignore anything
         * after \. up to the protocol end of copy data.  (XXX maybe better
         * not to treat \. as special?)
         */
        if (cstate->copy_src == COPY_FRONTEND)
        {
            int         inbytes;
 
            do
            {
                inbytes = CopyGetData(cstate, cstate->input_buf,
                                      1, INPUT_BUF_SIZE);
            } while (inbytes > 0);
            cstate->input_buf_index = 0;
            cstate->input_buf_len = 0;
            cstate->raw_buf_index = 0;
            cstate->raw_buf_len = 0;
        }
    }
    else
    {
        /*
         * If we didn't hit EOF, then we must have transferred the EOL marker
         * to line_buf along with the data.  Get rid of it.
         */
        switch (cstate->eol_type)
        {
            case EOL_NL:
                Assert(cstate->line_buf.len >= 1);
                Assert(cstate->line_buf.data[cstate->line_buf.len - 1] == '\n');
                cstate->line_buf.len--;
                cstate->line_buf.data[cstate->line_buf.len] = '\0';
                break;
            case EOL_CR:
                Assert(cstate->line_buf.len >= 1);
                Assert(cstate->line_buf.data[cstate->line_buf.len - 1] == '\r');
                cstate->line_buf.len--;
                cstate->line_buf.data[cstate->line_buf.len] = '\0';
                break;
            case EOL_CRNL:
                Assert(cstate->line_buf.len >= 2);
                Assert(cstate->line_buf.data[cstate->line_buf.len - 2] == '\r');
                Assert(cstate->line_buf.data[cstate->line_buf.len - 1] == '\n');
                cstate->line_buf.len -= 2;
                cstate->line_buf.data[cstate->line_buf.len] = '\0';
                break;
            case EOL_UNKNOWN:
                /* shouldn't get here */
                Assert(false);
                break;
        }
    }
 
    /* Now it's safe to use the buffer in error messages */
    cstate->line_buf_valid = true;
 
    return result;
}
 
/*
 * CopyReadLineText - inner loop of CopyReadLine for text mode
 */
static bool
CopyReadLineText(CopyFromState cstate)
{
    char       *copy_input_buf;
    int         input_buf_ptr;
    int         copy_buf_len;
    bool        need_data = false;
    bool        hit_eof = false;
    bool        result = false;
 
    /* CSV variables */
    bool        first_char_in_line = true;
    bool        in_quote = false,
                last_was_esc = false;
    char        quotec = '\0';
    char        escapec = '\0';
 
    if (cstate->opts.csv_mode)
    {
        quotec = cstate->opts.quote[0];
        escapec = cstate->opts.escape[0];
        /* ignore special escape processing if it's the same as quotec */
        if (quotec == escapec)
            escapec = '\0';
    }
 
    /*
     * The objective of this loop is to transfer the entire next input line
     * into line_buf.  Hence, we only care for detecting newlines (\r and/or
     * \n) and the end-of-copy marker (\.).
     *
     * In CSV mode, \r and \n inside a quoted field are just part of the data
     * value and are put in line_buf.  We keep just enough state to know if we
     * are currently in a quoted field or not.
     *
     * These four characters, and the CSV escape and quote characters, are
     * assumed the same in frontend and backend encodings.
     *
     * The input has already been converted to the database encoding.  All
     * supported server encodings have the property that all bytes in a
     * multi-byte sequence have the high bit set, so a multibyte character
     * cannot contain any newline or escape characters embedded in the
     * multibyte sequence.  Therefore, we can process the input byte-by-byte,
     * regardless of the encoding.
     *
     * For speed, we try to move data from input_buf to line_buf in chunks
     * rather than one character at a time.  input_buf_ptr points to the next
     * character to examine; any characters from input_buf_index to
     * input_buf_ptr have been determined to be part of the line, but not yet
     * transferred to line_buf.
     *
     * For a little extra speed within the loop, we copy input_buf and
     * input_buf_len into local variables.
     */
    copy_input_buf = cstate->input_buf;
    input_buf_ptr = cstate->input_buf_index;
    copy_buf_len = cstate->input_buf_len;
 
    for (;;)
    {
        int         prev_raw_ptr;
        char        c;
 
        /*
         * Load more data if needed.  Ideally we would just force four bytes
         * of read-ahead and avoid the many calls to
         * IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(), but the COPY_OLD_FE protocol
         * does not allow us to read too far ahead or we might read into the
         * next data, so we read-ahead only as far we know we can.  One
         * optimization would be to read-ahead four byte here if
         * cstate->copy_src != COPY_OLD_FE, but it hardly seems worth it,
         * considering the size of the buffer.
         */
        if (input_buf_ptr >= copy_buf_len || need_data)
        {
            REFILL_LINEBUF;
 
            CopyLoadInputBuf(cstate);
            /* update our local variables */
            hit_eof = cstate->input_reached_eof;
            input_buf_ptr = cstate->input_buf_index;
            copy_buf_len = cstate->input_buf_len;
 
            /*
             * If we are completely out of data, break out of the loop,
             * reporting EOF.
             */
            if (INPUT_BUF_BYTES(cstate) <= 0)
            {
                result = true;
                break;
            }
            need_data = false;
        }
 
        /* OK to fetch a character */
        prev_raw_ptr = input_buf_ptr;
        c = copy_input_buf[input_buf_ptr++];
 
        if (cstate->opts.csv_mode)
        {
            /*
             * If character is '\\' or '\r', we may need to look ahead below.
             * Force fetch of the next character if we don't already have it.
             * We need to do this before changing CSV state, in case one of
             * these characters is also the quote or escape character.
             *
             * Note: old-protocol does not like forced prefetch, but it's OK
             * here since we cannot validly be at EOF.
             */
            if (c == '\\' || c == '\r')
            {
                IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(0);
            }
 
            /*
             * Dealing with quotes and escapes here is mildly tricky. If the
             * quote char is also the escape char, there's no problem - we
             * just use the char as a toggle. If they are different, we need
             * to ensure that we only take account of an escape inside a
             * quoted field and immediately preceding a quote char, and not
             * the second in an escape-escape sequence.
             */
            if (in_quote && c == escapec)
                last_was_esc = !last_was_esc;
            if (c == quotec && !last_was_esc)
                in_quote = !in_quote;
            if (c != escapec)
                last_was_esc = false;
 
            /*
             * Updating the line count for embedded CR and/or LF chars is
             * necessarily a little fragile - this test is probably about the
             * best we can do.  (XXX it's arguable whether we should do this
             * at all --- is cur_lineno a physical or logical count?)
             */
            if (in_quote && c == (cstate->eol_type == EOL_NL ? '\n' : '\r'))
                cstate->cur_lineno++;
        }
 
        /* Process \r */
        if (c == '\r' && (!cstate->opts.csv_mode || !in_quote))
        {
            /* Check for \r\n on first line, _and_ handle \r\n. */
            if (cstate->eol_type == EOL_UNKNOWN ||
                cstate->eol_type == EOL_CRNL)
            {
                /*
                 * If need more data, go back to loop top to load it.
                 *
                 * Note that if we are at EOF, c will wind up as '\0' because
                 * of the guaranteed pad of input_buf.
                 */
                IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(0);
 
                /* get next char */
                c = copy_input_buf[input_buf_ptr];
 
                if (c == '\n')
                {
                    input_buf_ptr++;    /* eat newline */
                    cstate->eol_type = EOL_CRNL;    /* in case not set yet */
                }
                else
                {
                    /* found \r, but no \n */
                    if (cstate->eol_type == EOL_CRNL)
                        ereport(ERROR,
                                (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                                 !cstate->opts.csv_mode ?
                                 errmsg("literal carriage return found in data") :
                                 errmsg("unquoted carriage return found in data"),
                                 !cstate->opts.csv_mode ?
                                 errhint("Use \"\\r\" to represent carriage return.") :
                                 errhint("Use quoted CSV field to represent carriage return.")));
 
                    /*
                     * if we got here, it is the first line and we didn't find
                     * \n, so don't consume the peeked character
                     */
                    cstate->eol_type = EOL_CR;
                }
            }
            else if (cstate->eol_type == EOL_NL)
                ereport(ERROR,
                        (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                         !cstate->opts.csv_mode ?
                         errmsg("literal carriage return found in data") :
                         errmsg("unquoted carriage return found in data"),
                         !cstate->opts.csv_mode ?
                         errhint("Use \"\\r\" to represent carriage return.") :
                         errhint("Use quoted CSV field to represent carriage return.")));
            /* If reach here, we have found the line terminator */
            break;
        }
 
        /* Process \n */
        if (c == '\n' && (!cstate->opts.csv_mode || !in_quote))
        {
            if (cstate->eol_type == EOL_CR || cstate->eol_type == EOL_CRNL)
                ereport(ERROR,
                        (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                         !cstate->opts.csv_mode ?
                         errmsg("literal newline found in data") :
                         errmsg("unquoted newline found in data"),
                         !cstate->opts.csv_mode ?
                         errhint("Use \"\\n\" to represent newline.") :
                         errhint("Use quoted CSV field to represent newline.")));
            cstate->eol_type = EOL_NL;  /* in case not set yet */
            /* If reach here, we have found the line terminator */
            break;
        }
 
        /*
         * In CSV mode, we only recognize \. alone on a line.  This is because
         * \. is a valid CSV data value.
         */
        if (c == '\\' && (!cstate->opts.csv_mode || first_char_in_line))
        {
            char        c2;
 
            IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(0);
            IF_NEED_REFILL_AND_EOF_BREAK(0);
 
            /* -----
             * get next character
             * Note: we do not change c so if it isn't \., we can fall
             * through and continue processing.
             * -----
             */
            c2 = copy_input_buf[input_buf_ptr];
 
            if (c2 == '.')
            {
                input_buf_ptr++;    /* consume the '.' */
 
                /*
                 * Note: if we loop back for more data here, it does not
                 * matter that the CSV state change checks are re-executed; we
                 * will come back here with no important state changed.
                 */
                if (cstate->eol_type == EOL_CRNL)
                {
                    /* Get the next character */
                    IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(0);
                    /* if hit_eof, c2 will become '\0' */
                    c2 = copy_input_buf[input_buf_ptr++];
 
                    if (c2 == '\n')
                    {
                        if (!cstate->opts.csv_mode)
                            ereport(ERROR,
                                    (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                                     errmsg("end-of-copy marker does not match previous newline style")));
                        else
                            NO_END_OF_COPY_GOTO;
                    }
                    else if (c2 != '\r')
                    {
                        if (!cstate->opts.csv_mode)
                            ereport(ERROR,
                                    (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                                     errmsg("end-of-copy marker corrupt")));
                        else
                            NO_END_OF_COPY_GOTO;
                    }
                }
 
                /* Get the next character */
                IF_NEED_REFILL_AND_NOT_EOF_CONTINUE(0);
                /* if hit_eof, c2 will become '\0' */
                c2 = copy_input_buf[input_buf_ptr++];
 
                if (c2 != '\r' && c2 != '\n')
                {
                    if (!cstate->opts.csv_mode)
                        ereport(ERROR,
                                (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                                 errmsg("end-of-copy marker corrupt")));
                    else
                        NO_END_OF_COPY_GOTO;
                }
 
                if ((cstate->eol_type == EOL_NL && c2 != '\n') ||
                    (cstate->eol_type == EOL_CRNL && c2 != '\n') ||
                    (cstate->eol_type == EOL_CR && c2 != '\r'))
                {
                    ereport(ERROR,
                            (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                             errmsg("end-of-copy marker does not match previous newline style")));
                }
 
                /*
                 * Transfer only the data before the \. into line_buf, then
                 * discard the data and the \. sequence.
                 */
                if (prev_raw_ptr > cstate->input_buf_index)
                    appendBinaryStringInfo(&cstate->line_buf,
                                           cstate->input_buf + cstate->input_buf_index,
                                           prev_raw_ptr - cstate->input_buf_index);
                cstate->input_buf_index = input_buf_ptr;
                result = true;  /* report EOF */
                break;
            }
            else if (!cstate->opts.csv_mode)
            {
                /*
                 * If we are here, it means we found a backslash followed by
                 * something other than a period.  In non-CSV mode, anything
                 * after a backslash is special, so we skip over that second
                 * character too.  If we didn't do that \\. would be
                 * considered an eof-of copy, while in non-CSV mode it is a
                 * literal backslash followed by a period.  In CSV mode,
                 * backslashes are not special, so we want to process the
                 * character after the backslash just like a normal character,
                 * so we don't increment in those cases.
                 */
                input_buf_ptr++;
            }
        }
 
        /*
         * This label is for CSV cases where \. appears at the start of a
         * line, but there is more text after it, meaning it was a data value.
         * We are more strict for \. in CSV mode because \. could be a data
         * value, while in non-CSV mode, \. cannot be a data value.
         */
not_end_of_copy:
        first_char_in_line = false;
    }                           /* end of outer loop */
 
    /*
     * Transfer any still-uncopied data to line_buf.
     */
    REFILL_LINEBUF;
 
    return result;
}
 
/*
 *  Return decimal value for a hexadecimal digit
 */
static int
GetDecimalFromHex(char hex)
{
    if (isdigit((unsigned char) hex))
        return hex - '0';
    else
        return tolower((unsigned char) hex) - 'a' + 10;
}
 
/*
 * Parse the current line into separate attributes (fields),
 * performing de-escaping as needed.
 *
 * The input is in line_buf.  We use attribute_buf to hold the result
 * strings.  cstate->raw_fields[k] is set to point to the k'th attribute
 * string, or NULL when the input matches the null marker string.
 * This array is expanded as necessary.
 *
 * (Note that the caller cannot check for nulls since the returned
 * string would be the post-de-escaping equivalent, which may look
 * the same as some valid data string.)
 *
 * delim is the column delimiter string (must be just one byte for now).
 * null_print is the null marker string.  Note that this is compared to
 * the pre-de-escaped input string.
 *
 * The return value is the number of fields actually read.
 */
static int
CopyReadAttributesText(CopyFromState cstate)
{
    char        delimc = cstate->opts.delim[0];
    int         fieldno;
    char       *output_ptr;
    char       *cur_ptr;
    char       *line_end_ptr;
 
    /*
     * We need a special case for zero-column tables: check that the input
     * line is empty, and return.
     */
    if (cstate->max_fields <= 0)
    {
        if (cstate->line_buf.len != 0)
            ereport(ERROR,
                    (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                     errmsg("extra data after last expected column")));
        return 0;
    }
 
    resetStringInfo(&cstate->attribute_buf);
 
    /*
     * The de-escaped attributes will certainly not be longer than the input
     * data line, so we can just force attribute_buf to be large enough and
     * then transfer data without any checks for enough space.  We need to do
     * it this way because enlarging attribute_buf mid-stream would invalidate
     * pointers already stored into cstate->raw_fields[].
     */
    if (cstate->attribute_buf.maxlen <= cstate->line_buf.len)
        enlargeStringInfo(&cstate->attribute_buf, cstate->line_buf.len);
    output_ptr = cstate->attribute_buf.data;
 
    /* set pointer variables for loop */
    cur_ptr = cstate->line_buf.data;
    line_end_ptr = cstate->line_buf.data + cstate->line_buf.len;
 
    /* Outer loop iterates over fields */
    fieldno = 0;
    for (;;)
    {
        bool        found_delim = false;
        char       *start_ptr;
        char       *end_ptr;
        int         input_len;
        bool        saw_non_ascii = false;
 
        /* Make sure there is enough space for the next value */
        if (fieldno >= cstate->max_fields)
        {
            cstate->max_fields *= 2;
            cstate->raw_fields =
                repalloc(cstate->raw_fields, cstate->max_fields * sizeof(char *));
        }
 
        /* Remember start of field on both input and output sides */
        start_ptr = cur_ptr;
        cstate->raw_fields[fieldno] = output_ptr;
 
        /*
         * Scan data for field.
         *
         * Note that in this loop, we are scanning to locate the end of field
         * and also speculatively performing de-escaping.  Once we find the
         * end-of-field, we can match the raw field contents against the null
         * marker string.  Only after that comparison fails do we know that
         * de-escaping is actually the right thing to do; therefore we *must
         * not* throw any syntax errors before we've done the null-marker
         * check.
         */
        for (;;)
        {
            char        c;
 
            end_ptr = cur_ptr;
            if (cur_ptr >= line_end_ptr)
                break;
            c = *cur_ptr++;
            if (c == delimc)
            {
                found_delim = true;
                break;
            }
            if (c == '\\')
            {
                if (cur_ptr >= line_end_ptr)
                    break;
                c = *cur_ptr++;
                switch (c)
                {
                    case '0':
                    case '1':
                    case '2':
                    case '3':
                    case '4':
                    case '5':
                    case '6':
                    case '7':
                        {
                            /* handle \013 */
                            int         val;
 
                            val = OCTVALUE(c);
                            if (cur_ptr < line_end_ptr)
                            {
                                c = *cur_ptr;
                                if (ISOCTAL(c))
                                {
                                    cur_ptr++;
                                    val = (val << 3) + OCTVALUE(c);
                                    if (cur_ptr < line_end_ptr)
                                    {
                                        c = *cur_ptr;
                                        if (ISOCTAL(c))
                                        {
                                            cur_ptr++;
                                            val = (val << 3) + OCTVALUE(c);
                                        }
                                    }
                                }
                            }
                            c = val & 0377;
                            if (c == '\0' || IS_HIGHBIT_SET(c))
                                saw_non_ascii = true;
                        }
                        break;
                    case 'x':
                        /* Handle \x3F */
                        if (cur_ptr < line_end_ptr)
                        {
                            char        hexchar = *cur_ptr;
 
                            if (isxdigit((unsigned char) hexchar))
                            {
                                int         val = GetDecimalFromHex(hexchar);
 
                                cur_ptr++;
                                if (cur_ptr < line_end_ptr)
                                {
                                    hexchar = *cur_ptr;
                                    if (isxdigit((unsigned char) hexchar))
                                    {
                                        cur_ptr++;
                                        val = (val << 4) + GetDecimalFromHex(hexchar);
                                    }
                                }
                                c = val & 0xff;
                                if (c == '\0' || IS_HIGHBIT_SET(c))
                                    saw_non_ascii = true;
                            }
                        }
                        break;
                    case 'b':
                        c = '\b';
                        break;
                    case 'f':
                        c = '\f';
                        break;
                    case 'n':
                        c = '\n';
                        break;
                    case 'r':
                        c = '\r';
                        break;
                    case 't':
                        c = '\t';
                        break;
                    case 'v':
                        c = '\v';
                        break;
 
                        /*
                         * in all other cases, take the char after '\'
                         * literally
                         */
                }
            }
 
            /* Add c to output string */
            *output_ptr++ = c;
        }
 
        /* Check whether raw input matched null marker */
        input_len = end_ptr - start_ptr;
        if (input_len == cstate->opts.null_print_len &&
            strncmp(start_ptr, cstate->opts.null_print, input_len) == 0)
            cstate->raw_fields[fieldno] = NULL;
        else
        {
            /*
             * At this point we know the field is supposed to contain data.
             *
             * If we de-escaped any non-7-bit-ASCII chars, make sure the
             * resulting string is valid data for the db encoding.
             */
            if (saw_non_ascii)
            {
                char       *fld = cstate->raw_fields[fieldno];
 
                pg_verifymbstr(fld, output_ptr - fld, false);
            }
        }
 
        /* Terminate attribute value in output area */
        *output_ptr++ = '\0';
 
        fieldno++;
        /* Done if we hit EOL instead of a delim */
        if (!found_delim)
            break;
    }
 
    /* Clean up state of attribute_buf */
    output_ptr--;
    Assert(*output_ptr == '\0');
    cstate->attribute_buf.len = (output_ptr - cstate->attribute_buf.data);
 
    return fieldno;
}
 
/*
 * Parse the current line into separate attributes (fields),
 * performing de-escaping as needed.  This has exactly the same API as
 * CopyReadAttributesText, except we parse the fields according to
 * "standard" (i.e. common) CSV usage.
 */
static int
CopyReadAttributesCSV(CopyFromState cstate)
{
    char        delimc = cstate->opts.delim[0];
    char        quotec = cstate->opts.quote[0];
    char        escapec = cstate->opts.escape[0];
    int         fieldno;
    char       *output_ptr;
    char       *cur_ptr;
    char       *line_end_ptr;
 
    /*
     * We need a special case for zero-column tables: check that the input
     * line is empty, and return.
     */
    if (cstate->max_fields <= 0)
    {
        if (cstate->line_buf.len != 0)
            ereport(ERROR,
                    (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                     errmsg("extra data after last expected column")));
        return 0;
    }
 
    resetStringInfo(&cstate->attribute_buf);
 
    /*
     * The de-escaped attributes will certainly not be longer than the input
     * data line, so we can just force attribute_buf to be large enough and
     * then transfer data without any checks for enough space.  We need to do
     * it this way because enlarging attribute_buf mid-stream would invalidate
     * pointers already stored into cstate->raw_fields[].
     */
    if (cstate->attribute_buf.maxlen <= cstate->line_buf.len)
        enlargeStringInfo(&cstate->attribute_buf, cstate->line_buf.len);
    output_ptr = cstate->attribute_buf.data;
 
    /* set pointer variables for loop */
    cur_ptr = cstate->line_buf.data;
    line_end_ptr = cstate->line_buf.data + cstate->line_buf.len;
 
    /* Outer loop iterates over fields */
    fieldno = 0;
    for (;;)
    {
        bool        found_delim = false;
        bool        saw_quote = false;
        char       *start_ptr;
        char       *end_ptr;
        int         input_len;
 
        /* Make sure there is enough space for the next value */
        if (fieldno >= cstate->max_fields)
        {
            cstate->max_fields *= 2;
            cstate->raw_fields =
                repalloc(cstate->raw_fields, cstate->max_fields * sizeof(char *));
        }
 
        /* Remember start of field on both input and output sides */
        start_ptr = cur_ptr;
        cstate->raw_fields[fieldno] = output_ptr;
 
        /*
         * Scan data for field,
         *
         * The loop starts in "not quote" mode and then toggles between that
         * and "in quote" mode. The loop exits normally if it is in "not
         * quote" mode and a delimiter or line end is seen.
         */
        for (;;)
        {
            char        c;
 
            /* Not in quote */
            for (;;)
            {
                end_ptr = cur_ptr;
                if (cur_ptr >= line_end_ptr)
                    goto endfield;
                c = *cur_ptr++;
                /* unquoted field delimiter */
                if (c == delimc)
                {
                    found_delim = true;
                    goto endfield;
                }
                /* start of quoted field (or part of field) */
                if (c == quotec)
                {
                    saw_quote = true;
                    break;
                }
                /* Add c to output string */
                *output_ptr++ = c;
            }
 
            /* In quote */
            for (;;)
            {
                end_ptr = cur_ptr;
                if (cur_ptr >= line_end_ptr)
                    ereport(ERROR,
                            (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                             errmsg("unterminated CSV quoted field")));
 
                c = *cur_ptr++;
 
                /* escape within a quoted field */
                if (c == escapec)
                {
                    /*
                     * peek at the next char if available, and escape it if it
                     * is an escape char or a quote char
                     */
                    if (cur_ptr < line_end_ptr)
                    {
                        char        nextc = *cur_ptr;
 
                        if (nextc == escapec || nextc == quotec)
                        {
                            *output_ptr++ = nextc;
                            cur_ptr++;
                            continue;
                        }
                    }
                }
 
                /*
                 * end of quoted field. Must do this test after testing for
                 * escape in case quote char and escape char are the same
                 * (which is the common case).
                 */
                if (c == quotec)
                    break;
 
                /* Add c to output string */
                *output_ptr++ = c;
            }
        }
endfield:
 
        /* Terminate attribute value in output area */
        *output_ptr++ = '\0';
 
        /* Check whether raw input matched null marker */
        input_len = end_ptr - start_ptr;
        if (!saw_quote && input_len == cstate->opts.null_print_len &&
            strncmp(start_ptr, cstate->opts.null_print, input_len) == 0)
            cstate->raw_fields[fieldno] = NULL;
 
        fieldno++;
        /* Done if we hit EOL instead of a delim */
        if (!found_delim)
            break;
    }
 
    /* Clean up state of attribute_buf */
    output_ptr--;
    Assert(*output_ptr == '\0');
    cstate->attribute_buf.len = (output_ptr - cstate->attribute_buf.data);
 
    return fieldno;
}
 
 
/*
 * Read a binary attribute
 */
static Datum
CopyReadBinaryAttribute(CopyFromState cstate, FmgrInfo *flinfo,
                        Oid typioparam, int32 typmod,
                        bool *isnull)
{
    int32       fld_size;
    Datum       result;
 
    if (!CopyGetInt32(cstate, &fld_size))
        ereport(ERROR,
                (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                 errmsg("unexpected EOF in COPY data")));
    if (fld_size == -1)
    {
        *isnull = true;
        return ReceiveFunctionCall(flinfo, NULL, typioparam, typmod);
    }
    if (fld_size < 0)
        ereport(ERROR,
                (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                 errmsg("invalid field size")));
 
    /* reset attribute_buf to empty, and load raw data in it */
    resetStringInfo(&cstate->attribute_buf);
 
    enlargeStringInfo(&cstate->attribute_buf, fld_size);
    if (CopyReadBinaryData(cstate, cstate->attribute_buf.data,
                           fld_size) != fld_size)
        ereport(ERROR,
                (errcode(ERRCODE_BAD_COPY_FILE_FORMAT),
                 errmsg("unexpected EOF in COPY data")));
 
    cstate->attribute_buf.len = fld_size;
    cstate->attribute_buf.data[fld_size] = '\0';
 
    /* Call the column type's binary input converter */
    result = ReceiveFunctionCall(flinfo, &cstate->attribute_buf,
                                 typioparam, typmod);
 
    /* Trouble if it didn't eat the whole buffer */
    if (cstate->attribute_buf.cursor != cstate->attribute_buf.len)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
                 errmsg("incorrect binary data format")));
 
    *isnull = false;
    return result;
}