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107 lines
2.9 KiB
C
107 lines
2.9 KiB
C
#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include "csv.h"
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#define READ_BLOCK_SIZE 65536
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#define QUICK_GETC( ch, fp )\
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do\
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{\
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if ( read_ptr == read_end ) {\
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fread_len = fread( read_buf, sizeof(char), READ_BLOCK_SIZE, fp );\
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if ( fread_len < READ_BLOCK_SIZE ) {\
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read_buf[fread_len] = '\0';\
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}\
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read_ptr = read_buf;\
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}\
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ch = *read_ptr++;\
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}\
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while(0)
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/*
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* Given a file pointer, read a CSV line from that file.
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* File may include newlines escaped with "double quotes".
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*
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* Warning: This function is optimized for the use case where
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* you repeatedly call it until the file is exhausted. It is
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* very suboptimal for the use case of just grabbing one single
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* line of CSV and stopping. Also, this function advances the
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* file position (in the fseek/ftell sense) unpredictably. You
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* should not change the file position between calls to
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* fread_csv_line (e.g., don't use "getc" on the file in between
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* calls to fread_csv_line).
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*
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* Other arguments:
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* size_t max_line_size: Maximum line size, in bytes.
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* int *done: Pointer to an int that will be set to 1 when file is exhausted.
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* int *err: Pointer to an int where error code will be written.
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*
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* Warning: Calling this function on an exhausted file (as indicated by the
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* 'done' flag) is undefined behavior.
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*
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* See csv.h for definitions of error codes.
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*/
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char *fread_csv_line(FILE *fp, int max_line_size, int *done, int *err, int rst) {
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static FILE *bookmark;
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static char read_buf[READ_BLOCK_SIZE], *read_ptr, *read_end;
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static int fread_len, prev_max_line_size = -1;
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static char *buf;
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char *bptr, *limit;
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char ch;
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int fQuote;
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if ( max_line_size > prev_max_line_size ) {
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if ( prev_max_line_size != -1 ) {
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free( buf );
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}
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buf = malloc( max_line_size + 1 );
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if ( !buf ) {
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*err = CSV_ERR_NO_MEMORY;
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prev_max_line_size = -1;
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return NULL;
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}
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prev_max_line_size = max_line_size;
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}
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bptr = buf;
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limit = buf + max_line_size;
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if (( bookmark != fp ) || ( rst )) {
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read_ptr = read_end = read_buf + READ_BLOCK_SIZE;
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bookmark = fp;
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}
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for ( fQuote = 0; ; ) {
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QUICK_GETC(ch, fp);
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if ( !ch || (ch == '\n' && !fQuote)) {
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break;
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}
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if ( bptr >= limit ) {
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free( buf );
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*err = CSV_ERR_LONGLINE;
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return NULL;
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}
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*bptr++ = ch;
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if ( fQuote ) {
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if ( ch == '\"' ) {
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QUICK_GETC(ch, fp);
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if ( ch != '\"' ) {
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if ( !ch || ch == '\n' ) {
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break;
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}
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fQuote = 0;
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}
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*bptr++ = ch;
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}
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} else if ( ch == '\"' ) {
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fQuote = 1;
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}
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}
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*done = !ch;
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*bptr = '\0';
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return strdup(buf);
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}
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