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/**
* Get a list of ending positions for each column name based on the ending position of each column name
* where the first row is of the below form (dash = whitespace):
* ----COLUMN1----COLUMN2-----COLUMN3----
*
* Approach:
* - read the first [256k] of data [to do: alternatively, read only the first line]
* - merge all read lines into a single line where line[i] = 'x' for each position i at which
* a non-white char appeared in any scanned line
* - from the merged line, find each instance of white followed by not-white,
* but ignore the first instance of it
*/
static enum zsv_status auto_detect_fixed_column_sizes(struct fixed *fixed, struct zsv_opts *opts, unsigned char *buff,
size_t buffsize, size_t *buff_used, char verbose) {
size_t max_lines = fixed->max_lines ? fixed->max_lines : 9999999999;
enum zsv_status stat = zsv_status_ok;
fixed->count = 0;
char *line = calloc(buffsize, sizeof(*buff));
if (!line) {
stat = zsv_status_memory;
goto auto_detect_fixed_column_sizes_exit;
}
memset(line, ' ', buffsize);
*buff_used = fread(buff, 1, buffsize, opts->stream);
if (!*buff_used) {
stat = zsv_status_no_more_input;
goto auto_detect_fixed_column_sizes_exit;
}
size_t lines_read = 0;
size_t line_end = 0;
size_t line_cursor = 0;
char first = 1;
char was_space = 1;
char was_line_end = 0;
for (size_t i = 0; i < *buff_used && (!line_end || max_lines == 0 || lines_read < max_lines);
i++, line_cursor = was_line_end ? 0 : line_cursor + 1) {
was_line_end = 0;
// TO DO: support multi-byte unicode chars?
switch (buff[i]) {
case '\n':
case '\r':
if (line_cursor > line_end)
line_end = line_cursor;
was_line_end = 1;
was_space = 1;
lines_read++;
break;
case '\t':
case '\v':
case '\f':
case ' ':
was_space = 1;
break;
default:
line[line_cursor] = 'x';
if (was_space) {
if (!line_end) { // only count columns for the first line
if (first)
first = 0;
else
fixed->count++;
}
}
was_space = 0;
}
}
if (!first)
fixed->count++;
if (!line_end) {
stat = zsv_status_error;
goto auto_detect_fixed_column_sizes_exit;
}
if (verbose)
fprintf(stderr, "Calculating %zu columns from line:\n%.*s\n", fixed->count, (int)line_end, line);
// allocate offsets
free(fixed->offsets);
fixed->offsets = NULL; // unnecessary line to silence codeQL false positive
fixed->offsets = calloc(fixed->count, sizeof(*fixed->offsets));
if (!fixed->offsets) {
stat = zsv_status_memory;
goto auto_detect_fixed_column_sizes_exit;
}
// now we have our merged line, so calculate the sizes
// do the loop again, but assign values this time
int count = 0;
was_space = 1;
first = 1;
if (verbose)
fprintf(stderr, "Running --fixed ");
size_t i;
for (i = 0; i < line_end; i++) {
if (line[i] == 'x') {
if (was_space) {
if (first)
first = 0;
else {
if (verbose)
fprintf(stderr, "%s%zu", count ? "," : "", i);
fixed->offsets[count++] = i;
}
}
was_space = 0;
} else
was_space = 1;
}
if (!first) {
if (verbose)
fprintf(stderr, "%s%zu", count ? "," : "", i);
if (i)
fixed->offsets[count++] = i;
fixed->count = count;
}
if (verbose)
fprintf(stderr, "\n");
// add a buffer to the last column in case subsequent lines are longer than what we scanned
if (fixed->count)
fixed->offsets[fixed->count - 1] += 50;
auto_detect_fixed_column_sizes_exit:
free(line);
return stat;
}
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