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git/vcs-svn/line_buffer.c
David Barr 3bbaec00a8 Add stream helper library
This library provides thread-unsafe fgets()- and fread()-like
functions where the caller does not have to supply a buffer.  It
maintains a couple of static buffers and provides an API to use
them.

[rr: allow input from files other than stdin]
[jn: with tests, documentation, and error handling improvements]

Signed-off-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-08-14 19:35:37 -07:00

97 lines
2 KiB
C

/*
* Licensed under a two-clause BSD-style license.
* See LICENSE for details.
*/
#include "git-compat-util.h"
#include "line_buffer.h"
#include "obj_pool.h"
#define LINE_BUFFER_LEN 10000
#define COPY_BUFFER_LEN 4096
/* Create memory pool for char sequence of known length */
obj_pool_gen(blob, char, 4096)
static char line_buffer[LINE_BUFFER_LEN];
static char byte_buffer[COPY_BUFFER_LEN];
static FILE *infile;
int buffer_init(const char *filename)
{
infile = filename ? fopen(filename, "r") : stdin;
if (!infile)
return -1;
return 0;
}
int buffer_deinit(void)
{
int err;
if (infile == stdin)
return ferror(infile);
err = ferror(infile);
err |= fclose(infile);
return err;
}
/* Read a line without trailing newline. */
char *buffer_read_line(void)
{
char *end;
if (!fgets(line_buffer, sizeof(line_buffer), infile))
/* Error or data exhausted. */
return NULL;
end = line_buffer + strlen(line_buffer);
if (end[-1] == '\n')
end[-1] = '\0';
else if (feof(infile))
; /* No newline at end of file. That's fine. */
else
/*
* Line was too long.
* There is probably a saner way to deal with this,
* but for now let's return an error.
*/
return NULL;
return line_buffer;
}
char *buffer_read_string(uint32_t len)
{
char *s;
blob_free(blob_pool.size);
s = blob_pointer(blob_alloc(len + 1));
s[fread(s, 1, len, infile)] = '\0';
return ferror(infile) ? NULL : s;
}
void buffer_copy_bytes(uint32_t len)
{
uint32_t in;
while (len > 0 && !feof(infile) && !ferror(infile)) {
in = len < COPY_BUFFER_LEN ? len : COPY_BUFFER_LEN;
in = fread(byte_buffer, 1, in, infile);
len -= in;
fwrite(byte_buffer, 1, in, stdout);
if (ferror(stdout)) {
buffer_skip_bytes(len);
return;
}
}
}
void buffer_skip_bytes(uint32_t len)
{
uint32_t in;
while (len > 0 && !feof(infile) && !ferror(infile)) {
in = len < COPY_BUFFER_LEN ? len : COPY_BUFFER_LEN;
in = fread(byte_buffer, 1, in, infile);
len -= in;
}
}
void buffer_reset(void)
{
blob_reset();
}