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[gzip] read similar to brotli and zstd

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This commit is contained in:
Witold Filipczyk 2022-05-29 18:59:40 +02:00
parent 8d97cc7641
commit 4b5f18c2e3
1 changed files with 43 additions and 65 deletions
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108
src/encoding/gzip.c
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@ -26,7 +26,10 @@ struct deflate_enc_data {
/* The file descriptor from which we read. */
int fdread;
size_t sent_pos;
uint8_t *buffer;
unsigned int decoded:1;
unsigned int last_read:1;
unsigned int after_first_read:1;
unsigned int after_end:1;
@ -61,6 +64,8 @@ deflate_open(int window_size, struct stream_encoded *stream, int fd)
data->last_read = 0;
data->after_first_read = 0;
data->after_end = 0;
data->sent_pos = 0;
data->decoded = 0;
if (window_size > 0) {
err = inflateInit2(&data->deflate_stream, window_size);
@ -83,86 +88,58 @@ deflate_gzip_open(struct stream_encoded *stream, int fd)
return deflate_open(MAX_WBITS + 32, stream, fd);
}
static char *deflate_gzip_decode_buffer(struct stream_encoded *st, char *data, int len, int *new_len);
static int
deflate_read(struct stream_encoded *stream, char *bufc, int len)
deflate_read(struct stream_encoded *stream, char *buf, int len)
{
unsigned char *buf = (unsigned char *)bufc;
struct deflate_enc_data *data = (struct deflate_enc_data *) stream->data;
int err = 0;
int l = 0;
if (!data) return -1;
assert(len > 0);
if (data->last_read) return 0;
if (!data->decoded) {
size_t read_pos = 0;
char *tmp_buf = (char *)mem_alloc(len);
int new_len;
data->deflate_stream.avail_out = len;
data->deflate_stream.next_out = buf;
if (!tmp_buf) {
return 0;
}
do {
int l = safe_read(data->fdread, tmp_buf + read_pos, len - read_pos);
do {
if (data->deflate_stream.avail_in == 0) {
l = safe_read(data->fdread, data->buf,
ELINKS_DEFLATE_BUFFER_LENGTH);
if (!l) break;
if (l == -1 && errno == EAGAIN) {
continue;
}
if (l == -1) {
if (errno == EAGAIN)
break;
else
return -1; /* I/O error */
} else if (l == 0) {
/* EOF. It is error: we wait for more bytes */
return -1;
}
read_pos += l;
} while (1);
data->deflate_stream.next_in = data->buf;
data->deflate_stream.avail_in = l;
if (deflate_gzip_decode_buffer(stream, tmp_buf, len, &new_len)) {
data->decoded = 1;
}
restart:
err = inflate(&data->deflate_stream, Z_SYNC_FLUSH);
if (err == Z_DATA_ERROR && !data->after_first_read
&& data->deflate_stream.next_out == buf) {
/* RFC 2616 requires a zlib header for
* "Content-Encoding: deflate", but some HTTP
* servers (Microsoft-IIS/6.0 at blogs.msdn.com,
* and reportedly Apache with mod_deflate) omit
* that, causing Z_DATA_ERROR. Clarification of
* the term "deflate" has been requested for the
* next version of HTTP:
* http://www3.tools.ietf.org/wg/httpbis/trac/ticket/73
*
* Try to recover by telling zlib not to expect
* the header. If the error does not happen on
* the first inflate() call, then it is too late
* to recover because ELinks may already have
* discarded part of the input data.
*
* TODO: This fallback to raw DEFLATE is currently
* enabled for "Content-Encoding: gzip" too. It
* might be better to fall back to no compression
* at all, because Apache can send that header for
* uncompressed *.gz.md5 files. */
data->after_first_read = 1;
inflateEnd(&data->deflate_stream);
data->deflate_stream.avail_out = len;
data->deflate_stream.next_out = buf;
data->deflate_stream.next_in = data->buf;
data->deflate_stream.avail_in = l;
err = inflateInit2(&data->deflate_stream, -MAX_WBITS);
if (err == Z_OK) goto restart;
}
data->after_first_read = 1;
if (err == Z_STREAM_END) {
data->last_read = 1;
break;
} else if (err != Z_OK) {
data->last_read = 1;
break;
}
} while (data->deflate_stream.avail_out > 0);
mem_free(tmp_buf);
}
if (data->decoded) {
int length = len < (data->deflate_stream.total_out - data->sent_pos) ? len : (data->deflate_stream.total_out - data->sent_pos);
assert(len - data->deflate_stream.avail_out == data->deflate_stream.next_out - buf);
return len - data->deflate_stream.avail_out;
if (length <= 0) {
mem_free_set(&data->buffer, NULL);
} else {
memcpy(buf, (void *)((char *)(data->buffer) + data->sent_pos), length);
data->sent_pos += length;
}
return length;
}
return -1;
}
static char *
@ -206,7 +183,7 @@ restart2:
enc_data->after_first_read = 1;
stream->next_in = data;
stream->avail_in = len;
goto restart2;
goto restart2;
}
}
} while (error == Z_OK && stream->avail_in > 0);
@ -217,11 +194,12 @@ restart2:
error = Z_OK;
}
enc_data->buffer = (uint8_t *)buffer;
if (error == Z_OK) {
*new_len = stream->total_out;
return (char *)buffer;
} else {
mem_free_if(buffer);
mem_free_set(&enc_data->buffer, NULL);
return NULL;
}
}