--- /dev/null
+#include "pysam.h"
+
+/* The MIT License
+
+ Copyright (c) 2008 Broad Institute / Massachusetts Institute of Technology
+
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+
+ The above copyright notice and this permission notice shall be included in
+ all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ THE SOFTWARE.
+*/
+
+/*
+ 2009-06-29 by lh3: cache recent uncompressed blocks.
+ 2009-06-25 by lh3: optionally use my knetfile library to access file on a FTP.
+ 2009-06-12 by lh3: support a mode string like "wu" where 'u' for uncompressed output */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include "bgzf.h"
+
+#include "khash.h"
+typedef struct {
+ int size;
+ uint8_t *block;
+ int64_t end_offset;
+} cache_t;
+KHASH_MAP_INIT_INT64(cache, cache_t)
+
+#if defined(_WIN32) || defined(_MSC_VER)
+#define ftello(fp) ftell(fp)
+#define fseeko(fp, offset, whence) fseek(fp, offset, whence)
+#else
+extern off_t ftello(FILE *stream);
+extern int fseeko(FILE *stream, off_t offset, int whence);
+#endif
+
+typedef int8_t bgzf_byte_t;
+
+static const int DEFAULT_BLOCK_SIZE = 64 * 1024;
+static const int MAX_BLOCK_SIZE = 64 * 1024;
+
+static const int BLOCK_HEADER_LENGTH = 18;
+static const int BLOCK_FOOTER_LENGTH = 8;
+
+static const int GZIP_ID1 = 31;
+static const int GZIP_ID2 = 139;
+static const int CM_DEFLATE = 8;
+static const int FLG_FEXTRA = 4;
+static const int OS_UNKNOWN = 255;
+static const int BGZF_ID1 = 66; // 'B'
+static const int BGZF_ID2 = 67; // 'C'
+static const int BGZF_LEN = 2;
+static const int BGZF_XLEN = 6; // BGZF_LEN+4
+
+static const int GZIP_WINDOW_BITS = -15; // no zlib header
+static const int Z_DEFAULT_MEM_LEVEL = 8;
+
+
+inline
+void
+packInt16(uint8_t* buffer, uint16_t value)
+{
+ buffer[0] = value;
+ buffer[1] = value >> 8;
+}
+
+inline
+int
+unpackInt16(const uint8_t* buffer)
+{
+ return (buffer[0] | (buffer[1] << 8));
+}
+
+inline
+void
+packInt32(uint8_t* buffer, uint32_t value)
+{
+ buffer[0] = value;
+ buffer[1] = value >> 8;
+ buffer[2] = value >> 16;
+ buffer[3] = value >> 24;
+}
+
+static inline
+int
+bgzf_min(int x, int y)
+{
+ return (x < y) ? x : y;
+}
+
+static
+void
+report_error(BGZF* fp, const char* message) {
+ fp->error = message;
+}
+
+int bgzf_check_bgzf(const char *fn)
+{
+ BGZF *fp;
+ uint8_t buf[10],magic[10]="\037\213\010\4\0\0\0\0\0\377";
+ int n;
+
+ if ((fp = bgzf_open(fn, "r")) == 0)
+ {
+ fprintf(pysamerr, "[bgzf_check_bgzf] failed to open the file: %s\n",fn);
+ return -1;
+ }
+
+#ifdef _USE_KNETFILE
+ n = knet_read(fp->x.fpr, buf, 10);
+#else
+ n = fread(buf, 1, 10, fp->file);
+#endif
+ bgzf_close(fp);
+
+ if ( n!=10 )
+ return -1;
+
+ if ( !memcmp(magic, buf, 10) ) return 1;
+ return 0;
+}
+
+static BGZF *bgzf_read_init()
+{
+ BGZF *fp;
+ fp = calloc(1, sizeof(BGZF));
+ fp->uncompressed_block_size = MAX_BLOCK_SIZE;
+ fp->uncompressed_block = malloc(MAX_BLOCK_SIZE);
+ fp->compressed_block_size = MAX_BLOCK_SIZE;
+ fp->compressed_block = malloc(MAX_BLOCK_SIZE);
+ fp->cache_size = 0;
+ fp->cache = kh_init(cache);
+ return fp;
+}
+
+static
+BGZF*
+open_read(int fd)
+{
+#ifdef _USE_KNETFILE
+ knetFile *file = knet_dopen(fd, "r");
+#else
+ FILE* file = fdopen(fd, "r");
+#endif
+ BGZF* fp;
+ if (file == 0) return 0;
+ fp = bgzf_read_init();
+ fp->file_descriptor = fd;
+ fp->open_mode = 'r';
+#ifdef _USE_KNETFILE
+ fp->x.fpr = file;
+#else
+ fp->file = file;
+#endif
+ return fp;
+}
+
+static
+BGZF*
+open_write(int fd, int compress_level) // compress_level==-1 for the default level
+{
+ FILE* file = fdopen(fd, "w");
+ BGZF* fp;
+ if (file == 0) return 0;
+ fp = malloc(sizeof(BGZF));
+ fp->file_descriptor = fd;
+ fp->open_mode = 'w';
+ fp->owned_file = 0;
+ fp->compress_level = compress_level < 0? Z_DEFAULT_COMPRESSION : compress_level; // Z_DEFAULT_COMPRESSION==-1
+ if (fp->compress_level > 9) fp->compress_level = Z_DEFAULT_COMPRESSION;
+#ifdef _USE_KNETFILE
+ fp->x.fpw = file;
+#else
+ fp->file = file;
+#endif
+ fp->uncompressed_block_size = DEFAULT_BLOCK_SIZE;
+ fp->uncompressed_block = NULL;
+ fp->compressed_block_size = MAX_BLOCK_SIZE;
+ fp->compressed_block = malloc(MAX_BLOCK_SIZE);
+ fp->block_address = 0;
+ fp->block_offset = 0;
+ fp->block_length = 0;
+ fp->error = NULL;
+ return fp;
+}
+
+BGZF*
+bgzf_open(const char* __restrict path, const char* __restrict mode)
+{
+ BGZF* fp = NULL;
+ if (strchr(mode, 'r') || strchr(mode, 'R')) { /* The reading mode is preferred. */
+#ifdef _USE_KNETFILE
+ knetFile *file = knet_open(path, mode);
+ if (file == 0) return 0;
+ fp = bgzf_read_init();
+ fp->file_descriptor = -1;
+ fp->open_mode = 'r';
+ fp->x.fpr = file;
+#else
+ int fd, oflag = O_RDONLY;
+#ifdef _WIN32
+ oflag |= O_BINARY;
+#endif
+ fd = open(path, oflag);
+ if (fd == -1) return 0;
+ fp = open_read(fd);
+#endif
+ } else if (strchr(mode, 'w') || strchr(mode, 'W')) {
+ int fd, compress_level = -1, oflag = O_WRONLY | O_CREAT | O_TRUNC;
+#ifdef _WIN32
+ oflag |= O_BINARY;
+#endif
+ fd = open(path, oflag, 0666);
+ if (fd == -1) return 0;
+ { // set compress_level
+ int i;
+ for (i = 0; mode[i]; ++i)
+ if (mode[i] >= '0' && mode[i] <= '9') break;
+ if (mode[i]) compress_level = (int)mode[i] - '0';
+ if (strchr(mode, 'u')) compress_level = 0;
+ }
+ fp = open_write(fd, compress_level);
+ }
+ if (fp != NULL) fp->owned_file = 1;
+ return fp;
+}
+
+BGZF*
+bgzf_fdopen(int fd, const char * __restrict mode)
+{
+ if (fd == -1) return 0;
+ if (mode[0] == 'r' || mode[0] == 'R') {
+ return open_read(fd);
+ } else if (mode[0] == 'w' || mode[0] == 'W') {
+ int i, compress_level = -1;
+ for (i = 0; mode[i]; ++i)
+ if (mode[i] >= '0' && mode[i] <= '9') break;
+ if (mode[i]) compress_level = (int)mode[i] - '0';
+ if (strchr(mode, 'u')) compress_level = 0;
+ return open_write(fd, compress_level);
+ } else {
+ return NULL;
+ }
+}
+
+static
+int
+deflate_block(BGZF* fp, int block_length)
+{
+ // Deflate the block in fp->uncompressed_block into fp->compressed_block.
+ // Also adds an extra field that stores the compressed block length.
+
+ bgzf_byte_t* buffer = fp->compressed_block;
+ int buffer_size = fp->compressed_block_size;
+
+ // Init gzip header
+ buffer[0] = GZIP_ID1;
+ buffer[1] = GZIP_ID2;
+ buffer[2] = CM_DEFLATE;
+ buffer[3] = FLG_FEXTRA;
+ buffer[4] = 0; // mtime
+ buffer[5] = 0;
+ buffer[6] = 0;
+ buffer[7] = 0;
+ buffer[8] = 0;
+ buffer[9] = OS_UNKNOWN;
+ buffer[10] = BGZF_XLEN;
+ buffer[11] = 0;
+ buffer[12] = BGZF_ID1;
+ buffer[13] = BGZF_ID2;
+ buffer[14] = BGZF_LEN;
+ buffer[15] = 0;
+ buffer[16] = 0; // placeholder for block length
+ buffer[17] = 0;
+
+ // loop to retry for blocks that do not compress enough
+ int input_length = block_length;
+ int compressed_length = 0;
+ while (1) {
+ z_stream zs;
+ zs.zalloc = NULL;
+ zs.zfree = NULL;
+ zs.next_in = fp->uncompressed_block;
+ zs.avail_in = input_length;
+ zs.next_out = (void*)&buffer[BLOCK_HEADER_LENGTH];
+ zs.avail_out = buffer_size - BLOCK_HEADER_LENGTH - BLOCK_FOOTER_LENGTH;
+
+ int status = deflateInit2(&zs, fp->compress_level, Z_DEFLATED,
+ GZIP_WINDOW_BITS, Z_DEFAULT_MEM_LEVEL, Z_DEFAULT_STRATEGY);
+ if (status != Z_OK) {
+ report_error(fp, "deflate init failed");
+ return -1;
+ }
+ status = deflate(&zs, Z_FINISH);
+ if (status != Z_STREAM_END) {
+ deflateEnd(&zs);
+ if (status == Z_OK) {
+ // Not enough space in buffer.
+ // Can happen in the rare case the input doesn't compress enough.
+ // Reduce the amount of input until it fits.
+ input_length -= 1024;
+ if (input_length <= 0) {
+ // should never happen
+ report_error(fp, "input reduction failed");
+ return -1;
+ }
+ continue;
+ }
+ report_error(fp, "deflate failed");
+ return -1;
+ }
+ status = deflateEnd(&zs);
+ if (status != Z_OK) {
+ report_error(fp, "deflate end failed");
+ return -1;
+ }
+ compressed_length = zs.total_out;
+ compressed_length += BLOCK_HEADER_LENGTH + BLOCK_FOOTER_LENGTH;
+ if (compressed_length > MAX_BLOCK_SIZE) {
+ // should never happen
+ report_error(fp, "deflate overflow");
+ return -1;
+ }
+ break;
+ }
+
+ packInt16((uint8_t*)&buffer[16], compressed_length-1);
+ uint32_t crc = crc32(0L, NULL, 0L);
+ crc = crc32(crc, fp->uncompressed_block, input_length);
+ packInt32((uint8_t*)&buffer[compressed_length-8], crc);
+ packInt32((uint8_t*)&buffer[compressed_length-4], input_length);
+
+ int remaining = block_length - input_length;
+ if (remaining > 0) {
+ if (remaining > input_length) {
+ // should never happen (check so we can use memcpy)
+ report_error(fp, "remainder too large");
+ return -1;
+ }
+ memcpy(fp->uncompressed_block,
+ fp->uncompressed_block + input_length,
+ remaining);
+ }
+ fp->block_offset = remaining;
+ return compressed_length;
+}
+
+static
+int
+inflate_block(BGZF* fp, int block_length)
+{
+ // Inflate the block in fp->compressed_block into fp->uncompressed_block
+
+ z_stream zs;
+ int status;
+ zs.zalloc = NULL;
+ zs.zfree = NULL;
+ zs.next_in = fp->compressed_block + 18;
+ zs.avail_in = block_length - 16;
+ zs.next_out = fp->uncompressed_block;
+ zs.avail_out = fp->uncompressed_block_size;
+
+ status = inflateInit2(&zs, GZIP_WINDOW_BITS);
+ if (status != Z_OK) {
+ report_error(fp, "inflate init failed");
+ return -1;
+ }
+ status = inflate(&zs, Z_FINISH);
+ if (status != Z_STREAM_END) {
+ inflateEnd(&zs);
+ report_error(fp, "inflate failed");
+ return -1;
+ }
+ status = inflateEnd(&zs);
+ if (status != Z_OK) {
+ report_error(fp, "inflate failed");
+ return -1;
+ }
+ return zs.total_out;
+}
+
+static
+int
+check_header(const bgzf_byte_t* header)
+{
+ return (header[0] == GZIP_ID1 &&
+ header[1] == (bgzf_byte_t) GZIP_ID2 &&
+ header[2] == Z_DEFLATED &&
+ (header[3] & FLG_FEXTRA) != 0 &&
+ unpackInt16((uint8_t*)&header[10]) == BGZF_XLEN &&
+ header[12] == BGZF_ID1 &&
+ header[13] == BGZF_ID2 &&
+ unpackInt16((uint8_t*)&header[14]) == BGZF_LEN);
+}
+
+static void free_cache(BGZF *fp)
+{
+ khint_t k;
+ khash_t(cache) *h = (khash_t(cache)*)fp->cache;
+ if (fp->open_mode != 'r') return;
+ for (k = kh_begin(h); k < kh_end(h); ++k)
+ if (kh_exist(h, k)) free(kh_val(h, k).block);
+ kh_destroy(cache, h);
+}
+
+static int load_block_from_cache(BGZF *fp, int64_t block_address)
+{
+ khint_t k;
+ cache_t *p;
+ khash_t(cache) *h = (khash_t(cache)*)fp->cache;
+ k = kh_get(cache, h, block_address);
+ if (k == kh_end(h)) return 0;
+ p = &kh_val(h, k);
+ if (fp->block_length != 0) fp->block_offset = 0;
+ fp->block_address = block_address;
+ fp->block_length = p->size;
+ memcpy(fp->uncompressed_block, p->block, MAX_BLOCK_SIZE);
+#ifdef _USE_KNETFILE
+ knet_seek(fp->x.fpr, p->end_offset, SEEK_SET);
+#else
+ fseeko(fp->file, p->end_offset, SEEK_SET);
+#endif
+ return p->size;
+}
+
+static void cache_block(BGZF *fp, int size)
+{
+ int ret;
+ khint_t k;
+ cache_t *p;
+ khash_t(cache) *h = (khash_t(cache)*)fp->cache;
+ if (MAX_BLOCK_SIZE >= fp->cache_size) return;
+ if ((kh_size(h) + 1) * MAX_BLOCK_SIZE > fp->cache_size) {
+ /* A better way would be to remove the oldest block in the
+ * cache, but here we remove a random one for simplicity. This
+ * should not have a big impact on performance. */
+ for (k = kh_begin(h); k < kh_end(h); ++k)
+ if (kh_exist(h, k)) break;
+ if (k < kh_end(h)) {
+ free(kh_val(h, k).block);
+ kh_del(cache, h, k);
+ }
+ }
+ k = kh_put(cache, h, fp->block_address, &ret);
+ if (ret == 0) return; // if this happens, a bug!
+ p = &kh_val(h, k);
+ p->size = fp->block_length;
+ p->end_offset = fp->block_address + size;
+ p->block = malloc(MAX_BLOCK_SIZE);
+ memcpy(kh_val(h, k).block, fp->uncompressed_block, MAX_BLOCK_SIZE);
+}
+
+int
+bgzf_read_block(BGZF* fp)
+{
+ bgzf_byte_t header[BLOCK_HEADER_LENGTH];
+ int count, size = 0, block_length, remaining;
+#ifdef _USE_KNETFILE
+ int64_t block_address = knet_tell(fp->x.fpr);
+ if (load_block_from_cache(fp, block_address)) return 0;
+ count = knet_read(fp->x.fpr, header, sizeof(header));
+#else
+ int64_t block_address = ftello(fp->file);
+ if (load_block_from_cache(fp, block_address)) return 0;
+ count = fread(header, 1, sizeof(header), fp->file);
+#endif
+ if (count == 0) {
+ fp->block_length = 0;
+ return 0;
+ }
+ size = count;
+ if (count != sizeof(header)) {
+ report_error(fp, "read failed");
+ return -1;
+ }
+ if (!check_header(header)) {
+ report_error(fp, "invalid block header");
+ return -1;
+ }
+ block_length = unpackInt16((uint8_t*)&header[16]) + 1;
+ bgzf_byte_t* compressed_block = (bgzf_byte_t*) fp->compressed_block;
+ memcpy(compressed_block, header, BLOCK_HEADER_LENGTH);
+ remaining = block_length - BLOCK_HEADER_LENGTH;
+#ifdef _USE_KNETFILE
+ count = knet_read(fp->x.fpr, &compressed_block[BLOCK_HEADER_LENGTH], remaining);
+#else
+ count = fread(&compressed_block[BLOCK_HEADER_LENGTH], 1, remaining, fp->file);
+#endif
+ if (count != remaining) {
+ report_error(fp, "read failed");
+ return -1;
+ }
+ size += count;
+ count = inflate_block(fp, block_length);
+ if (count < 0) return -1;
+ if (fp->block_length != 0) {
+ // Do not reset offset if this read follows a seek.
+ fp->block_offset = 0;
+ }
+ fp->block_address = block_address;
+ fp->block_length = count;
+ cache_block(fp, size);
+ return 0;
+}
+
+int
+bgzf_read(BGZF* fp, void* data, int length)
+{
+ if (length <= 0) {
+ return 0;
+ }
+ if (fp->open_mode != 'r') {
+ report_error(fp, "file not open for reading");
+ return -1;
+ }
+
+ int bytes_read = 0;
+ bgzf_byte_t* output = data;
+ while (bytes_read < length) {
+ int copy_length, available = fp->block_length - fp->block_offset;
+ bgzf_byte_t *buffer;
+ if (available <= 0) {
+ if (bgzf_read_block(fp) != 0) {
+ return -1;
+ }
+ available = fp->block_length - fp->block_offset;
+ if (available <= 0) {
+ break;
+ }
+ }
+ copy_length = bgzf_min(length-bytes_read, available);
+ buffer = fp->uncompressed_block;
+ memcpy(output, buffer + fp->block_offset, copy_length);
+ fp->block_offset += copy_length;
+ output += copy_length;
+ bytes_read += copy_length;
+ }
+ if (fp->block_offset == fp->block_length) {
+#ifdef _USE_KNETFILE
+ fp->block_address = knet_tell(fp->x.fpr);
+#else
+ fp->block_address = ftello(fp->file);
+#endif
+ fp->block_offset = 0;
+ fp->block_length = 0;
+ }
+ return bytes_read;
+}
+
+int bgzf_flush(BGZF* fp)
+{
+ while (fp->block_offset > 0) {
+ int count, block_length;
+ block_length = deflate_block(fp, fp->block_offset);
+ if (block_length < 0) return -1;
+#ifdef _USE_KNETFILE
+ count = fwrite(fp->compressed_block, 1, block_length, fp->x.fpw);
+#else
+ count = fwrite(fp->compressed_block, 1, block_length, fp->file);
+#endif
+ if (count != block_length) {
+ report_error(fp, "write failed");
+ return -1;
+ }
+ fp->block_address += block_length;
+ }
+ return 0;
+}
+
+int bgzf_flush_try(BGZF *fp, int size)
+{
+ if (fp->block_offset + size > fp->uncompressed_block_size)
+ return bgzf_flush(fp);
+ return -1;
+}
+
+int bgzf_write(BGZF* fp, const void* data, int length)
+{
+ const bgzf_byte_t *input = data;
+ int block_length, bytes_written;
+ if (fp->open_mode != 'w') {
+ report_error(fp, "file not open for writing");
+ return -1;
+ }
+
+ if (fp->uncompressed_block == NULL)
+ fp->uncompressed_block = malloc(fp->uncompressed_block_size);
+
+ input = data;
+ block_length = fp->uncompressed_block_size;
+ bytes_written = 0;
+ while (bytes_written < length) {
+ int copy_length = bgzf_min(block_length - fp->block_offset, length - bytes_written);
+ bgzf_byte_t* buffer = fp->uncompressed_block;
+ memcpy(buffer + fp->block_offset, input, copy_length);
+ fp->block_offset += copy_length;
+ input += copy_length;
+ bytes_written += copy_length;
+ if (fp->block_offset == block_length) {
+ if (bgzf_flush(fp) != 0) {
+ break;
+ }
+ }
+ }
+ return bytes_written;
+}
+
+int bgzf_close(BGZF* fp)
+{
+ if (fp->open_mode == 'w') {
+ if (bgzf_flush(fp) != 0) return -1;
+ { // add an empty block
+ int count, block_length = deflate_block(fp, 0);
+#ifdef _USE_KNETFILE
+ count = fwrite(fp->compressed_block, 1, block_length, fp->x.fpw);
+#else
+ count = fwrite(fp->compressed_block, 1, block_length, fp->file);
+#endif
+ }
+#ifdef _USE_KNETFILE
+ if (fflush(fp->x.fpw) != 0) {
+#else
+ if (fflush(fp->file) != 0) {
+#endif
+ report_error(fp, "flush failed");
+ return -1;
+ }
+ }
+ if (fp->owned_file) {
+#ifdef _USE_KNETFILE
+ int ret;
+ if (fp->open_mode == 'w') ret = fclose(fp->x.fpw);
+ else ret = knet_close(fp->x.fpr);
+ if (ret != 0) return -1;
+#else
+ if (fclose(fp->file) != 0) return -1;
+#endif
+ }
+ free(fp->uncompressed_block);
+ free(fp->compressed_block);
+ free_cache(fp);
+ free(fp);
+ return 0;
+}
+
+void bgzf_set_cache_size(BGZF *fp, int cache_size)
+{
+ if (fp) fp->cache_size = cache_size;
+}
+
+int bgzf_check_EOF(BGZF *fp)
+{
+ static uint8_t magic[28] = "\037\213\010\4\0\0\0\0\0\377\6\0\102\103\2\0\033\0\3\0\0\0\0\0\0\0\0\0";
+ uint8_t buf[28];
+ off_t offset;
+#ifdef _USE_KNETFILE
+ offset = knet_tell(fp->x.fpr);
+ if (knet_seek(fp->x.fpr, -28, SEEK_END) != 0) return -1;
+ knet_read(fp->x.fpr, buf, 28);
+ knet_seek(fp->x.fpr, offset, SEEK_SET);
+#else
+ offset = ftello(fp->file);
+ if (fseeko(fp->file, -28, SEEK_END) != 0) return -1;
+ fread(buf, 1, 28, fp->file);
+ fseeko(fp->file, offset, SEEK_SET);
+#endif
+ return (memcmp(magic, buf, 28) == 0)? 1 : 0;
+}
+
+int64_t bgzf_seek(BGZF* fp, int64_t pos, int where)
+{
+ int block_offset;
+ int64_t block_address;
+
+ if (fp->open_mode != 'r') {
+ report_error(fp, "file not open for read");
+ return -1;
+ }
+ if (where != SEEK_SET) {
+ report_error(fp, "unimplemented seek option");
+ return -1;
+ }
+ block_offset = pos & 0xFFFF;
+ block_address = (pos >> 16) & 0xFFFFFFFFFFFFLL;
+#ifdef _USE_KNETFILE
+ if (knet_seek(fp->x.fpr, block_address, SEEK_SET) != 0) {
+#else
+ if (fseeko(fp->file, block_address, SEEK_SET) != 0) {
+#endif
+ report_error(fp, "seek failed");
+ return -1;
+ }
+ fp->block_length = 0; // indicates current block is not loaded
+ fp->block_address = block_address;
+ fp->block_offset = block_offset;
+ return 0;
+}
projects / pysam.git / blobdiff