diff options
author | Jannis Hoffmann <jannis@fehcom.de> | 2024-07-09 13:58:20 +0200 |
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committer | Jannis Hoffmann <jannis@fehcom.de> | 2024-07-09 13:58:20 +0200 |
commit | 249866e3d1e11dc72eaa1305f4bb479ded92ef38 (patch) | |
tree | 7118c5f58e29fe61c100e4d067bb90ba8d52589e /src/cdbread.c | |
parent | 96cf8dffe4f7b0b910f790066ae622dc429eb522 (diff) |
reorganized file structure
Moved c files into src/.
Corrected VERSION file.
Removed BUILD and FILES.
Diffstat (limited to 'src/cdbread.c')
-rw-r--r-- | src/cdbread.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/src/cdbread.c b/src/cdbread.c new file mode 100644 index 0000000..c8ffa42 --- /dev/null +++ b/src/cdbread.c @@ -0,0 +1,169 @@ +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/mman.h> +#include <unistd.h> +#include "error.h" +#include "seek.h" +#include "byte.h" +#include "cdbread.h" + +/** + @file cdbread.c + @author djb + @source ucspi-tcp, fastforward + @brief read entries from a cdb +*/ + +uint32 cdb_unpack(unsigned char *buf) +{ + uint32 num; + num = buf[3]; num <<= 8; + num += buf[2]; num <<= 8; + num += buf[1]; num <<= 8; + num += buf[0]; + return num; +} + +void cdb_free(struct cdb *c) +{ + if (c->map) { + munmap(c->map,c->size); + c->map = 0; + } +} + +void cdb_findstart(struct cdb *c) +{ + c->loop = 0; +} + +void cdb_init(struct cdb *c,int fd) +{ + struct stat st; + char *x; + + cdb_free(c); + cdb_findstart(c); + c->fd = fd; + + if (fstat(fd,&st) == 0) + if (st.st_size <= 0xffffffff) { + x = mmap(0,st.st_size,PROT_READ,MAP_SHARED,fd,0); + if (x + 1) { + c->size = st.st_size; + c->map = x; + } + } +} + +int cdb_read(struct cdb *c,char *buf,unsigned int len,uint32 pos) +{ + if (c->map) { + if ((pos > c->size) || (c->size - pos < len)) goto FORMAT; + byte_copy(buf,len,c->map + pos); + } + else { + if (seek_set(c->fd,pos) == -1) return -1; + while (len > 0) { + int r; + do + r = read(c->fd,buf,len); + while ((r == -1) && (errno == EINTR)); + if (r == -1) return -1; + if (r == 0) goto FORMAT; + buf += r; + len -= r; + } + } + return 0; + + FORMAT: + errno = EPROTO; + return -1; +} + +static int match(struct cdb *c,char *key,unsigned int len,uint32 pos) +{ + char buf[32]; + int n; + + while (len > 0) { + n = sizeof(buf); + if (n > len) n = len; + if (cdb_read(c,buf,n,pos) == -1) return -1; + if (byte_diff(buf,n,key)) return 0; + pos += n; + key += n; + len -= n; + } + return 1; +} + +int cdb_findnext(struct cdb *c,char *key,unsigned int len) +{ + char buf[8]; + uint32 pos; + uint32 u; + + if (!c->loop) { + u = cdb_hash(key,len); + if (cdb_read(c,buf,8,(u << 3) & 2047) == -1) return -1; + uint32_unpack(buf + 4,&c->hslots); + if (!c->hslots) return 0; + uint32_unpack(buf,&c->hpos); + c->khash = u; + u >>= 8; + u %= c->hslots; + u <<= 3; + c->kpos = c->hpos + u; + } + + while (c->loop < c->hslots) { + if (cdb_read(c,buf,8,c->kpos) == -1) return -1; + uint32_unpack(buf + 4,&pos); + if (!pos) return 0; + c->loop += 1; + c->kpos += 8; + if (c->kpos == c->hpos + (c->hslots << 3)) c->kpos = c->hpos; + uint32_unpack(buf,&u); + if (u == c->khash) { + if (cdb_read(c,buf,8,pos) == -1) return -1; + uint32_unpack(buf,&u); + if (u == len) + switch(match(c,key,len,pos + 8)) { + case -1: + return -1; + case 1: + uint32_unpack(buf + 4,&c->dlen); + c->dpos = pos + 8 + len; + return 1; + } + } + } + + return 0; +} + +int cdb_find(struct cdb *c,char *key,unsigned int len) +{ + cdb_findstart(c); + return cdb_findnext(c,key,len); +} + +uint32 cdb_hashadd(uint32 h,unsigned char c) +{ + h += (h << 5); + return h ^ c; +} + +uint32 cdb_hash(char *buf,unsigned int len) +{ + uint32 h; + + h = CDB_HASHSTART; + while (len) { + h = cdb_hashadd(h,*buf++); + --len; + } + return h; +} |