mirror of
https://github.com/netsurf-browser/netsurf
synced 2024-12-24 21:16:50 +03:00
405 lines
8.8 KiB
C
405 lines
8.8 KiB
C
/*
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* Copyright 2006 Rob Kendrick <rjek@rjek.com>
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* Copyright 2006 Richard Wilson <info@tinct.net>
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*
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* This file is part of NetSurf, http://www.netsurf-browser.org/
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*
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* NetSurf is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* NetSurf is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* \file
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* Write-Once hash table for string to string mappings.
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*
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* This implementation is unit tested, if you make changes please
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* ensure the tests continute to pass and if possible, through
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* valgrind to make sure there are no memory leaks or invalid memory
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* accesses. If you add new functionality, please include a test for
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* it that has good coverage along side the other tests.
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*/
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#include <stdint.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <string.h>
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#include <zlib.h>
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#include <errno.h>
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#include "utils/log.h"
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#include "utils/hashtable.h"
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struct hash_entry {
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char *pairing; /**< block containing 'key\0value\0' */
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unsigned int key_length; /**< length of key */
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struct hash_entry *next; /**< next entry */
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};
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struct hash_table {
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unsigned int nchains;
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struct hash_entry **chain;
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};
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/** maximum length of line for file or inline add */
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#define LINE_BUFFER_SIZE 512
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/**
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* Hash a string, returning a 32bit value. The hash algorithm used is
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* Fowler Noll Vo - a very fast and simple hash, ideal for short strings.
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* See http://en.wikipedia.org/wiki/Fowler_Noll_Vo_hash for more details.
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*
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* \param datum The string to hash.
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* \param len Pointer to unsigned integer to record datum's length in.
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* \return The calculated hash value for the datum.
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*/
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static inline unsigned int hash_string_fnv(const char *datum, unsigned int *len)
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{
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unsigned int z = 0x811c9dc5;
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const char *start = datum;
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*len = 0;
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if (datum == NULL)
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return 0;
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while (*datum) {
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z *= 0x01000193;
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z ^= *datum++;
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}
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*len = datum - start;
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return z;
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}
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/**
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* process a line of input.
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*
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* \param hash The hash table to add the line to
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* \param ln The line to process
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* \param lnlen The length of \ln
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* \return NSERROR_OK on success else NSERROR_INVALID
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*/
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static nserror
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process_line(struct hash_table *hash, uint8_t *ln, int lnlen)
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{
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uint8_t *key;
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uint8_t *value;
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uint8_t *colon;
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key = ln; /* set key to start of line */
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value = ln + lnlen; /* set value to end of line */
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/* skip leading whitespace */
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while ((key < value) &&
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((*key == ' ') || (*key == '\t'))) {
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key++;
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}
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/* empty or comment lines */
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if ((*key == 0) || (*key == '#')) {
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return NSERROR_OK;
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}
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/* find first colon as key/value separator */
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for (colon = key; colon < value; colon++) {
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if (*colon == ':') {
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break;
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}
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}
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if (colon == value) {
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/* no colon found */
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return NSERROR_INVALID;
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}
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*colon = 0; /* terminate key */
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value = colon + 1;
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if (hash_add(hash, (char *)key, (char *)value) == false) {
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NSLOG(netsurf, INFO,
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"Unable to add %s:%s to hash table", ln, value);
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return NSERROR_INVALID;
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}
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return NSERROR_OK;
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}
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/**
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* adds key/value pairs to a hash from a memory area
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*/
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static nserror
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hash_add_inline_plain(struct hash_table *ht, const uint8_t *data, size_t size)
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{
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uint8_t s[LINE_BUFFER_SIZE]; /* line buffer */
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unsigned int slen = 0;
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nserror res = NSERROR_OK;
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while (size > 0) {
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s[slen] = *data;
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if (s[slen] == '\n') {
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s[slen] = 0; /* replace newline with null termination */
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res = process_line(ht, s, slen);
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slen = 0;
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if (res != NSERROR_OK) {
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break;
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}
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} else {
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slen++;
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if (slen > sizeof s) {
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NSLOG(netsurf, INFO, "Overlength line\n");
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slen = 0;
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}
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}
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size--;
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data++;
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}
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if (slen > 0) {
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s[slen] = 0;
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res = process_line(ht, s, slen);
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}
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return res;
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}
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/**
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* adds key/value pairs to a hash from a compressed memory area
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*/
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static nserror
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hash_add_inline_gzip(struct hash_table *ht, const uint8_t *data, size_t size)
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{
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nserror res;
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int ret; /* zlib return value */
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z_stream strm;
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uint8_t s[LINE_BUFFER_SIZE]; /* line buffer */
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size_t used = 0; /* number of bytes in buffer in use */
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uint8_t *nl;
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strm.zalloc = Z_NULL;
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strm.zfree = Z_NULL;
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strm.opaque = Z_NULL;
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strm.next_in = (uint8_t *)data;
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strm.avail_in = size;
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ret = inflateInit2(&strm, 32 + MAX_WBITS);
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if (ret != Z_OK) {
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NSLOG(netsurf, INFO, "inflateInit returned %d", ret);
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return NSERROR_INVALID;
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}
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do {
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strm.next_out = s + used;
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strm.avail_out = sizeof(s) - used;
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ret = inflate(&strm, Z_NO_FLUSH);
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if ((ret != Z_OK) && (ret != Z_STREAM_END)) {
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break;
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}
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used = sizeof(s) - strm.avail_out;
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while (used > 0) {
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/* find nl */
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for (nl = &s[0]; nl < &s[used]; nl++) {
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if (*nl == '\n') {
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break;
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}
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}
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if (nl == &s[used]) {
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/* no nl found */
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break;
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}
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/* found newline */
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*nl = 0; /* null terminate line */
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res = process_line(ht, &s[0], nl - &s[0]);
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if (res != NSERROR_OK) {
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inflateEnd(&strm);
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return res;
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}
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/* move data down */
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memmove(&s[0], nl + 1, used - ((nl + 1) - &s[0]) );
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used -= ((nl +1) - &s[0]);
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}
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if (used == sizeof(s)) {
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/* entire buffer used and no newline */
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NSLOG(netsurf, INFO, "Overlength line");
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used = 0;
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}
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} while (ret != Z_STREAM_END);
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inflateEnd(&strm);
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if (ret != Z_STREAM_END) {
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NSLOG(netsurf, INFO, "inflate returned %d", ret);
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return NSERROR_INVALID;
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}
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return NSERROR_OK;
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}
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/* exported interface documented in utils/hashtable.h */
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struct hash_table *hash_create(unsigned int chains)
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{
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struct hash_table *r = malloc(sizeof(struct hash_table));
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if (r == NULL) {
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NSLOG(netsurf, INFO, "Not enough memory for hash table.");
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return NULL;
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}
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r->nchains = chains;
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r->chain = calloc(chains, sizeof(struct hash_entry *));
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if (r->chain == NULL) {
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NSLOG(netsurf, INFO,
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"Not enough memory for %d hash table chains.", chains);
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free(r);
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return NULL;
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}
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return r;
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}
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/* exported interface documented in utils/hashtable.h */
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void hash_destroy(struct hash_table *ht)
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{
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unsigned int i;
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if (ht == NULL)
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return;
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for (i = 0; i < ht->nchains; i++) {
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if (ht->chain[i] != NULL) {
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struct hash_entry *e = ht->chain[i];
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while (e) {
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struct hash_entry *n = e->next;
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free(e->pairing);
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free(e);
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e = n;
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}
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}
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}
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free(ht->chain);
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free(ht);
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}
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/* exported interface documented in utils/hashtable.h */
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bool hash_add(struct hash_table *ht, const char *key, const char *value)
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{
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unsigned int h, c, v;
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struct hash_entry *e;
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if (ht == NULL || key == NULL || value == NULL)
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return false;
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e = malloc(sizeof(struct hash_entry));
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if (e == NULL) {
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NSLOG(netsurf, INFO, "Not enough memory for hash entry.");
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return false;
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}
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h = hash_string_fnv(key, &(e->key_length));
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c = h % ht->nchains;
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v = strlen(value) ;
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e->pairing = malloc(v + e->key_length + 2);
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if (e->pairing == NULL) {
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NSLOG(netsurf, INFO,
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"Not enough memory for string duplication.");
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free(e);
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return false;
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}
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memcpy(e->pairing, key, e->key_length + 1);
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memcpy(e->pairing + e->key_length + 1, value, v + 1);
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e->next = ht->chain[c];
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ht->chain[c] = e;
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return true;
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}
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/* exported interface documented in utils/hashtable.h */
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const char *hash_get(struct hash_table *ht, const char *key)
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{
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unsigned int h, c, key_length;
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struct hash_entry *e;
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if (ht == NULL || key == NULL)
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return NULL;
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h = hash_string_fnv(key, &key_length);
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c = h % ht->nchains;
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for (e = ht->chain[c]; e; e = e->next)
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if ((key_length == e->key_length) &&
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(memcmp(key, e->pairing, key_length) == 0))
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return e->pairing + key_length + 1;
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return NULL;
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}
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/* exported interface documented in utils/hashtable.h */
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nserror hash_add_file(struct hash_table *ht, const char *path)
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{
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nserror res = NSERROR_OK;
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char s[LINE_BUFFER_SIZE]; /* line buffer */
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gzFile fp; /* compressed file handle */
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if (path == NULL) {
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return NSERROR_BAD_PARAMETER;
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}
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fp = gzopen(path, "r");
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if (!fp) {
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NSLOG(netsurf, INFO,
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"Unable to open file \"%.100s\": %s", path,
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strerror(errno));
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return NSERROR_NOT_FOUND;
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}
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while (gzgets(fp, s, sizeof s)) {
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int slen = strlen(s);
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s[--slen] = 0; /* remove \n at end */
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res = process_line(ht, (uint8_t *)s, slen);
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if (res != NSERROR_OK) {
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break;
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}
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}
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gzclose(fp);
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return res;
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}
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/* exported interface documented in utils/hashtable.h */
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nserror hash_add_inline(struct hash_table *ht, const uint8_t *data, size_t size)
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{
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if ((data[0]==0x1f) && (data[1] == 0x8b)) {
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/* gzip header detected */
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return hash_add_inline_gzip(ht, data, size);
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}
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return hash_add_inline_plain(ht, data, size);
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}
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