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ngx_http_sub_filter_module
/*
* Copyright (C) Igor Sysoev
* Copyright (C) Nginx, Inc.
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
typedef struct {
ngx_http_complex_value_t match;
ngx_http_complex_value_t value;
} ngx_http_sub_pair_t;
typedef struct {
ngx_str_t match;
ngx_http_complex_value_t *value;
} ngx_http_sub_match_t;
typedef struct {
ngx_uint_t min_match_len;
ngx_uint_t max_match_len;
u_char index[257];
u_char shift[256];
} ngx_http_sub_tables_t;
typedef struct {
ngx_uint_t dynamic; /* unsigned dynamic:1; */
ngx_array_t *pairs;
ngx_http_sub_tables_t *tables;
ngx_hash_t types;
ngx_flag_t once;
ngx_flag_t last_modified;
ngx_array_t *types_keys;
ngx_array_t *matches;
} ngx_http_sub_loc_conf_t;
typedef struct {
ngx_str_t saved;
ngx_str_t looked;
ngx_uint_t once; /* unsigned once:1 */
ngx_buf_t *buf;
u_char *pos;
u_char *copy_start;
u_char *copy_end;
ngx_chain_t *in;
ngx_chain_t *out;
ngx_chain_t **last_out;
ngx_chain_t *busy;
ngx_chain_t *free;
ngx_str_t *sub;
ngx_uint_t applied;
ngx_int_t offset;
ngx_uint_t index;
ngx_http_sub_tables_t *tables;
ngx_array_t *matches;
} ngx_http_sub_ctx_t;
static ngx_uint_t ngx_http_sub_cmp_index;
static ngx_int_t ngx_http_sub_output(ngx_http_request_t *r,
ngx_http_sub_ctx_t *ctx);
static ngx_int_t ngx_http_sub_parse(ngx_http_request_t *r,
ngx_http_sub_ctx_t *ctx, ngx_uint_t flush);
static ngx_int_t ngx_http_sub_match(ngx_http_sub_ctx_t *ctx, ngx_int_t start,
ngx_str_t *m);
static char * ngx_http_sub_filter(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);
static void *ngx_http_sub_create_conf(ngx_conf_t *cf);
static char *ngx_http_sub_merge_conf(ngx_conf_t *cf,
void *parent, void *child);
static void ngx_http_sub_init_tables(ngx_http_sub_tables_t *tables,
ngx_http_sub_match_t *match, ngx_uint_t n);
static ngx_int_t ngx_http_sub_cmp_matches(const void *one, const void *two);
static ngx_int_t ngx_http_sub_filter_init(ngx_conf_t *cf);
static ngx_command_t ngx_http_sub_filter_commands[] = {
{ ngx_string("sub_filter"),
NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2,
ngx_http_sub_filter,
NGX_HTTP_LOC_CONF_OFFSET,
0,
NULL },
{ ngx_string("sub_filter_types"),
NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
ngx_http_types_slot,
NGX_HTTP_LOC_CONF_OFFSET,
offsetof(ngx_http_sub_loc_conf_t, types_keys),
&ngx_http_html_default_types[0] },
{ ngx_string("sub_filter_once"),
NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
ngx_conf_set_flag_slot,
NGX_HTTP_LOC_CONF_OFFSET,
offsetof(ngx_http_sub_loc_conf_t, once),
NULL },
{ ngx_string("sub_filter_last_modified"),
NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
ngx_conf_set_flag_slot,
NGX_HTTP_LOC_CONF_OFFSET,
offsetof(ngx_http_sub_loc_conf_t, last_modified),
NULL },
ngx_null_command
};
static ngx_http_module_t ngx_http_sub_filter_module_ctx = {
NULL, /* preconfiguration */
ngx_http_sub_filter_init, /* postconfiguration */
NULL, /* create main configuration */
NULL, /* init main configuration */
NULL, /* create server configuration */
NULL, /* merge server configuration */
ngx_http_sub_create_conf, /* create location configuration */
ngx_http_sub_merge_conf /* merge location configuration */
};
ngx_module_t ngx_http_sub_filter_module = {
NGX_MODULE_V1,
&ngx_http_sub_filter_module_ctx, /* module context */
ngx_http_sub_filter_commands, /* module directives */
NGX_HTTP_MODULE, /* module type */
NULL, /* init master */
NULL, /* init module */
NULL, /* init process */
NULL, /* init thread */
NULL, /* exit thread */
NULL, /* exit process */
NULL, /* exit master */
NGX_MODULE_V1_PADDING
};
static ngx_http_output_header_filter_pt ngx_http_next_header_filter;
static ngx_http_output_body_filter_pt ngx_http_next_body_filter;
static ngx_int_t
ngx_http_sub_header_filter(ngx_http_request_t *r)
{
ngx_str_t *m;
ngx_uint_t i, j, n;
ngx_http_sub_ctx_t *ctx;
ngx_http_sub_pair_t *pairs;
ngx_http_sub_match_t *matches;
ngx_http_sub_loc_conf_t *slcf;
slcf = ngx_http_get_module_loc_conf(r, ngx_http_sub_filter_module);
if (slcf->pairs == NULL
|| r->headers_out.content_length_n == 0
|| ngx_http_test_content_type(r, &slcf->types) == NULL)
{
return ngx_http_next_header_filter(r);
}
ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_sub_ctx_t));
if (ctx == NULL) {
return NGX_ERROR;
}
if (slcf->dynamic == 0) {
ctx->tables = slcf->tables;
ctx->matches = slcf->matches;
} else {
pairs = slcf->pairs->elts;
n = slcf->pairs->nelts;
matches = ngx_pcalloc(r->pool, sizeof(ngx_http_sub_match_t) * n);
if (matches == NULL) {
return NGX_ERROR;
}
j = 0;
for (i = 0; i < n; i++) {
matches[j].value = &pairs[i].value;
if (pairs[i].match.lengths == NULL) {
matches[j].match = pairs[i].match.value;
j++;
continue;
}
m = &matches[j].match;
if (ngx_http_complex_value(r, &pairs[i].match, m) != NGX_OK) {
return NGX_ERROR;
}
if (m->len == 0) {
continue;
}
ngx_strlow(m->data, m->data, m->len);
j++;
}
if (j == 0) {
return ngx_http_next_header_filter(r);
}
ctx->matches = ngx_palloc(r->pool, sizeof(ngx_array_t));
if (ctx->matches == NULL) {
return NGX_ERROR;
}
ctx->matches->elts = matches;
ctx->matches->nelts = j;
ctx->tables = ngx_palloc(r->pool, sizeof(ngx_http_sub_tables_t));
if (ctx->tables == NULL) {
return NGX_ERROR;
}
ngx_http_sub_init_tables(ctx->tables, ctx->matches->elts,
ctx->matches->nelts);
}
ngx_http_set_ctx(r, ctx, ngx_http_sub_filter_module);
ctx->saved.data = ngx_pnalloc(r->pool, ctx->tables->max_match_len - 1);
if (ctx->saved.data == NULL) {
return NGX_ERROR;
}
ctx->looked.data = ngx_pnalloc(r->pool, ctx->tables->max_match_len - 1);
if (ctx->looked.data == NULL) {
return NGX_ERROR;
}
ctx->offset = ctx->tables->min_match_len - 1;
ctx->last_out = &ctx->out;
r->filter_need_in_memory = 1;
if (r == r->main) {
ngx_http_clear_content_length(r);
if (!slcf->last_modified) {
ngx_http_clear_last_modified(r);
ngx_http_clear_etag(r);
} else {
ngx_http_weak_etag(r);
}
}
return ngx_http_next_header_filter(r);
}
static ngx_int_t
ngx_http_sub_body_filter(ngx_http_request_t *r, ngx_chain_t *in)
{
ngx_int_t rc;
ngx_buf_t *b;
ngx_str_t *sub;
ngx_uint_t flush, last;
ngx_chain_t *cl;
ngx_http_sub_ctx_t *ctx;
ngx_http_sub_match_t *match;
ngx_http_sub_loc_conf_t *slcf;
ctx = ngx_http_get_module_ctx(r, ngx_http_sub_filter_module);
if (ctx == NULL) {
return ngx_http_next_body_filter(r, in);
}
if ((in == NULL
&& ctx->buf == NULL
&& ctx->in == NULL
&& ctx->busy == NULL))
{
return ngx_http_next_body_filter(r, in);
}
if (ctx->once && (ctx->buf == NULL || ctx->in == NULL)) {
if (ctx->busy) {
if (ngx_http_sub_output(r, ctx) == NGX_ERROR) {
return NGX_ERROR;
}
}
return ngx_http_next_body_filter(r, in);
}
/* add the incoming chain to the chain ctx->in */
if (in) {
if (ngx_chain_add_copy(r->pool, &ctx->in, in) != NGX_OK) {
return NGX_ERROR;
}
}
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"http sub filter \"%V\"", &r->uri);
flush = 0;
last = 0;
while (ctx->in || ctx->buf) {
if (ctx->buf == NULL) {
ctx->buf = ctx->in->buf;
ctx->in = ctx->in->next;
ctx->pos = ctx->buf->pos;
}
if (ctx->buf->flush || ctx->buf->recycled) {
flush = 1;
}
if (ctx->in == NULL) {
last = flush;
}
b = NULL;
while (ctx->pos < ctx->buf->last) {
rc = ngx_http_sub_parse(r, ctx, last);
ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"parse: %i, looked: \"%V\" %p-%p",
rc, &ctx->looked, ctx->copy_start, ctx->copy_end);
if (rc == NGX_ERROR) {
return rc;
}
if (ctx->saved.len) {
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"saved: \"%V\"", &ctx->saved);
cl = ngx_chain_get_free_buf(r->pool, &ctx->free);
if (cl == NULL) {
return NGX_ERROR;
}
b = cl->buf;
ngx_memzero(b, sizeof(ngx_buf_t));
b->pos = ngx_pnalloc(r->pool, ctx->saved.len);
if (b->pos == NULL) {
return NGX_ERROR;
}
ngx_memcpy(b->pos, ctx->saved.data, ctx->saved.len);
b->last = b->pos + ctx->saved.len;
b->memory = 1;
*ctx->last_out = cl;
ctx->last_out = &cl->next;
ctx->saved.len = 0;
}
if (ctx->copy_start != ctx->copy_end) {
cl = ngx_chain_get_free_buf(r->pool, &ctx->free);
if (cl == NULL) {
return NGX_ERROR;
}
b = cl->buf;
ngx_memcpy(b, ctx->buf, sizeof(ngx_buf_t));
b->pos = ctx->copy_start;
b->last = ctx->copy_end;
b->shadow = NULL;
b->last_buf = 0;
b->last_in_chain = 0;
b->recycled = 0;
if (b->in_file) {
b->file_last = b->file_pos + (b->last - ctx->buf->pos);
b->file_pos += b->pos - ctx->buf->pos;
}
*ctx->last_out = cl;
ctx->last_out = &cl->next;
}
if (rc == NGX_AGAIN) {
continue;
}
/* rc == NGX_OK */
cl = ngx_chain_get_free_buf(r->pool, &ctx->free);
if (cl == NULL) {
return NGX_ERROR;
}
b = cl->buf;
ngx_memzero(b, sizeof(ngx_buf_t));
slcf = ngx_http_get_module_loc_conf(r, ngx_http_sub_filter_module);
if (ctx->sub == NULL) {
ctx->sub = ngx_pcalloc(r->pool, sizeof(ngx_str_t)
* ctx->matches->nelts);
if (ctx->sub == NULL) {
return NGX_ERROR;
}
}
sub = &ctx->sub[ctx->index];
if (sub->data == NULL) {
match = ctx->matches->elts;
if (ngx_http_complex_value(r, match[ctx->index].value, sub)
!= NGX_OK)
{
return NGX_ERROR;
}
}
if (sub->len) {
b->memory = 1;
b->pos = sub->data;
b->last = sub->data + sub->len;
} else {
b->sync = 1;
}
*ctx->last_out = cl;
ctx->last_out = &cl->next;
ctx->index = 0;
ctx->once = slcf->once && (++ctx->applied == ctx->matches->nelts);
continue;
}
if (ctx->looked.len
&& (ctx->buf->last_buf || ctx->buf->last_in_chain))
{
cl = ngx_chain_get_free_buf(r->pool, &ctx->free);
if (cl == NULL) {
return NGX_ERROR;
}
b = cl->buf;
ngx_memzero(b, sizeof(ngx_buf_t));
b->pos = ctx->looked.data;
b->last = b->pos + ctx->looked.len;
b->memory = 1;
*ctx->last_out = cl;
ctx->last_out = &cl->next;
ctx->looked.len = 0;
}
if (ctx->buf->last_buf || ctx->buf->flush || ctx->buf->sync
|| ngx_buf_in_memory(ctx->buf))
{
if (b == NULL) {
cl = ngx_chain_get_free_buf(r->pool, &ctx->free);
if (cl == NULL) {
return NGX_ERROR;
}
b = cl->buf;
ngx_memzero(b, sizeof(ngx_buf_t));
b->sync = 1;
*ctx->last_out = cl;
ctx->last_out = &cl->next;
}
b->last_buf = ctx->buf->last_buf;
b->last_in_chain = ctx->buf->last_in_chain;
b->flush = ctx->buf->flush;
b->shadow = ctx->buf;
b->recycled = ctx->buf->recycled;
}
ctx->buf = NULL;
}
if (ctx->out == NULL && ctx->busy == NULL) {
return NGX_OK;
}
return ngx_http_sub_output(r, ctx);
}
static ngx_int_t
ngx_http_sub_output(ngx_http_request_t *r, ngx_http_sub_ctx_t *ctx)
{
ngx_int_t rc;
ngx_buf_t *b;
ngx_chain_t *cl;
#if 1
b = NULL;
for (cl = ctx->out; cl; cl = cl->next) {
ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"sub out: %p %p", cl->buf, cl->buf->pos);
if (cl->buf == b) {
ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
"the same buf was used in sub");
ngx_debug_point();
return NGX_ERROR;
}
b = cl->buf;
}
#endif
rc = ngx_http_next_body_filter(r, ctx->out);
if (ctx->busy == NULL) {
ctx->busy = ctx->out;
} else {
for (cl = ctx->busy; cl->next; cl = cl->next) { /* void */ }
cl->next = ctx->out;
}
ctx->out = NULL;
ctx->last_out = &ctx->out;
while (ctx->busy) {
cl = ctx->busy;
b = cl->buf;
if (ngx_buf_size(b) != 0) {
break;
}
if (b->shadow) {
b->shadow->pos = b->shadow->last;
}
ctx->busy = cl->next;
if (ngx_buf_in_memory(b) || b->in_file) {
/* add data bufs only to the free buf chain */
cl->next = ctx->free;
ctx->free = cl;
}
}
if (ctx->in || ctx->buf) {
r->buffered |= NGX_HTTP_SUB_BUFFERED;
} else {
r->buffered &= ~NGX_HTTP_SUB_BUFFERED;
}
return rc;
}
static ngx_int_t
ngx_http_sub_parse(ngx_http_request_t *r, ngx_http_sub_ctx_t *ctx,
ngx_uint_t flush)
{
u_char *p, c;
ngx_str_t *m;
ngx_int_t offset, start, next, end, len, rc;
ngx_uint_t shift, i, j;
ngx_http_sub_match_t *match;
ngx_http_sub_tables_t *tables;
ngx_http_sub_loc_conf_t *slcf;
slcf = ngx_http_get_module_loc_conf(r, ngx_http_sub_filter_module);
tables = ctx->tables;
match = ctx->matches->elts;
offset = ctx->offset;
end = ctx->buf->last - ctx->pos;
if (ctx->once) {
/* sets start and next to end */
offset = end + (ngx_int_t) tables->min_match_len - 1;
goto again;
}
while (offset < end) {
c = offset < 0 ? ctx->looked.data[ctx->looked.len + offset]
: ctx->pos[offset];
c = ngx_tolower(c);
shift = tables->shift[c];
if (shift > 0) {
offset += shift;
continue;
}
/* a potential match */
start = offset - (ngx_int_t) tables->min_match_len + 1;
i = ngx_max(tables->index[c], ctx->index);
j = tables->index[c + 1];
while (i != j) {
if (slcf->once && ctx->sub && ctx->sub[i].data) {
goto next;
}
m = &match[i].match;
rc = ngx_http_sub_match(ctx, start, m);
if (rc == NGX_DECLINED) {
goto next;
}
ctx->index = i;
if (rc == NGX_AGAIN) {
goto again;
}
ctx->offset = offset + (ngx_int_t) m->len;
next = start + (ngx_int_t) m->len;
end = ngx_max(next, 0);
rc = NGX_OK;
goto done;
next:
i++;
}
offset++;
ctx->index = 0;
}
if (flush) {
for ( ;; ) {
start = offset - (ngx_int_t) tables->min_match_len + 1;
if (start >= end) {
break;
}
for (i = 0; i < ctx->matches->nelts; i++) {
m = &match[i].match;
if (ngx_http_sub_match(ctx, start, m) == NGX_AGAIN) {
goto again;
}
}
offset++;
}
}
again:
ctx->offset = offset;
start = offset - (ngx_int_t) tables->min_match_len + 1;
next = start;
rc = NGX_AGAIN;
done:
/* send [ - looked.len, start ] to client */
ctx->saved.len = ctx->looked.len + ngx_min(start, 0);
ngx_memcpy(ctx->saved.data, ctx->looked.data, ctx->saved.len);
ctx->copy_start = ctx->pos;
ctx->copy_end = ctx->pos + ngx_max(start, 0);
/* save [ next, end ] in looked */
len = ngx_min(next, 0);
p = ctx->looked.data;
p = ngx_movemem(p, p + ctx->looked.len + len, - len);
len = ngx_max(next, 0);
p = ngx_cpymem(p, ctx->pos + len, end - len);
ctx->looked.len = p - ctx->looked.data;
/* update position */
ctx->pos += end;
ctx->offset -= end;
return rc;
}
static ngx_int_t
ngx_http_sub_match(ngx_http_sub_ctx_t *ctx, ngx_int_t start, ngx_str_t *m)
{
u_char *p, *last, *pat, *pat_end;
pat = m->data;
pat_end = m->data + m->len;
if (start >= 0) {
p = ctx->pos + start;
} else {
last = ctx->looked.data + ctx->looked.len;
p = last + start;
while (p < last && pat < pat_end) {
if (ngx_tolower(*p) != *pat) {
return NGX_DECLINED;
}
p++;
pat++;
}
p = ctx->pos;
}
while (p < ctx->buf->last && pat < pat_end) {
if (ngx_tolower(*p) != *pat) {
return NGX_DECLINED;
}
p++;
pat++;
}
if (pat != pat_end) {
/* partial match */
return NGX_AGAIN;
}
return NGX_OK;
}
static char *
ngx_http_sub_filter(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
ngx_http_sub_loc_conf_t *slcf = conf;
ngx_str_t *value;
ngx_http_sub_pair_t *pair;
ngx_http_compile_complex_value_t ccv;
value = cf->args->elts;
if (value[1].len == 0) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "empty search pattern");
return NGX_CONF_ERROR;
}
if (slcf->pairs == NULL) {
slcf->pairs = ngx_array_create(cf->pool, 1,
sizeof(ngx_http_sub_pair_t));
if (slcf->pairs == NULL) {
return NGX_CONF_ERROR;
}
}
if (slcf->pairs->nelts == 255) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"number of search patterns exceeds 255");
return NGX_CONF_ERROR;
}
ngx_strlow(value[1].data, value[1].data, value[1].len);
pair = ngx_array_push(slcf->pairs);
if (pair == NULL) {
return NGX_CONF_ERROR;
}
ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));
ccv.cf = cf;
ccv.value = &value[1];
ccv.complex_value = &pair->match;
if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
return NGX_CONF_ERROR;
}
if (ccv.complex_value->lengths != NULL) {
slcf->dynamic = 1;
} else {
ngx_strlow(pair->match.value.data, pair->match.value.data,
pair->match.value.len);
}
ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));
ccv.cf = cf;
ccv.value = &value[2];
ccv.complex_value = &pair->value;
if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
return NGX_CONF_ERROR;
}
return NGX_CONF_OK;
}
static void *
ngx_http_sub_create_conf(ngx_conf_t *cf)
{
ngx_http_sub_loc_conf_t *slcf;
slcf = ngx_pcalloc(cf->pool, sizeof(ngx_http_sub_loc_conf_t));
if (slcf == NULL) {
return NULL;
}
/*
* set by ngx_pcalloc():
*
* conf->dynamic = 0;
* conf->pairs = NULL;
* conf->tables = NULL;
* conf->types = { NULL };
* conf->types_keys = NULL;
* conf->matches = NULL;
*/
slcf->once = NGX_CONF_UNSET;
slcf->last_modified = NGX_CONF_UNSET;
return slcf;
}
static char *
ngx_http_sub_merge_conf(ngx_conf_t *cf, void *parent, void *child)
{
ngx_uint_t i, n;
ngx_http_sub_pair_t *pairs;
ngx_http_sub_match_t *matches;
ngx_http_sub_loc_conf_t *prev = parent;
ngx_http_sub_loc_conf_t *conf = child;
ngx_conf_merge_value(conf->once, prev->once, 1);
ngx_conf_merge_value(conf->last_modified, prev->last_modified, 0);
if (ngx_http_merge_types(cf, &conf->types_keys, &conf->types,
&prev->types_keys, &prev->types,
ngx_http_html_default_types)
!= NGX_OK)
{
return NGX_CONF_ERROR;
}
if (conf->pairs == NULL) {
conf->dynamic = prev->dynamic;
conf->pairs = prev->pairs;
conf->matches = prev->matches;
conf->tables = prev->tables;
}
if (conf->pairs && conf->dynamic == 0 && conf->tables == NULL) {
pairs = conf->pairs->elts;
n = conf->pairs->nelts;
matches = ngx_palloc(cf->pool, sizeof(ngx_http_sub_match_t) * n);
if (matches == NULL) {
return NGX_CONF_ERROR;
}
for (i = 0; i < n; i++) {
matches[i].match = pairs[i].match.value;
matches[i].value = &pairs[i].value;
}
conf->matches = ngx_palloc(cf->pool, sizeof(ngx_array_t));
if (conf->matches == NULL) {
return NGX_CONF_ERROR;
}
conf->matches->elts = matches;
conf->matches->nelts = n;
conf->tables = ngx_palloc(cf->pool, sizeof(ngx_http_sub_tables_t));
if (conf->tables == NULL) {
return NGX_CONF_ERROR;
}
ngx_http_sub_init_tables(conf->tables, conf->matches->elts,
conf->matches->nelts);
}
return NGX_CONF_OK;
}
static void
ngx_http_sub_init_tables(ngx_http_sub_tables_t *tables,
ngx_http_sub_match_t *match, ngx_uint_t n)
{
u_char c;
ngx_uint_t i, j, min, max, ch;
min = match[0].match.len;
max = match[0].match.len;
for (i = 1; i < n; i++) {
min = ngx_min(min, match[i].match.len);
max = ngx_max(max, match[i].match.len);
}
tables->min_match_len = min;
tables->max_match_len = max;
ngx_http_sub_cmp_index = tables->min_match_len - 1;
ngx_sort(match, n, sizeof(ngx_http_sub_match_t), ngx_http_sub_cmp_matches);
min = ngx_min(min, 255);
ngx_memset(tables->shift, min, 256);
ch = 0;
for (i = 0; i < n; i++) {
for (j = 0; j < min; j++) {
c = match[i].match.data[tables->min_match_len - 1 - j];
tables->shift[c] = ngx_min(tables->shift[c], (u_char) j);
}
c = match[i].match.data[tables->min_match_len - 1];
while (ch <= c) {
tables->index[ch++] = (u_char) i;
}
}
while (ch < 257) {
tables->index[ch++] = (u_char) n;
}
}
static ngx_int_t
ngx_http_sub_cmp_matches(const void *one, const void *two)
{
ngx_int_t c1, c2;
ngx_http_sub_match_t *first, *second;
first = (ngx_http_sub_match_t *) one;
second = (ngx_http_sub_match_t *) two;
c1 = first->match.data[ngx_http_sub_cmp_index];
c2 = second->match.data[ngx_http_sub_cmp_index];
return c1 - c2;
}
static ngx_int_t
ngx_http_sub_filter_init(ngx_conf_t *cf)
{
ngx_http_next_header_filter = ngx_http_top_header_filter;
ngx_http_top_header_filter = ngx_http_sub_header_filter;
ngx_http_next_body_filter = ngx_http_top_body_filter;
ngx_http_top_body_filter = ngx_http_sub_body_filter;
return NGX_OK;
}
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