Fixed Valgrind complaints about uninitialized values. In ngx_http_source_charset(), name->data was left uninitialized, and only name->len was set. Since it is used in debug logging, this resulted in the following complaints from Valgrind on systems with musl libc: ==42== Conditional jump or move depends on uninitialised value(s) ==42== at 0x12BC66: memcpy (string.h:51) ==42== by 0x12BC66: ngx_sprintf_str (ngx_string.c:586) ==42== by 0x12C03C: ngx_vslprintf (ngx_string.c:255) ==42== by 0x127694: ngx_log_error_core (ngx_log.c:135) ==42== by 0x1B8795: ngx_http_charset_header_filter (ngx_http_charset_filter_module.c:252) Similarly, ngx_http_split_args() returned uninitialized arg->data, which was then copied to r->args, and also used in debug logging: ==42== Conditional jump or move depends on uninitialised value(s) ==42== at 0x12BC10: memcpy (string.h:50) ==42== by 0x12BC10: ngx_sprintf_str (ngx_string.c:586) ==42== by 0x12C03C: ngx_vslprintf (ngx_string.c:255) ==42== by 0x127694: ngx_log_error_core (ngx_log.c:135) ==42== by 0x184EFB: ngx_http_internal_redirect (ngx_http_core_module.c:2526) ==42== by 0x1D8CCC: ngx_http_try_files_handler (ngx_http_try_files_module.c:209) Fix is to initialize data to NULL. Note that, while memcpy(p, NULL, 0) is also formally undefined now, it is used in multiple places in the code, and expected to be allowed in C2y (see WG14 proposals N3177, N3261, "Allow zero length operations on null pointers"). Prodded by Valgrind.

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_CRC_H_INCLUDED_
#define _NGX_CRC_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>


/* 32-bit crc16 */

static ngx_inline uint32_t
ngx_crc(u_char *data, size_t len)
{
    uint32_t  sum;

    for (sum = 0; len; len--) {

        /*
         * gcc 2.95.2 x86 and icc 7.1.006 compile
         * that operator into the single "rol" opcode,
         * msvc 6.0sp2 compiles it into four opcodes.
         */
        sum = sum >> 1 | sum << 31;

        sum += *data++;
    }

    return sum;
}


#endif /* _NGX_CRC_H_INCLUDED_ */