/* ==================================================================== 
 * The Kannel Software License, Version 1.0 
 * 
 * Copyright (c) 2001-2018 Kannel Group  
 * Copyright (c) 1998-2001 WapIT Ltd.   
 * All rights reserved. 
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met: 
 * 
 * 1. Redistributions of source code must retain the above copyright 
 *    notice, this list of conditions and the following disclaimer. 
 * 
 * 2. Redistributions in binary form must reproduce the above copyright 
 *    notice, this list of conditions and the following disclaimer in 
 *    the documentation and/or other materials provided with the 
 *    distribution. 
 * 
 * 3. The end-user documentation included with the redistribution, 
 *    if any, must include the following acknowledgment: 
 *       "This product includes software developed by the 
 *        Kannel Group (http://www.kannel.org/)." 
 *    Alternately, this acknowledgment may appear in the software itself, 
 *    if and wherever such third-party acknowledgments normally appear. 
 * 
 * 4. The names "Kannel" and "Kannel Group" must not be used to 
 *    endorse or promote products derived from this software without 
 *    prior written permission. For written permission, please  
 *    contact org@kannel.org. 
 * 
 * 5. Products derived from this software may not be called "Kannel", 
 *    nor may "Kannel" appear in their name, without prior written 
 *    permission of the Kannel Group. 
 * 
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED 
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
 * DISCLAIMED.  IN NO EVENT SHALL THE KANNEL GROUP OR ITS CONTRIBUTORS 
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,  
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT  
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR  
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,  
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE  
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,  
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 * ==================================================================== 
 * 
 * This software consists of voluntary contributions made by many 
 * individuals on behalf of the Kannel Group.  For more information on  
 * the Kannel Group, please see <http://www.kannel.org/>. 
 * 
 * Portions of this software are based upon software originally written at  
 * WapIT Ltd., Helsinki, Finland for the Kannel project.  
 */ 

/*
 *
 * ws.c
 *
 * Author: Markku Rossi <mtr@iki.fi>
 *
 * Copyright (c) 1999-2000 WAPIT OY LTD.
 *		 All rights reserved.
 *
 * Public entry points to the WMLScript compiler and the main compile
 * function.
 *
 */

#include "wsint.h"
#include "ws.h"
#include "wsstree.h"
#include "wsasm.h"

/********************* Types and definitions ****************************/

#define WS_CHECK_COMPILE_ERROR()				\
    do {							\
        if (compiler->errors != 0) {                    	\
            if (compiler->errors & WS_ERROR_B_MEMORY)		\
                result = WS_ERROR_OUT_OF_MEMORY;		\
            else if (compiler->errors & WS_ERROR_B_SYNTAX)	\
                result = WS_ERROR_SYNTAX;			\
            else if (compiler->errors & WS_ERROR_B_SEMANTIC)	\
                result = WS_ERROR_SEMANTIC;			\
            else						\
                /* This shouldn't happen. */			\
                result = WS_ERROR;				\
            goto out;						\
        }							\
    } while (0);

/********************* Static variables *********************************/

/* Human readable names for the result codes. */
static struct
{
    WsResult code;
    char *description;
} result_codes[] = {
    { WS_OK, "success" },
    { WS_ERROR_OUT_OF_MEMORY, "out of memory" },
    { WS_ERROR_SYNTAX, "syntax error" },
    { WS_ERROR_SEMANTIC, "compile error" },
    { WS_ERROR_IO, "IO error" },
    { WS_ERROR, "error" },

    { 0, NULL },
};

/********************* Prototypes for static functions ******************/

/* Compile the input stream `input' with the compiler `compiler' and
   return the byte-code in `output_return' and its length in
   `output_len_return'.  The function returns a WsResult error code
   describing the success of the compilation. */
static WsResult compile_stream(WsCompilerPtr compiler,
                               const char *input_name, WsStream *input,
                               unsigned char **output_return,
                               size_t *output_len_return);

/* The default I/O function to send the output to stdout and stderr.
   The argument `context' must be a `FILE *' file to which the output
   is written. */
static void std_io(const char *data, size_t len, void *context);

/* A comparison function for functions entries when sorting them by
   their usage counts.  The function is stable maintaining their
   original order if their usage counts are equal. */
static int sort_functions_cmp(const void *a, const void *b);

/********************* Global functions *********************************/

WsCompilerPtr ws_create(WsCompilerParams *params)
{
    WsCompilerPtr compiler = ws_calloc(1, sizeof(*compiler));

    if (compiler == NULL)
        return NULL;

    /* Store user params if specified. */
    if (params)
        compiler->params = *params;

    /* Basic initialization. */

    compiler->magic = COMPILER_MAGIC;

    if (compiler->params.stdout_cb == NULL) {
        compiler->params.stdout_cb = std_io;
        compiler->params.stdout_cb_context = stdout;
    }
    if (compiler->params.stderr_cb == NULL) {
        compiler->params.stderr_cb = std_io;
        compiler->params.stderr_cb_context = stderr;
    }

    return compiler;
}


void ws_destroy(WsCompilerPtr compiler)
{
    if (compiler == NULL)
        return;

    ws_free(compiler);

#if WS_MEM_DEBUG
    if (ws_has_leaks())
        ws_dump_blocks();
#endif /* WS_MEM_DEBUG */
}


WsResult ws_compile_file(WsCompilerPtr compiler, const char *input_name,
                         FILE *input, FILE *output)
{
    WsResult result;
    WsStream *stream;
    unsigned char *bc;
    size_t bc_len;

    /* Initialize the input stream. */
    stream = ws_stream_new_file(input, WS_FALSE, WS_FALSE);
    if (stream == NULL)
        return WS_ERROR_OUT_OF_MEMORY;

    result = compile_stream(compiler, input_name, stream, &bc, &bc_len);

    ws_stream_close(stream);

    if (result == WS_OK) {
        /* Store the result to the file. */
        if (fwrite(bc, 1, bc_len, output) != bc_len)
            result = WS_ERROR_IO;

        ws_bc_data_free(bc);
    }

    return result;
}


WsResult ws_compile_data(WsCompilerPtr compiler, const char *input_name,
                         const unsigned char *input, size_t input_len,
                         unsigned char **output_return,
                         size_t *output_len_return)
{
    WsResult result;
    WsStream *stream;

    /* Initialize the input stream. */
    stream = ws_stream_new_data_input(input, input_len);
    if (stream == NULL)
        return WS_ERROR_OUT_OF_MEMORY;

    result = compile_stream(compiler, input_name, stream, output_return,
                            output_len_return);

    ws_stream_close(stream);

    return result;
}


void ws_free_byte_code(unsigned char *byte_code)
{
    ws_bc_data_free(byte_code);
}


const char *ws_result_to_string(WsResult result)
{
    int i;

    for (i = 0; result_codes[i].description; i++) {
        if (result_codes[i].code == result)
            return result_codes[i].description;
    }

    return "unknown result code";
}

/********************* Lexer's memory handling helpers ******************/

WsBool ws_lexer_register_block(WsCompiler *compiler, void *ptr)
{
    void **n;

    if (ptr == NULL)
        return WS_TRUE;

    n = ws_realloc(compiler->lexer_active_list,
                   ((compiler->lexer_active_list_size + 1) * sizeof(void *)));
    if (n == NULL)
        return WS_FALSE;

    compiler->lexer_active_list = n;
    compiler->lexer_active_list[compiler->lexer_active_list_size++] = ptr;

    return WS_TRUE;
}


WsBool ws_lexer_register_utf8(WsCompiler *compiler, WsUtf8String *string)
{
    if (!ws_lexer_register_block(compiler, string))
        return WS_FALSE;

    if (!ws_lexer_register_block(compiler, string->data)) {
        compiler->lexer_active_list_size--;
        return WS_FALSE;
    }

    return WS_TRUE;
}


void ws_lexer_free_block(WsCompiler *compiler, void *ptr)
{
    int i;

    if (ptr == NULL)
        return;

    for (i = compiler->lexer_active_list_size - 1; i >= 0; i--) {
        if (compiler->lexer_active_list[i] == ptr) {
            memmove(&compiler->lexer_active_list[i],
                    &compiler->lexer_active_list[i + 1],
                    (compiler->lexer_active_list_size - i - 1) * sizeof(void *));
            compiler->lexer_active_list_size--;

            ws_free(ptr);
            return;
        }
    }

    ws_fatal("ws_lexer_free_block(): unknown block 0x%lx",
             (unsigned long) ptr);
}


void ws_lexer_free_utf8(WsCompiler *compiler, WsUtf8String *string)
{
    if (string == NULL)
        return;

    ws_lexer_free_block(compiler, string->data);
    ws_lexer_free_block(compiler, string);
}

/********************* Static functions *********************************/

static WsResult compile_stream(WsCompilerPtr compiler, const char *input_name,
                               WsStream *input, unsigned char **output_return,
                               size_t *output_len_return)
{
    WsResult result = WS_OK;
    WsUInt32 i;
    WsListItem *li;
    WsUInt8 findex;
    WsUInt8 num_locals;
    WsBcStringEncoding string_encoding = WS_BC_STRING_ENC_UTF8;

    /* Initialize the compiler context. */

    compiler->linenum = 1;
    compiler->input_name = input_name;

    compiler->num_errors = 0;
    compiler->num_warnings = 0;
    compiler->num_extern_functions = 0;
    compiler->num_local_functions = 0;
    compiler->errors = 0;
    compiler->last_syntax_error_line = 0;

    /* Allocate fast-malloc pool for the syntax tree. */

    compiler->pool_stree = ws_f_create(1024 * 1024);
    if (compiler->pool_stree == NULL) {
        result = WS_ERROR_OUT_OF_MEMORY;
        goto out;
    }

    /* Allocate hash tables. */

    compiler->pragma_use_hash = ws_pragma_use_hash_create();
    if (compiler->pragma_use_hash == NULL) {
        result = WS_ERROR_OUT_OF_MEMORY;
        goto out;
    }

    compiler->functions_hash = ws_function_hash_create();
    if (compiler->functions_hash == NULL) {
        result = WS_ERROR_OUT_OF_MEMORY;
        goto out;
    }

    /* Allocate a byte-code module. */

    if (compiler->params.use_latin1_strings)
        string_encoding = WS_BC_STRING_ENC_ISO_8859_1;

    compiler->bc = ws_bc_alloc(string_encoding);
    if (compiler->bc == NULL) {
        result = WS_ERROR_OUT_OF_MEMORY;
        goto out;
    }

    /* Save the input stream. */
    compiler->input = input;

    /* Parse the input. */
#if WS_DEBUG
    global_compiler = compiler;
#endif /* WS_DEBUG */

    ws_yy_parse(compiler);

    /* Free all lexer's active not freed blocks.  If we have any blocks
       on the used list, our compilation was not successful. */
    {
        size_t j;

        for (j = 0; j < compiler->lexer_active_list_size; j++)
            ws_free(compiler->lexer_active_list[j]);
        ws_free(compiler->lexer_active_list);

        compiler->lexer_active_list = NULL;
    }

    WS_CHECK_COMPILE_ERROR();

    /* Sort functions if allowed and it helps. */
    if (!compiler->params.no_opt_sort_bc_functions
        && compiler->num_functions > 7) {
        WsUInt32 i;

        ws_info(compiler, "optimize: sorting functions");

        /* Fetch the usage counts from the functions hash. */
        for (i = 0; i < compiler->num_functions; i++) {
            WsFunctionHash *fh = ws_function_hash(compiler,
                                                  compiler->functions[i].name);
            compiler->functions[i].usage_count = fh->usage_count;
        }

        /* Sort functions.  */
        qsort(compiler->functions, compiler->num_functions,
              sizeof(compiler->functions[0]), sort_functions_cmp);

        /* Patch the function indexes. */
        for (i = 0; i < compiler->num_functions; i++) {
            WsFunctionHash *fh = ws_function_hash(compiler,
                                                  compiler->functions[i].name);
            compiler->functions[i].findex = i;
            fh->findex = i;
        }
    }

    /* Linearize functions */
    for (i = 0; i < compiler->num_functions; i++) {
        WsFunction *func = &compiler->functions[i];

        ws_info(compiler, "linearizing function `%s'...", func->name);

        compiler->pool_asm = ws_f_create(100 * 1024);
        if (compiler->pool_asm == NULL) {
            result = WS_ERROR_OUT_OF_MEMORY;
            goto out;
        }

        compiler->next_label = 0;
        compiler->asm_head = compiler->asm_tail = NULL;

        /* Create variables namespace. */
        compiler->next_vindex = 0;
        compiler->variables_hash = ws_variable_hash_create();
        if (compiler->variables_hash == NULL) {
            result = WS_ERROR_OUT_OF_MEMORY;
            goto out;
        }

        /* Define the formal arguments to the namespace. */
        for (li = func->params->head; li; li = li->next) {
            WsFormalParm *parm = li->data;

            ws_variable_define(compiler, parm->line, WS_FALSE, parm->name);
        }

        WS_CHECK_COMPILE_ERROR();

        /* Linearize it. */
        for (li = func->block->head; li; li = li->next)
            ws_stmt_linearize(compiler, li->data);

        WS_CHECK_COMPILE_ERROR();

        /* Optimize symbolic assembler.  This function does nothing if
           no optimizations were requested. */
        ws_asm_optimize(compiler);

        /* Print the resulting symbolic assembler if requested. */
        if (compiler->params.print_symbolic_assembler)
            ws_asm_print(compiler);

        WS_CHECK_COMPILE_ERROR();

        /* Generate byte-code */

        ws_buffer_init(&compiler->byte_code);
        ws_asm_linearize(compiler);

        WS_CHECK_COMPILE_ERROR();

        /* Disassemble the output if requested. */
        if (compiler->params.print_assembler)
            ws_asm_dasm(compiler, ws_buffer_ptr(&compiler->byte_code),
                        ws_buffer_len(&compiler->byte_code));

        /* Calculate the number of local variables */
        num_locals = compiler->next_vindex - func->params->num_items;

        /* Add the function to the byte-code module. */
        if (!ws_bc_add_function(compiler->bc, &findex,
                                func->externp ? func->name : NULL,
                                func->params->num_items,
                                num_locals,
                                ws_buffer_len(&compiler->byte_code),
                                ws_buffer_ptr(&compiler->byte_code))) {
            result = WS_ERROR_OUT_OF_MEMORY;
            goto out;
        }

        /* Cleanup and prepare for the next function. */

        ws_buffer_uninit(&compiler->byte_code);

        ws_hash_destroy(compiler->variables_hash);
        compiler->variables_hash = NULL;

        ws_f_destroy(compiler->pool_asm);
        compiler->pool_asm = NULL;
    }

    /* Linearize the byte-code structure. */
    if (!ws_bc_encode(compiler->bc, output_return, output_len_return))
        result = WS_ERROR_OUT_OF_MEMORY;

out:

    /* Cleanup. */

    ws_f_destroy(compiler->pool_stree);
    compiler->pool_stree = NULL;

    ws_hash_destroy(compiler->pragma_use_hash);
    compiler->pragma_use_hash = NULL;

    /* Free functions. */
    for (i = 0; i < compiler->num_functions; i++)
        ws_free(compiler->functions[i].name);
    ws_free(compiler->functions);

    ws_hash_destroy(compiler->functions_hash);
    compiler->functions_hash = NULL;

    ws_bc_free(compiler->bc);
    compiler->bc = NULL;

    compiler->input = NULL;

    ws_f_destroy(compiler->pool_asm);
    compiler->pool_asm = NULL;

    ws_hash_destroy(compiler->variables_hash);
    compiler->variables_hash = NULL;

    ws_buffer_uninit(&compiler->byte_code);

    /* All done. */
    return result;
}


static void std_io(const char *data, size_t len, void *context)
{
    fwrite(data, 1, len, (FILE *) context);
}


static int sort_functions_cmp(const void *a, const void *b)
{
    WsFunction *fa = (WsFunction *) a;
    WsFunction *fb = (WsFunction *) b;

    if (fa->usage_count > fb->usage_count)
        return -1;
    if (fa->usage_count < fb->usage_count)
        return 1;

    if (fa->findex < fb->findex)
        return -1;

    return 1;
}