feat: implement parsing of http title

.gitignore

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+*.o
+compile_commands.json

Makefile

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+CC=gcc
+CFLAGS=-g3
+CFILES=tinyparser.c
+OUTPUT=tinyparser
+
+all: 
+	$(CC) $(CFLAGS) $(CFILES) -o $(OUTPUT)
+
+run: 
+	./$(OUTPUT)
+
+clean: 
+	rm -rf $(OUTPUT)

README

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++================+
+|   tinyparser   |
++================+
+
+HTTP parsing prototype and algorithm development environment for tinyproxy - my
+new proxy.

tinyparser.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "tinyparser.h"
+
+enum errs err = err_init;
+enum states state = state_init;
+enum methods method = method_init;
+char *uri = NULL; 
+char *ver = NULL;
+int uri_len = 0;
+int ver_len = 0;
+
+int read_line(char **cursor, int cursor_size) {
+    int diff = 0; 
+    char *match = strchr(*cursor, '\n');
+
+    if (!match)
+        match = (*cursor)+cursor_size-1;
+        
+    diff = match - (*cursor);
+    *cursor += diff + 1;
+    
+    return diff;
+}
+
+int cmp_orig(char *ch, char *orig, char *limit) {
+    int diff = 0;
+    for (; *orig != '\0' && *ch != '\0' && ch < limit; orig++, ch++, diff++) 
+        if (*orig != *ch)
+            return -1;
+
+    return diff;
+}
+
+int cmp_ascii(char *ch, char *limit) {
+    int diff = 0; 
+    for (; *ch != '\0' && *ch != ' ' && ch < limit; ch++, diff++) {
+        if (*ch >= '0' && *ch <= '9')   continue;
+        if (*ch >= 'A' && *ch <= 'Z')   continue;
+        if (*ch >= 'a' && *ch <= 'z')   continue;
+        if (*ch >= '#' && *ch <= '/')   continue;
+        if (*ch == '!')                 continue;
+        if (*ch == ':')                 continue;
+        if (*ch == ';')                 continue;
+        if (*ch == '=')                 continue;
+        if (*ch == '?')                 continue;
+        if (*ch == '@')                 continue;
+        if (*ch == '[')                 continue;
+        if (*ch == ']')                 continue;
+        if (*ch == '_')                 continue;
+        if (*ch == '~')                 continue;
+
+        return -1;
+    }
+
+    return diff;
+}
+
+int parse_title(char *title_offset, int title_len) {
+    int title_cursor = 0;
+
+    while (state != state_title_ok && state != state_title_err) {
+        if (title_cursor >= title_len) {
+            state = state_title_err;
+            err = err_parse_title;
+        }
+
+        int ret = 0; 
+        char *ch = title_offset+title_cursor;
+        char *lim = title_offset+title_len-1;
+
+        switch (state) {
+        case state_init: 
+            state = state_title_method;
+            break;
+        case state_title_method: 
+            if ((ret = cmp_orig(ch, "GET", lim))) {
+                title_cursor += ret;
+                state = state_title_after_method;
+                method = method_get;
+                break;
+            }
+            if ((ret = cmp_orig(ch, "POST", lim))) {
+                title_cursor += ret;
+                state = state_title_after_method;
+                method = method_post;
+                break;
+            }
+            if ((ret = cmp_orig(ch, "HEAD", lim))) {
+                title_cursor += ret;
+                state = state_title_after_method;
+                method = method_head;
+                break;
+            }
+
+            state = state_title_err;
+            err = err_parse_title_method;
+            break;
+        case state_title_after_method: 
+            title_cursor++;
+            state = state_title_uri;
+            break;
+        case state_title_uri: 
+            if ((ret = cmp_ascii(ch, lim)) <= 0) {
+                state = state_title_err;
+                err = err_parse_title_uri;
+                break;
+            }
+
+            if (!(uri = strndup(ch, ret))) {
+                state = state_title_err;
+                err = err_memory;
+                break;
+            }
+
+            uri_len = ret;
+            title_cursor += ret;
+            state = state_title_after_uri;
+            break;
+        case state_title_after_uri: 
+            title_cursor++; 
+            state = state_title_version;
+            break;
+        case state_title_version: 
+            if ((ret = cmp_ascii(ch, lim)) <= 0) {
+                state = state_title_err;
+                err = err_parse_title_version;
+                break;
+            }
+
+            if (!(ver = strndup(ch, ret))) {
+                state = state_title_err;
+                err = err_memory;
+                break;
+            }
+
+            ver_len = ret;
+            title_cursor += ret;
+            state = state_title_ok;
+            break;
+        case state_title_ok: 
+            for (;ch < lim;ch++) {
+                if (*ch == ' ') continue;
+                if (*ch == '\t') continue;
+                if (*ch == '\0') continue;
+
+                state = state_title_err;
+                err = err_parse_title;
+                break;
+            }
+            break;
+        case state_title_err:
+            fprintf(stderr, "failed\n");
+            return -1;
+            break;
+        default: 
+            break;
+        }
+    }
+
+    return 0;
+}
+
+int parse_request(char *buffer) {
+    int ret; 
+    int buffer_size = strlen(buffer);
+
+    char *title_offset = buffer;
+    int title_len = read_line(&buffer, buffer_size);
+
+    if ((ret = parse_title(title_offset, title_len)) < 0) {
+        fprintf(stderr, "Failed parsing title\n");
+        return -1;
+    }
+
+    return 0;
+}
+
+int main(void) {
+    int ret; 
+    char *str = strdup(TEST_ONE);
+
+    ret = parse_request(str);
+    if (ret < 0) {
+        fprintf(stderr, "Failed parsing request\n");
+        return -1;
+    }
+
+    fprintf(stderr, "Finished parsing request\n");
+
+    free(str);
+    
+    return 0;
+}

tinyparser.h

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+#ifndef PARSER_H
+#define PARSER_H
+
+#define LINE_BUF 1024
+#define TEST_ONE "GET / HTTP/1.1\r\n"\
+                 "Host: archive.0xdeadbeer.xyz\r\n"\
+                 "User-Agent: curl/8.9.1\r\n"\
+                 "Accept: */*\r\n"
+
+enum errs {
+    err_init = 0,
+    err_generic,
+    err_memory,
+    err_parse_title,
+    err_parse_title_method,
+    err_parse_title_uri,
+    err_parse_title_version
+};
+
+enum states {
+    state_init = 0,
+    state_title_method,
+    state_title_after_method,
+    state_title_uri,
+    state_title_after_uri,
+    state_title_version,
+    state_title_ok,
+    state_title_err
+};
+
+enum methods {
+    method_init = 0,
+    method_get,
+    method_post,
+    method_head
+};
+
+enum headers {
+    header_a_im = 0,
+    header_accept,
+    header_accept_charset,
+    header_accept_datetime,
+    header_accept_encoding,
+    header_accept_language,
+    header_access_control_request_method,
+    header_access_control_request_headers,
+    header_authorization,
+    header_cache_control,
+    header_connection,
+    header_content_encoding,
+    header_content_length,
+    header_content_md5,
+    header_content_type,
+    header_cookie,
+    header_date,
+    header_expect,
+    header_forwarded,
+    header_from,
+    header_host,
+    header_http2_settings,
+    header_if_match,
+    header_if_modified_since,
+    header_if_none_match,
+    header_if_range,
+    header_if_unmodified_since,
+    header_max_forwards,
+    header_origin,
+    header_pragma,
+    header_prefer,
+    header_proxy_authorization,
+    header_range,
+    header_referer,
+    header_te,
+    header_trailer,
+    header_transfer_encoding,
+    header_user_agent,
+    header_upgrade,
+    header_via,
+    header_warning,
+
+    header_upgrade_insecure_requests,
+    header_x_requested_with,
+    header_dnt,
+    header_x_forwarded_for,
+    header_x_forwarded_host,
+    header_x_forwarded_proto,
+    header_front_end_https,
+    header_x_http_method_override,
+    header_x_att_deviceid,
+    header_x_wap_profile,
+    header_proxy_connection,
+    header_x_uidh,
+    header_x_csrf_token,
+    header_x_request_id,
+    header_x_correlation_id,
+    header_correlation_id,
+    header_save_data,
+    header_sec_gpc,
+
+    header_accept_ch,
+    header_access_control_allow_origin,
+    header_access_control_allow_credentials,
+    header_access_control_expose_headers,
+    header_access_control_max_age,
+    header_access_control_allow_methods,
+    header_access_control_allow_headers,
+    header_accept_patch,
+    header_accept_ranges,
+    header_age,
+    header_allow,
+    header_alt_svc,
+    header_content_disposition,
+    header_content_language,
+    header_content_location,
+    header_content_range,
+    header_delta_base,
+    header_etag,
+    header_expires,
+    header_im,
+    header_last_modified,
+    header_link,
+    header_location,
+    header_p3p,
+    header_preference_applied,
+    header_proxy_authenticate,
+    header_public_key_pins,
+    header_retry_after,
+    header_server,
+    header_set_cookie,
+    header_strict_transport_security,
+    header_tk,
+    header_vary,
+    header_www_authenticate,
+    header_x_frame_options,
+    header_content_security_policy,
+    header_expect_ct,
+    header_nel,
+    header_permissions_policy,
+    header_refresh,
+    header_report_to,
+    header_status,
+    header_timing_allow_origin,
+    header_x_content_duration,
+    header_x_content_type_options,
+    header_x_powered_by,
+    header_x_redirect_by,
+    header_x_ua_compatible,
+    header_x_xss_protection
+};
+
+#endif